Panorama of Shorty Crater, Station 4, assembled from seven color-balanced frames taken by Gene Cernan on the east end of the south rim. Note the red streak on the interior crater wall at left, the long black ash streak left of center, and the two red splotches and black splotches below the rim boulder on the far wall at ~110 m distance. These features will be discussed in more detail in Section 2. (Derivative composite of NASA photos AS17-137-21005, -21000, -21001, -21002, -21003, -21004, and -21024. Copyright © 2018 by Tranquillity Enterprises, s.p. Courtesy of Tranquillity Enterprises, s.p.1).
The second day of exploration may have been the most productive period of lunar explorations since Neil Armstrong spent 20 minutes sampling the area around Eagle at Tranquillity Base. It included a long Rover traverse to the base of the South Massif and then several stations on the way back to the Challenger. The samples collected provide new insights into all the major geological features of the valley of Taurus-Littrow— dark mantle regolith, light mantle avalanche deposits, impact-generated breccias at the base of the South Massif, pyroclastic ash deposits at Shorty Crater, and two major varieties of mare basalt lava.
On our second day on the Moon, I awakened to the sound of Richard Wagner’s (“Ride of the Valkyries”), a traditional, pre-final exams occurrence at Caltech where the music blared forth from every speaker in the Student Houses that could face the four large patios inside the complex of Student Houses. I immediately assumed that CapCom Gordon Fullerton, also in the Caltech Class of ‘57, instigated this familiar awaking. He had lived in Fleming House, a fierce sports rival of Dabney House where I resided. We actually began our freshman year in 1953 in the same 15 person academic section (Section J) only to be separated when Gordon showed his intellectual stripes during the first quarter and was moved into Section A. He had joined Air Force ROTC that ultimately led him into an outstanding test pilot career, assignment to the Manned Orbiting Laboratory Program, and then into the astronaut corps. Interesting how career paths diverge and then join once again.
“Good morning, Challenger,” Fullerton said calmly without giving anything away.
Less certain about instigators of the “Ride of the Valkyries” in the MOCR, I said, “Sounded like Parker had the duty [of picking the wake-up music]— both monumental and epic.” Although married at that time and not living on campus, Parker, also a Wagner fan, had been a Caltech student; but now I think he and Fullerton conspired on this choice of music.
“Jack, that’s supposed to take you back to Caltech final’s week,” admitted Fullerton.
“Dum de dum, dum… Dum de dum, dum, DUM!” (the first bars of the introductory theme music from the American TV series, “Dragnet”, starring Jack Webb), I replied. “How’s everything look, Gordy?”
“Couldn’t look better. How’s it look to you?”
“Well, it’s nice to have rested some.”
“Rog. I’m sure of that.” Sleeping in one-sixth gravity on the Moon came much more naturally than sleeping in zero gravity. The gravity and the hammocks gave just enough pressure to feel like a bed but not so much pressure that I felt the need to turn over. I would sleep on my back for a couple of hours, wake up and listen to be sure that all the spacecraft pumps and fans sounded normal, check the Caution and Warning panel, and then go back to sleep. In the sense of the welcome sounds of systems that make a spacecraft habitable, space is not “silent” as some astronauts often alleged.
About five hours of total sleep left me feeling rested versus my usual sleep on Earth of about seven or eight hours. My tiredness at the end of the previous day probably was more mental than physical. Most importantly, my forearms now felt normal, again. This rapid recovery probably resulted from the fact that I had fatigued the muscles, that is, used up their stored energy; but I had not suffered lactic acid induced tissue damage. Improved blood circulation in one-sixth gravity appears to remove these metabolic toxins rapidly from muscle tissue.
“How do our consumables look today?” I asked, quietly, having already scanned the Caution and Warning panel. As expected, only the yellow Caution light for intentionally disabled PRE AMPS (ATTITUDE CONTROL JETS PRE-AMPlifiers) remained illuminated. On the other hand, we would not be able to detect very slow changes in consumables that might indicate to Mission Control that we had an abnormal decline of oxygen, water, helium pressure, or rocket fuel or oxidizer.
“They look good, as expected,” Fullerton replied. “Right on.”
“You awake, Gene?”
“Gene, can you reach the Urine Line Heater circuit breaker from the hammock? I can get the switch from underneath.”
“I don’t see any changes on the quantity gauges and Gordy says that everything looks normal too down there.”
“Sounds good.” I had the “watch” responsibility to monitor the communications uplink during the rest period, so Cernan did not yet have his Snoopy Cap (with the built-in earphones) on and had not heard my brief conversation with Fullerton.
“How’d you sleep?” I enquired, having noticed he seemed restless at times during the night.
“If you are ready to get going, I’ll stand up and unhook my hammock so you have more room to maneuver.”
“Yeah. Let’s get going. It’s going to be a busy day.”
Cernan and I unhooked and stowed the hammocks and their restraints, with me commenting to Fullerton, “Be through in a jiffy,” as I completed my morning urination. Fortunately, our low residue diet actually succeeded in eliminating bowel movements during our stay on the Moon.
“Stow your sleep restraint up there…? I mean, your hammock… Either way. I’ll stuff all mine in this compartment here, if you’ll just get yours in there. Otherwise, we can rearrange it. See how it looks first.” We tried to keep loose items stowed in their assigned places to maintain control of the cabin so as to be prepared for any emergency liftoff. We had placed several things behind elastic netting attached around the cabin that served for temporary storage.
“Gordy, you guys held comm pretty well last night,” I said after a couple of minutes. “I only remember one break.” If the uplink carrier frequency lost lock, I would hear static in my Snoopy Cap earphones.
“[I’ll] take you off biomed for a minute. …PREAMP’s light is on, like it’s supposed to [be]… Well, how about it, Gordy?” I asked. “Are we Stay or No Stay for EVA-2 prep?”
“You’re Stay. Never any doubt.”
“Thank you, sir…” Then I told Cernan that I was “preparing to give Fullerton a Crew Status report. [Did you] take any medication?”
“No,” Cernan replied.
“How much sleep did you get?”
“About six hours, tell them.”
I am not sure Cernan slept this much, as he continued to fret over the fender he broke.
“[Also, I need to] report the food from yesterday…” “Okay, Gordy. [Crew] status report is excellent. No medication for either one of us. CDR slept 6 hours pretty good; I slept 6 hours intermittent, but generally good.”
“And we’ve eaten well, I think. The food’s a little bit confused since we had our little minor [food stowage] ‘explosion’ in the cabin, but I think you could say it’s good. We’ve had a lot to drink, a lot of juices. We ate the frankfurters. We’re-sharing a lot of the stuff because it’s not symmetrically packed [anymore]. If you want more details, it will take time. …And, Gordy, we did not eat the corn chowder.”
“Roger. You did not eat the corn chowder, but most everything else on the menu. Is that right?”
“Yeah, we got just about everything else. We go into…maybe mixed up two meals, but essentially meal B and C for yesterday were eaten, except for the corn chowder.”
“Okay, Jack. …We’re wondering if you could come up with a quantitative estimate on the water you’ve each drunk and also your PRD (Personal Radiation Dosimeter) readings.”
“Stand by, Gordy. That (water estimate) may be difficult… Yeah, we’ll get the PRD a little bit later when we start suiting up.”
“Yeah; okay. That’ll be fine. My mistake.” Actually, the Flight Surgeon made the mistake of asking Fullerton for something that would come later as a matter of course.
“Hey, Gordy,” Cernan jumped in, having put on his Snoopy Cap, “on this water [issue]. We saturated ourselves before we went out. I finished my [suit] drink bag out in the suit on the surface. Jack finished about better than three-quarters of his. We’ve had water and tea and then the juice, and we have been drinking water constantly, post-EVA. And to give you a quantity is almost impossible.”
“Okay; that’s fine.”
“If the water’s down, it’s probably because we’ve been drinking it.” I am suggesting that they can estimate how much we drank better than we can. “And I’m ready for your lift-off PAD data.”
“Okay. For [CSM] rev 26, lift-off time is 138:40:15; 27 is 140:38:49; (28 is) 142:37:22; 144:35:55; 146:34:29; 148:33:03. And the last one, rev 32, is 150:31:37. Go ahead [with a readback].”
“Okay; rev 26. Is that the first one (orbit), Gordy?” Always good to be absolutely sure which orbit started the sequence of liftoff times.
“Okay. Rev 26 is 138:40:15; 140:38:49; 142:37:22; 144:35:55; 146:34:29; 148:33:03; 150:31:37. And what’s our present rev?”
“Okay; I’ll have to check that myself. …We’re on rev 25. He’s (Evans) about three-quarters of the way across the front side. Coming up backside will start 26.” Each rev started at the point over the farside where we had entered lunar orbit.
“And, for your information, he’s running the VHF Sounder, and it’s working fine.”
“That’s good to hear.”
“By the way, good morning, Gordy,” Cernan said.
“Good morning, Commander.”
“How does America itself look?”
“Just as good as ever. [He’s] ahead on the consumables [and] no problem on the spacecraft systems. [There’re] only minor funnies in the SIM (Scientific Instrument Module) Bay, but even it is almost 100 percent [on line].”
“And I guess from…I didn’t hear your comment, but I assume Challenger’s the same way.”
“That’s affirm. That’s the way it looks here, anyway…”
“When you are through waking up, why don’t you grab some breakfast packs?”, I suggested.
After a few minutes, Fullerton called, “Challenger, Houston. We’ve been working, while you’ve been sleeping, on a fix for the missing fender. John Young has been over working it out in the suit with the mock-up Rover, and we have about probably 5 to 10 minutes worth of words on how you [might] want to go about [doing] that. Whenever you have that much time to listen— it’ll be mostly listening on your part— let us know.”
“Okay, Gordy. Will do.”
“What is the problem with the water?” Cernan asked me as he pulled out breakfast packages, now stuffed haphazardly back in their compartment.
“I am not sure. Every thing looks good on our gauges. …I guess they are having trouble tracking our drinking and food prep.” A couple of minutes later, I called Fullerton. “Gordy, you’ve implied that we may be a little behind on water [use]. Is that correct?”
“No. That’s not the problem, Jack. I think our concern was more that you were taking enough onboard internally…”
“That’s right. [We wanted to be sure] that you were drinking enough. That’s what we were worried about.”
“Okay; we’ll keep pushing it! …What do we have for breakfast over there?” I asked Cernan.
“I have scrambled eggs, peaches, peanut butter and jelly bread, and most importantly bacon squares. …Lets see. … Looks like you have the same,” replied Cernan.
“And cold scrambled eggs,” I added, inadvertently keying my mike while thinking how nice it would be to have hot water in Challenger like we had in America. “I think that the orange drink and the cocoa both have potassium added. I think I will just drink water. The last thing I need is Young-Duke diarrhea during the EVA.”
[Too much potassium in the diet gave both John Young and Charlie Duke bad diarrhea on Apollo 16. NASA and its medical advisors had reacted erroneously to Jim Irwin’s post-rendezvous heart episode on Apollo 15, thinking it was due to a potassium deficiency rather than an inherent heart problem that many years later took Irwin’s life. I argued successfully for lower doses in our diet; but I still did not want to take any chances.]
“Gordy, we’re going to start to eat here,” Cernan reported. “Why don’t you talk to us about that fender?”
“Okay; let me round up John Young. He stepped out for a second. We’ll have him here in a minute. Might as well let the resident expert on fenders talk. …Okay; I’ll now turn the microphone over to Captain Young.” On Apollo 16, Young had broken a fender off his Rover, and had a good perspective on how serious the problem would be without a fix. As mentioned previously, however, Support Team member, Terry Neal, had done the real work of working out a fix.
“Hey, Geno. This is John. We spent…”
“Hello, John,” Cernan interrupted. “How you doing?”
“Oh, just fine. You guys are doing a superb job; really beautiful. …Hey, we spent some time on this fender problem and worked out a pretty simple-minded procedure, which involves essentially taking four of those [backup] chronopaque pages out of your lunar surface maps— ones which are not going to be used for discussing the site— taping them together with gray [duct] tape so that you end up with a piece of paper about 15 inches by 10-1/2 inches, and then using the AOT (Alignment Optical Telescope) lamp clamps, pre-position them full opened, taking them out [in the ETB], taking that piece of paper out [of the ETB], laying it on top of the fender guide rails, and clamping the edges of it with the AOT lamp clamps. It’s simple and straightforward, and the beauty of it is you’re only spending about 2 minutes in the clamping operation, and it could save you up to about 12 [minutes of] dusting, I think maybe. …What do you think?”
I really felt justified in not worrying about Mission Control being able to come up with a fix. We no longer needed the stiff, chronopaque maps Young mentioned. They covered areas away from the prime-landing site in case Cernan had landed so far off target that new traverses would need to be planned.
“Yeah, John,” Cernan replied, but probably not realizing that detailed procedures were ready, he said, “I think we ought to try something; because you told me [about the dust problem after Apollo 16], but I guess you can’t appreciate it until you see it happen yourself. That dust— without that fender— is just almost unacceptable. This sounds pretty good. How do you want those things taped together?” I am sure that we would have still done the planned EVAs without a fix; however, timelines would have been adjusted to account for a lot more dusting of the battery covers and LCRU.
“You just take four pages and allow. …Well, I’ve got the detailed procedures here, if you’re ready to copy. Over.”
I shook my head and pointed to our breakfast.
“Well, no. I’m not ready to copy yet, but what do you do? Tape the four squares into a bigger square about 16 by 20?” It is clear that Cernan had not listened to Young very carefully.
“Yeah. Allow about an inch of overlap, and tape both sides of them. …And then you get the AOT clamps off the utility lights and open the clamp jaws to max. And you stow the clamps, and you roll up the paper. …Roll up your [new] fender short-wise and put a gray (tape) tab over that and stow it in the ETB. You got both the clamps and the paper fender in the ETB. …And then when you get out to the Rover, you lay the edge of your fender over the inboard guide rail and clamp it, and then you lay the other edge of the sheet over the outboard rail and clamp it. And the only thing you really have to worry about is making sure that the inboard clamp is right over the shock strut so that you don’t get any interference with the LRV structure when you turn the wheels.”
“Yeah, that’s the type of thing I was going to ask about,” Cernan added, “some of those subtle points. There really should be quite a ways… Well, I’ll look at it. …But almost vertical over the hub, right?”
“Yeah, on the inboard one,” replied Young. “On the outboard one, if you put it a little further back aft on the wheel, it allows you to give your paper fender a little more rigidity.”
“And you just say [to] lay them over the guide rails (and) sort of…so the clamps are also over the guide rails.” These “guide rails” are about a quarter of an inch wide and thick enough to give the clamps a good hold on the remaining fender. “And not try and align the makeshift fender in the guide rails itself, huh?” Where Cernan got this idea, I don’t know. He may have felt like he needed to show that he knew as much as Young and his team did about how to fix the fender.
“No. Just clamp the thing right to the rails. Just allow a little overlap, and clamp that rascal right down. And I know you can tighten those clamps down so good it’ll never get loose!” Young said with a laugh. “I know you can do it if I can do it.” Cernan’s large hands gave him a very strong grip.
“Okay, John. I think I know what you’re talking about,” Cernan replied, “and I’d sure like to give it a stab. The only hooker is [that] I hope that tape holds the fenders together well enough…those pieces well enough.”
“Roger,” Young confirmed. “One of the things— when you’re taping the pages together— that you want to be careful of is that you make sure and get the air bubbles out so when you get in the vacuum, it doesn’t open up by itself. And maybe you can put an [taped] X across there (the joint) to make sure that, if you get any separation, it’s still held together pretty good. We think the tape will work because back about in [Apollo] 13, we were using it just sort of incidentally in the thermal vacuum chamber, and it worked okay there for some reason.”
“It would seem to stick on the surface okay— if I could find a dust-free spot— when I put that other fender on earlier,” recalled Cernan about his original attempt to fix the fender.
“Yeah, I agree,” replied Young.
“As far as how much of the new fender to overlap on the present fender, just make it about symmetrical with the other side (that is, the undamaged, left-rear fender), and that probably ought to give me plenty of overlap, huh?” Cernan had begun to complicate what sounded like a fairly straightforward procedure.
“Well, are you talking about over the dovetail part of it,” Young asked, “or are you talking about off the aft end of the vehicle?”
“I’m talking about the present fender that’s on there, the aft end of that [right rear] fender. About how much overlap do you want with this makeshift fender? Just give me an idea. I think I could figure out when I get there, but I’d rather have your feelings before I do.”
“We think if you get it out about 4 inches past [the end of] that fender… You understand what this looks like when you get it put on the fender. It just looks like sort of a roll, and you end up with a sort of a straight fender right at the back end of the Rover. A sort of a straight…about half a pipe straight out there. And, if you get it out 4 or 5 inches, that will keep the dust from coming back over the vehicle.”
“Yeah. That would be about 4 or 5 inches. Great.”
“Yes, it’s just sort of like a horizontal fender, like on an old automobile.”
I had been listening and trying to adsorb what Young had worked out. Speaking to Cernan, I said, “I thought I understood what he was talking about. Pipe…”
“Say again, Geno.”
“Hey, John. This is Jack. Did you say “pipe” there a minute ago? P-i-p-e?”
“Yeah, but it doesn’t roll up into a circle; it’s sort of a…a hemisphere. I mean it’s half of one.”
“Oh, okay. I thought I was with you until you said “pipe”, and then you lost me. Okay. I think I understand, too.”
“You know the problem I have with communications.”
“Hey, thank you, babe,” Cernan said. “We’ll give it a try. We can get something to work.”
The imagination and motivation of the Support Team always amazed me. Taking inventory of what we had onboard, it seemed that, in just a few hours, they had thought of and tested everything about the fix. I think Cernan had worried about his screw-up during the night, but I don’t remember ever giving it a thought after knowing they were working on it. Unlike most of the other astronauts, I had spent a lot of time, professional and social, with the Flight Controllers and their support teams. Indeed, during other missions, I had participated in solving problems as they arose. I was confident that they would give us a good solution.
“Okay,” Young concluded. “And we can watch you on the tube (TV) and make recommendations. I think you’ve got the idea of it. You know Terry Neal thought of these AOT clamps; and that’s a great idea because you can clamp those things on that old dovetail [of the rail] …You can put [such] a force on there that those chronopaque pages will never get loose.”
“Yeah,” Cernan agreed. “Those other clamps I was thinking about— paper clip-type clamps— would never hack it.”
“We tried that,” Young replied. “They just don’t have the push.
“Sounds good, babe; appreciate it.”
“Okay. We’ve got a detailed procedure here if you want to copy it; just in case.”
“Yeah. Stand by one, though.”
While we ate breakfast, Cernan continued to worry about and discuss with Fullerton where he thought we had landed. This continued to be a waste of time for two reasons: first, the photographs would eventually show exactly where we were, and second, we were close enough to the pre-mission plan that it would not make any difference to the traverse objectives of EVA-2 and EVA-3. He eventually admitted that it was a matter of pride to know immediately where we had landed even though he used up valuable time trying to figure it out.
“Gordy, while we’re eating, have you got a short synopsis of the news?” Cernan asked.
“Yeah. Sure do. Stand by one. …We’d like Biomed, Left, please.”
“I don’t have any sensors on, Gordy. …You have to wait until I start putting my suit on…”
“Okay. As you might have expected, front pages around the country are headlining last night’s EVA with photographs taken from TV monitors showing you and Jack going about your tasks. I might add that the TV camera is really spectacular. It couldn’t have been a clearer or more beautiful picture, both for fidelity and color…” Unfortunately, NASA was unable to preserve the original recording film, so this clarity has never been reproduced.
“In other news, South Vietnam’s President Thieu has suggested that all prisoners of war be released before Christmas. He has also asked that all Vietnamese parties be included in peace negotiations. South Vietnam and the Viet Cong are now not directly represented in the secret talks now under way in Paris [between North Vietnam and the United States]. Meanwhile, [U.S. Secretary of State Henry] Kissinger met for more than 4 hours yesterday with Hanoi representative Le Duc Tho. The two negotiators are expected to meet again this afternoon.
“The former President, Harry Truman, is still resting quietly, although his condition remains serious according to his doctors. American poet Mark van Doren died at the age of 78. He was a professor of literature at Columbia and a winner of the 1940 Pulitzer Prize for his poetry.
President Nixon announced yesterday that he wants to extend wage/price controls beyond the scheduled April 30 expiration date. He also plans to freeze new hiring, promotions, and pay increases for executives of the Federal Government, which doesn’t affect us, I guess.”
“How about me?” I asked facetiously as Fullerton, by use of “us”, was referring to military personnel. Ignoring me, Fullerton continued.
“The Republican National Committee has a new chairman— George H. W. Bush of Houston— who is now Ambassador to the United Nations. He will continue his UN post through the present session of the General Assembly. Both national political parties are now headed by Texans. As you recall, Robert Strauss of Dallas became Chairman of the Democratic National Committee last Saturday.”
[In a later life, I worked with both these gentlemen: George H. W. Bush in 1981-82, while he was Vice-President, and I was United States Senator from New Mexico working on regulatory reform, and Robert Strauss in 1989, when we both were members of then President Bush’s Government Ethics Commission.]
“And Jack, I’m sorry to say that you’ve been replaced. The Nimbus 5 weather satellite is now operating in orbit after its launch from Vandenberg early Monday morning.”
“Can it talk?” I rebutted but again was ignored.
“Joe Namath tried mightily to lead the Jets to the play-offs, but the Oakland Raiders grounded the Jets in the fourth quarter, 24 to 16. I think you have already heard that score. Namath passed more than 400 yards, but New York only scored one touchdown.
“And the last item concerns the Houston weather. There’s been two kinds of weather since you all left us: that’s cold and light rain and cold and heavy rain, and it’s still doing it. Fog and drizzly rain are here now, and we’re only supposed to get up to the mid-40’s (Fahrenheit) and probably down to 32 tonight. Over.”
“Holy Smoley!” Cernan exclaimed. “That doesn’t sound too good on the weather. I’m going to take a look; right here up the overhead window…Gordy, you’re right. There’s a band of clouds that comes right up the coast of Mexico. Looks like it covers most of the Gulf [of Mexico] and then gets very dense as it comes up into the Texas area and southeastern part of the United States with a counter-clockwise rotation which gets very dense down over the Atlantic, I believe, off the southern east coast of the (United) States. And, from about, oh, I’m guessing, maybe the center of Texas straight north and straight east, it looks like the whole country’s clobbered. …Baja (California) looks nice; west coast of Mexico looks nice. …And (at) Taurus-Littrow, the weather’s great.”
“Hey, Houston, Challenger,” I called, while continuing to eat breakfast.
“Roger. Gordy, how’s the ALSEP doing? And, in that light, I hope you people will take as close a look as you can at the signal strength and its variation and see if you get some idea whether, when I go after the neutron flux tomorrow, if I ought to work on that antenna alignment again. I’m still a little bit concerned about it.”
“Okay, Jack. We’ll consider that; although, they’ve been getting good performance out of the Central Station, as I understand. A couple of problems with the experiments [exist]. One was the LEAM (Lunar Ejecta and Meteorites) data isn’t synching up like it should. I’ll have to get a further, more complete story on that. And we’re thinking that’s…mostly a ground software problem.”
“I’m joking!” I interrupted, not really wanting to go back to the ALSEP. Little did I know what was in store.
“The other one (problem),” continued Fullerton, “is the LSG (Lunar Surface Gravimeter – actually a long period seismometer designed to be a gravity wave detector) isn’t leveling up properly. We’ll cover this further in the planning briefing for the EVA here; but we’re probably going to let you off. …I mean, have Geno let Jack off [the Rover] at the ALSEP and take another look at the leveling on the LSG. That’ll be at the end of the EVA[-2].”
This statement about the LSG was the first hint of a problem that eventually would cost me at least half an hour of exploration time. The LSG experimenters first assumed, I guess understandably, that I had not deployed the instrument properly. On the other hand, I had kept them informed throughout the deployment, so they should have worried that it was some internal problem.
“Roger,” I replied. “I may just run out there and let Gene pick me up after we, …well, while he fixes the fender…maybe. We’ll work that out, Gordy. I’m joking, but maybe I could go kick the LEAM; that might help it.”
“Let’s make sure we’ve got all our problems solved down here before you do that,” Fullerton said.
“Okay.” As I continued to eat breakfast, I used the Leitz monocular to examine some of the visible mountain slopes. “Hey, [looking at] Family Mountain, [particularly] the northeast facing slope, although lower [than other slopes], has boulders and outcrops, …I mean, …belay the [use of] ‘outcrop’.”
[Using the term “outcrop” constituted bad form for a field geologist, not having the opportunity to examine whether or not an exposure of rock remained attached to bedrock or not. Without a close-up look, it would be difficult to tell if the boulders had been broken off bedrock and transported some distance from a bedrock source. I later began using the term “source-crop” when evidence existed, such as structural alignment, that visible boulders exposed at the surface came from a bedrock source.]
I tried again. “It (the mountain slope) has boulders [rolled] from local block concentrations. [It] looks very much like the South Massif [slope] does.”
“Roger,” replied Fullerton.
[Future studies of false color images produced from the United States supplied Moon Mineralogy Mapper flown on India’s 2012 Chandrayaan-1 lunar orbit spacecraft suggest that rocks similar to those of the Sculptured Hills make up Family Mountain as well as Bear Mountain to the east of the landing site. Such rocks probably also lie below the basalt that partially fills the valley, giving a very irregular, knobby, Sculptured Hills-like topography on the pre-basalt floor.]
Clearing my throat, I told Cernan, “The old sinuses are [stuffed up].” My reaction to the lunar dust continued, even though the LiOH filters had completely cleared the cabin air. “I am surprised that my nasal turbinates are reacting this way.”
“Is it getting worse? Cernan asked.
“No, I don’t think so.”
“Do you want my peaches,” he offered.
“I’ve about filled up, I think.”
“[I have some extra] chocolate?”
“No, I’ve had two,” I replied. “By the way, don’t let me hold a seismic charge with my hands while we are driving, today. That was a major mistake on my part, yesterday.”
“Wilco… Let me use the monocular.”
“Hey, Gordo”, Cernan began, “We’re still eating, but let me give you a few observations. That outcrop I talked about (before the first EVA) that was way at the top of the South Massif at the break of slope— at the very top of the break in slope— …almost looks…it’s hard to tell that it’s an in-place outcrop up there. It’s hard to convince myself that it is. It looks like there’s some very large, 3 to 4-meter rocks up there and a lot of smaller fragments. I’ve seen that type of thing in a number of places over the South Massif. However, I…do see…they also…they seem to be sitting on top of the South Massif surface, but I do see one other [boulder] area that it looks like there is a… It is protruding from within some kind of mantle on the South Massif, so conceivably some of that could be in place (outcrop). An additional impression I got is…is that, at least with the monocular, that those boulders look much more angular than what we’ve seen here [near the LM] and, for the most part, they appear to be— if covered at all— very little [covered] by mantle except for the one I just mentioned.”
“And, Gordy,” I joined in, “through the monocular, in contrast to the tan-gray of the South Massif, those large blocks up there look blue— fairly distinctly blue-gray— not unlike, [as] Gene mentioned yesterday, [how] anorthosites look in certain terrestrial environments.”
[Anorthosites on Earth tend to be white to blue-gray rocks that consist largely of the low sodium varieties of the mineral plagioclase (anorthite”) a calcium-aluminum silicate. We did not have strong expectations of finding large masses of anorthosite in the massifs of Taurus-Littrow as they appeared to be made up of the extensive ejecta blankets of melt-breccias from several large basin-forming events, the last three largest, Crisum, Serenitatis and Imbrium, and possibly Tranquillitatis (some questions exist about this being an impact basin), created craters 700 to over a 1000 km in diameter. The blue-gray color of some of the boulder concentrations on the South Massif, nonetheless, at this point raised the possibility that we might encounter large blocks of anorthosite at Stations 2, 6 and 7, located at the base of the massif walls of the valley. The first boulder we would sample at the base of the South Massif, however, opened up other possibilities (see Station 2, below↓). These boulder fields also have been imaged in high resolution by the Narrow Angle Camera (NAC) on the Lunar Reconniasance Orbiter (LRO) and may be incorporated in a mass of impact melt draped over the crest and upper slope of the South Massif (LROC image M1266925685). ]
“And, Gordy,” continued Cernan, now thinking about how we would navigate to the base of the South Massif, “now that I get my three-dimensional eyeballs working, I can look up on the Scarp out to 9 and 10 o’clock (means 11 to 12 o’clock). It’s practically the same [tan-gray] color as the South Massif. It just looks to be very undulating; I see no outcrops evident from here. I think I can just about see where Hole-in-the-Wall is but it’s so subtle that I can’t really tell you much about it. And the local terrain— which I think is the southern rim of Camelot— just about blanks out where Hole-in-the-Wall should be. Just about covers it up. But what I can see is a small little saddle through our local horizon here in front of us. …I can see out there just about— oh, I’d say— 100 meters or so to the south of Hole-in-the-Wall. And it just looks like a subtle, undulating slope. We can’t really tell too much about the steepness from here.”
“Part of the problem, Gene, may be that the scarp is at zero phase from here and topo details are washed out.” Cernan was looking almost directly down sun so that variations in detailed topography were washed out by backscattered sunlight.
“Yeah, you are right. We will have to get closer to really find Hole-in-the-Wall.”
“I wonder it it might be just to the left of the rim of Camelot.”
“Hole-in-the-Wall” refers to a north-south ramp-like portion of the Lee-Lincoln Scarp, with lower slopes than elsewhere that we planned to use in our climb up the scarp on the way to Station 2. I chose the name “Hole-in-the-Wall” to commemorate part of the country’s Western Heritage that referred to remote and partially hidden canyons where outlaws hid out at various times.
Fig. 11.1. A pre-flight estimate of the appearance of the horizon from the LM from a 1972 Bell Laboratories Memo described in the Apollo Lunar Surface Journal (ALSJ). The area marked “Access Region” to the scarp was later re-named “Hole-in-the-Wall” as explained in text. (From the ALSJ).
“Okay, Geno, we…” Fullerton hesitated. “Standby one… Okay. I had something for you but we just decided to cancel the call. Although when you do get out the Prep-and-Post Card, I have one write-in for you. So just holler when it’s handy.”
“Okay. We’re wrapping up our eating and drinking here now, Gordy. We’ll be ready to go in a minute.”
“Okay.” At this point, relative to the original flight plan, we are about an hour behind. Although this would not turnout to be significant in our total EVA time, a good part of the time loss can be attributed to Cernan’s continued pre-occupation with determining exactly where we had landed.
“I wonder if we have more of that salve for my hands,” Cernan asked.
“I think there is another tube in the Hygiene Kit,” I replied, “if I can remember where that is stowed. I also want to use more stuff on my lips, today.”
“Gordy. Challenger,” I called. “Could you ask somebody there in the FAO (Flight Activity Officer) console where the hygiene kit is stowed?”
“Okay. Will do. …Jack, …take a look on the right-hand-side stowage compartment, there, on the forward lower corner under the LEC kit compartment.”
“Gordy. You broke up with a [transmitting antenna] changeover or something. Say again…”
“Okay, Jack. You’re right; I got caught right in the middle of a site handover. Look on the right-hand side stowage compartment, forward lower corner, under the LEC kit compartment.” That compartment is just under my right hand controller.
“Fantastic! You picked the one place I’d never looked.”
[No matter how many hours you spend in simulators, you loose track of the many stowage compartments. On the other hand, most of those hours covered operations during critical mission phases— landing, ascent, rendezvous, etc.— and relatively little on the mundane issue of cabin stowage. All crews insisted on at least one run-through in the cabin with the flight hardware just to be sure there were no surprises with something they had never seen before or something that did not fit or work as expected. These exercises were known as “Crew Compartment Fit and Function (CCFF) checks” or C-squared/F-squared or CF-squared. Still, memory fails when there is a lot going on.]
“Houston. Challenger,” I called again.
“One quick thought about the [Surface] Gravimeter (the LSG). And I’m sure it’s been mentioned, but I’ll say it. During the CF-squared, we asked about that bundle of wires that has contact with the [internal] gimbal. And when I deployed it, that bundle still had contact with the gimbal and everybody at the CF-squared said that was okay. But, you might think about it. I don’t know what I could do to help if that is the problem. But that might be causing the problem here that it wouldn’t cause on Earth.”
“Okay, Jack. I’ll make sure the experts hear that…”
“Gordy, everything okay at home today?”
Missing Cernan’s point, Fullerton answered, “Yeah, everything is fine here.”
“Well, thank you,” Cernan countered, sarcastically
“I’m not sure I copy your question precisely. Haven’t talked to your home today, at all.”
“Okay. Don’t worry about it. I just thought you might have heard. …Well, if you hear, Gordy, just tell them they’re missed.”
“Okay; I’ll sure do that…”
“Gordy, has anybody heard from Tucson recently?” I queried.
“Check on that, Jack. Just a minute…”
“And, Gordy, if you have any updates to the EVA-2 checklist (Cuff Checklist), give me a yell.”
“Okay, the update I do have, …I think, [with] the EVA checklist changes [we have], we’ll just call you, real time. But, I do have one for the [EVA] Prep Card…”
“Go ahead,” I responded after grabbing the EVA Prep cue card and a pen.
“Okay. On the front side there, middle column, lower half at ‘138:45 OPS Connect’, halfway down, it says ‘Install Purge Valve in PGA, red to red’. Mark that ‘LMP serial number 211 [and] CDR, 208’. This is to maximize the OPS operation, should you have to use it.” We had removed the purge valves from the suits at the end of EVA-1 and would re-install them as we suited up. Each purge valve would have a slightly different flow rate and the EMU guys wanted to optimize them for each OPS pressure bottle, my OPS having a higher than expected pressure.
“Okay. Give me the numbers again, please.”
“LMP, 211; CDR, 208.”
“I take it those are serial numbers.”
“That’s right, the serial numbers on the purge valves.”
“Okay, Challenger. This is Houston. Would you like to have a little update on the EVA plans?” Parker took over the Capcom duties.
“Do you want me to take notes?” I asked.
“No, I don’t think there are essentially any notes required. I’ll make a few real-time call-ups to you; but, I don’t think there’s anything you really have to write down.”
“Okay, Bob,” I said, and then added, “I realize that things were getting a little hectic yesterday. But, if we end up making any changes where I don’t need to get a [seismic] charge in my hands, that’s an awfully good thing to call; because not only does it tire your hands out holding it, but it means you don’t get as many pictures or Rover samples or anything else.”
“Lets keep working the [EVA – Prep] Checklist while he talks,” Cernan suggested.
“Yeah, God knows how much input Bob has gotten from the Back Room planners. Hand me the food sticks when you close the food compartment, and I will get the drink bags from in back. They both go in the ISS on the DISKEY.”
“Roger. You guys were just ahead of us there. We were trying to get that up to you. …Okay. No, I don’t think there is anything here that really needs to be written down. I’ll go through [it] with you first, and we can talk about details and writing in [notes], if you want to, on any of them. But, I don’t think there is anything that really needs to be written in [the Cuff Checklists]. The EVA…is going to be essentially nominal, with two minor exceptions. One is we’ve allowed about 5 minutes extra at the LM, before leaving, for the Rover fender fix; and John will be talking to you about that in a minute. And the second, [a] big change is that we’re also allowing 5 more minutes at the end of the EVA so that we can have extra time for dusting. And I suspect that, if the Rover fender fix works and we aren’t getting as dirty as we did last night, then we may gain back that 5 minutes. We’re also allowed… What we’ve done is we’ve taken the time here [at the LM] out of some of the tasks at Station 3 and Station 4. And, along with the fact that we think you’re a little bit farther east than planned, we’re allowing 4 minutes additional driving time. But again, that’s all real time, and if we’re doing well on time, we can reinstitute all those tasks and get rid of the 5 minutes that we are allowing here, there, or elsewhere. So that’s [some possibilities] just sort of to keep in your thinking…”
“Now, we need to top off the PLSS’s oxygen for one minute, each,” I noted. “You want to start with yours?”
“There is a possibility that we’ll have some additional overhead at each stop, depending on what the Rover battery temperatures are when you get out this morning. If they’re high again, then we’ll have to probably park— at least on some of the stops, if not all— with the up-Sun heading and dusting the battery covers and then opening them to let them cool. But, again, that will depend upon what we find on the Rover batteries when we get out this morning…”
“Here’s the EVA-2 Prep and Post Card I was modifying to cover the Purge Valves. Stick it on the Velcro up there so we won’t hit it with the PLSSs.”
“The variations that we found on the surface of the South Massif indicating a possibility of layering— I guess you saw those mostly with the monocular— and the observation of boulder tracks and the size of the Massif emphasizes the importance of sampling boulders that can be traced to sources at various elevations on the Massif. And I guess we should say that’s ‘hopefully’. And we’ll just have to see what happens when we get down to Station 2 on that. But, if we see boulders with tracks, I’m sure you guys remember that they obviously will have a higher priority…”
[With this request, the geologists in the Science Back Room anticipated something that I would not really get to think about much until the high-resolution images came back from the Lunar Reconnaissance Orbiter 40 years later. No tracks leading to boulders have been found on the South Massif above Station 2; however, tracks lead off the North Massif to each of the boulders at Station 6 and Station 7. The lack of tracks on the slope of the South Massif above Station 2 is puzzling as tracks just to the north do lead to boulders in Nansen crater. Tracks to the boulders we would sample there clearly had been erased by continued impact gardening of the surface.]
“Since we didn’t get to Emory,” continued Parker, “and since we didn’t really get to the rim of Steno itself, the question of sampling of the actual subfloor is still somewhat ambiguous, although there is a large consensus opinion that says that we sampled the subfloor when we sampled that intermediate gabbro yesterday at both the ALSEP and Station 1. There is a possible alternative conclusion, which says that the subfloor has not been sampled, but that these blocks that we sampled and the surface are both parts of a later flow. And, in that line, we’re still looking for specific observations which will help us distinguish whether or not the dark mantle is a separate unit from the intermediate gabbro that we’re seeing or, whether it’s the…” Someone interrupted Parker at this point. “Stand by. …Okay. …Or whether it just represents the top of [a] very well churned up layer of a flow that was later than the subfloor, if you see what I’m saying there. …All this says that we’re very much more interested in Station 5 [at the rim of Camelot], as you might expect, than we were before. And I guess, for this reason, we’ll be trying to keep to the timeline a bit tighter than usual to guarantee that we’ve got some time left over at Station 5. And, we’re also interested in perhaps moving Station 5 from its present location there in the southwest of Camelot over to the southeast or east or some location where we have a feeling that we’ve got big boulders up on the rim.”
[Camelot Crater, at about 600 meters in diameter, excavated about 120 m into the subfloor material (based on a depth to diameter ratio of 0.2, with material originally being ejected to the rim from about 60 m depth. Pre-mission planning, based on low-resolution images from Apollo 15, assumed that Camelot was a relatively young crater. Later considerations, however, suggest that Camelot may be about 500 million years old and the boulders at the rim consist of gradually exposed boulders from the crater wall rather than impact ejecta. (See Chapter 13)]
“This would be so we could sample, hopefully, some of the white material and some of the boulders together and get a better confirmation that the material from deep in the subfloor unit is this intermediate gabbro, as opposed to just material from the upper part of the subfloor. It’s just a matter of proving to ourselves whether or not the boulders we sampled yesterday are from deep within the subfloor, or only at the surface of the subfloor; or, perhaps, as I said, the other alternative being that the intermediate gabbro is part of the dark mantle, and we’re seeing a churned-up regolith on top of it…sort of being the gaseous (vesicular) upper part of the flow having been broken down rather rapidly into the dark mantle. …Okay, stand by a minute…
“To summarize that again, …I guess I got ahead of myself here in the little spiel they (Science Support Room) wrote up. At the present time we have two working hypotheses for the dark mantle and gabbro relationships to each other. One: the crystalline rocks that we found— the gabbros— are an upper unit of the subfloor with their dark mantle cover unrelated to them in time. Key observations that they suggest here are stratigraphy at Camelot— Station 5— and other deep craters. Especially, perhaps, (dig) a trench in sheltered spots which are ungardened (undisturbed by micrometeorite impacts)— as in ‘plowed’— [and look] for an older regolith underneath the dark mantle, if such a thing could be found. We don’t think we found that yesterday— or, [take] a look at the superposition relations between dark mantle and boulders. Are there instances of the mantle on the boulders or, inversely, of small boulders on the mantle?”
[These thoughts still reflected the dominant pre-mission hypothesis that the dark mantle unit was a significantly younger, discrete volcanic deposit than rock units beneath it, rather than younger volcanic material mixed with regolith developed on the subfloor.]
“The second working hypothesis is that the dark mantle is regolith derived from a vitreous, vesicular, [basalt] flow top of the crystalline rock flow beneath. And, it (the write up) again goes [on] to say that perhaps the gabbro we sampled yesterday was indeed the late flow; and the regolith was derived from the vitreous, vesicular flow top, as it were. Again, many of the same observations are called for. In particular, they’d be interested then in looking at the coarser fines as they define as [being] from a millimeter to 20 millimeters (in grain size), for some sort of transitional lithologies and textures. In other words, what do the small, walnut-size rocks look like, if you can, in hand specimens?
[Parker read from a briefing paper put together by Bill Muehlberger and his team of geologists, probably including Gordon “Gordy” Swann, Edwin “Ed” Wolfe, George Ulrich, Robert “Bob” Sutton, Barbel “Barbara” Lucchitta, Leon “Lee” Silver, and others. Their original draft probably had been severely edited by others along with various phrases added by Parker as he read it to us. Saying, “pay close attention to superposition relationships,” could summarize the entire briefing, that is, what material or rocks lie on top of other material or rocks. Said even another way, what appears to be older and what appears to be younger. In 1671, Nicolas Steno, a Dane who had become a Catholic priest in Italy, first formally noted the importance of these superposition relationships for determining a relative sequence of ages for rock units in a gravity field. (I had named Steno Crater in honor of this critical first insight into nature’s laws.) The absence of clear evidence of the nature of the dark mantle, seemingly so obvious on low-resolution pre-mission photographs, continued to puzzle the field geology team as well as me. This apparent contradiction resulted from my initial close-up field observations near Steno Crater on EVA-1 being within the obscuration effects of regolith formation. As regolith forms through the effect of numerous repeated meteor impacts, the boundaries between surface contacts become increasingly diffuse.]
“Jack, turn off the BIOMED Telemetry,” Cernan asked, looking at the Checklist. “We slept in our LCGs (Liquid Cooled Garmets), but we still have to put our UCTAs (Urine Collection and Transfer Assemblies) back on.”
“Okay. …I’m glad I remembered to stretch my next UCTA condom on the hand controller before going to sleep. Having the one from yesterday fitting too tightly was really painful. I think I may have broken some capillaries when I forced pee through the restriction. I will never listen again when they say it (the penis) shrinks on the Moon.”
“If I can get more specific in terms of EVA mechanics,” Parker began again, “let me say that we’ll call out— in real time— the deletion of the tasks at Stations 3 and 4, if they become necessary. And what we’re planning on doing is: deleting the trench in the base of the scarp at Station 3, and also deleting the radial sample on Shorty [Crater] at Station 4. That’s provisionally what we’re planning on. And depending on how the time is going, we’ll call that out real time. We also have…the [EVA] experiments [that] remain pretty much the same. We’ll deploy the charges at the same locations as we’re planning in the checklist at the present time.
“For your planning further ahead, we don’t anticipate any significant changes in EVA-3. The charge #5, which we were going to deploy at Emory but didn’t, will not be deployed during EVA-2, but we’ll deploy it on EVA-3 out at station 10. And, what we’re going to do there is, when you take the [one] eighth pounder (charge #4) and put it between the seats, we’ll then have the three pounder (charge #5) left over, and we’d like to put that on one of the footpads in the Sun; that’s probably either the minus Z (east) or minus Y (south) footpad. And, we’ll leave it there in the Sun until the start of EVA-3; in which case, we’ll put it in the Rover underneath the LMP’s seat. And, thermally, that looks okay.” This seeming complex arrangement accommodates the four charges on the second pallet and the charge remaining from EVA-1.
“There is a probability that we’re going to play the ‘return to the ALSEP game,’ and we’re going to do this for a couple of reasons. One, we’re going to go back and look at getting some more ALSEP photos. I guess Gordy [Fullerton] says you’ve got that (information). And, that will probably be— in fact, it will certainly be, if it happens— at the end of EVA-3 when you go back to get the neutron flux probe. I might also say with regard to EVA-3 that, obviously, we’re more interested in Station 10 than we were before. Again, there remains concern that we have not sampled the subfloor and Sherlock [Crater] might be another place to do this.
“Another ‘return to the ALSEP’ goodie that we’re looking at— if we have the consumables today when you get back from finishing Station 5— is that the Lunar Surface Gravimeter has been unable to level itself over the night; and they sent some, you know, some thousand commands trying to get it straightened out, and they say it looks as though it’s not level. And, so, we’d like Jack to go back with his practiced hands-on-bubble-levels [experience] and recheck that after Station 5 today— if there’s sufficient consumables. And, we’ve planned for Gene to just let Jack off and let him walk back to the LM, after he gets off and looks at that.”
“And, that’s…about everything we have,” Parker concluded. “As I say, in summary, the big changes are going to be extra time at the beginning, taking care of the fender extension, and the probability of extra time at the end. Although we’ll have to see how well the fender works and how things go. The probability of extra time at the end [is] to allow for dusting. And the time spent on those particular activities we’ll probably end up taken out of the tasks at Station 3 and Station 4. Over. Comments?”
“I am going to put my biomed sensors and Bio Belt on,” Cernan declared. “Did you turn the telemetry OFF?”
“Yes,” I had my sensors and Bio Belt on during the rest period.
“Okay, Bob,” I replied, continuing to multitask between listening and working through the Checklist. “We copy all that. Obviously, you’re going to have to catch us in real time on some of the details there…on the charges and the task deletions. One question: did you say we were going to delete the trench at Station 3?”
“Roger. The trench at the base of the Scarp, in other words, some of the stuff that you would be doing while Gene was taking the double core.”
“What do you gain by that?”
“Well. No comment on that, Jack.”
“If you haven’t deleted Cernan’s tasks, then what am I supposed to do?”
“You’re supposed to help Gene, I guess.”
“Well, but that’s not the way we worked it, Bob.” Clearly, I was upset by ALSEP concerns still affecting exploration plans and that the Back Room folks were thinking that they could both change the well thought out activities for Stations 2 and 4 and try to take away my field initiatives without knowing what would be encountered once we reached those locations. Many hours had been spent considering how possible volatiles from along the Lee-Lincoln fault scarp could be sampled at Station 3 by a combination of a double core and samples from a trench. In the case of Station 4 at Shorty Crater, there was a faint possibility that Shorty would be the only young volcanic crater in the valley we potentially would be able to investigate. As will be seen, all this did not bode well for Station 3 efficiency or for the time we could allot for Station 4.
“Let’s play that one in real time,” I finally concluded, rather than argue these points with Parker.
“Roger. That’s why I said there’s no point in marking up the checklist on that, Jack. Let me hit you with one more thing concerning the [Rover] battery temps. An initial reaction down here is that the battery temps were high on deployment because of particularly unfavorable heat soaking on the way out. And the Marshall [Space Flight Center, Huntsville] people are hopeful that they’ll be back to normal this morning. However, we’re obviously anxious, as I’m sure you are, to get an early reading on the battery temps. …That’s number 1.”
“And number 2, just for the off chance that the [temperature] meter’s not working— [although] I think we’ve pretty much discounted that— because of the way the meter worked yesterday. …But, on the off chance that the meter’s not working, you might just lean over and see if the meter is reading zero before you punch in the circuit breakers, because that would give us at least a partial confirmation in that direction, that there’s not something wrong with the [meter] offset. If they’re sitting there reading 30 to 40 degrees [without power], then that probably says something about the offset. And, beyond that…”
“I’ll look at that, Bob,” interrupted Cernan, “what the meter has indicated in terms of a temperature change. I’ll look and see if there’s a bias on them at all.”
“Rog. We again also think that that’s (a meter problem) probably not too likely.”
As Parker had been off duty when I talked to Allen before going to sleep, I summarized some of those thoughts for him. “Bob, I think, based on what I saw yesterday, that the chances are pretty good that all the big blocks out here in the dark mantle area will be pretty much the gabbro. By the way, I looked at that [one sample] with a hand lens last night, and I don’t know that you got the report, and I’m back to saying that it’s probably closer to 30 to 40 percent plagioclase. It’s probably just a good gabbro, a clinopyroxene gabbro, and it apparently has a fair amount of ilmenite in it. There’s some bright, shiny flakes within the vugs and some dark minerals in the matrix that are probably ilmenite.
“And one other additional possibility, then, is that the mantling we’re seeing here is just dark, fine glass— darker than usual, because of the iron and the titanium in the rocks themselves. Also, the probability, I think, still has to be considered that you’re dealing with a true [pyroclastic] mantle that has been gardened enough that, at least where we’re seeing it now— in the first few tens of centimeters [of the regolith]— that it is unrecognizable as a mantling unit, [at least not] yet. The relationship to the large boulders is, I think, one right now of just filleting and a small amount of covering because of the local gardening process. We haven’t seen any clearly mantling relationships between the dark mantle or the surface materials here and the large boulders.” Indeed, discoveries at Station 4 ultimately would show that my second alternative involving pyroclastics would be right on the mark.
“Okay. Copy that. And, we’ll be anxious to see what else you find out today. …And one last word for your interest: the Marshall people have decided to allow us to go to 140 degrees on this EVA with the batteries, if necessary.” As if we would stop using the LRV if the temperatures went higher.
“Okay,” Cernan noted.
“Now John (Young) would like to talk to you about the fender fix.”
“Okay. Hold on for 30 seconds…
“Jack, I finally have my biomed hooked up. Switch the telemetry to LEFT so they can look at it before we suit up.”
“Wilco. You have LEFT.”
“Hey, while John’s talking to me,” Cernan said, “why don’t you check my biomed out? We’re going ‘LEFT’.”
“Okay, fine,” Fullerton said, as he came back on following Parkers discussion of the EVA-2 plans. “We’ll take a check, Geno. Let me ask you one question here on Jack’s PLSS water fill. We’re showing about 3 pounds too much water in the LM system, and we’re wondering if you got the Aux tanks filled up in Jack’s PLSS. Two questions. Were you sure to have the Aux valve open and did you see good clear water in the sight gauge with no bubbles after the fill? Over.” This sight gauge gave the only way to tell if the AUX tank filled up along with the PRIMARY tank.
“I guess we’d have to say ‘yes’ to those questions; but if you’ve got a question on it we can go through it again. I’d rather do that than take a chance [on running out of cooling water].”
“Let me make sure we want to do that. While we’re making sure, I checked with both home fronts. Nassau Bay and Tucson are both in good shape. Geno, Tracy upstaged you for about 30 minutes last night on local TV during her own interview there, and drew everybody away from watching EVA during that time. She did very well.
“Yeah, that sort of figures,” Cernan said with a smile. Tracy was nine years old at the time of her interview with Jim Hartz of NBC’s Tonight Show.
“Gene, I hate to fall behind the timeline any more, but we had better check my water, again. I was sure we got it right, but we better be sure.”
“Hey, Gordo, why do you say ‘Jack’s PLSS’?” Cernan asked. “Did you see the water drop in the LM when we charged mine?”
“It was the profile of the water quantity as you were filling both PLSSs,” explained Fullerton, “and it was the fill during Jack’s fill that looked suspicious…like just maybe 3 pounds less than there should have been [of] flow when you were filling Jack’s.”
“Yeah, well, you know it’s (the sight gauge) only [a] passive [way] to know whether or not you’ve got it filled,” countered Cernan. “[But] I sure don’t want to go out there and have him just have some partial water. So let’s do the conservative thing.”
“Okay. I’ll verify that,” declared Fullerton. “There was some drinking water going out at that time, too, which muddles up the data a little bit, so we’re not absolutely certain on that.
“Okay. We weren’t drinking water while we were filling the PLSS, however. …Okay. You come up with what you think’s best on that, and I’m ready to copy John.”
“Okay, Geno,” Young replied, “I don’t think you need to copy this. Sort of just ad-lib it. With your four, chronopaque maps, tape two maps and allow about an l-inch overlap to (create) a 15-inch by 10-1/2-inch configuration. …That’s an estimate. And then repeat with two other maps, and then tape the two maps— now four maps— tape them together, and you’ll end up with a sheet that’s about 15 inches by 19 inches— a sheet of chronopaque. And then tape both sides of it— the overlapping edges— to strengthen it. And you can further strengthen it if you tape an “X” of tape across both sides of it.
“And then, on the roll up, on the long axis, secure it with a strip of tape and put it in the ETB. And, on that strip of tape you secure it with, be sure and leave a tab on the end of it so you can get it off with your gloves. And then remove clamps from both the utility light units, and open the clamp jaws to max. And then tighten the mounting bracket that you’ve got on it [the clamps] so [that] it will not be swinging around; and stow the clamps in the ETB. You got that, Gene?”
“Now you’ve got everything you need. And it’s all put together and all ready to be fastened to the Rover. And then when you get the ETB in the (Rover) seat, you unroll the chronopaque sheet and you locate the front edge— with the long axis fore and aft— even with the [rear] axle. And you lay the edge of the sheet over the inboard guide rail and you clamp it. And you lay the other edge of the sheet over the outboard guide rail and clamp it. And, as I said, the inboard clamp must be directly over the axle to avoid interference while steering. And tighten the clamps securely— both of them. And then while you’re driving around out there by yourself, it would be good if Jack could take a look at it and see if you’re getting any unusual dynamics. And at Station 2 [after a long drive)] you should inspect the fender for any unusual wear that might have been caused by this mass out there on the fender [or] of those clamps bouncing up and down.
“One thing about it, doing it in a suit, Gene, you have to push in with your leg and hold [the maps on the fender]; and it’s sort of a two-handed job. And I’m not sure in one-sixth g if you can position the fender, the pseudo-fender, on there without Jack, say, holding on to the long end behind the Rover so that won’t fall off. It works okay in one g for one man. But I’m not sure it’s not a two-man proposition in one-sixth [g]. Over.”
“We’ll take a look at it, babe.”
“Okay, and you really have to bear down to get those things (the clamps) on the dovetail [guide rail] there.”
“I just want to make sure of the geometry now. We want to take two of those pages and put the 10-inch sides together overlapping, right?”
“Then take two more and put the 10-inch sides together overlapping, right?”
“And then take those two pieces you’ve got now and put them end to end, so you’ve got a long fender. Sounds right to me. Sound right to you?”
“Well, you end up with all four pieces in a big rectangle,” Young summarized. “You see what I’m saying? You’ve got a 15-inch by 19-inch sheet of paper.
“Yeah, we got it,” Cernan said, as I nodded my head as I finished copying the instructions. “We got it, John. And I copy the overlap and everything. If you had no overlap, I guess you’d have about 16 by 20.”
“That’s correct. But you need to overlap,” Young emphasized, “and taping both sides of it gives it more strength, which you need in that situation …You just want to make sure it’s (the overlap) not more than an inch, or you won’t have enough to cover up those dovetails.
“Okay, babe, we’re going to work on it right now.”
“Here are the four contingency maps we will not need,” I said.
“Looks like we have plenty of duct tape.”
“Like everything else on the Earth, the Rover will be held together with gray duct tape,” I joked.
“Jack and Gene, this is Gordo, again. On the PLSS charge, we’re recommending you hook up Jack’s [PLSS] according to the decal. Go right ahead and… Stand by one. …Go by the decal and do the full 5-minute fill on Jack’s PLSS. It’ll take that long to get the AUX tank filled up, if it was indeed empty. And maybe that’s something you can start and (also) work on the paper (chronopaque) taping. Over.” The decal referred to is printed on a piece of fabric, sewn to the PLSS cover.
“Let’s set my PLSS on the Midstep, and get started.”
A few minutes later, as Cernan worked on his new fender, I said, “Gordy. I’m on step 4 on the decal, …[that is] Step 5 on the decal.” This tells me to watch the sight gauge until bubbles stop.
“Okay, Jack,” Fullerton replies. “John Covington advises that the sight gauge is not a certain indicator that you’re filled; and so we’re just going to go by time to be sure, and kind of disregard the sight gauge readings— as a positive indication anyway.”
“Okay, [I] understand that from the past, and we went exactly by time before. We’ll try it again here.”
“Okay, Gordy. Is that about 5 minutes?” I asked.
“Stand by. I’ll see if anybody timed you here. That’s affirm; 5 minutes now…”
“Okay. Step 7 is complete.”
“And we did not see any water flow to speak of, so it probably was full.
“Yeah, the condensate indications here were that it (the tank) was full.”
“It’s better to be sure.”
“No question,” I agreed. As annoying as this cooling water redo was, I had confidence in the Mission Control team to know it had to be done. A great deal of their job consisted of risk management.
“Geno, this is Houston. We want to be sure to have one look at your Biomed before you get into the suit in case something’s wrong with it. And if you go right by the checklist, we’ll miss that look. So when you get to a convenient place, if you can go to LEFT and have us take a look at it, we’d appreciate it.”
“Gordy, apparently you… Okay. Stand by… I called it (LEFT) out, [earlier, but] I didn’t give it (the connection) to you. Stand by one…” Cernan had missed connecting his sensors to his Biobelt. “Okay. Now it’s yours.”
[Use of the expression “it’s yours” related to anything we did that gave access to spacecraft systems or data that Mission Control could not access without some action by the crew. In a way, crews used the expression to remind everyone, including themselves, that it was a “manned spacecraft”, requiring human input to fully operate. On the other hand, without Mission Control’s analyses of telemetry, analyses we could not do onboard, accomplishing the mission objectives would have been impossible. For example, we had no way to know that we had three pounds of excess water over predicted usage and that a PLSS cooling water recharge might have been incomplete.]
“That [biomed telemetry] looks good, Geno. You can press on with the suiting operation, there.”
“Call me the little old fender maker,” Cernan said.
“How’s your taping coming, Gene? Need some help?”
“Yeah,” Cernan replied. He was using the top of the Ascent Engine cover as a work surface as it was the only flat surface available. “Hold these two maps together while I will tape them. …Okay, now let me work that tape down on the maps as hard as I can. John says that will prevent bubbling …Now, two more maps…good…work the tape down hard, again. …Now, hold the two sections together. …Tape is good. …That should do it.’
“Don’t forget to tape the edges on the other side and to put the X on,” I reminded him.
“Oh, yeah. …Good old duct tape! …That should do it. Now, if you will roll this new fender up, let me hold it with a tape tab long enough that I can get a hold of it out there. …Not bad.”
“I’ll put it in the ETB, if you can get the two clamps off the AOT and open them up, full.”
“Okay. …Here are the clamps for the ETB,” offered Cernan, after some struggle to dismantle the lights from the clamps. His hands had not recovered from being abraded, yesterday.
“We are ready to become lunar auto mechanics, I guess. …I am going to start suiting up, if you think we are ready.”
“Go for it.”
“S-Band Voice going to Voice,” I informed Fullerton as I went back to the Checklist.
“Roger… Jack, Houston. With respect to the PLSS water fill, last thing we heard you say was ‘doing step 7’. We just want to verify that you did go ahead and do step 8, which is connect the waste management system to the PLSS Aux vent for 10 seconds. Over.
“Yes, that was all done, Gordy. We just got sidetracked [working on the new fender], and I didn’t call you.
“Okay. Thank you.
EVA-2 Suiting Up and Opening the Front Door
“Okay, suit up time,” I announced to our little world in the Challenger. “AUDIO circuit breaker going open and I am going off LM communications. …I have my EVA-2 Cuff Checklist over here in the Storage Compartment and that goes on my left suit arm before I do anything else. …My Snoopy Cap and gloves are on the Comm Panel over here. …Neck ring cover is off and stowed. …So, now the Checklist says I need a Drink Bag and a Food Stick from the BRA. …Thanks. …Drink Bag and Food Stick are installed. …If you will hold the left side of the zipper, I will see if I still fit in this thing (suit).” Getting into the suit with a little lunar gravity was much easier that suiting up in zero g.
“Okay, Jack. Lift your legs up towards me, and I will take the Jett Bag off them. Where do I put the Jett Bag?”
“Let’s see. …It goes in your Stowage Compartment. …You want to read the Checklist from here on to be sure I don’t miss something?”
“Okay. LCG Plug goes in the Purse.”
“Connect the UCTA.”
I took the condom off the hand controller and attached the stretched end to me and the unstretched end to the UCTA and said,
“Done. …Boy, I would hate to not have that right.”
Without the cooling provided by the LGC, extended work on the lunar surface would have been impossible.
“You want me to get your zippers?”
“Sure. …Make sure they are locked.”
“Zipped and Locked. …Now don your Snoopy Cap and connect to the suit. …Give me your Electrical Connector Cap, and I will put it in the Purse.”
“Here you go. What’s next?”
“On your ECS panel; SUIT ISOLATION – ACTIVATION OVERRIDE.”
“Now, connect LM O2 Red to Blue and Blue to Red.” This will provide temporary air-cooling before attaching the PLSS hoses and activating PLSS oxygen flow.
“That is probably easier for you to do,” I suggested.
“Okay…and LM H2O…and Comm…are connected, too. …Next, SUIT ISOLATION goes to SUIT FLOW.” This required me to turn toward the back of the cabin and face the ECS panel.
“SUIT GAS DIVERTER – PULL to EGRESS.”
“CABIN GAS RETURN – EGRESS.”
“AUDIO CB – CLOSE.”
“Okay, Gordo. Jack’s coming up [on comm.], and I’m going off the air.”
“Okay, Gordy. LMP is suited, and… Stand by. 24128 – PRD is 24128. …Hello, Houston. Did you copy the LMP?”
“Roger. Copy. 24128. …How come you guys are not on ‘Flight Director’ like I am?” Parker joked. He had transmitted on the wrong communications loop in the MOCR.
“And, Bob, 17040 is Commander [PRD].”
“Say that again, please, Geno.”
“The last two digits are 40.”
“Thank you. Thank you.” Once in a while, even a simple relay of some numbers can get confused during space communications.
Cernan then repeated the steps for suiting up, as I read them from the Checklist. We had lost more time because of the new fender construction and the PLSS cooling water recharge. Now we were about an hour and twenty minutes behind the planned timeline.
“Bob, how do you read the Biomed on the LMP?”
“Stand by, Jack. …It looks beautiful, Jack. I think that means ‘loud and clear’,” Parker joked, equating telemetry of heart rate and respiration to voice. And, Challenger, have you changed your ECS LiOH can?”
“Bob, we did not. I guess we missed that in the checklist,” I replied.
“That’s sort of towards the end of [page] 3-9…”
“Bob, I guess we’re not quite there yet [with Suiting up the CDR].” Once in a while, the MOCR and Parker would miss where we had said we were in the Checklist.
“Okay. Copy that.”
“Okay, I’ll get your zippers… and, if you can get your LM hoses, Red to Blue and Blue to Red, I’ll change the LiOH canister.” Changing the LiOH CO2 scrubber entailed opening the canister cover on the ECS panel, removing the used one, stowing it in the jettison bag, inserting the new canister, and making sure the cover locked shut.
“Okay, Bob. The canister’s changed.”
“Roger. We saw that [on telemetry]. Thank you.”
“Okay. Copy that.”
“Bob, how do you read me?” Cernan asked after connecting to LM communications.
“Loud and clear, Geno.”
“Battery management’s going [ahead],” I reported, as I once again prepared to go through those steps in the Checklist.
“[ED Bats] 37.2; both batteries.”
“Okay, Jack. Just like always.”
“PCM is HIGH [bit rate]. You ready for the batteries?”
“Stand by [on the batteries]. We’re still trying to acquire the HIGH bit rate…”
“And, Geno, we have good [bio] data from you on the Surgeon [Console]. And we have HIGH bit rate.”
“Well, that’s good to hear. I got good data up here,” Cernan said, meaning his heart rate and respiration seemed fine to him.
“Yeah, we’re GO to do the battery management now, Jack. We’ve got the HIGH bit rate.
“Roger.” I began to run through an abbreviated sequence of switch positions on panel 14 to my right so that the LM Controllers and I could make sure that three of our Descent Batteries, designated as 3, 4 and LUNAR, were performing as expected. A full check of all batteries had been performed prior to our rest period after EVA-1. With the ED battery voltages already checked and reported, I went to BAT 4 on the POWER/TEMP MONITOR switch, turned BAT 4 to ON and checked that the Talkback was gray, indicating the battery was on line. After putting the POWER/TEMP MONITOR switch to BAT 3, put the LUNAR battery CDR bus switch to OFF/RESET and saw the expected barberpole on the Talkback. Then, I turned on BAT 3 and saw that its Talkback was gray. Using the POWER/TEMP switch, I checked that the volts on the CDR, LMP and AC electrical buses, reading off the gauge in the upper left of panel 14, were about 30 as expected. While I went through this full sequence, Thorson at the LM CONTROL Console in the MOCR watched the more precise telemetry readouts on the batteries and the buses.
“And a thought for the day,” Parker said. “We’re not sure that there is going to be any need for the scissors outside today. And if you guys wanted to keep from picking them up off the ground and worrying about them, you might just leave them inside if you haven’t packed them already.”
“I think we should take them with us,” I told Cernan, “you never know what might come up with the fender fix and the SEP cover.”
“I agree.” I was surprised at Mission Control’s recommendation not to have one of our contingency tools available on the Rover, particularly in light of the repair that we would need to undertake on the fender.
“Bob, you never know!” Cernan exclaimed. ‘We’re going to take them out with us. So just make a note that we bring them back in, would you?”
“Okay. I’ll make a little note again.”
“Battery’s [management] complete,” I reported, “and [I’m waiting for] your cue on [switching to] the Low Bit Rate.”
“You can go LOW bit rate again. And it (the battery management) looked good to us, too.”
Now that we were back in the suits again, we shifted over to the EVA Prep and Post Cue Card and repeated the preparations we had gone through prior to EVA-1. Part of this process put us back on voice activated comm. (VOX). Checklist discipline and check and double check were the key to not making a mistake that might cost you your life or, at very least, force an early termination of the EVA.
When we took our last big drink of Challenger’s water before locking our helmets in place, the following exchange occurred:
“Let’s get another zap of (drinking) water here,” suggested Cernan… “If I have any more water I’ll float out there.”
“Good Navy man,” I said with a laugh.
“Be a good place to fill with water, you’d make a nice rec[reation] site out of this valley. You could put some cabins up on the side of the massifs. Nice flat bottom, no trees.
“No snags,” I added, always the true fisherman.
“The fishing ought to be pretty good if you stocked it.”
“Have a Bear Island and a Family Island,” I commented, referring to Bear and Family Mountains that would project out of our fanciful lake.
With a laugh, Cernan continued, “We’re going to [have to] fill up the other end though, so it (the water) doesn’t drain out.”
“Looks funny like that.”
[As I put on my EVA gloves for the second time, I realized, to my great relief that my forearm fatigue had disappeared, entirely. This surprised me as I had expected some residual soreness as one would experience with similar fatigue on Earth. Opening and closing the fingers in a pressurized glove resembled squeezing a tennis or handball repetitively. In a relatively short time, your forearm muscles get tired and, as you have to continue using your hands, they begin to ache. This forces you to slow down all hand activity to a level you can continue to tolerate and still get jobs done. After my sleep, however, the tiredness and ache had gone away, and there was no soreness. I started over as fresh as the day before. I would guess that this rapid recovery takes place because, in the lunar one-sixth gravity, the cardiovascular circulation is much more efficient in removing metabolic toxins, such as lactic acid, from the muscles. Muscle fiber never gets damaged or semi-permanently inflamed. The fatigue and ache would return during the upcoming EVA; however, it helped to know that it would go away with rest and was not compounded, day after day. Astronauts assembling the Space Station found that specialized physical training largely could eliminate this fatigue problem. Even though I worked out every day during training, I wish we had been smart enough to ask for advice from professional physical trainers.]
We missed a Checklist callout for Cernan to turn on his PLSS fan after putting on his helmet. This prompted Parker to say, “Geno, we don’t see your [PLSS] fan on. If you’ve got your helmet on, you ought to have your fan on.”
“Thank you, Bob. Good call.” Eventually, Cernan would have realized oxygen was not circulating, but it still was helpful to have this noticed by the MOCR.
“The royal MOCR ‘we’,” I interjected, to bring attention to the ultimate authority of the Flight Director, Gerry Griffin in this case, in calling the shots during a mission. He had been alerted by John Covington on the EVA Console about this missed item and immediately told Parker to alert us.
Finally, after about 50 minutes of PLSS donning and systems and pressure checks, detailed in Chapter 9, we were ready to head outside.
“Okay, and we’d like your GO, Robert,” requested Cernan.
“You’re GO for Depress,” Parker responded after Griffin had polled the active systems and EVA-related consoles in the MOCR and receive a shouted “GO Flight!” from each.
“Okay. Jack, [on panel] 16, CABIN REPRESS [circuit breaker], – OPEN; and [then] CABIN REPRESS VALVE – CLOSED.” This begins the process of bringing the cabin pressure down to 3.5 psi, but also tests the suits’ response to this change. By these actions, I prevented any automatic attempt to repressurize the cabin when the dump valve on the hatch is opened.
“Okay, CABIN REPRESS. Circuit breaker first, right?” I asked, just to be sure.
“Circuit breaker first. ‘CABIN REPRESS – OPEN’,” repeated Cernan
“Let me turn around here. …Okay, it’s OPEN.”
“And ‘REPRESS VALVE – CLOSED.’ “
“It’s going CLOSED,” I said, now facing the ECS panel behind my LMP position.
“And then stay over there as far as you can, ‘cause I got to get the overhead dump valve [to depress].
“Okay, I’m over as far as I can get. I can turn around [and face forward] and give you more room.”
“Yeah, turn around, and you’ll have to look at the Cabin [pressure gauge],” Cernan reminded me.
“Watch yourself there,” I warned as he hit Panel 11 with his RCU.
“You went awful weak all of a sudden,” Cernan reported “Are you…”
“Hello. How do you read?”
“Very weak. Give me a call again.”
“Very weak?” I asked.
“Okay. My volume [control on the RCU] got…”
“You…hit your volume [control],” I told him.
“[It’s] Okay, now.”
“Let me get over here…”
“Wait a minute,” Cernan said.
“Is that enough?”
“No, your arm’s in the way. …Okay. I can get at it now,” Cernan reported as I moved my arm toward the ceiling.”
“You want to go to… Let me get that [Checklist],” I said. “ ‘OPEN, then AUTO at 3.5.’ Okay, go ahead,” I continued as I could now see the cabin pressure gauge.
“Okay. [Pressure is] coming down. I can see it (the valve) open.”
“There it is. That’s 5 [psi]…4 and a half…4…Stand by. MARK it [3.5 psi].”
“Okay, it’s (the valve) AUTO,” Cernan reported.
“Okay, [cabin pressure is] about 3.4. And, I…[am] looking at a watch. …And my cuff gauge went up to 5.0. Good. …Suit circuit’s at 4.6. That’s okay. And I’m (suit pressure) decaying. Are you decaying?”
“I’m decaying.” This decay in pressure was the result of our breathing down the oxygen in the suit and having the exhaled CO2 removed by the LiOH canister in the PLSS. The PLSS oxygen pressure regulator would take over when the suit pressure reached 3.7 psi, but the fact that suit pressure was decaying verified that the regulator was preventing O2 flow into the suit.
“We can start our watch,” I said as this action was the cue for the start of EVA-2.
“My watch is started. At 5:30, more or less.” This time is Central Standard Time in the afternoon of Tuesday, 11 December 1972.
“At 5:30,” repeated Cernan, “yes, sir. …Press on [with the Checklist].”
“Okay. ‘OVERHEAD [or] FORWARD DUMP VALVE – OPEN.’ “
“Okay, baby!” Cernan said with a grunt, as he worked to open the dump valve in the forward hatch. “It’s open all the way.”
“Okay, and pressure’s coming down,” I observed.
“Okay. I believe it,” he replied as our suit pressure rose in response.
Now looking at the Cuff Checklist, I said, “We get a tone and an H2O flag,” because the cooling system was still off. Hearing a pop, I suggested, “You just popped your [suit] Relief [valve], I think.”
“Yeah, I’m at my relief pressure now…” The increasing differential between Cernan’s suit pressure and the lowering Cabin pressure has caused his Relief Valve to open. “What’s Cabin [pressure] now?” he asked.
“Cabin is 1.2 [psi). …[Now at] one…”
“Well, let’s see if I can partially get this Forward Hatch open.”
“It’s (the Cabin) point seven [psi], still.”
“Point five… Point three. You got it [open] at what…about point two yesterday?”
“Why don’t you move over as far to the right as you can, …so I can bend down.”
“Well, I think that’s as good as I can do,” I said still trying to push back into the right side panels.
“Okay. That’s good. I can reach it. …No, [can’t open it]… Too much pressure on it yet.”
“About point three [psi]. …Okay. There’s my H2O flag,” I reported. The PLSS warnings at this stage provided alerts that pressure is low enough for the cooling sublimator to work, but I had not turned on any flow as yet, and that the warning system functioned as expected.
“Well, in that case, let me see if I can’t get this [open]. …Oh, man!”
“Get it opened?”
“It’s unlocked, isn’t it?” I asked just to double check.
“Yeah, I unlocked it earlier.”
“[Cabin Pressure is] still point two…
“Yeah, it’s unlocked,” verified Cernan. “…Here it comes.”
“There goes all the junk out there again,” I observed. “Guess that’s ice. …Probably cleaned some of the dust out, I hope.” I did not see any dust leave the cabin; however, by this time, most of the dust had settled below the perforated floorboard and probably could not enter the air stream. The ice came from the freezing of moisture remaining in the cabin air.
“Yeah, there goes a lot of junk. Sure wish it would clean the dust out. But it isn’t. It’s cleaning everything else out.”
“Okay, Geno. We turn our PLSS [sublimator] water ON.”
“If we can get to it. …[That] feels like a water valve,” I said as I reached to the right forward corner of my PLSS.
“Okay. Mine’s on,” Cernan reported.
“LMP’s water’s on. …Okay. …Okay? …Open [the Hatch].”
“My water flag is clear!” he exclaimed.
“That just means you’ve got feedwater pressure.”
“Okay,” Cernan began, as he looked at his EVA-2 Cuff Checklist, “ ‘Open hatch. Rest until cooling sufficient; verify PGA 3.7 – 4.6.’ Now mine’s coming through 4.8; let me stand there a second. ‘CWEA status, PREAMPS and ECS.’ “
“Rog.” These were the two caution lights that should have been on.
“[Is the] Water Sep Component Light on?” Cernan asked, as he could not see it from where he was standing.
“Rog. …I mean ‘affirm’. Get my terminology straight here.” The term “Roger” should be used for “understood” and not “yes.”
“Okay, Jack. I’m going to start doing about a 90 [degree turn] here.” Cernan is going to turn to face aft so that he can exit the hatch on his belly.
“Okay. Let me… I need to turn around [and face toward you] as soon as you do [turn] so I can help you get under that [DISKEY]. …That’s better.”
“Okay; it knocked it off. Okay. I’m out of the way now, if you can move your left leg. …Okay. I got an O2 Flag. And it’s cleared. The [suit] pressure is 4.6. …Okay, Houston. If you’re happy, CDR is going to get out.”
“Roger. We’re happy, Geno,” Parker replied.
“Okay, I’m going to get back out of your way. …Okay. Hatch is full open. …And you’re still…you’re scraping your [PLSS]…just a little bit. Just get your buttons down there. That’s good. Okay. Oh, hey, remind me to fix your…”
“PLSS straps,” finished Cernan
“…your donning straps.”
Okay. …That is ice [blowing out], by the way, Jack, …Oh, man! I tell you, [this is tough] with a stiff suit. …I’m still at 4.5 (psi). …But, I am out here on the porch.”
“Oh, man. Okay, I’m out here.”
“I’ve ‘assisted’ you,” I said, looking at the unnecessary instruction the “Assist CDR” on my Cuff Checklist page. “Here comes the jett bag whenever you’re ready.” I moved to the left side of the cabin and swung the hatch full open into my LMP space.
“Well, let me get… Okay. I’m all set. Man, I wish this suit would come down to 3.8.”
“Here it (the jettison bag) comes.”
“Okay, any time. Give it (the bag) a[nother] swat. …There you go.”
“Oh, the beauty of [one-sixth g],” I exclaimed as I gave the jett bag a slight kick. Cernan then dropped the jett bag to the surface, later to be kicked under the Challenger.
“Okay; let me look at something here,” chuckled Cernan as he found another Support Crew insert in his Checklist.
“I was just turning my checklist pages,” as he worked to open the dump valve in the forward hatch.
“Oh. Here you go,” I said, pushing the ETB out the hatch.
“I need… What you got next – ETB?”
“Can you reach it?” I asked.
“Yeah. …[Have to] get it hooked up here [on the LEC lanyard].”
“Okay. ‘Turn the tape recorder OFF’,” I read to myself. “Tape recorder’s OFF.”
“Big hook [on the lanyard]. That’s a legacy of Gemini Nine,” Cernan reminisced about lessons learned from the EVA on his 1966 Gemini 9 flight as he lowered the ETB on the LEC.”
[Cernan’s Gemini 9 EVA and two subsequent Gemini EVAs did not go well with fatigue and inefficiency. The experiences led to much more rigorous training and planning than Cernan had undertaken. Aldrin’s very successful EVA on Gemini 12, the last of the Gemini Project, included extensive underwater work in the Water Emersion Facility, addition of exterior hand holds and foot restraints, and more planned rest periods. The Gemini EVA experiences, good and bad, provided a legacy for all future EVAs.]”
“ ‘MAX’ [sensitivity on the comm circuit]… ‘EVA decals’ [for circuit breaker positions],” I continued.
“ETB is hanging. …[Is] that all I need?
“I think so. You hit your comm [wheel] again,” I said, noting a change in audio quality.
“No, I didn’t; I’m okay.”
“What happened to the static? Did we lose Houston? …Hello, Houston…”
“We read you loud and clear,” Parker interjected.
“Oh, you must have switched to [another ground station]. …Oh, I don’t know.”
“Okay. I’m going down the ladder,” reported Cernan.
“All of a sudden, all the noise is gone,” I said, “…that’s very good.”
“ ‘Godspeed the crew of Apollo 17,’ ” Cernan pretended to read. “I think I’ll read that every time I come down the ladder.”
“Okay. All the circuit breakers are verified,” I said. “[Audio] noise is back.”
“Okay. My visor’s coming down,” Cernan reported, as he moved out into the sunshine.
“Utility lights are off,” I continued through the final pre-egress checks. “We’re not going to use the [Sequence] Camera. …Okay, I get to get out!”
“Okay, Houston. On this fine Tuesday evening, as I step out on the plains of Taurus-Littrow, Apollo 17 is ready to go to work,” proclaimed Cernan with his usual dose of pomposity.
“Roger, Geno. Good deal,” acknowledged Parker.
“And the first thing I’ll do is give you a TGE [reading]. …Let me turn it on. And you want a reading. Okay. It’s on. Bob, and the reading is 222, 262, 207; that’s 222, 262, 207.” This reading is a check on any drift in the TGE, as it had been sitting in the shade of the Challenger since EVA-1 ended.
“Roger. We copy that, Gene.”
Watching my movement out of the hatch, Cernan observed, “Looks good from here, Jack. Keep coming.”
“Come on, hatch!” I exclaimed as I reached in to pull the hatch partially closed.”
“Oh, what a nice day.
“Funny,” I noted, “there’s not a cloud in the sky. Except in the Earth.”
“Take it nice and easy today,” said Cernan to himself, “and get accustomed [to moving in one-sixth gravity]. Whee! …I’ll be right there, Jack, to get the [PLSS] antenna— as soon as I turn the [Rover] LCRU on.”
“Okay. I’m on the ladder,” I declared. “Door is closed.” Without further comment, I grabbed both rails of the ladder and slid quickly down to the landing pad and on to the lunar surface for the second time. My attention, however, continued to be focused on getting all our “housekeeping” done so that we could start to explore again. I first joined Cernan at the Rover so we could deploy each other’s PLSS antennas.
“Okay, [TV] Power switch is INTERNAL,” said Cernan as he went through his Checklist items for the LCRU (Lunar Communitions Relay Unit). “I’m in MODE 3 (remote operation). LCRU blankets are OPEN 100 percent. [S-Band] AGC (Automatic Gain Control) is 4.0 plus, and power is about 1.8 (27.8 v). Temps are about 1.6 or 1.4 (48.2 F).” Self-radiation, even without mirrors, had cooled the LCRU about 13 degrees since activation at the start of EVA-1. This was a very good sign that we would not have thermal problems with the LCRU.
“…And we have a good picture there, Geno,” Parker commented almost immediately. “Thank you.”
“Already, huh?” Cernan had aligned the large S-Band at the end of EVA-1 and, for some reason, sounded surprised that it had remained so, possibly forgetting that the Earth would not have changed its relative position to Taurus-Littrow as the Moon’s near side always faces the Earth.
“Well, let me just tweak you up a little bit,” continued Cernan. “Okay, I’ve got you (the Earth) tweaked, right in the middle [of the antenna bore sight].”
“Thank you. And, Gene, after you finish closing up both those battery covers up front there, why don’t you go back and give us that [Rover battery] temperature reading and then put the [battery bus] breakers in and then give us another temperature reading on the batteries.”
“Yes, sir; I’ll do that. Jack, here, let’s get (deploy) the [PLSS] antennas…”
“You want to get [bend lower]?” I asked. …“You want to hang on the Rover?” I needed to be able to reach the top of the OPS that attached to the top of the PLSS.
“I guess… Well, okay.”
“I think it’s easier,” I reminded him.
“Now, I’m low, so get mine, now. I’m [standing] in a hole.” Cernan has about three inches more height than I, making a big difference in seeing the top of the OPS where the antenna is fastened down.
“Okay; you’re [antenna is] up. …Standby. …Get down there yet [again]. Got to secure the [OPS thermal] flaps. Okay, you’re all right,” I said, as I bent my knees as much as possible so he could do the same for me.
“Okay, your [antenna is] up…”
“Okay.” I then went to the left rear of the Rover to start the activation of the SEP. “Power switch is going to STANDBY. And the temperature is 80 [degrees F]. (The SEP receiver has a temperature sensor that will shut the instrument off if it gets warmer than 108ºF.) And I’ll close the blankets… You know what [has] happened? The Velcro came unbonded. That’s why those [SEP dust covers] don’t hold down. We probably ought to get a piece of tape on those. Because they’ve got a set [of radiators] and it’s going to get dusty. The blankets [are loose]… There’s no Velcro left to hold the SEP blankets down, Bob.” I left it to the Science Support Room to worry about this new problem while I continued down the Checklist and went back to the ladder to get the ETB.
“Okay, I copy that, Jack,” acknowledged Parker.
“Do you have a reading on the gravimeter?” I asked Parker as I approached the Challenger.
“Yeah, I took a [calibration] reading, Jack,” Cernan replied, thinking I was talking to him.
“It’s measuring right now, Jack,” Parker answered, “we’ll get it (the new reading) later.”
“All right,” Cernan said.
“Okay. I hope I didn’t hit it with some dust,” I reported, coming to a quick stop at the ladder near the TGE.
“Hey, it is not measuring, Bob.” Cernan reminded him.
“Oh, that’s right. Sorry about that,” apologized Parker.
“…All I did was take a reading. I turned it on and took a reading,” continued Cernan.
“You’re right, you’re right, and I’m wrong.”
“…The [unpowered Rover] battery temperatures are 0 and 0,” Cernan noted, showing that no bias existed in the gauge with power off.
“Bob, there’s your pendulum,” I told Parker in response to his pre-mission request that I push the LEC a little to demonstrate pendulum motion in one-sixth gravity. Actually, my push excited several oscillation modes in addition to a pendulum motion. “It’s not a very good one (demonstration). I’ll work on that. …Are you going to be there for a minute, Gene?”
“Just putting these batteries [breakers] in,” Cernan replied. “I’m done on this,” Then to Parker, he said, “Oh, you’ll be glad to hear this. We got 70 [degrees] on Battery 1 and about 92 on Battery 2.”
“Beautiful! Beautiful — 70 and 92. I copy.” Parker’s excitement came from the indication that the radiative cooling of the Rover’s wax thermal sink since the end of EVA-1 worked as designed by radiating heat to deep space. The respective temperatures at the end of EVA-1 had been 108 and 123 degrees.
“Yes, sir!” exclaimed Cernan, happy to have one less thing to worry about. “Let me just verify this (navigation circuit breaker) is in, Jack, and I’ll be all done. …Okay. You’ve got it. I’m all done.”
“Okay, here’s your ‘old’ fender,” I said as I brought the ETB to the Rover and began to distribute its contents as required for the upcoming traverse. I had not noticed that Cernan had gone to the MESA to open a new Sample Return Container (SRC-2).
“Yeah, I’ll work on that…shortly. …Well, I think I’m going to INTERMEDIATE cooling to start with here.
“Okay. I think I will, too. That’s a good idea.”
“One zap of cold (MAX cooling) to see if it’s working. …It’s working,” observed Cernan as a pulse of cold water coursed through his long underwear (LGC). “And back to INTERMEDIATE…”
Meanwhile, I took film magazines out of the ETB and put most of them under Cernan’s rover seat. Looking at my Cuff Checklist, I said, “Okay. [There are] lots of mags. …Okay, Mag Romeo is going to go on the old 500 [mm camera] in a minute. Mag India is in there. Mag Kilo…Mag Juliet…Mag Bravo, Mag Delta.” I suspect that I was all business in using normal piloting names for the magazines, rather than using women’s names as I had on EVA-1, because of a focus on getting to the traverse to Station 2 and the South Massif as quickly as possible.
Over at the MESA with SRC-2, Cernan anticipates not being able to keep the lid closed after sealing the interior roll of ultra clean aluminum in a sample bag, “I have the same problem with this SRC [as with the last one], I’ll bet. …Okay, Bob, the SRC organic sample has been sealed. And the SRC lid is staying almost closed, about 2 or 3 inches open; if that’s fine, I’d like to leave that.
“Go ahead and leave it, Gene,” Parker replied, quickly. “If it’s not [okay], we’ll get back with you on it.”
“Okay. I’m going to hit your gravimeter here,” continued Cernan as he punched the GRAV button to get a new reading started. “MARK it, …and the light is flashing.”
“Polarizing filter…utility light clamps…scissors,” I noted as I finished emptying the ETB at the Rover.
“And, Jack,” Parker said, “[if] you’re getting ready to take care of the charge, remember EP-4 (1/8 pound) goes between the Rover seats, and EP-5 (3 pound) we’re going to put on one of the footpads in the Sun. Probably either the minus Z (east) or the minus Y (south) footpad, whichever is more convenient. Probably the minus Z is. Just as long as it is sitting in the Sun is the important thing on the (choice of) footpad.”
“Okay…” Taking these two seismic charges off the back of the Rover allowed me to discard the first charge transporter under the Challenger, freeing up its mounting spot for the second transporter holding charges 1, 2, 3 and 8.
“Boy, oh boy!” exclaims Cernan as he tries to remove a new LCRU battery from the MESA. “Going to be a… Why won’t that come out? …Well, Bob, I’m having a little trouble getting the LCRU battery out. I’ll have to go back and use two hands.” He tried to remove the battery with a new Sample Containment Bag in his other hand.
“Okay. That sounds like a familiar problem,” Parker said.
“Well, you got any ‘familiar’ answers?” Cernan said, a little irritated at Parker’s flippant comment.
“Someone who’s been there before,” Parker, with John Young sitting beside him in the MOCR, “says you just got to work it back and forth until it comes loose.
“Okay. …I can get that, Jack,” Cernan said to me as I brought the ETB back to hang on its lanyard at the ladder. “I’ve got to…work here anyway.”
“Want to hang it (the ETB) up?”
I then took EP-5 to the sunny -Z footpad. “Okay, Bob, it’s on the minus Z [pad] and…one corner is facing directly into the Sun. …That’s EP-5.” Facing a corner into the sun would warm two of the four sides of the charge.
“Roger that. And I copy [charge] number 4 was put between the seat.”
“Yeah, it’s between the seat, or will be very soon.”
“Boy, this is ridiculous. Ridiculous,” complained Cernan as he continued to try to get a good grip on the LCRU battery in the back of the MESA.
“Whoops,” I said as I headed to the Rover but then turned around, reminding myself, “I need that other [EP] transporter.” This meant going to the Challenger’s Quad II equipment bay where the transporter was stowed.
“Well,” Cernan said, still struggling at the MESA, “it’s nothing worth getting upset about it, but it sure makes you start out [behind]…when you shouldn’t have to [delay] this way.”
“Come on,” I reminded him, “just don’t wear your hands out now.”
“Need a little help?” I asked.
“No, I think I can do it, just got to wiggle…”
“…Jiggle it gently and sort of let it come free there,” Parker broke in, passing on advice from Young. “It’s a matter of it wedging itself in, of course, on the parallel rails.”
“Yeah. I…I see what’s happening, Bob. …It’s still ridiculous.” Cernan was still irritated at Parker’s unnecessary analysis.
Moving on with my tasks, I asked, “Bob, did you hear my comment about the…about the SEP receiver?”
“Roger. That the [thermal] blankets won’t stay closed. We’re talking about that down here.”
“Boy, a bag of [packing] peanuts!” Cernan exclaimed, as he finally worked the battery out of the MESA. “Whew!! Man in space. Without them we’d be lost.”
“Without them we wouldn’t have the LCRU and the MESA probably,” I added with a chuckle.
“Manischewitz. Okay. Let me see what I can do for you while I’m here. Okay. …‘LCRU battery under seat [and] Dust Brush to LCRU.’ Okay. I’ll go get that; then I’ll get to work,” Cernan said as he went over to the ladder hook for the brush.
“Hey, Bob, what’s my shadow length right now?” Again, I wanted to calibrate my EVA-2 shadow “ruler” to help me estimate near-field sizes and distances.
“Stand by. I’ll ask. …We’ll get it for you momentarily. …Okay, Jack. We’ve got four-point-five meters or one-five feet.”
“4.5 meters, huh? Hmmm,” I mused as I pondered how long my shadow looked. My estimate was about 3 meters. From then on, I added a factor of 50% to my estimates of distances and crater diameters.
“15 feet!?” said a surprised Cernan. “Is that how long I am on the ground? No wonder I’ve misjudged distance! Zap! …Hello there, Houston,” he continued, waving at the TV.
“Hello there,” Parker replied. …Okay, Jack. And do we have the new charge transporter on the pallet?”
“I’ll say yes, but you could have looked for yourself [with the TV].” I was beginning to resent responding to every little question, but, in fairness, Ed Fendell followed his own whims on where to point the TV in spite of the fact that the Checklist roughly choreographed our activities.
“Well, we just looked away.” The Flight Director should have insisted that the TV follow the action as closely as possible. Cameras that automatically track individual crew may aid future interactions during lunar and Martian operations.
“Yeah, it’s here,” Cernan answered. “It’s here, Bob.
“Copy that. I won’t ask if we got the L-C-R-U battery. That one, I did see.”
“Yeah, we got it. You don’t think I’d leave it here.” The LCRU battery would be carried under his Rover seat as backup.
“Okay. …[SCB] 7 [goes to the gate]. …Boy, this gate’s working like a charm. ‘Transfer from [SCB-] 5 to 7’.” While I went to the Challenger’s 8:00 o’clock position (southeast) to take another color photographic panorama, Cernan moved three core tubes, a core tube cap dispenser, and two extra packs of sample bags from EVA-1’s SCB 5 to SCB-7, and then he put SCB-7 under my seat. The empty SCB-5 is supposed to go on his PLSS, SCB-4 on mine, and SCB-6 on the gate.
“The (photographic) pan’s complete (AS17 137 20867-93). …And, Bob, those pans around here have more pictures (than normal 12-photo pans) because I’m having…to be sure I get the massifs; I’m having to take extra pictures.” This panorama site was opposite the Challenger’s 8:00 o’clock position, opposite the now re-covered QUAD III where the ALSEP had been stowed.
Fig. 11.2. Part of my 8:00 o’clock pan showing the LM, the North Massif, and albedo contrasts caused by foot and LRV tracks. The vertical arrow on the North Massif at right marks the location of the boulder at Station 6 we will sample on EVA-3. (Composite of NASA photos AS17-137-20872–20875).
[The first frames of the panorama provide excellent views of the South Massif, Family Mountain, and the North Massif. They also show a strong albedo contrast between the regolith surface and the underlying dark regolith exposed by our foot and rover traffic. This contrast results from the Descent Engine exhaust gases winnowing of dark fine particles away from higher albedo coarse particles. Frame 20875 includes the boulders we planned to visit at Station 6 on EVA-3. The crossing trough lineations on the Sculptured Hills noted on the photographs taken at Station 1 remain visible at this ~12 degree higher sun position. The similarity in the physiographic appearances of the East Massif, Bear Mountain and Sculptured Hills shows well in frame 20882.]
“Okay. …And I guess we’d suggest that, if you haven’t talked about it already, that you work on the fender before you do the Geo Prep (geology traverse preparation). You don’t have your cameras and bags to worry about at that point.”
“Would that be a good time for Jack to go to the ALSEP, do you think? Or do you think we both have to do this fender?”
Fig. 11.3. Another part of the 8:00 o’clock pan showing a portion of the Sculptured Hills at far left, the East Massif in the middle, and Bear Mountain at right. The foot traffic is leading towards Poppie Crater. (Composite of NASA photos A17-137-20881–20883).
“No. The ALSEP work we’re not going to do until the end of the EVA. …And, Jack, if Cernan’s working there on unstowing SCB whatever-it-is— 5, yeah, 5— maybe when you put the camera down, you might want to shoot off a few 500-millimeter frames of the North and South Massifs, if they look interesting. I can’t tell from the TV. That might be an opportune time to grab a couple.”
“If they look interesting!?” I said, not believing Parker could say such a thing. “If they look interesting!? Now what kind of thing is that to say?”
Ignoring my sarcasm, Parker, continued, “Then, when Gene gets done configuring that SCB-5, we’d like to get on with the fender fix. Then, we’ll do the Geo Prep after that.”
“We’ll get on with it, Bob,” Cernan acknowledged.
“My God, we got a lot of loose stuff in SCB-7,” I commented. “Okay, Bob. I got three core tubes. …Well, wait a minute. …Only got one core cap dispenser. Let me get the other one. …Well, that’s (one) all I wanted. Okay: ‘three core tubes, two 20-bag dispensers, one core cap dispenser, and the short can.’ ”
“Jack…” Cernan called.
“Yeah. Are you ready to work [on the fender]?” I replied, wrongly anticipating his question.
“…see this [piece of glass] right here?”
“I’m going to put that right there [for later].”
“Okay, …Are you ready to work?” I asked, while preparing to take a series of 500 mm photographs of the slopes of the Massifs.
“Just let me turn my [Checklist] page here. …Almost [ready]; stand by. …Okay. I already got one [SCB] on the gate… That didn’t count. …Okay. …[Jack, do you] want a couple of 20-bag dispensers [to hang on the cameras]?”
“Well, I’m waiting for you to…”
“Well, let’s get this done.”
“You want to…”
“Here,” Cernan said as he handed me the 20-bag dispensers.
“Well, what are you doing now?” I asked, wondering when we were going to work on the fender.
“I was just getting this gear out now to work on the fender.
“Okay,” I said, putting the 500 mm camera on Cernan’s Rover seat.”
“I’m not to Geo Prep yet,” he said as he finished shuffling SCBs around.
“Here you are,” Cernan said as he held out the dispensers.
“Wait a minute.”
“We’ll just set these [dispensers] here [on your seat]. …And there’s another one. Okay; SCB-7 goes under your seat.”
“Okay. I’ll get that. …Your camera has the (sample) bags on it,” I informed him.
“You might just put it (the camera) there, and I’ll come over and get those [fender] maps and everything…” Strangely, almost as if he was avoiding working on the fender he broke, Cernan was jumping back and forth, apparently thinking about the fender but still trying to stick with items called out in the Cuff Checklist. He finally settled on finishing his Checklist items. “That (SCB-7) goes under your seat. Let me get [SCB] 4. Okay, we got [SCBs] 4 and 6. I’m going to start on the [fender]. …We got SCB-4. …[It] goes to you, and SCB-6 goes on the gate, yet, Jack, but let’s pick that up with Geo Prep, and let me get that fender gear. Where’s the (new fender)?”
“It’s in your seat pan.”
“In my seat pan? Okay.”
“I should have put it over here [in my seat pan]. That was just where it ended up.” I normally unloaded the ETB at Cernan’s Rover seat.
“You already use the 500?” Cernan asked.
“No, I didn’t get a chance to,” I answered as I configured the EVA-2 maps on the accessory staff mounted on my side of the Rover console.”
“Okay. You might do it while I try the fender, and then you’re here to help me in case I need it.”
“All your (fender) stuff’s right there, Gene.”
“Oh, okay. I see it. Well, let’s hope it does the job…”
“Okay, SCB-7’s in (under) my seat,” I said. “And I put the return-to-LM map in there, too; it’s just going to be in the way anywhere else. …Let me check something, though,” I mused looking at that map. “On the way to Hole-in-the-Wall, we want to drive…”
“[toward the] top of the notch,” finished Parker.
“Hope this thing [replacement fender] gets stiff,” Cernan stated. “It’s just a flapper [now]. Sure isn’t stiff like I want it to be.”
“You want me to hold it there [on the inside fender rail]?”
“Yeah, you’re going to have to, I reckon. But, that may do the job. Let’s see, does it (the new fender) come over the [full old fender]? …I want it about right above the axle. …Move your hand a minute. Let me align it. Okay. Hold it right there. Let me get the [clamp]…”
“Let me move it up just a little bit. …Right there. Okay. Hold it right there. Let me see how much room I’ve got coming out. …I want to turn this [clamp] around [90 degrees]. We can tape that other end, Jack. There you go.”
“It’s tending to fold a little bit [in the middle],” I observed.
“I think… Yeah, but the dust will be coming up from under it. Let’s see.”
“[Higher] temperature [from the sun on it], I think, is making it fold.”
“Now, that’ll give us plenty of room down there. Yeah, I just don’t want to interfere with the steering.”
“You think that’ll stop the dust that way?” I asked.
“Well, it’ll stop some of it, if it stays on,” Cernan replied, hopefully.
“Well, what I mean, it’s not projecting outward at all. It’s curling back under.”
“Well, when I put a clamp here, and a clamp here, [let’s] see what will happen?” He demonstrates how the taped maps turn into a more ridged partial tube when held against the inner and outer rails of the old fender.
“Oh, okay. …Is that about where you want it? …Lean against me, if you need to,” I offered as Cernan had difficulty reaching the position of the inboard clamp.
“Trying to figure out… No, I’ve got to clamp it right on that rail; it’s (there’s) not much to clamp it to on the inside,” Cernan noted.
“No,” I said as he rotated the clamp knob towards the ground. “Keep the knob up. There, you got it.”
“Hold it right there. We got it all folded up on this side?”
“Why don’t you try the outside [first],” I suggested.
“Let it (the new fender) go a minute, okay?
“Why don’t you try the outside, first? Fix it [in position],” I suggested, thinking that it would be easier to put the clamp on there and anchoring it into position for the inside clamp.
“Inside first [would] probably be better, guys,” Parker interjected, passing on advice from Young, sitting next to him at the Capcomm Console.
“Got enough overlap there?” I asked, as Cernan ignored Young’s advice and took mine.
“Nope, I want a little more.”
Ignoring Young’s advice, Cernan says, “And I am going to try this side because I can get my overlap over here. …Okay. Now, hold it right there while I clamp it down. …Well, that paper [fender] isn’t going to come off, and the clamp’s not going to come off, I’ll say that. I don’t know how much we’re going to get out of the fender but…”
“Okay, that’s fixed [in position]?” I asked.
“Can you fix that [tighter] at all?”
“Yep. That ought to give us a little strengthening, stiffening. …Yeah.”
“Pretty tight,” I agreed.
“Yep,” he grunted, continuing to turn the clamp knob slightly. “Tighter for the road. I don’t want to lose that. …Man, that’s tight. Now, let’s see if I can get this one [on the inside]… Jack, why don’t you come on this side (rear) and hold the fender down right there…” We trade places. “Hold it right about there.”
“Okay. You want to get it (the clamp) outboard a little more. …I mean aft?”
“No, I want to keep it above this center, …the hub here, …for steering purposes,” he declared.
“Yeah, Okay. …Is that fixed for the…”
“Well… I’ll take a look at it. I’m going to tighten it down [some] so it stays, then I’m going to take a look at it. I might turn this thing (second clamp) down, too.”
“Yeah; I was just going to suggest that…”
“Let me take a look before I get it too tight. …Well, I’ll tell you, that’s (the new fender) going to help some.”
“Yup. It may do the trick,” I agreed.
“I can’t see what’s under this rail too well, but I know that clamp is on. It’s on tight.”
“Gene, it looks [good],” I said in encouragement.
“Let me move this [edge a little]…”
“Move your left hand a little [so I can get a better grip],” I requested. “Okay. Tighten that now.”
“Get this out of the way.”
“Looks as if [the new fender twisted],” I observed.
“Let me loosen it, and get it a little straighter.”
“Yeah, I think you need to straighten it,” I agreed.
“Boy, I had it tight,” said Cernan as he loosened the inboard clamp.
“Yeah, but you know you’ve got another piece [of old fender] in there so….”
“Yeah, that’s why it’s crooked, it’s over those [broken] pieces.”
“Yeah,” I responded. “Well, you might want to move it. …If you could move it this way about…an inch, you’d be past the ridge you got [hung up on].”
“Well, I’m just taking John’s (Young) word on the steering,” explained Cernan
“I’m keeping [the clamp] above the hub here,” he pointed out, again.
“Okay; tighten her down then. …I think that’ll stay.”
“I think it’ll stay!” exclaimed Cernan.
“Why don’t I turn this one (clamp knob),” pointing to the outboard clamp and its ball and socket position adjustment.
“Okay. You won’t get that any tighter,” answered Cernan, misunderstanding my intention.
“No, I mean, why don’t I turn that [clamp knob position adjustment] down because it’ll [be] that much less to run into [around the wheel]. …There you go,” I encourage Cernan as he makes the adjustment.
“Well, not too close to that wheel. Okay?”
“I think that’s good.”
“Too bad we don’t have one more clamp,” Cernan said, wishfully. “Well, one more clamp would probably interfere with the steering.”
“I think that’ll stop the [forward] rooster tail,” I concluded, “because that’s [what’s] swinging [dust] forward…”
“I think that’ll stop a lot of it, Houston,” reported Cernan.
Fig. 11.4a. Result of the Rover fender repair that employed four, unneeded chronopaque field maps, taped together with gray duct tape, and attached to the broken fender rails with two auxiliary light clamps from the Challenger’s cabin. This view shows the repair at the start of the drive from the LM to Station 2. (NASA Photo AS17-135-20542.)
“Okay. Let’s go,” I urged, knowing that we had just lost another five minutes.
“The [EVA] maps are configured,” I reported as I got back to the Checklist items.
Fig. 11.4b. The status of the fender repair after driving ~8 km to Station 2. It has withstood the rigors of the drive extremely well— note the dust on the blue Traverse Gravimeter mounted on the Geopallet. In this view, I am already seated for the drive to Station 3. An as yet unfilled Sample Containment Bag (SCB) #8 is mounted on the right side of my PLSS just outside the auxiliary water cylinder (NASA photo AS17-137-20979).
“That sounds like a good attempt, men,” Parker said, referring to the fender repair. “We’ll hope it works.”
“Does that look good to John,” Cernan asked, noting that the TV was inspecting our work, “from what he did? That tape will keep it…”
“It looks exactly what his did, he (John Young) says.” “Yeah, but he didn’t run in the dust [down there],” Cernan replied, “so I guess we’ll have to give it a trial run. That’ll help some.” (See Figs. 11.4a,b)
“Roger on that. We’re anxiously waiting.
“Okay, Jack. I’m going to HIGH [cooling] for a little bit. Okay. I need…”
“Oh, shoot,” I said, as I handed Cernan an SCB. I had grabbed the wrong SCB from the MESA, trying to gain a little time.
“No, I want [SCB-] 4.”
“I took 8 off [the MESA].
“No, sir. I want 4 and 6… Why don’t you just substitute…
“Hey, I just took 8 off,” I called to Parker. “Can we use 8 instead of 6?”
“Yeah, we can,” Cernan agreed.
“Yeah,” Parker also agreed. “I don’t see there’s any reason why you shouldn’t be able to use that, Jack. Go ahead. We’ll just mark it down.
“Okay. Turn around, Jack. Hey, Bob, we’ll use 8 instead of 4 [on Jack’s PLSS].”
“Understand 8 will be on the LMP.”
“That’s affirm; 8 will be on the LMP.” It was important to make sure that the Lunar Receiving Laboratory knew which bag contained which samples.
“Geno, you went to MIN [cooling] instead of MAX,” I warned him as I had a good look at the forward, lower right corner of his PLSS.
“I think you’re right. I just realized that…”
“Got it (SCB-8 on my PLSS)?” I asked Cernan.
“Yep, let me go to MAX here for a minute. We need [SCB-] 6 off of there, Jack.” Actually, SCB-6 was planned to go on the gate.
“Oh, 5 stays back here, huh?”
“We need 6 to the gate,” Cernan said, now referring to his Checklist. “It’s probably behind 4 [on the Pallet], isn’t it?”
“Yeah, probably,” I replied.
“Well, put 4 on the gate, guys, …and put 5 on the Commander,” Parker suggested.
“Yeah. Okay,” I responded. “4 is going on the gate and 5 on the Commander.
“Okay, Bob,” Cernan added, “a little paperwork for you, but that’s all right.” We depended on Ray Zedekar, Dan Bland, and John Covington at the EVA console to keep track of these kinds of changes. “Now, I got to do some more stowing on you when you get that (SCB-4) on [the gate].”
“They’re in the [the hooks on the gate]. …Where do you want me?”
“[Give me] your left side.”
“I mean…which way are you going to turn?”
“Oh, man, does that Velcro get tough. …Okay, you’ve got a core cap dispenser [in the bag]. Stand by; let me fix these (straps) for you while I’m here. …Okay. Here’s your doffing harness on this side. Don’t move yet, I’ve got something I’ve got to do to you.” He needed to get the drive tube rammer for my SRC.
“Okay; turn around,” he requested. “I’ll get your harness on the other (right) side.”
“Let me get yours (harness), too,” I reminded him.
“Okay, there you go,” Cernan said as he finished. “Okay, you’ve got a cap dispenser, you’ve got a [drive tube] rammer, and you’ve got…well, I guess SCB-8, if I’m not mistaken.”
“Yeah, that’s all right, they got it [recorded,” I said and then went to work on his harness. “Okay. That’s one (side of your PLSS harness).”
“Okay. You can give me SCB-5 then, and…”
“Yeah, …Can you move? …Move a little bit [away from the gate]. There you go. …Okay. There you are.”
“You got it?” said Cernan as he started to move away.
“In fact, I’ve got to tighten up your [straps],” I told him.
“We’ve got to take a picture of that fender, if it works,” Cernan reminded himself.
“Wait a minute. No. …If you weren’t so tall, …you just invariably stand so I have to get in a hole! Okay. Now let me tighten up your whole shooting match here. It’s loose again. Hang on.”
“Between Velcro and snaps, the world could never fall apart. …Okay…”
“All set?” Cernan asked.
“You’re set,” I answered.
“Okay. I’m going to get a hammer, and then I’ll get the TGE [reading].”
“I’m going to get my camera,” I informed him, “and I’ll go to the SEP site.” This would be a run of about 140 meters. I also grabbed the LRV Sampler in case a “rock of opportunity” presented itself.
“Okay. Why don’t you start to the SEP site, Jack,” Parker broke in, possibly not hearing me, although, with his Maxwell Smart (character from the U.S. TV Sitcom “Get Smart”, 1965-1970) sense of humor, you never knew. “And, also, I presume that the Dust Brush is on the Rover now.”
“It is,” replied Cernan.
“Okay. Copy that.”
“Jack, when I drive out there [to pick you up] why don’t you watch the rear wheel.”
“I will. Give me a yell when you start to drive.”
“[Watch] both the steering and the rooster tail. …Oh, I hope it (TGE reading) is not all zeros. Okay, Bob. 670, 017, 701; 670, 017, 701. …Okay, and the SCB is good. It’s closed. It’s in the shade…or ‘SRC’, I guess.” There was always some confusion between the SCB, the Sample Containment Bag on our PLSSs, and the “SRB,” the Sample Retaining Bag used at the Challenger for large samples. That was why we usually referred to the SRB as the “Big Bag.”
“Okay. And, Jack,” Parker called, “when you get out to the SEP site, you might give us a reading on what the solar panels look like. …How [did] they survive the night with the tape on them?”
“I wouldn’t think of not doing that. I’m curious myself,” I said.
“The TGE is on the LRV,” announced Cernan. “Okay. I’m making an inventory. I’ve got the LCRU battery. Okay. We got [seismic charges] 1, 3 and 2 and 8; LCRU blankets are OPEN 100 percent. Battery covers are CLOSED. Dust Brush is on the LCRU. TGE is on the Rover. Jack, can you verify we got the right mags and a polar filter…Polarization [filter]?
“Yes, sir. I verified that.”
“You better put that 500 [mm camera] back under the seat,” I reminded him.
“Yep. That’s where it’s going.”
I reached the SEP after a little less than two minutes of “skiing”. This relatively slow rate of 4.5 km/hr resulted from my stopping to look closely at some of the larger boulders as I skied by.
“Well, Bob, it looks like [the SEP] tape survived. As I stand behind the panels, the left-hand panel may be tilted at about…well, less than 5 degrees. Probably about 2 or 3 [degrees], but that’s all. Looks pretty good right now.”
“Okay; beautiful. Thank you. Good fix.”
“Okay, Bob, I’m going to take the TV from you,” Cernan said.
Fig. 11.5. My cross-sun photo of rock sample 70275 (white circle) ca. 2 m from the SEP. The white rectangle marks the location of the enlargement below showing the “rain-drop” regolith pattern in most of this photo. (NASA photo AS17-135-20539).
“And the [SEP] transmitter’s going ON. …If I can do it without destroying it,” I said with a laugh, trying not to stumble into the transmitter. Along with the LRV Sampler, I should have taken my scoop with me to lean on.
“Yeah. That’s (bending) hard to do out there, Jack,” Cernan sympathized. “Okay. TV camera going Position (Mode) 1 (OFF).”
“[SEP] Transmitter’s on. [I’ll] fix the level there. …Okay. The level is on the inner ring again. The gnomon [shadow] has moved a little bit, but not much. But you would expect that, I guess,” noting that the Sun had moved south a few degrees as well as west about 11 degrees since I deployed the transmitter near the end of EVA-1.
“Yeah,” agreed Parker. “Seeing [that] the other end of the gnomon up there in the sky (the Sun) has moved a little bit.”
“Yeah. That’s what I said.”
“Okay,” Cernan said as he took inventory before climbing back on the Rover. “Camera, tongs, and I’ll drive. West [SEP antenna] leg, heading 270. Camera is on [my RCU]. Bob, I’m on…I guess [frame] 26. Yes sir, frame 27, mag Charlie.”
As I bagged a sample while waiting for Cernan, I said, “I had to relearn how to document samples, Bob. I just have. The first part of my [film] roll, will have a lot of random exposures and focuses (AS17-135-20536,-37). …Okay, we’re back in business. And while I’m waiting for Gene, [I’m] getting a rock. It looks a little finer grained than the others we’ve seen. [It’s] in the LRV sampler along with some soil., and that’s (sampling) done. Hey, that’s a neat sampler— only way to fly. Okay. And that’s in bag 22E (70270-75; see Fig. 11.5↑). It has the stereo documentation (AS17-135-20539,-40) and a locator to the LM (AS17-135-20541), and it’s about 2 meters from the SEP… 22 Echo,” I repeated.
“Roger. Copy that. Did you ever find any sign of that brown, fine-grained rock you saw on the way out to the SEP yesterday?”
Ignoring Parker’s ribbing about his sampling of some packing material the day before, Cernan said, “Bob, let me give you some readings, so I can get going… Amp hours, 108, 100; volts are 68, 68; batteries are 80 and 102; and motors are all off-scale low. I’m on the way. …On the way, Jack.”
“Oh, there you are over there, huh?”
“And, Jack, how’s the rooster tail look on that fender?” Parker asked.
“Looks like it’s (rooster tail) going backwards,” I said as I took a photo (AS17-135-20541) of the Rover in motion.
Fig. 11.6. An enlargement from the photo I took of Cernan on his way to the SEP showing the rooster tails being interrupted by fenders on three of the rover wheels. The repaired fender is on the right rear wheel and is invisible in this view but clearly not allowing dust to spray forward. (From NASA photo AS17-135-20541).
“I don’t see anything coming up over the top,” observed Cernan.
“Looks like a good fix,” I concluded as he came closer to me.
“Okay, Jack; I got to come around. …I’m going to come on this side (north) and head west.”
‘Okay. Watch those [antenna lines]. …You got the [SEP] antennas [in sight]?” I am calling Cernan’s attention to the four, 35m long, perpendicular lines we laid out at the end of EVA-1.
“I’ve got one over here.”
“Okay, I’ll give you a line on the other one,” I said.
“I’m getting close.”
“Okay. Turn,” I commanded.
‘Where is it?”
“Right here. I’m [standing] on it.”
“Okay. And I see the other one. …Let me [align the Rover] parallel [to] that line [you are on].”
“[Point the] Low gain, Gene, please; after you get stopped,” requested Parker.
“I guess that’s about 2 or 3 meters [from the west antenna wire], huh, Jack? You can better see where it is at.”
“Yeah, that’s good, Geno. Okay…”
“Heading 270. …Am I ten meters from the transmitter? Probably not, huh?”
Fig. 11.7. My LRV navigation calibration starting point photos combined into a pan of the SEP site. The SEP instrument is to the right of the LRV, which is parked parallel to and on this side of the western part of the antenna I laid down at the start of EVA-1. The southern part of the antenna is in one of the tire tracks leading from the SEP package at right. (NASA photos AS17-135-20544, -20545, -20546).
“You’re pretty…no, you need to go about 5 meters [west].”
“How far am I?” he asked. “See if it’s okay.”
“You’re about 3 meters…4 meters [from SEP].”
“Hey, Bob, I’m 3 meters to the west of the transmitter and about 2 and 1/2 meters south of the line going west (see Fig. 11.7). Is that okay?
“There’s no problem there, Gene,” answered Parker. “Don’t move. It’s just they had to be less than those numbers.”
“Okay. That’s where I am.” With the SEP transmitter and receiver ON, we would drive along the west antenna on a constant heading to calibrate the data recorded in the receiver. Afterwards, the receiver collected good data during most of this EVA’s rover traverses.
“I’m getting your photos (AS17-135-20542–546; Fig. 11.7),” I told Parker as I documented the SEP calibration starting point.
“Okay; and let me give them a voltage reading,” Cernan said, “and I’m still reading 68 and 68.”
“We don’t need those,” Parker, responded, “we just got them.”
“I know, I just wanted to keep you honest,” Cernan said. Parker missed that the Checklist called for this voltage reading at this point.
“And give us the Nav numbers.”
“265 [bearing], 0.2 [distance], and 0.1 [range].”
“We want heading, pitch, roll, and sun dial there, Gene.”
“Okay. I’m sorry, Bob. …Okay; you want a Nav update here?”
“Nav initialize, Geno.”
“Yes, sir; you do. …Yes, sir; I’m sorry.” No need to apologize as, by not sticking with the words of the Checklist, Parker had confused things.
“Go to the next [Checklist] page,” Parker added, unnecessarily.
“Let me change my [Rover] position here, just a skosh…” Cernan needed to head the Rover directly away from the Sun to get a shadow from the gnomon on the scale on the console. The Sun is 12 degrees south of due east.
“Bob,” I broke in, “what was that last LRV sample number I gave you?”
“Twenty-two Echo, two-two Echo,” replied Parker.
“23 Echo (70250-55), if that followed in sequence, is another rock near the SEP, documented in the same way.”
[Post-mission examination and analysis of rock fragments 70255 and 70275 (see Fig. 11.5↑) showed they consist of fine-grained (varoilitic), non-vesicular ilmenite-olivine basalt. Their fine-grained nature suggest relatively near surface crystallization with rapid cooling of the original lava. These basalt samples are unusual, however, in that they only have, respectively, ~15 and 17% plagioclase versus ~ 48 and 45% pyroxene, ~5 and 10% olivine, and ~31 and 26% ilmenite. 70255 contains about 2% vugs that probably are partially recrystallized vesicles. 70275 has aggregated phenocrysts of olivine and ilmenite in a feathery matrix of pyroxene and plagioclase but no vugs and few vesicles.
The composition of 70255 lies well within the Type A basalt field whereas 70725 falls in the continuum between Type A and Type B basalts at the defined boundry between them. A broad discussion of the petrology, radiometric ages, and internal strutures of mare basalts observed and sampled in Taurus-Littrow, including these two samples, is provided in Chapter 13.
A laser ablation 40-39Ar age for 70255 has been reported as 3.87 ± 0.02 indicating that it might be older than most other Taurus-Littrow basalt samples; however, evaluation of the very broad range of determined isotopic ages for Taurus-Littrow basalts has not been completed.
Micrometeors have eroded all surfaces of 70275 (see Fig. 11.5↑ enlargement of the heavily bombarded “rain drop” surface in which the sample sits), and it has a cosmic ray exposure age of 109 Myr. In contrast, only one surface of 70255 has been significantly exposed to micrometeors.
The regolith samples, 70250 and 70270, that accompanied basalt samples 70255 and 70275, respectively, have intermediate Is/FeO maturity indexes of 43 and 56, reflecting their relatively high ilmenite content that appears to reduce the rate of maturation (see Chapter 13).]
“Okay, Bob. 265, 0.3, 0.1; roll is 1 right, pitch is 0, and the sun-shaft device is 0. I’m heading 281 degrees,” Cernan reported so that the Rover navigation system could be aligned.
“Stand by,” requested Parker, as Bill Perry at the Rover Console in Mission Control calculated what his correct heading should be and how much Cernan should torque the navigation gyroscope to enter that heading.
“The [SEP] recorder is ON and the Receive Power switch is ON,” I reported from the right rear of the Rover. …And, [Gene,] I guess you’re going to hand me EP-4,” I said as I temporarily handed EP-4 to Cernan across the Rover console. “[And I’ll] get rid of this [LRV sampler].” I attached the sampler to the Rover’s Accessory Staff for later accessibility. Then, I stood sideways to my seat, gave a leap and a kick, landed about where I intended in the seat. I spent a minute or so hooking up my seat belt, making sure that the belt was not twisted as happened as we left Station 1.
“Okay,” Parker broke in, “282 is the preferred [heading for this update] but that’s too small [an error] to bother torquing, Gene. You’re good as is. We’re ready for you guys to go.”
“Okay. That looks good, because I have to come left just a skosh there to proceed parallel down the west line.”
“Okay. We’re ready for you guys to go. We presume you have the SEP photos, Jack.”
“Yes, I do,” I confirmed, as my seat belt latch connected.
“Okay. And you can give us a frame count, if you want. Remember to pick up EP-4 when you get in the Rover.”
“We got it [(EP-4), and the frame count is 17.”
“Copy 17 for the LMP, and we need a NAV RESET to verify there, Gene.”
“I did NAV RESET; I’m reading all balls (zeros). And it [the display] is back to OFF.”
“And did you happen to check the SEP temperature when you turned it on, Gene? [I mean,] Jack? The receiver, [that is]?”
“No. I didn’t; I didn’t. Doubt if it changed much since I called you [before leaving the Challenger].”
“Okay. We’ll catch it at Station 2.”
“Okay, Jack, we got transmitter and receiver both ON, huh?”
Parker, continued down his list of questions and reminders before I could answer. “Low gain antenna [setting] is 240, and we’re ready for you guys to leave. Give us a MARK on the leave.”
“Okay. Here you go, Jack; we need… The SEP receiver and transmitter (are) both ON, huh?”
“Yes, sir.” I had reported this previously, but apparently no one was listening.
“And, Gene, remember we want a MARK when you pass the end of the antenna.”
“Gonna drive fairly slowly, huh?” I asked as a reminder.
“Yep, until I get past the end. I got to get my heading changed about 10 degrees to parallel it. We’re still in the same relative position, Bob.”
“Very good. We are moving right now.”
“We’re MARKing that.”
“Slowly,” Cernan said to himself…”Okay. Stand by, Bob… MARK it (the end of the antenna).
“Okay. Copy that.”
Traverse to Station 2
“We want to go past the LM at heading 260, Jack,” Cernan said, as he looked at the sketch map we both had on the facing page of our Cuff Checklists.
“Well, we want to get at 080 (bearing) and 0.4[ km] (range) and get rid of this charge,” I noted. AS17-135-20550–62 constitutes the traverse photographs between the SEP and the seismic charge near the ALSEP. As our route kept us moving down-sun, definition of detailed surface features was largely washed out by the lack of visible shadows.
Fig. 11.8. The three EVA routes during the Apollo 17 mission. During EVA-2, the route from the SEP site (ca. 300 m east of the LM) followed the lower track marked EVA 2 to Nansen at left, then returned via the upper route. (NASA/ASU/GSFC photo with label additions by the editor).
“Okay, 17, a couple of words there as you drive along. Let me give them to you early here. One, we didn’t bother to change all the numbers on the checklist; but, by and large, because we think we’re 200 meters east of where we were [planning to land], you should probably increase all those [distance] numbers, except for the explosive package numbers, by about two-tenths [km] to get the distance at which you will come across these areas. Again it’s about 0.4 [or] 0.5 [ km] that we expect to deploy EP-4. The more important number though is that it’s 0.2 [ km] west of the ALSEP. As you pass the ALSEP, you might note what the range and distance are reading at that point.”
Fig. 11.9. Examples of the series of photos I took on the way from the SEP site to Nansen at Station 2 (located at the base of the South Massif to the right of the LM) with the Hasselblad camera attached to the RCU on my chest. (Top): We are heading towards the LM (note dust on the TV camera lens). (Bottom): The boulders are just south of Geophone rock (NASA photos AS17-135-20550, -20553).
Mission Control has now taken into account what Evans has told them about our landing point and is close to having it right in spite of all the conversations about various mis-identified landmarks.
“Okay,” I replied. “Range is the one that changes on…no, wait a minute…” Before continuing, I pointed to a small crater that Cernan was headed toward.”
“I got it,” Cernan asserted. “I’ll get it [off to the side].”
Going back to the question of when does the range indicator change, I asked, “Which is it? Range changes every half…on the half kilometer?” I correctly was thinking “half of one-tenth” kilometer rather than half kilometer but said “kilometer”.
“Roger, Jack,” answered Parker, not realizing my misstatement. “The range is what changes in the middle at 50 meters and 150 meters.”
“Okay. The fender fix is working so far,” I remarked, not noticing any rain of regolith out ahead like we had at the end of EVA-1.
“Let me get around your [geophone] flag,” Cernan said. “There’s your flag way out there, isn’t it?”
“Yeah,” I agreed. He was referring to the flag at the southern end of the north-south geophone line.
“Let me get around that. Man, that’s really giving the ALSEP some room.”
“Yeah. Okay, Bob,” I said as I took traverse photos “we’re still seeing the light-colored gabbroic rocks. I think the reason I said 50 percent [plagioclase] was because, in this light, they look light-colored, and that’s probably largely because of the zap-pit halos. …Through the hand lens, it looked like a standard gabbro (about 30 percent plagioclase).” As I could watch blocks as we drove by that were out of zero phase-angle with the Sun, I could see far more detail than shown in traverse photographs.
“And, Bob, I’m full out at about 11 [clicks],” observed Cernan, meaning “kilometers per hour”.
“Okay, you can turn right, now,” I said as we had left our 260 heading to go around the geophone flag.
“I’m full out at about 11 clicks right now,” Cernan repeated.
“Oops. You drove [through a crater].”
“Can you give me a call as you pass by the ALSEP as you get ready to deploy the charge, please?” Parker requested.
“We’re almost due south of the ALSEP now,” I replied.”
“…[I’ve] got to work my way through [craters and boulders] here,” commented Cernan. (see Fig. 11.9↑, right).
“Go about 0.2 kilometers further than that,” Parker continued.
“It’s a little rocky out here,” I said to Cernan.
“Yeah, it sure is.”
“In the area we are now,” I began another terrain description, but then asked Cernan, “did you get a distance [at the ALSEP]? That was [about 0.4 km].”
“We just clicked to (zero-zero)-four (350m). I want to move over this way just a skosh.”
“Okay, [we’re] just south of my geophone 2 flag now,” I reported.
“If you just clicked to 4,” inserted Parker, “let’s go to 6 then, just past the click on 6 (550m).”
“Okay,” replied Cernan. “And they want about 080 [as a bearing to the SEP transmitter of]… [We’re] plenty good enough. I got to start heading right out here, right toward my topographic [target]…”
“Hole-in-the-Wall should be just to the left of the notch [in the rim of Camelot],” I said.
“Yep. That’s exactly where I’m heading.”
“And I think we’re coming up closer to the rim of Camelot,” I speculated. “It’s starting to look like a crater now.” I had been getting glimpses of the slightly more elevated west to north rim of Camelot. Driving up and across the southeastern portions of its ejecta blanket gave only a slight impression of going up a slope. With this route, we hoped to get a passing view of the area planned for Station 5 on the south rim of Camelot. I wanted to make sure that boulders would be there for sampling in a few hours on the way back to Challenger. Such boulders at the rim were thought to be the deepest sample of the subfloor material that we could get. Revisiting this assumption and the geology of Station 5 some 45 years later, I concluded that Camelot is much older thant we then thought and that the boulders at the rim were exposed crater wall rocks (see Chapter 13).
“Looking down-Sun,” I continued, “I see no major albedo changes except for the very fresh craters which are brighter…by maybe 20 percent. The surface…”
“How are we doing [for distance]?” interrupted Cernan.
“5,” I noted, as we approached a change to 006 or 550m.
“Here’s your charge [location]. Pick a spot, Jack.”
“Okay; can you swing right out over there,” I said, pointing to a relatively large area largely clear of large boulders, “…about 10 meters ahead?”
“Give me a shallow turn,” I directed.
“Okay. And I’ll set it right there in that [depression]. …Can you move forward, and I’ll get it in that little depression?”
“You see [the depression] on the other side of the rock [to our right]?”
“Yeah. …Okay, Bob; 083 [bearing], 0.6 [distance], and 0.5 [range].” The bearing and range are relative to the SEP transmitter location where the Rover navigation system had been initialized. (see Fig. 11.7↑.
“Okay. Copy that.
“Okay.” With the Rover stopped, I began to go through my seismic charge activation routine for EP-4. “Pin 1 is pulled and safe; Pin 2 is pulled and safe; Pin 3, pulled and safe. …Ever stop and ask yourself what I’m doing!?” I referred to the fact that I was pulling pins to activate an explosives charge equivalent to about one-quarter pound of TNT.
“Yes,” laughed Cernan.
Ninety hours later, this charge, and the seven others we would deploy, would be detonated individually by a signal from Earth with their seismic energy being recorded through the geophones I set out on EVA-1 as part of the ALSEP. Each explosion would leave a new, small crater on the Moon.
“If you can give us a frame count, we’d appreciate it,” Parker called. “And I might remind you two to both check that…you’re at MIN cooling since you’ve got a long drive ahead of you there.”
“Don’t fall over!” Cernan exclaimed as I deployed the seismic charge by leaning as far to the right as my lap belt would allow, placing it outside the Rover wheels and fenders. I had previously pulled out the long antenna and used it as a handle to set the charge on the surface. As we left the site and to make sure we did not hit the charge, Cernan would continue his turn to the right to keep it in sight.
“Hey, I lost my sample thing,” I exclaimed as I noticed the stack of Dixie Cup sample bags had disappeared from the end of the UHT.
“[Is it] on the floor?” Cernan asked.
“I hope so…”
“That [charge] looks good?”
“Yeah, it’s going to stay [upright].”
“Okay. Have you got anything [else to do]?” Cernan inquired. “If not, I’ll do a [turn for a] partial [photo pan] for you.”
“Yeah. We got to do a partial,” I agreed. “I’d like to know where that sampler is. Well, we can do without it, I guess.”
“Well, it’ll sure be nice to [have it]. What did it do; come off the end [of the UHT]?”
Fig. 11.10. The last 2 images of my LRV pan documenting the location of the explosive charge. The “big block” referred to in text can be seen below the high gain antenna (HGA) pointing handle at left in the top photo and in the middle right of the bottom photo. EP-4 is just to the right of that block, also seen enlarged in Fig. 11.11. (NASA photos AS17-135-20568, -20569).
Fig. 11.11. Enlargement from AS17-135-205688 showing EP-4 in situ in a small depression marked by the arrow. The white box top and antenna holder can be seen although the tilted antenna itself is unresolvable at this distance.
“Yeah, I think I can check it [out], though,” I said as I clicked off 7 photos during Cernan’s slow circle turn. This partial panorama to document the location of the charge relative to the ALSEP is made up of AS17-35-20563-69.
“Getting your [photographic] pan?”
“Yeah. …If you go around to seeing that big block there by the ALSEP, then you can forget it (the rest of the turn).” I am referring to the big boulder south of the ALSEP, along the geophone line. Once that object is in the pan, the location of the charge will be well fixed (AS17-135 20569).
“Okay. I’ll just come on around, and I’ll pick up my tracks. Do you want to get that sampler? Can you see it?”
“I think I’d better look,” I finally concluded, reluctantly because of time.
“All right. Take a look.”
“Bob, one stop here for about two seconds.” I have to get off the Rover, so we will lose more than two seconds.
“Hold this,” I requested as I handed the UHT to Cernan and dismounted the Rover as quickly as possible. “Okay. It’s down there [in the foot pan].”
“Why don’t you put it on real quick and…”
“I don’t know why [it came off]. …It was hard to put on. Surprised it came off,” I commented.
“Here, let me hold the end.” Cernan offered.
“You got them (UHT locking pins) retracted?”
“Retracted. …Still retracted; let me know when.”
“Okay.” I am having trouble connecting the sample bag head to the UHT, probably because of both the gloves and some dust in the connector.
“Okay. It’s loose [again]. Retracted. How you want it?”
“Retract it (the pins) again.”
“No.…Let go, let go. …No, it’s just not hooking,” I said as the UHT and sampler came apart, again.
“Okay. Try it. …Push it in once more.”
“Okay. …The best I can do. I’ll just lock …I’ll twist it down on there and maybe it’ll hold.”
“Okay. Twist it tight .…I got the rod.,” Cernan said as he gripped the handle of the UHT as I twisted the sampler on it as hard as I could.
“Okay. I’ll just have to be careful,” I concluded, as the twisted connection seemed to hold. Had we lost the use of the LRV sampler, an invention of mine, we would have not obtained many samples that decades later proved to be very important to a number of debris flow and regolith studies (Chapter 13).
“I’ve got it (the heavy, female end of my seat belt).”
“[You have it?]”
“I’ve got it.”
“Okay,” I said as I did my jump and kick to get into the seat.
“You’ll have to put it (male end) in. Push down.
“Okay. …Ah!” I exclaimed as the belt connections seemed to come together.
“Okay; let’s go. …Every time you pick your seatbelt up [it gets twisted]. …Here it is, it’s untwisted now. …All set?”
“Just about,” I answered as I fumbled to make a blind seat belt connection.
“…Jack, a reminder, Parker broke in, seemingly oblivious to my difficulties with the sampler and my lap belt. “We’re still seeing you in INTERMEDIATE. You probably will want to go to MIN before you get back on.”
“He’s back on [the Rover] now.”
“I’m in [place] now.”
“And we’re rolling,” added Cernan.
“Let’s go to Hole-in-the-Wall,” I said with enthusiasm but having lost several minutes due to the UHT-sampler connection failure. Traverse photographs between the seismic charge site and the first Rover sample site consist of AS135-20570-622.
“One other thing,” Parker opined, “I might mention to you guys as you’re driving here, Jack, before you start talking again, is that, as you go by Camelot, you might keep an eye out for blocks along the rim there, because, remember, we may be wanting to come back and move Station 5 to an area where there’s blocks, unless there are blocks at the present, nominal Station 5. So you might keep an eye for that and plan for the way back.” Parker must have been under pressure from someone to re-state the obvious.
“A second thing” he continued, “a reminder: if you do stop for a Rover sample or one thing or another along the way, give us a call and keep us informed, because we’re timing you on the way out and the assumption is, of course, that driving time out equals drive-back time. And we’re under a 63-minute limit to get you from the LM out to the Station 2 because of OPS drive-back. So, keep us informed so we can keep a good tab.”
“Okay, Bob. Okay. We’ll keep you informed,” I replied, somewhat exasperated. Parker should have filtered out interruptions about items that we had discussed or trained to do many times before launch. It can be a fine line, however, between too many reminders and too few.
“Bob, I got the thing (forward drive control) ‘two-blocked’, and I’m averaging probably 10 to 11 clicks. It’s not exactly straight-line navigation, but I think I can hold most of it.” I had never heard Cernan use the term “two-blocked” before. It may have come out of his subconscious Navy heritage. In the days of sailing ships, to be “two-blocked” with a block-and-tackle meant that with two pulleys or blocks working hard together, one could do no more than that.
“Watch the crater,” I called out. “There you go. …I tell you, when Gene decides to turn, [look out]. …Whoo!” Although Cernan would say he was always in control of the Rover, driving down-sun meant that craters could be almost invisible until we were in them. It helped to have two sets of eyes watching for them.
“And, Jack, a reminder on photos. Yesterday, you apparently took quite a few on the way back from Station 1 to the SEP, and we’re right nominal on budget now. But, considering the fact that we didn’t do much sampling, if you continue to use them at the rate you did yesterday coming back from Station 1, at least as we understand it, you’ll be pushing us pretty hard in the [film] budget. Should be [a photo] every 50 meters or every 100 meters.”
“Bob, okay.” Rover traverse photographs came out of discussions about the difficulties that the Apollo 15 crew had in figuring out where they were on their initial traverse. In addition, they would help determine the general location and context of terrain and my geological observations during the traverse.
“And you want to hear something?” I asked, having stored up some observations while Mission Control worried about Station 5 and film budgets.
“Roger. I’ll listen now…”
“Okay. The surface is not changing in terms of the detail [textures]. The surface texture of the fine-grained regolith still has the raindrop pattern. The blocks still look very much like what we sampled yesterday around the LM. They’re light-colored, apparently gabbros, with zap pits, …[that is,] zap halos. Occasional (some) craters show lighter colored ejecta; all the way down to [craters], say, half a meter in size (diameter). Other craters that are just as blocky [on a small scale] as those with bright halos have no brightness associated with them. Most of the brightest craters have a little central pit in the bottom which is glass lined. The pit is, maybe, a fifth of the diameter of the crater itself. It’s a fairly standard thing for most of these fresher craters, is [to have] that little central pit.” I had just outlined the sequence of initial degradation of impact craters by micro-meteor erosion: loss of glass lining in the pits, loss of bright halos, and smoothing of the central pit. Impact glass apparently breaks up faster than space weathering darkens the surface of the newly exposed regolith.
“Okay, we’re just south of the (east) rim of Camelot,” I reported.
“There is a light mantle on the other [west] side [of Camelot]. Look at that crater,” exclaimed Cernan as the north rim and wall of Camelot came into view. “Whoo!”
“We’ve got the… Ooh, and there’s Camelot (AS17-135-20588-97),” I said, very impressed by the view.
“Oh, Whoo! Manischewitz. Take a couple of pictures looking at that,” suggested Cernan.”
“Okay. Can you swing [right] a little?”
“Okay, I got them.”
“That is a 600-meter crater!” exclaimed Cernan.
“And it is very blocky [at the rim]… We won’t have any problem finding blocks on the rim of Camelot,” I informed Parker.
“Rog. How about bearing and range to help us pick out the LM location.”
“Okay. 083, 1.2, and 1.0,” replied Cernan. It had been 12 minutes and 17 seconds since we left the SEP, giving an average change in range of 4.9 km per hour. My traverse photographs between the rim of Camelot and the next Rover sample site are AS17-135-20591-622.
“Okay. Thank you. Thank you.”
“Bob, listen!” My frustration with Parker’s ill-considered interruptions came to the surface. Not much geology out of the geologist, yet.
“There’s a little…” I started again only to have Cernan interrupt.
“Man, are there blocks there.”
Fig. 11.12. (Top): Driving upslope on the eastern flank of Camelot Crater. The two large boulders along the sloping line from the HGA pointing handle mark the crater rim. (Bottom): Part of the rim and interior of Camelot Crater seen from the southeast, marked by the horizontal line of reseau crosses. (NASA photos AS17-135-20577, -20590).
“Now,” I tried again, “that little crater in the [Camelot] ejecta did not, …at least [at] the rim of Camelot, did not bring up blocks on the (its) rim.” (45 years later, this would turn out to be a prescient observation relative to the age of Camelot Crater. See Chapter 13.) It may have been (an impact in) an old depression. …Bob, there is [an] extremely blocky area, …I think [the planned] Station 5 was over there where that block area is. …The light-colored areas on the (overhead) photos are essentially blocky. They’re probably 30 percent [covered with] blocks. Many of them are in the 2- to 3- to 4-meter size range. All of them look light-colored (and, from a distance), look like the gabbro we sampled [around the Challenger]. They have light-halo zap pits on them. I see only occasional grayer varieties, which I believe are the non-vesicular ones (rocks) like we also sampled. …But the light-colored gabbros are dominant.”
“Thank you,” Parker said.
As Cernan skirted the boulder field on the rim of Camelot, I continued, “Station 5 would have been— rather than in a light-colored area— would have been in a very blocky area. Station 5 is probably still very good for blocks.”
“Okay. Thank you.” Pre-mission, we had noted that on the low-resolution photographs portions of Camelot’s rim looked to be a lighter gray than other parts of its ejecta blanket. I could now see that these lighter areas consisted of concentrations of large blocks and, as a result, produced a higher albedo than the surface of the surrounding regolith that included dark agglutinates as well as many fewer rock fragments.
“There is probably as [many] big blocks there (at the planned Station 5 location) as anywhere on the rim that we’ve seen,” I added in somewhat tortured syntax. “We ought to be going between Horatio and Camelot now,” I told Cernan after a quick referral to the map. Our planned route to Hole-in-the-Wall would take us near the south rim of Horatio.
“No,” said Cernan, apparently thinking I had asked him something. “I’m going to give them a call when we’re due south of Camelot and see if they can’t get a position on us. …Hold it, Jack!” he added as he suddenly came up on a larger than expected crater.
“Ooh, watch it,” I responded.
“Hold it! Hold it!” Cernan yelled as the Rover bounced from side to side. One traverse photograph suggests that we may have rolled about 30 degrees to the right (see Fig. 11.13↓ (top)).
“You can go around that [next] one,” I suggested, as an even deeper crater loomed in front of the Rover.
“You betcha. …Whoo! That slowed the speed up a little bit. You can unwrinkle your toes now,” joked Cernan.
“Okay,” I said with a laugh. “Oh, I wasn’t worried, Gene. …Watch that block there; it’s probably more than 14 inches [high].” 14 inches was the absolute clearance of the Rover chassis, but with the wheels sinking an inch or so into the regolith at times, the effective clearance was even less. “And I got a fairly close look at the rock, and it is the vesicular, …[that is, it] looks very much like the vesicular clinopyroxene (magnesium-iron silicate) gabbro [seen earlier].”
[Along this traverse down the ejecta blanket of Camelot, I hoped to see if I could observe alternating areas of vesicular and non-vesicular rock. Such alternation would indicate that the Camelot impact had penetrated several lava flows. The more vesicular rocks would have been close to the top of a flow where cooling and solidification occurred rapidly enough to trap gases in the vesicles. With slower cooling deeper in a flow, the gases would have time to migrate upward, leaving a more-dense, less vesicular rock. We were moving too fast and there were too few blocks along our route for me to come to any definitive conclusion about multiple flows other than to say that no pattern jumped out from my rapid observations of boulders we passed. This would be consistent with later analysis of seismic profiling data that indicates the valley was partially filled by either a single thick flow or a series of flows on which no detectable regolith had developed or that had cooled as a single unit.]
“Now, the surface of Camelot is mantled— or the rim— is mantled with the same dark-gray material,” I continued, making some observations on the nature of the surface of Camelot’s ejecta blanket, “and it has the same surface texture: a very fine raindrop pattern. The saturation crater size does not look bigger than a half a meter, if that.”
[Saturation crater size constitutes the size of the smallest crater for which “new impacts destroy as many such craters as they add.” Over a large enough area, this size becomes a measure of the age of the surface, that is, the larger the saturation crater size, the exponentially older is the surface.]
Traverse photographs AS17-135-20604-22 show how few rocks larger than a few centimeters exist at the surface along this part of our route between Camelot and Horatio. At the time, this fact surprised me as we were crossing an area well within the expected one crater diameter reach of continuous rocky ejecta from Camelot as well as from Horatio. This observation, as well as others, indicates that Camelot Crater is much older than we had supposed, based on analysis of the pre-mission photographs. Many years later, analysis of the degree of topographic degredation (diffusion) indicated that Camelot formed about 500 200 million years ago (See Chapter 13).
“Okay, Bob, I’m going to give you 081, 1.6, and 1.4,” Cernan reported. “We’re south of the center of Camelot.”
“Okay. Thank you, Gene,” acknowledged Parker.
“…We ought to see Horatio here pretty quick,” I predicted.
“I think it’s right up in front of us.”
“Yeah, I think you’re right…”
“We can definitely see the light mantle as it comes out over the valley here,” observed Cernan, “and we’re looking at Hole-in-the-Wall, although it’s still too subtle. We’re looking right at Lara, as a matter of fact.”
“Yeah. There’s Lara, very clear; and Hole-in-the-Wall [to the left of Lara], you can see it.”
“Yep,” I repeated, kidding.
“There’s Horatio way over there where those blocks are. See it?” asked Cernan.
Fig. 11.13. (Top): The result of my chauffeur driving my half of the LRV into a small, but deep crater. Blocks at the upper right edge next to the reseau cross are on the interior west wall of Horatio Crater. (Bottom): Fewer large blocks characterize the continuing ride to Station 2. (NASA photos AS17-135-20609, -615).
“Yeah, that’s Horatio. We’re right on course, sir. There’s a little depression we didn’t talk about, though, that’s between Horatio and Camelot. But it’s a depression and not a blocky crater at all. As a matter of fact, the total block population has changed. Once we get away from the rim of Camelot, the block frequency is quite a bit smaller (lower). It’s down, maybe to less than 1 percent of the surface.” This would be a strong indication that we had driven off the Camelot ejecta blanket on to that of the older Horatio.
“Much easier driving with the Rover,” commented Cernan. “Boy, am I glad we got that fender on. Very obvious that the Rover navigation (driving) [is easier here] because of the [fewer] blocks and because of the [relatively] smaller craters, and very subtle type craters, in this area.”
“There are up to 2-meter [diameter], bright-halo, blocky craters and, …that’s blocky-walled craters. …That may be instant rock (regolith breccia) rather than… I think it is [instant rock] rather than [the] bedrock [that we saw] in the rim area of Camelot.”
“Horatio has got to be… There’s Horatio, right there,” asserted Cernan.
“Yeah,” I agreed. “That’s Horatio.”
“Let me give (have) another mark on the southern rim of Horatio,” Parker interjected, again.
“Okay.” Then I continued my terrain descriptions. “The [Lee-Lincoln] Scarp looks very smooth from here. No obvious outcrops [visible] at this time (distance). …[The nearby craters] don’t seem to be penetrating to any bedrock in the area we’re traversing now— just to the southeast of Horatio. Horatio has a blocky wall; however, the upper several tens of meters, probably, of rim look as if it’s either mantled— or composed of— the light-gray regolith material we’ve been driving on. The blocks [on the wall] do not come [up] to the rim of Horatio.” This is in contrast to the blocks at the rim of Camelot and suggests that Horatio is the older crater whose rim rocks have been totally degraded to regolith.
“I don’t know if I want to take you down there or not,” Cernan interjected as he approached a significant depression in the area between Horatio and Camelot. “Yeah, Jack, hold on; I’ll take you down there.
“Horatio has quite a different appearance than Camelot,” I continued. “And that’s the main one [difference]— the blocks do not get to the rim. …Watch your roll,” I said with a laugh. “I know it’s (the roll) not much, but it seems like a lot.
“I’ve just got to go around that crater.
“Yeah. …It looks like— if Horatio is any gauge, the rim [stratigraphic] thickness of maybe— and this is a wild guess, Bob— but maybe an average of 20 or 30 meters [of] stratigraphic thickness lies above the exposures of the subfloor— [those] exposures being blocks in the wall. And some of those blocks, again, are several meters, if not 5 to 10 meters in diameter. And they’re concentrated on the west rim (wall) that I can see. …There are very few blocks on the east— excuse me— there are very few blocks on the east, north, and south walls of Horatio.”
[An examination of LROC photographs confirms my observation that blocks are prominently exposed on Horatio’s west wall but not elsewhere (also see Fig. 11.13↑ (top), suggesting that Camelot ejecta covers such wall exposures elsewhere in Horatio. The west rim of Horatio lies about a crater diameter from the west rim of Camelot and, therefore, in an area where Camelot ejecta would be relatively thin.]
“Okay, Bob. We’re on the southern rim [of Horatio]; 078 (bearing), 2.3 (distance), and 2.0 (range) [relative to the SEP transmitter].”
“Yeah. We’re maybe 100 meters south of the rim,” I added and then revised my statement. “Actually, we’re on the rim crest. We’re 100 meters south of the break in slope into the crater.” Strangely, none of the traverse photos I took in the vicinity of Horatio (AS17-135-20610-22; see Fig. 11.13↑ (top)) show these features of Horatio (except some of the blocks on the west rim); however, the crater lay off to my right, so I could not point the camera toward the rim and we did not stop specifically for photographs.
“It’s an undulating, hummocky traverse terrain in there, Jack. …These little craters make it bumpy; but, other than that, it’s really smooth sailing!”
“That’s right. This is what I sort of expected the dark mantle to look like, rather than what we landed on. Not more than one percent of the surface (is covered with blocks), and that percentage continues right over the rim crest of Horatio down onto the wall until you hit the big blocks [on the wall].” It was not until about 45 years later that I was able to make a close study of Camelot and realized that it was several hundreds of millions of years old (see Chapter 13). Thus, we were driving over an old regolith surface that had been developed on the Camelot ejecta blanket.
“What’s this depression?” Cernan asked. “That’s not [Bronte]. …No, we’re not to Bronte yet.”
“No, I don’t have any [idea]. No, we’re not at Bronte…”
“And how about an amps and a mobility, [that is] …a speed reading,” requested Parker.
“I’ve been pushing anywhere from 9 to 11 clicks, and most of the time that’s full out, and amperes are bouncing around 100 apiece.”
“Okay, watch these down-Sun craters,” I advised, as he had to turn towards the north a few degrees. “They’re hard to see.”
“I know they are.”
“We’re climbing, Jack,” Cernan then observed. “Because I’ve been full bore most of the time, and all I can get out of it is 10 clicks; and when I decelerate, she decelerates in a hurry. What’s our next stop here? A sample at 3.9?”
“Ahhh…080/3.9,” I said, after looking at the Checklist.
“Well, I’m sitting on 080 right now and 2.6 (range). I think we’ve got to add a little bit to that if they’re right [about where we landed].”
“Stand by,” Parker said. “We’ll get a new correction [for the sample] for you guys on that shortly.” Ray Zedakar and company, back in the MOCR, were re-figuring where they thought we were based on the Camelot and Horatio position fixes they now had.
“The surface is not changing,” I said as I went on with observations. “We see no craters that seem to penetrate into bedrock out in here— that is, [craters] with blocky rims— and that’s quite a contrast to the area we sampled at Station 1A yesterday. I cannot see in my field-of-view any blocky-rim craters. There are slight (small) craters with fragmental walls and rims, but it looks like instant rock (regolith breccia) rather than the subfloor material.”
“Jack, can you see over there to the left— I’ll turn a little bit [south]— on the dark area of the South Massif where you get those impressed lineations? See them going from left upward to the right?”
“Yeah. I see what you mean; right.”
“That’s what I saw out my window.”
“Yeah, they go obliquely up the slope,” I added.
“They’re more like wrinkles, they’re linear wrinkles.”
“Yeah. Crenulations, you might say, in the slope that look something like those I saw from orbit, looking in the shadowed area…or at the edge of the shadows.”
[Lunar geologists had puzzled over “wrinkles” or lineations on mountain slopes since reported and photographed by Scott and Irwin on Apollo 15. Geological Survey geologists did some variable lighting simulations using model slopes of random roughness that they sprinkled with rock dust. Just moving a grazing light around gave similar apparent lineations on these model slopes. As noted in photographs of the Sculptured Hills (Chapter 10 – Station 1), however, some large-scale lineations may reflect true bedrock structure. Also, the linear arrangement of lines of possible boulder outcrops on the slopes of the South Massif are very different from these more subtle lineations and may be outcrops of different layers of ejecta from several basin-forming events, such as Crisium, Serenitatis and Imbrium.]
“Bob, we’ve seen craters as much as 20 meters— maybe 30 meters— in diameter without blocky rims,” I reported. “…The rim block population is not much different than the average for the terrain in here…” This observation suggests a regolith depth of at least 4-6 m, The Surface Electrical Properties Experiment data indicate regolith depths of 15-20 m. in this area, possibly due to overlap of Camelot ejecta on that from Horatio.
Boy, I’ll tell you,” asserted Cernan. “If we can’t recognize a change in that albedo when we get onto that white mantle, I’m going to be surprised.” (AS17-135-20616).
Fig. 11.14. A portion of the Lee-Lincoln Scarp stretching from left-to-right just below the base of (West) Family and Family Mountains and behind the HGA pointing handle. (NASA photo AS17-135-20616).
“Mark my words,” I agreed. …”The light mantle is just what Gene has said, it’s… That’s it, right now. There are some very bright craters in it. They stand out. …Bright-haloed craters scattered over it that seem to be quite a bit brighter than anything we have out here on the dark mantle. …See those blocks over there? [Those are] the first different-colored blocks I’ve seen; they’re sort of…”
“Where are you looking?”
“Over to the right a little bit.”
“Darker gray, a little bit,” Cernan observed.
“Watch yourself here. …Okay. …There’s a crater with a big mass of block in the bottom. It looks like it might be a secondary [impact ejecta] fragment from somewhere.”
“Do you want to get a photo as we go by?”
“Yeah. Can you swing a little bit to the right?” I asked.
Fig. 11.15. The secondary impact crater discussed in text. The LRV-1 rock sample 72135 is taken from there. (NASA photo AS17-135-20623).
“That might be worth a [LRV sample]. How’s our time for traverse, Bob? Do we have time for an LRV sample?”
“You’re doing great, so far. We’re looking for that first LRV sample at about 4.2; that’s in the light mantle. [Get the sample,] if you can do it quickly, but we weren’t planning on it.”
“Want one here?” Cernan asked me.
“Yeah, let’s get [one]. …Can you get [close]?”
“Go ahead,” he said as he stopped next to the boulder in the crater.
“Swing a little bit to the right now,” I guided.
“Right up across that little ray.”
“And I’ll try to get a chunk of whatever [this is]. Okay, I want… Keep going; keep going. …Whoa, whoa, whoa.” None of the photographs actually show the “big mass of block in the bottom”. My memory is that we snuggled the Rover up next to a large, fractured boulder to get the sample, but the photographs do not confirm this. My guess is that the boulder was always just off the right edge of my image frames.
“Okay. Let me get the [Rover power] switch off. [We are at] 082, 3.0, and 2.6. …And, Bob, I’ve been making 10 to 12 clicks coming across the surface; and, as I say, for the most part, that’s full bore except where I have to do some rapid changes.”
“Okay,” replied Parker. “And, by and large, the [Science] Back Room is interested in you guys pressing on to Station 2.” The “Back Room” scientists apparently weren’t as interested in targets of opportunity as I was. Meanwhile, I had grabbed the Rover accessory staff with my left hand and leaned as far to the right as I could to get a rock and some regolith in a Dixie Cup bag.
“Okay, we are… [Jack,] just watch the LCRU.”
“Okay, Gene. That’s a pretty big rock in there,” I said as I swung the head of the sample around to Cernan so that he could remove the bag with the sample in it.
“Okay. …Hold it. Hold it down further. …Down,” requested Cernan as I had the bags too high for him to extract the bag with the sample from the others.
“It’s got quite a bit of dirt in it, [Gene]. …[Bob,] I think this is a block from a linear strewn-field of very irregular and jagged rocks that are southwest of a crater that’s 10 to 15 meters in diameter. It looks like the material that may have formed the crater, and you can look at some of the pictures and make up your own decision. …Can you get it in there?” I asked, as Cernan tried to put it in the SCB hanging from the accessory staff. “Okay. You got it.”
“No, no. No, I didn’t.”
“The bag’s (the SCB) not open,” he explained.
“Well, okay. Yeah, that’s bad.”
“Can you push it in? Pull down [on the bottom]. …Okay. It’s down [in the SCB]. 26 Echo (72130-35), Bob. We’re on our way.”
[Sample 72135 turned out to be an impact-generated breccia (“cataclasite”) composed entirely of fragments of olivine-ilmenite basalt, glass, and orange and black ash. The clasts appear to be much finer grained, more rapidly cooled lava than the gabbro I had been describing. Indeed, the impact may have penetrated to and created the sampled basaltic breccia out of the jumbled, fine grained basalt slabs that characterize the tops of “pahoehoe” lava flows on Earth. The photographs appear to confirm that the sample came from a ray or strewn-field of fragments and blocks ejected from the nearby impact crater. In contrast to the earlier estimate of 10-15 m for the depth of the regolith, the regolith at this spot would appear to be about 2-3 m deep in order for the impact to excavate below it and into subfloor material.
The regolith associated with 72135, that is, sample 72131, has an intermediate Is/FeO maturity index of 60 with a relatively high TiO2/TiO2+FeO ratio of 0.38, but no agglutinate or other fragment concentration data is available.]
“…And, you got a frame count, Jack?” Parker asked.
“Oh, yeah. Let me [look]…”
“And I did get my locator [photo back to the Challenger] here,” Cernan reported.
Fig. 11.16. Rock sample 71235 that I picked up by leaning out of the rover near a secondary impact crater. It became the designated LRV-1 sample (see Fig. 11.19↓ for location). (NASA photo S73-16201).
“Okay. I got mine, [too]” I added “…And the frame count is 95. …Holy cow! I’d better slow down my picture taking.” This film pack needed to last until we arrived at Station 2.
[In addition to the absence of a photograph of the boulder in the crater that I described, neither of our photographic sequences include the locater back to the Challenger both of us say we obtained. I have not been able to find an explanation for these discrepancies other than we both missed triggering our camera shutters.]
“Roger, Jack,” agreed Parker.
“We’re in a little area where the fragment population may be up to 3 percent. It’s getting a little more like what we saw around the LM. In fact, I would say it was comparable [to that area] now, …but nothing like [the block coverage at] Station 1.”
“I’m going down this [crater] slope and up the other side, Jack.”
“And the next planned Rover sample will be at a distance (he meant “range”) of 4.2,” Parker informed us, “so, 080 (bearing) and 4.2 (range). And it will be in the light mantle if…that [predicted light mantle location] disagrees with those numbers.”
“Okay. It’s in the first prong of light mantle, as I recall. Is that right?” I asked.
“Roger; the [left] thumb.” The mapped light mantle unit formed a plume-like pattern somewhat like a palm-down left hand that extended from the base of the South Massif up to five kilometers over the subfloor regolith surface on which we were driving (Fig. 11.17).
“Okay, Bob,” reported Cernan. “Your heading at 260 looks like it’s right on [for Hole-in-the-Wall], by the way, from what I see on the skyline.”
“Okay. And how’s the low-gain antenna holding up?”
“Well, I’m moving it, so I guess you’re getting it,” Cernan replied.
“Yeah, we’re getting it. Just checking.”
“Bob, the [large] blocks I see still seem to be the gabbro,” I continued with descriptions of the terrain we were crossing, “except for that one sample we took, which I hope was (is) what I thought it was…” namely, an impact breccia from another location.
Fig. 11.17a. View of the valley of Taurus-Littrow from America showing the major surface units, including the plume-like deposit of light mantle material across the valley entrance. The star marks the landing site. Lunar Reconnaissance Orbiter (LRO) oblique image M1182232465 confirms that the southeastern portion of the light mantle, including the “left thumb”, is older than most of the mapped unit (See Chapter 13) (NASA Photo AS17-147-22467).
Fig. 11.17b.The oblique LROC image referred to in Fig. 11.17a which highlights the light mantle avalanche material composed of the larger, brighter younger material on the western side and the smaller, darker older material of the “thumb” on the eastern side. (NASA/Goddard/ASU LROC photo M1182232465LR).
[My statement that the blocks “still seem to be the gabbro” was based on my mental images of that rock type’s weathered appearance in the area of the Challenger. This extrapolation technique helps field geologists map a much larger area than they could if every boulder or outcrop were examined in detail. Even though a rock’s “weathered appearance” usually contrasts significantly from that of a freshly broken surface, that weathered aspect usually remains distinctive in any given environment. In this case, the micro-meteor eroded surfaces, with their white zap pits, permitted rapid evaluation that the blocks were similar to those examined more closely earlier. Specifically, they were coarsely crystalline with significant plagioclase. The boulder in the shallow crater that I sampled a few minutes earlier caught my eye because it was not weathered in the same way as the more common blocks of gabbro. That rock turned out to be distinctly different, that is, it is highly brecciated, fine-grained basalt rather than a single fragment of coarser grained gabbro.]
“Gee, it’s blocky here,” noted Cernan.
“Watch the [right wheel],” I warned as it approached a large rock.
“Ooh, that’s a big crater,” Cernan noted. “We got to get around here.”
“…That must be Bronte,” I judged, looking at our traverse photomap and noting the 200 m-diameter crater directly ahead.
“My God, is that big!”
“That’s bigger than I expected,” I remarked.
“Whoo! I got to go around this thing.”
“I got to go back here,” concluded Cernan as we saw no direct path through the ejecta blocks surrounding Bronte.
“There are some very [big] blocks,” I went on, “grayer than the normal gabbro we’ve seen, that have very large, egg-sized vesicles in them…” Bronte may have been the source of the rock represented by the rover sample we just took (72135; Fig. 11.16↑).
“Watch it, you got one (block) on your right there. …Here you go.”
“Yeah. I got them.”
“Okay. Don’t mind me, Gene,” I said as it often looked like he could not see all the blocks I could see from my right side vantage.
“No problem. That’s all right, because some of those down-Suns [obstacles] are hard to see. I want to get off this slope.” The gradual slope up which we were moving toward the west made the down-Sun washout of shadows worse than usual as it decreased the effective sun angle to close to zero.
“I wonder if I took a picture of that [Bronte] block field?” I thought out loud. “I hope I did. [Taking pictures is] getting to be so automatic that I’m not sure what I’m taking any more.” My next series of photographs (AS17-135-20630-36) do not show the blocky area of concern. I may have stopped taking photographs in order to help Cernan navigate between rocks. AS17-135-20630 (Fig. 11.18) shows the trace of the Scarp across the lower slopes of the North Massif as well as Hanover Crater.
Fig. 11.18. View of the Lee-Lincoln Scarp as the white curving streak above the central and right adjacent reseau crosses with Hanover Crater at the elbow near the base of the North Massif. (NASA photo AS17-135-20630).
“Okay. I’m going to go through this niche on a high point in the [rim] saddle here,” declared Cernan.
“Okay,” I agreed. “How does it figure, Bob? I think we’re just north of Bronte. Does that figure?”
“Rog. That seems to be about where you should be on the map here. We gather you’re circumnavigating a little bit. Comm’s dropping out from time to time.”
“080 [bearing], 3.5 [distance], and 2.9 [range],” Cernan reported, “and we’re on the north side of Bronte,”
“And it looks like Bronte has penetrated the dark mantle in here,” I noted. “It got [into] the subfloor, but there’s not an awful lot of [big] blocks around the rim. There are just some small ones…[small] compared to what we saw around [Camelot]. Watch it.”
“[It’s nothing compared with] what we saw around Horatio or [rather] in the walls of Horatio and around [the rim of] Camelot. Nothing, also, like we saw yesterday at Station 1. …Bob, that characteristic little dimple in the bottom of the [small] craters is still with us, and it’s invariably glass-lined in the fresh ones. …Now, that’s not a complete lining. It just seems to be [shiny] glass agglutinates, if you will, that’s holding the fragments in the bottom of the crater together. There’s one on the side of an older crater. We’re back into about a one percent [block] coverage. I suspect that the reason our block population went up [back] there was because of Bronte.”
“An awful lot of these smaller, glass-lined little craters around,” added Cernan.
“Yeah, and you notice, Gene, what I was saying about the little dimple in the bottom? …Watch [for] the fresh ones, and they all have that little dimple as if that… You see, there’s one right there.
“Yeah, right there.”
“Man, you can predict it.”
“Jack, you know, I think the white mantle is starting right over there. See on your right?”
“Yeah, that’s the first [sign of it].”
“The place you can really see it is where it’s reflected off the slopes of the…of the [Lee-Lincoln Scarp] cliffs (slopes) out there, but I think, …I hate to say it, but Charlie [Duke] may be right.” Cernan is referring to the difficulty in seeing contacts between lunar regolith units when you are right on top of them. Obscuration of the light mantle contact with subfloor regolith due to impact mixing extends several tens of meters from these size craters, making what looks like a sharp contact at a distance appear much more diffuse up close.
“Well, Geno, one thing that may distinguish it is the bright-halo craters are brighter [in the light mantle].”
“But I can see it [in the distance] from here,” replied Cernan, “on the floor of the valley here.”
“On the Scarp it really shows up.”
“Block population is unchanged,” I said. “[It] still appears to be – where I can see large enough blocks – the gabbro, although there’s not as much to look at now in terms of blocks. The [regolith] surface characteristics have not changed. There are no craters that we see that are bringing up clear (unmistakably) blocky rims. Most of the fresh craters have instant rock (regolith breccia) around them. Around craters of the same size that are older and more subdued, that instant rock is apparently broken down. I suspect the small zapping breaks that [instant rock] down fairly quickly.”
“Okay, 17. Copy that,” acknowledged Parker. “You still making about 9 to 11 kilometers [per hour]?”
“No, sir. I’ve been making from 10 to 12, Bob – mostly 12.
“Can you give me a reading on the amps this time, Geno?”
“Stand by. I’ve got a little navigating to do. …Okay. …I’m read…I’m reading…I’m reading 100 – bouncing – around 100 on both of them.
“How about amps and not amp-hours?” Parker persisted in spite of the obvious difficulty in making readings while bouncing around.
“And I’m going up-and-down, hummocky terrain, I think with…”
“Watch your [right],” I interrupted. “You got a hole in front of you.”
“Ohh! There you go. Spun out a little bit,” I observed as the Rover’s rear end moved sideways.
“Yeah, let me get up here [on the rim of this crater].”
“Good vehicle you got here,” I commented, as the Rover’s low center of gravity forgave Cernan’s little driving glitch.
“Yeah. It takes a little getting used to, though.”
“I’m not sure I want to go through many of those [size craters].”
“No,” I agreed, wholeheartedly.
“Okay, Bob. I’ll give you an amp reading as soon as I can. Just stand by for it.
“All right. There’s no hurry. No hurry.”
“Would you believe my camera handle’s come off?” I said, suddenly. Vibration and use had apparently loosened the threaded bolt that held the camera handle to the RCU camera bracket and the camera body.
“The terrain gets a lot more locally hummocky with some well-rounded rims but very large-aspect-ratio craters— which you got to get around in here— in the 4 to 5-meter size,” Cernan said, outlining his driving difficulties. “Charlie, that…,” he continued, “ ‘Charlie!,’ ” he said in amazement at his slip in calling me “Charlie”. “I was thinking of white (light) mantle. That’s the white mantle we’re coming up on right up here.”
“Yeah,” I said, curtly, now worried about my camera coming out of its RCU bracket but still needing to take pictures along our route.
“See that on your right?”
“That’s it, there’s not going to be that much [albedo] difference.”
“Ooh!” I exclaimed, as Cernan went over a small crater that gave the Rover a hard bump.
“Not going to be that much [albedo] difference, but…. Look where you’re going,” he told himself.
“I got to watch I don’t lose my camera. It’s come loose.” At this point, I should have insisted that we stop and tighten my camera handle.
“See,” Cernan said, apparently oblivious to my camera problem, “now you can look where we’re going to come up on the white (light) mantle. It’s (the regolith) dusted with that light [dust]. …Look at it.”
“We’re only 100 meters from the light mantle.”
“Well…,” I said, skeptical of this distance estimate.
“How about giving us the range and bearing when you get to it?” requested Parker.
“Look at this crater in here,” Cernan continued. “We’re coming right up on it now.”
“…There certainly is a change in the general albedo, “I commented, “particularly in the craters. The craters are much brighter in their walls than we’ve seen before. …Although there still is a brown…a light [gray]…or a gray dusting over the top of it (the regolith) in here, but it’s clearly different— no question about that.”
“You can’t see the contact as you cross it, but we know we’re coming into something lighter. You can obviously see it.”
“Yeah. We ought to sample the rim of one of these craters when we get our LRV sample, because that’s what’s distinctly lighter.”
“How about a range and bearing, guys?” insisted Parker.
“We’re at 3.8[ km] here, and we can sample that rim. …083 (bearing), 4.4 (distance), 3.8 (range), and I’ve been…”
“How about right over there, Geno, [for the sample]? Can you get on the rim of that crater?” I asked.
“No, right to the right there…”
“…That light stuff. See the big crater here…and the light material right on the rim?”
“Yeah. I can get there,” Cernan agreed. “But I’m going to have to not give you much of a turn [for the photo pan] because it’s [too deep]…”
“That’s all right. I got the pictures. Now, if you can swing to the left a little bit and then back. …Whoa. Now, back right. Okay. Hope my camera stays on there [while I sample].”
“You like that?”
“Whoa. Yeah. Whoa, whoa.”
“Okay, Bob. We’re 083, 4.4, and 3.8; and I’ve been running about 20 to 25 amps, I think, on both [buses]. …We are in the light mantle. It’s not a contrasting ‘light’ like you might expect, or like we’re looking at on the Scarp as the Sun shines on it, but I don’t think there’s any question [we crossed the contact].” This range of 3.8 km was 0.4 km less than what had be given us as an updated location for this rover sample and the left thumb of the light mantle. This error is large enough to indicate that our position updates relative to Camelot and Horatio were off by several hundred meters.
“Yeah,” I agreed as I took the sample. “The craters that penetrate into it (the light mantle) are definitely different. However, the surface texture is unchanged. There may be fewer blocks…”
“Okay; bag 27 Echo, 27 Echo (72140-45) (soil sample from LRV-2, Fig. 11.19),” Cernan read off, as he took a bag from the Rover sampler.
Fig. 11.19. Location of soil samples 72140-45 from the first contact with the light mantle material in the “left thumb” of the debris flow from the South Massif at LRV-2. (From C. Meyer, Lunar Sample Compendium, 2010).
[Although 72140 came from a projection of light mantle material, it is significantly different in fragment concentrations than other light mantle regolith samples (see Chapter 13). Post-mission analysis found that about 17.9% of sub-sample 72141 contains rock and mineral fragments similar to those in South Massif regolith; however, it also contains significant basaltic material (15.1%, including 7.9% orange, black and colorless glass), indicating significant impact redistribution of material from nearby dark mantle regolith.
The agglutinate in 72141 totals about 51%. The sample’s high Is/FeO maturity index is 81, considerably more mature than earlier samples of regolith from the valley floor’s dark mantle. With an intermediate TiO2/TiO2+FeO ratio of 0.24, this became the first regolith sample to suggest that high apparent maturity correlates, in part, with low ilmenite content (see Chapter 13). A portion of the high maturation would have occurred since the light mantle was emplaced on the dark mantle; however, some maturation would have been inherited from the pre-avalanche South Massif regolith. In fact, later oblique, high sun images provided by LROC showed that this sample from the left thumb of the light mantle actually came from an avalanche significantly older than the main light mantle unit as shown by its lower albedo indicating longer exposure to maturation effects (Chapter 13).]
“Copy that. And frame count, Jack?” Parker asked even though it should have been obvious I was busy.
“[Put it in] your bag?” asked Cernan, referring to the SCB hanging on the Rover console. ‘We don’t want to lose it.”
To Parker, I said, “Stand by.”
“Hold it (the sampler) up,” requested Cernan as I held the sampler toward him so he could remove and close the cup containing the sample I had just scooped up.
“Okay. It’s (the sample) in there.”
“Is it in?” he asked to be sure. “Okay. Oops, the bag [on the accessory staff] won’t stay open…”
“Yeah. It will [stay open] after we get a couple of samples in there. Okay; my locator [photo]”.
“And my locator,” added Cernan.
[In examining photographs related to this sample site, it occured to me that we should have had a procedure for Cernan to back up the Rover so that the actual sample scar would be visible in these locater photographs. He could have done this easily while I put the sample in the SCB. No significant data on location was lost, but I do not recall that addition of a more accurate location procedure was ever considered.]
“I hope I don’t lose my camera.”
“I can’t reach it, or I’d help you.”
“Okay. [Frame count] 110,” I reported. “…I guess I didn’t do what I wanted to do, and that’s get that thing (the camera handle) really cinched down…”
“Boy, Bob,” Cernan said, “one of the remarkable things is the Sun-angle difference on that light mantle when you’re looking at the slopes of the Scarp versus what we’re on. I hate to use a familiar term, but my impression right here is there is more of a raindrop influence than back at the LM, or in the darker mantle.”
“Yeah. Might be,” I said, but skeptical of his raindrop statement.
“I think so,” insisted Cernan.
[At the time, I could think of no reason why the micro-meteor impact craters would be better preserved on the light mantle than elsewhere in the valley. If the average grain-size of the materials at the surface of the light mantle were different from regolith surfaces elsewhere, however, the patterns might vary from surface to surface. Indeed, a comparison of the particle sizes for light mantle samples with those from basaltic regolith shows that their size-frequencies peak at about 62 µm and 16 µm, respectively. This probably explains the difference we thought we observed. Additionally, the interiors of these small “raindrop” craters are darker than the exteriors due to the effect of sun angle (photometric darkening) and shadow. The light-dark contrast between the darker interior and the light mantle would be greater than on the dark mantle and may create a visual appearance of greater prominence. With time lapsed imagery from the Lunar Reconnaissance Orbiter Camera (LROC) available since 2016, there are suggestions that this “raindrop” pattern may not be only from micro-meteor impacts so much as from the broad spray of fine secondary debris ejected from larger craters. (see “raindrop” pattern in Fig. 11.5↑, for example).]
“I think,” I added, but not referring to the raindrop pattern, “the big thing is, though, that each one of these little [impact] craters is much more lightly colored [than we have seen before]. …There’s no [such] crater in view…that has a blocky rim. There’re fragmental (fragment-rich) rims based on, almost certainly, [the formation of] instant rock, but no blocky rims.”
“You know, one of the reasons those craters look lighter is because of their Sun angle [on the] walls of some of these little craters. …It’s the same material we’re driving on, I’ll bet. Yeah, there is instant rock right there, Jack; you’re right.”
“Yeah. …The fragment population is certainly less than one percent in here,” I observed.
“Right now, when I say fragments,” I clarified, “I’m talking about rocks that are greater than a centimeter in average diameter.”
“You know, it may be me, Bob; but it also seems to be a little bit more difficult to drive down-Sun in this area.”
“Yeah, I think it (down-sun albedo) is brighter, Geno. I was thinking that a minute ago, but it’s hard to make a [quantitative judgment]. …I think your normal (direct down-sun) albedo is greater.”
“Here’re some rocks now starting [to appear].”
“And the little craters still have the central pits,” I added.
“Okay,” Parker called. “We’re losing your comm a little bit, guys.”
“Well, we’re [pointing] right at you… [There are some boulders.]”
“Yeah, there’re a few,” I concurred. “There’re a few blocks. They still look like the gabbro, though. Hard to tell [for sure].” We were crossing an obviously thin projection of the light mantle so it would not be surprising if some gabbro boulders from older craters in the underlying subfloor material projected through the unit and any light mantle covering [on the blocks] had been removed by micro-meteor impacts.
“Well, a couple of them (blocks) looked to me like they had some very light crystals in them. See that?” Cernan asked, pointing to a boulder we were passing.
“I’m afraid those are zap pits,” I warned him.
“They could be.”
“I think I’ve been fooled by that, too, and that’s (number of white zap pits) what I [wrongly] estimated the plagioclase [content] by.” I was referring to my early estimate of 50 percent plagioclase in the gabbro versus the ~30 percent indicated by using a hand lens inside the Challenger, the second estimate being confirmed by post-mission analysis.
“Whooo!” exclaimed Cernan. “I just want to keep you out of those slopes [in craters], and I’ll tell you, I get you in some [other craters] by keeping you out of them.”
“That’s all right. …We’re getting a little more blocks in here. Of course, we’re approaching the dark mantle again. Now, you can see the difference. You got to look hard for it! But, you see those craters out in there are not white anymore.” We had crossed the left “thumb” of the light mantle and now were on an inlier of dark mantle I had named Tortilla Flats. (see Fig. 11.19↑)
“I got to get around that slope (crater wall).”
“Yeah,” I acknowledged. “Okay. You still got Hole-in-the-Wall picked out over there, don’t you?”
“Yeah, I got it. And, I’m trying to keep comm with them as I’m turning here. …And, I’ve been keeping the thing (low gain antenna) [pointed] on [the Earth]. I don’t know if they’re reading us, but I’ve been moving it.”
“Read you loud and clear, guys,” responded Parker.
“Looking up on the South Massif,” I said, trying to concentrate on what I could see rather than on how tired my right arm was becoming from holding on to the camera. “We’ve got real good views of the block-strewn fields [on the upper slopes of the South Massif]. There seems to be two dominant colorations of the rocks. The light-colored ones [are] very light tan to white, and then there are the blue-gray rocks. There’s one major outcrop of blue-gray about a sixth of the way down the slope [in] the center of the field-of-view we have [at present]; and it looks very much like similar blue-gray rocks right at the crest— the highest point from our vantage point.” Recent, high resolution and southwest looking oblique images from LROC suggest that these blue-gray rocks may be at the surface of an impact melt flow that drapes the upper portion of the South Massif.
[This view we had of the north facing, ~26º slope of the South Massif gave a good opportunity to view indications the basin ejecta history represented by the sequence of exposed rock ledges. Our exploration of the sides of the valley of Taurus-Littrow involved rocks deposited during the formation of various large basins centered within about 1000 km of the area (see Chapter 13). The South and North Massifs bounding the valley appear to be the sides of a graben fault (center mass down relative to the two side masses) as a part of the extraordinary, dynamic and violent impact of the asteroid or comet that created the nearest of these basins, the 740 km diameter Serenitatis basin. (See Chapter 13)]
“Bob, [do] you want another sample of the dark mantle here?” asked Cernan. “Could you use that?”
“Yeah, we want [a range and bearing] as soon as you get into the dark mantle. We’re estimating it’s (range) something like 4.3 [to] 4.5[ km]; somewhere in that vicinity.”
“We’re there,” I declared, as we reached a point well into the Tortilla Flats inlier of dark mantle bounded on the southeast and northwest by light mantle.
“Okay. We’re ready for another (sample), then.”
“We’re there,” I repeated. “Now, [Gene], let’s, …if you can, …[get] right over there,” pointing with my glove to a spot with several small rocks, “and maybe I can get a rock with it (the soil). See that batch of rocks there?”
“Right here?” he asked, turning to the right.
“Whoa,” I directed. “Yeah. Swing it. Whoa, now swing back over [left]…little more…little more. Whoa. Little more.”
“Can you reach it?”
“Now, if you go forward.”
“Can you reach it?”
“Hold it. Right there.”
“Okay, Bob; 082 (bearing to SEP), 5.0 (distance), and 4.3 (range).” These numbers give an average speed since leaving Challenger of 7.4 km/hr. “And CDR (Commander) is 3.85 [psi] (suit pressure) and about 70 percent (oxygen) and no [warning] flags.”
“I got it (the sample),” I said.
“You got it? Okay.”
“I got the rock. I got the rock, and there’s some dirt in there. Maybe I’d better get a little bit more dirt.”
“Yeah. …You don’t have any trouble getting dirt.”
“Can you see in there?” I asked, extending the sampler cup toward Cernan. “Is there much soil [in the cup]?”
“Oh, a little bit…”
“Okay. I’ll get this [additional] soil [in another cup].”
“Couple teaspoons full [of soil in addition to the rock]… 28 Echo (72150-55), Bob,” reported Cernan.
“Say again there, Seventeen.”
“Twenty-eight Echo,” repeated Cernan. “And that’s primarily a rock fragment. Jack’s getting a soil sample [that goes] with it.”
Fig. 11.20. Rock Sample 72155 showing a line of zap pits along a diagonal up the middle of the rock. (NASA photo S73-18234).
[Post-mission examination disclosed that 72155 consists of a fragment of fine-grained, vesicular, ilmenite-rich olivine basalt. It looks similar to the breccia clasts in a previous LRV sample (72135) suggesting that, at least at this locale, the bedrock under the dark mantle consisted of rapidly cooled lava from near the top of the subfloor gabbro.
The accompanying regolith sample, 72150, representing the dark mantle inlier within the light mantle, has a total of about 20.1% basalt material, including about 10.5% orange, black and colorless glass, a sharply higher amount as compared with the previous regolith sample from light mantle (72141). 72150’s agglutinate concentration is about 52.6%, and, unlike most ilmenite-rich dark mantle regolith, it has a high Is/FeO maturity index of 82. The high maturity index and agglutinate concentration, combined with an intermediate TiO2/TiO2+FeO ratio of 0.23 is at odds with other dark mantle regolith samples and suggests contamination by fine-grained light mantle material. Contamination possibly occurred as a result of clouds of fine-grained, mature material ejected during emplacement of the fluidized light mantle (see Chapter 13); however, the particle size distribution resembles other dark mantle regolith, being bell-shaped with a peak at about 50 µm.]
“Jack, look at the wrinkles over there on the North Massif,” commented Cernan as he took a locater photograph toward the easily recognized Lee-Lincoln scarp and Hanover Crater on the toe of the North Massif.
Fig. 11.21. The location of rock sample 72155 (white circle). A clear view of the bend in the Lee-Lincoln Scarp on the North Massif and Hanover Crater at the bend are seen in the distance. (NASA photo AS17-135-20649).
“Yeah,” I agreed. “There’s no question that there are apparent lineations all over these Massifs, in a variety of directions. Hey, look at how that Scarp goes up the side [of the North Massif] there. There’s a distinct change in texture. …As a matter of fact, the lineations are not present on the [top of the] Scarp that we can see [higher up from] where it crosses the North Massif. There is no sign of those lineations on [the top of the Scarp] there.” Forty some years later, I referred to this slope on the hanging wall of the Scarp as part of “shaken-not-stirred” terrain, produced by seismic degredation of surface features during faulting.
“Oh, man; yeah. I can see what you’re talking about now.”
“Look over by Hanover,” I said to emphasize my point and referring to a crater just to the north of the scarp trace on the North Massif.
“It looks like the Scarp overlays the North Massif, doesn’t it?”
“Yeah.” What had caught my eye was the absence, on the slopes below and south of the Scarp, of the crossing lineations characteristic of the slopes of the North Massif above and north of the Scarp. This, in turn, suggested a difference in operative surface or near-surface processes and/or age between the two slopes. Also, as discussed further later in this Chapter, seismic shaking associated with the formation of the Scarp may have obliterated the lineated texture on its lower south-facing slope but not affected the lineations on the nearby, south-facing slope of the more stable Massif.
“Okay,” Cernan began as he closed the LRV sample bag. “This last [sample] was 29 Echo (72161). …Okay, now I need to get [it] in that bag (SCB).” This Rover sample contained regolith from the tongue of dark mantle between the light mantle thumb and the main light mantle unit.
“Copy that. And that’s the soil?” inquired Parker.
“That’s affirm,” Cernan replied. “…Here’s another one (sample),” he said and handed me the second Dixie Cup to put in the SCB. I could reach the SCB to my left more easily than he could.
[As expected, post-mission analysis of 72161 disclosed that fragments and agglutinates (31%) derived from basalt and gabbro dominated this inlier of dark mantle regolith. This regolith sample also contained about 9% orange and black, non-impact glass in the greater than 90 µm size fraction, comparable to other dark mantle regolith samples. The sample has a maturity index of 87, like 81 for 72150, is high relative to dark mantle material elsewhere in the valley and relative to the low agglutinate percentage in this size fraction. This again suggests contamination by very fine-grained agglutinates derived from the light mantle, possibly carried by gases escaping from the avalanche that deposited the light mantle. Mixing of different regolith units also is suggested by other analyses. Relatively high concentrations of hydrogen (144 ppm) and carbon (204 ppm) in 72161 as compared to less than 100 ppm for each element in other dark mantle regolith may also be a consequence of gas transport of mature, light mantle agglutinates. Additional support for light mantle fines having mixed with dark mantle regolith in 72161 comes from particle size-frequency analysis of dark mantle sample 72150 as compared with light mantle sample 72140.]
“You’re going to… Don’t lose those [other bags on the sampler],” warned Cernan.
“I won’t. I’ll put it (the sampler) down [on the floor].”
“Okay, Bob, we are rolling.”
“And pray for me, Bob,” I added, “that I don’t lose my camera. …Okay. …Hanover is quite a ways up the slope [of the North Massif]. I don’t think we’d have gotten to it, as we [tentatively] planned that time. But the appearance you have of the Scarp/North Massif contact is one of the [top of the] scarp being smoother textured, less cratered, and certainly less lineated. (Rather than saying ‘scarp’ here, I should have referred to the surface to the south of the scarp.) And I wouldn’t be a bit surprised if it’s, as Gene says, younger [than the massif].”
“…It’s not just the slope,” added Cernan, “it’s the materials on the other side of the Scarp, on the west (southwest to south) side.”
[Recent examination of high-resolution images from the Lunar Reconnaissance Orbiter (LRO) and crater frequency analysis have added confirmation that scarps like the Lee-Lincoln Scarp probably result from relatively recent thrust faulting due to the current slow cooling and contraction of the Moon in contrast to an early history of heating and expansion. This conclusion, in turn, caused me to look more closely at both the LRO images of the valley of Taurus-Littrow as well as those taken by Evans during our stay there. Strong indications exist that the Scarp formed sharply and that adjoining regolith and its superposed craters were “shaken, not stirred”, giving the impression of a fresh mantle being deposited on the surface. This shaking process also may have been the reason for the lack of lineations on the top portion of the Scarp that crosses the North Massif that I just described. It also indicates that these lineations on the North Massif are not artifacts of lighting.]
“Okay, I’m going to have to really ease up on pictures. I forgot to give them a frame count.”
“Yeah,” agreed Parker. “We didn’t get a frame count. You want to give us a frame count there, Jack?” Parker’s strange sense of humor showed up, again, in excessive repetition.
“Well, Bob, …the problem is every time I take my hand off [the handle], my camera loosens up again.”
“Okay; I copy that. And our estimate is that if you continue to go between 50 and 100 meters between frames, we’ll make it.”
“Boy, I tell you,” exclaimed Cernan. “Are those Massifs getting to look big now! Holy Smoley!”
“That frame at the LRV sample was about 115,” I said, finally able to see the counter, again.
“I’ll tell you, that Scarp looks nice over there, too, doesn’t it?” (see Fig. 11.21↑)
“Yeah… Okay, we’re back down in our old friend, the dark mantle. And I think the zero-phase point is not as bright as it was. [We’re] passing a small crater, but the block population is still way down there in about— Whoops, watch that one (crater)— [the] one percent [range].” My photographs show that the walls and ejecta blankets of craters in the light mantle are distinctly brighter than those in this tongue of dark mantle. (AS17-135-20637-56)
Cernan increased our speed to about 10 or 12 km per hour, but to do so, he had to concentrate on the terrain ahead, particularly when going directly down Sun. Now and then, a small crater will suddenly become visible but too late to avoid.
Fig. 11.22. Examples of craters with brighter walls and rims in the light mantle area as we approach Hole-in-the-Wall and the Scarp. (NASA photo AS17-135-20640).
“And, Seventeen, for your benefit, we’re showing you with very good net mobility rates here; and things [are] looking quite good.” Parker is referring to being able to have all our planned time at Station 2. We have been driving for about 45 minutes since leaving the SEP site, 4.3 km behind us.
“Thank you,” I acknowledged. “Cernan’s doing a great job.”
“I’ll tell you, it takes all your time to drive, though,” explained Cernan. “You look around, and you’re in a hole.”
“Okay, here’s another small crater [with] instant rock (regolith breccia), the same little pit [at the center of the crater], and a spattering of glass holding the pit materials together. None of the glass linings look very coherent, Bob. They mainly just seem to be a sprinkling of glass that’s coating…the instant rock. …The craters at about 10 to 15 meters in diameter seem to have somewhat more blocky material in their rims. But they’re not clear-cut blocky rim craters. And here’s one that’s probably 50 meters across that has a fair number of blocks in the bottom. …Looks like it (the impact excavation) might have just about gotten down to where the gabbro (subfloor material) starts to be abundant again.” This observation indicates that the regolith thickness may be about 10 m at this location in the main body of the dark mantle. My more recent studies of the deep drill core indicate that the regolith is largely comprised of units of regolith ejected at different times from valley craters up to several kilometers away. New regolith forms slowly on the surfaces of each unit until buried by another mass of regolith ejecta.
“[I am going to] start heading toward 12 o’clock (west),” Cernan declared, “and I’m going to work my way up to Hole-in-the-Wall and from there on up, right?”
“Take a long, easy turnout [toward Hole-in-the-Wall].”
“Yeah,” I agreed, looking at our photomap.
Fig. 11.23. On the climb up the Hole-in-the-Wall ramp-like slope ending near the bright haloed crater left of center. The curving line from left to right across the photo just under the 2nd row of reseau crosses from the top and just above the bright crater marks the top of the scarp. (NASA photo AS17-135-20661).
“Got Hole-in-the-Wall, Bob,” he reported. “It’s a very long, very subtle, very gentle slope. We’ll just have to get some more words when we get there.” In addition to what we could see from orbit prior to landing, Hole-in-the-Wall had been visible on pre-mission photographs as an intersection between a lobe of the Scarp and it’s main body. This gave us a more gradual slope for the ~80 m change in elevation we needed to make during the climb to the top of this otherwise steeply sloping, geomorphological feature.
“Okay; we’re anxiously awaiting them. …How about a range and bearing while you’re at it?”
“I’ve been making 10 or 12 clicks (kilometers per hour) most of the time. …Okay, 082, (bearing), 5.6 (distance) and 4.9 (range).” This put us about half a kilometer from Hole-in-the-Wall. “And about 20 to 22 amps (the electric current to the Rover wheel motors) most of the time.”
“Okay, we’re losing a little bit of low-gain [signal] there, Geno.”
“I think you need to tilt it (low gain antenna) up a little,” I suggested. “[You are] probably undershooting the Earth. I don’t know [for sure].”
“Well, our pitch angle changes all the time,” replied Cernan. “That’s the problem. Bob, I have been within 10 to 20 degrees of you the whole time.
“Okay, Bob, we’re not in light mantle, I don’t think. …Maybe we are.”
“I think we are, Jack.”
“Yeah, I guess we are. …According to my geology map [we should be]. I guess we are. Gosh, I was going to say the craters are whiter than they have been. So, we’re back in it (light mantle). And even the zero-phase point’s brighter, too.” Redistribution and mixing of materials along the contact between the light and dark mantle over several tens of meters initially kept me from noticing this change while I concentrated on navigating toward Hole-in-the-Wall. Later analysis of crater size-frequency and exposure ages for the light mantle suggest that the contact has been exposed to impacts for about 75-107 million years (See Chapter 13), resulting in several tens of meters of lateral mixing. As I have continued to work on the geology of Taurus-Littrow, I have come to think that the crater count age of ~75 million years is close to the actual age of the avalanche that deposited the light mantle unit, primarily because rock exposure ages include pre-avalanche exposure to cosmic rays as well as the post-avalanche exposure.
“I think that place where we had those small, blocky craters was within the dark mantle,” Cernan observed. “They’re not evident here in the lighter stuff.”
“Boy, is that (South Massif) getting big. Whoo-ee!” Cernan suddenly exclaimed as a crater ahead surprised him. “Hold on.”
“Whooo-ee!” I repeated.
“That [motion of the Rover] really gives me a strange feeling,” I said with a good but somewhat nervous laugh as the Rover settled down again.
“Gives me a strange feeling too,” Cernan agreed. “Those [gyrations] are not intentional.
“I’m not sure I’ve got enough guts to make them intentional. …Man, everything’s getting to look big the closer you get. …Hole-in-the-Wall looks more promising, though, Bob.”
“Yeah, I don’t think that’s going to be any problem,” I observed.
“Until we get up and look back,” qualified Cernan, thinking about the return trip downhill. “Oh, man, what a trip this is going to be. Golly…”
“That MIN cooling is just about right, isn’t it,” I said, changing the subject.
“No, it’s just about warm for me,” Cernan disagreed, as he was working harder than I due to the driving actions. At this point, his metabolic rate ran about 10% higher than mine. “Bob, is my PLSS cooling working all right?”
“Rog. It looks like it’s working to us,” Parker responded, getting a thumbs-up from Bill Bates at the PLSS telemetry console.
Getting back to noting aspects of the local geology, I said, “Bob, the rock fragments [on crater rims] still look like gabbro. The craters tend to have white walls and white rims, which they don’t have in the dark mantled area. The block population is way down, [covering about] one percent or less. However, the bigger craters do have more blocks; but nowhere does that population seem to get above about five percent. And that’s on the walls and the rims of the craters, say, bigger than 15 meters [in diameter]. There’s one [crater] probably 20 meters in diameter that has some blocks on it (the rim).”
[My working hypothesis on the origin of the plume-like, light mantle unit overlying the valley floor and most of the Lee-Lincoln Scarp in this vicinity of the valley began to evolve during pre-mission studies of Apollo 15 photographs of Taurus-Littrow. As I then postulated, an avalanche of fluidized regolith from the north side of the South Massif could explain the photographed characteristics of the light mantle. A cluster of craters on the top of the South Massif further suggested that impacts possibly triggered an avalanche. As a ray of ejecta from the crater Tycho, 100 km in diameter and 2000 km to the southwest, appears to cross the South Massif and the valley, an exposure date on the surface material of the light mantle also might provide a date for the Tycho impact event. More recently, however, LROC images indicate that an older avalanche deposit lies below the light mantle, and I have hypothesized that both the avalanches were more likely triggered by separate moonquakes along the thrust fault that produced the Lee-Lincoln Scarp. The detailed geology of the light mantle is discussed in Chapter 13.]
“Have you seen Nemo [Crater]?” Cernan asked me. “I think Nemo is right over there, if I’m not mistaken. …I don’t know.”
“Nemo will be hard to see. But, yeah, it’s probably that one right in there,” I suggested, pointing with my left arm to a crater between Tortilla Flats and the Scarp.
“Or back here. There’s one back here.”
“Well, it’s pretty … Yeah, well… Yeah, that’s close to [the] Scarp. It’s (Nemo) probably right off your [left] wing there,” I concluded.
“Okay, I’m going straight ahead,” stated Cernan, “and then I’m going to make a left turn [into Hole-in-the-Wall].”
“Okay…” I turned my attention to Lara, a 700 m-diameter but subdued crater at the top of the Scarp and to the right of Hole-in-the-Wall. “We’re looking at Lara [Crater]. Now, [in] Lara, …I can see blocks in the northwest rim of Lara. At least, it’s rugged terrain; and it looks like blocky terrain. One spot [of blocks]: that’s all I see. It (the area of blocks) looks like it may be a couple hundred meters in average diameter. It starts maybe three-quarters of the way up the wall [of Lara] and goes right up to the rim.”
[LROC images show that lobes of light mantle extend down into Lara, indicating that the crater pre-dates the deposition of that material. Unlike the case of the similarly sized crater, Camelot, where large boulders of basalt are present largely at and near the rim, boulders around Lara are distributed on the wall and away from the rim much like the case with Horatio. This indicates that the Lara impact occurred significantly before that which formed Camelot (see Chapter 13) and well before the light mantle was emplaced. The visible boulders are likely to consist of subfloor basalt.]
“Hey, Bob,” Cernan began, “Hole-in-the-Wall seems to be a…”
“Hey,” I interrupted, pointing to a small crater we were passing. “Look at that. Look at that crater!!
“Right there? Yeah.”
“That central pit goes down about half the depth of the crater,” I continued, “and the crater is a fresh, 3-meter crater. It almost was a cylindrical pit!” These features suggest a significant change in the mechanical (geotechnical) properties of the light mantle with increasing depth.
“Hey, Bob, Hole-in-the-Wall is just a step,” reported Cernan, “headed down to the south or southeast on the Scarp. The Scarp is just about what I think we all expected it to be. It’s very rolling and relatively smooth. I don’t really see any [rock] outcrops exposed anywhere out here [on the Scarp] to the south.”
“No. You see, now there’s Station 3 area right up there.” The planned Station 3 lies at the base of the Scarp and a little northeast of Lara.
“Looks like maybe that set of [craters]…” I began, but then changed my mind. “See that bigger crater over there to the right of Lara? That probably is a good place for Station 3.
“Yeah, way over there,” Cernan agreed. “Okay, we’re going to find out something very shortly [about the Scarp].”
“It doesn’t look very rocky, Gene.”
“How about bearing and range, guys?” requested Parker.
“Bob, I’ll give it to you just as soon as I make my turn,” answered Cernan. “It’s not too far— 100 meters.”
“Are you going to turn over that [area] or go on closer [to the Scarp],” I asked him.
“No, I’m going right up straight ahead and then go on to the inside of that place (the Hole-in-the-Wall’s slot).”
“Yeah. That’s more than 100 meters,” I corrected, based on my personal calibration that distances seemed shorter than they are.
“081 (bearing) and 5.6 (range),” I read off for Cernan. “Now the [fresh] craters are getting very, very light colored in their rims and walls.”
“You notice when we’re in the light mantle looking at the Scarp at this angle,” Cernan asked me, “it loses some of its high albedo (brightness)?”
“Yeah. Yeah. I think we’re getting… Your eyes get used to it.” another factor may have been the photometric effect caused by the actual optical viewing angle of the sloping Scarp being well off zero-phase relative to the Sun.
“We’ve got a long depression to go around. …Okay, Jack, we got to watch it because I got to go around a long depression. That’s a crater over there.” Cernan began a series of turns to avoid some steep slopes in front of the Scarp.
“On the right; yeah.”
“I don’t know how I can get over there to… I may have to go up over there. I can’t go down that hole. That one’s not going to make it.”
“What’s your pitch?” I asked.
“Let’s go back here. We can’t get there. I’m going to go over here.”
“What was your pitch then, Geno?” I repeated.
“[To much,] primarily. I can’t go there.”
“Yeah, I think you’re right,” I agreed as I hung forward on my lap belt.
“We’ll go up this gentle slope. See what’s on top …Okay. Let me get my [bearings]…”
“We made a turn to the south a little bit at 081 and 5.7,” I informed Parker and then asked Cernan, “are you going to try to drive up there?” I was looking at a particularly steep part of the Scarp.
“I don’t think we’re going to have any choice.” At this point, Station 2 lay about 2.2 km and 20 minutes away. My sequence of photographs taken during the climb up Hole-in-the-Wall is AS17-135-20657-65 (see Fig. 11.23↑).
“Okay. Looks to me like just to the left of that white crater is a [clear route],” I suggested. (crater mentioned in Fig. 11.23↑) “Or even [go] right like you’re headed now and then bear up to the right.”
“Yeah. …[We’ll] find out how this (Rover) climbs in a minute.”
“Oh, I think you’re all right,” I assured Cernan.
“Okay, Bob, I’m starting up the Scarp at 081 (bearing), 6.6 (distance), and 5.7 (range).”
“This is the first tongue of the Scarp,” I reported, referring to a low, secondary scarp, southeast of Lara that runs roughly parallel to the main Scarp. A relatively flat area about 200 m wide separates the two scarps.
[More than four decades later, I estimated that the dip of the plane of the thrust fault that created the Lee-Lincoln Scarp is about 26º to the west. It appears that the various lobes of the Scarp are sections of the projecting hanging wall of the fault that collapsed onto the pre-existing surface, The regolith and underlying basalt that made up the collapsed hanging wall then were covered by several meters of the fine debris of the light mantle avalanche to give the subdued appearance they now have (see Chapter 13).]
“I don’t even think the Rover knows it’s going uphill,” stated Cernan. I’ve got about 37 or 8 amps. [We’ll] See what’s on top here.”
“You’re making about 8 clicks,” I told him.
“And I’m full bore,” he replied to my laughter. “Well, I’ll tell you, this Rover doesn’t know it’s going up a hill.
“Looks to me like you may be able to head just like you’re going.”
“Yeah. Hey, Bob, we’ll make it [up the Scarp]. …Get my [low-gain] antenna adjusted.”
“Whatever makes up the light mantle is,” I reported, “at least, the instant rock (regolith breccia) that it forms, is much lighter [in albedo] than anything we see [in the dark mantle]. Those [instant rock] fragments probably are 30 percent lighter than any fragments we see out on the dark mantle. And that’s around the fresh craters. But it (the surface) is not blocky…”
“Bob, are you still reading?” Cernan called.
“Roger. Read you loud and clear.”
“Okay, I just wanted to make sure my antenna’s working,” Cernan explained, facetiously, but it was clear Parker had been distracted by activities in the MOCR, “…We’re doing a little zigzag navigation. I literally came up a slope at about a heading of 240 (west southwest). We couldn’t get through the actual turn to the south because there is a big crater right at the foot of it (the secondary scarp). So we’re just making our way through some relatively local undulating slopes that get pretty steep, but it seems to be no problem [for the Rover].”
“Yeah, I think we’re in good shape,” I concurred. “Bob, I can’t… There are not any blocks big enough to really make a statement about what the [underlying] rock is. But it really doesn’t look like gabbro anymore.” I am getting a closer look at the blocks as we move more slowly than previously, and they probably are derived from the breccias of the South Massif.
“Okay, copy that,” Parker replied. “And a reminder that eventually you’re going to have to turn to the south a little bit to pick up the final thing (leg) at Station 2.”
“We’re not on top of that Scarp, yet,” I reminded Parker. “We’re still in the Hole-in-the-Wall rim (entrance). …Bob, as far as lineations in the soil or on the surface that are observable at this range (that is, close at hand), I don’t see any. I think there may be a finer raindrop pattern on the light mantle than maybe there was out on the dark [mantle]. But that’s an awfully hard judgment to make…” How you doing, Geno?”
“Doing fine. …Bob, we’ve slowed down [to] between about 5 to 8— maybe 5 to 10— clicks most of the time. I’m going to head right up there [over the Scarp], I think. [I have to] get around this crater.”
“Pretty healthy roll we’re going to have here,” I commented, as Cernan once again put me on the downhill side of the Rover in maneuvering around this particular crater.
“Yeah, I’m going to head more straight up the hill. Once I get up on top, I’ll be all right. I’m going to head down in this hole and then up that way. …I don’t mind pitch, but I sure don’t like roll.”
“I don’t either,” I agreed while hanging over the right frame of the Rover.
“Now, I’m going to head straight up that slope right there.”
“Bob, it looks like maybe the large fragments in here are still crystalline,” I observed. “They have white zap pits on them. But they do not yet really resemble the gabbros.” If crystalline, the white halos around micro-meteor impact pits suggested significant feldspar and limited magnesium and iron-rich minerals in the rocks.
“Okay, Jack. Copy that. Give us a hack when you get up on top of the Scarp there.”
“Let me tell you, Bob,” Cernan reported. “I’ve got to go cross-slope some of the time because the Rover is really working to go uphill now. …But we’re almost there.” The Rover drive system could climb up to 25º slopes. Steeper slopes could be navigated by driving at an angle to the slope while accepting a moderate roll angle.
“As I look up the Scarp to the west,” I said, adding to my previous comment, “there are some big blocks scattered around on our horizon; but, again, I would guess that we’re not dealing with more than 2 or 3 percent total coverage of blocks in here, if that.” These may have been blocks on the rims of craters or those associated with Lara, the shapes of neither being visible from this viewing angle.
“Well, I think, for the most part— for the most part— we’re on top,” declared Cernan.
“Yeah, …we’re on top,” I agreed.
“Bob, we’re at 078 (bearing), 7.2 (distance), and 6.2 (range),” read off Cernan.” This meant that the five-minute drive up Hole-in-the-Wall carried us about 600 m at a speed of about 7 kph. “Now, Jack, where was Nansen [Crater] with respect to those [boulder] tracks up there [on South Massif]?” Cernan referred here to tracks we later found led to boulders in the bottom of Nansen, to the west of Station 2.
“Well, they (the photo analysts) never really had any good tracks pinned down,” I recalled. “…You’ll be able to see Nansen, I think, soon as you get over this hill.”
“Boy, I tell you, when we look back (into the valley toward the LM), that’s going to be quite a sight if we can see into that Sun. We have been coming uphill! Well, I’d say this is the last straw to the top. And is she (the Rover) working! Come on, baby…”
“Okay. I think you bear [left some],” I suggested.
“I’m going to try to get over along the base of the Massif now,” Cernan said.
“Yeah,” I concurred. “Head towards that track area there, anyway. There are a lot of boulder tracks coming down from the blue-gray rocks, Bob. We’ll see whether or not we’re going to get to those tracks at Nansen, or we might want to move over to the tracks and see if we can find the boulder that made them.”
“Okay; if they’re in the vicinity, it might be a nice idea,” replied Parker.
“But there’s no question where those tracks come from,” I added. Photographs AS17-135-20666-74 show the distribution of craters, boulders and outcrops on the slopes of the South Massif. Photograph AS17-135-20674 (see Fig. 11.24(top)) also illustrates the line of concentrated boulders in the moat to the east of where we would establish Station 2. The vast majority of boulders have come to rest within a single roll of the break in slope, indicating a constant slope from their source but that their residual momentum at the break in slope was very small. The boulders we would sample at Station 2 lie to the far right in this photograph.
Fig. 11.24. (Top): A view of a portion of the trough or moat to the east of Nansen Crater and Station 2 showing the concentration of boulders at the break in slope between it and the north-facing slope of the South Massif. (Bottom): A closer view of the 2 boulders seen at far right in the top view. We are parked on the interior eastern slope just inside the rim of Nansen. (NASA photos AS17-135-20674, -75).
“And we gather you’re slowing down to about 5 clicks now, coming up this last rise,” Parker surmised.
“Yeah. I’m back up to about 7 to 10 now, Bob. The slowdown is because that’s about all it will take!”
Looking up at the South Massif, dead ahead, I observed, “Bob, I have the impression that there is a dipping zone (not a horizontal plane) of blue-gray outcrops or block concentrations up there on the Massif that trends from the high point, just beneath the Earth, cross-slope; and probably the apparent dip is— oh, I don’t know— 10 or 15 degrees (down) to the east. It looks like those outcrops may match up along that trend.” LROC images later suggested that this line of blocks may be the edge of a mass of impact melt deposited on the crest of the South Massif.
“Jack, I’m going to head right along this ridge because I think that’s the depression (Nansen) we were talking about.”
“Yep, that’s Nansen down there [to the right].”
“Where are you looking?” Cernan asked. “Right there?” he continued, pointing just to the right of our heading.
“I think, right below [those boulder tracks].”
“I think you’re right. I think that’s it. Let me get over here [to the east], and then I’ll head a little bit to the south.”
“Yeah,” I agreed, “we’re a little more west, I think, than we intended to be.”
“Yeah, I think you’re right. …Bob, …what is it (Station 2 position)? 078 (bearing) and 6.5 (range)?”
While Cernan navigated, I summarized my passing looks at the few boulders I had seen around the larger craters. “Bob, I’ve had an impression, and I can’t prove it yet, that we’re dealing with more heterogeneous rock. Possibly there are breccias (rocks made up of fragments of other rocks) in here. But it’s awfully hard to tell right now. They’re very light-colored rocks, I think even lighter colored than the gabbros.”
“Okay. We’ll soon find out.” Parker stated the obvious.
I began to try to correlate boulders with tracks on the Massif slope, but began to have reservations about being able to get to boulders with obvious tracks leading to them. “I’m afraid those [boulders with tracks are all in Nansen]. …I think we can follow those [boulder] tracks. The pictures, maybe, [will show boulder sources.]”
“Yeah, I think we can see some of those coming down,” added Cernan.
“I think the ones from the big outcrop of blue-gray rock, though, are the ones going into Nansen,” I countered. Nansen’s inner wall, unfortunately, would be too steep and deep to access, although, with hindsight based on the rover’s recent performance, we probably could have worked our way in and out of Nansen by spiraling down its south wall, but we would have sacrificed sampling time at Station 2 to do so.
“Bob, my best guess,” began Cernan, “let’s see…— 077 (bearing), 7.7 (distance), 6.6 (range) — is that we’re coming up on the northern side of Nansen. …And, let me tell you, this is quite a Rover ride. …But it’s quite a machine, I tell you! I think it would do a lot more than we’d let it.”
With a laugh, I agreed. “That’s right. …I think that big crater up there on the side [of the Massif] is the one that you can see in the photographs, just above Station 2.” (AS17-135-20672, Fig. 11.25)
Fig. 11.25. The big crater to which I refer is just above the HGA pointing handle at left, and Station 2 is just out of sight below the central reseau cross. (NASA photo AS17-135-20672).
“Yeah,” concurred Cernan. “I think if I come up here, do a hard left turn. You unbuckle your belt, [and] you’ll roll right down into the bottom of Nansen.”
“I’m afraid you’re right…”
“And remember,” Parker said, “we’re going to about 068 (bearing) and about 7.4 (range) will be Station 2. At least that’s our estimate.” This was unnecessary speculation at this point, as we would select the actual best place for Station 2 activities.
“Okay, there’s Nansen over there, huh?” asked Cernan.
“Well, I think so,” I replied, not willing to fully commit with only the very uppermost portions of the depression visible.
“Yeah. I think you’re right. It’s got to be it. Got to be it.”
“Yeah, Bob, I think we’re into a breccia population now,” I reported. “I think the blocks in the light mantle are largely breccias. They’re mottled in their [surface] characteristics. The white zaps do not seem to be nearly as apparent. They tend to be chalky when they get hit. At least, in the large craters (large zap pits), the walls are chalky looking. …Oh, yeah! We’ve got boulders in Station 2!”
“Yeah, they’re there.”
“Yeah, sir. …Boy, I tell you, if I hang on to this camera until you stop and can tighten it up, it’ll be a miracle.” I switched hands as often as needed, but my forearms still ached from working against the pressure in the gloves.
“Bob, how long have we been driving?”
“Stand by. We estimate you’ve got about a kilometer and a half to go— a little over a kilometer, anyway. Stand by, we’ll check on the time. You’re doing great.”
“Man, this has been a trip,” I observed in spite of my aching arms.
“Man, I tell you,” Cernan agreed. “You know, we’re really up on top of this thing (Nansen). Whoo!”
“You guys have been driving 64 minutes, and that counts the time to stop and deploy the (explosive) charge and pick up the Rover samples.”
“Hey, Bob,” I called. “We’re very clearly going downhill now, into the trough area that surrounds the Massif, [that is,] between the [light] mantle and the Massif. But the trough is much greater in extent than just Nansen’s scale. It’s probably a kilometer wide. I never realized that it was so much of a depression in here.”
[Nansen, rather than being a partially buried impact crater, actually forms a much deeper than average part of a continuous trough-like depression along the northern base of the South Massif. The existence of this trough suggests (1) its fault-bounded volume has been increasing at a rate greater than the rate of accumulation of debris from the slope above or (2) the valley floor has separated from the Massif due to faulting recently enough that down slope migration of debris has not had enough time to fill the resulting trough (See Chapter 13).]
“I’m not sure we’re going to be able to see the LM,” I speculated, thinking about the fact that Station 2 would still be in a portion of the trough.
“Okay. How about a range and bearing readout,” Parker requested, seemingly unnecessarily. Mission Control, however, was continuously evaluating the level of consumables in our PLSS versus time in case we would have to walk back to the Challenger.
“074 (bearing), 8.2 (distance traveled), 6.9 (range),” Cernan responded. “We won’t be able to see the LM from down here. We’ll be too low to see it. Fact is, I don’t think I can see that far.” It is not clear what he had on his mind by this last remark.
“The surface patterns are still the same, Bob,” I reported. “The main difference being that we’re getting, probably, a gradual increase in block population; and the blocks seem to be of a different character. They may be breccias. …And around the crater [we are passing] here, that’s maybe 75 meters in diameter, there’s probably 5 percent blocks— fragments, I should say— greater than a centimeter [in diameter].”
“Boy, look at all the dust without that [new] fender,” Cernan said, looking down at the dust flowing to the ground off the left front fender. “I hate to think of what it would have been like with that fender gone.”
“Yeah. …There’s a good-sized block, sort of blue-gray.”
“Looking up there, Jack, I ought to get some 500s [photos] looking right up that hill, but…well, you may want to do that out a ways [from the base of the Massif]. …Some of that stuff is mantled, or buried, in the Massif material. Some of [the boulders] just seem to be laying on it (the surface), of course.”
“Yeah. Well, I think it has to do with how long it’s [a rock] been there,” I reasoned. “You’ll tend to get the down-slope movements forming uphill fillets, and that’s what a lot of it looks like.”
“Most of it is uphill fillets,” Cernan agreed. “Most of it [the fillets] is pretty sharp. …But my guess, from back at the LM, that those blocks on the massif were much more angular, I think, is a good guess because that’s what they look like to me here.”
“And looking up into our blue-gray outcrop area,” I added, “I still have even more the impression that there’s a planar orientation that [apparently] dips off to the southeast. Maybe just [sub-horizontal] fracturing, but [it’s] pretty clear up there, I think. …It (the apparent dip) may be [caused by] shadows, [however].
“The LM (means ‘the Earth’) is now 50 percent of the Massif height away from the Massif. How’s that? I think we will keep it (Earth) on top.” Cernan refers to the probability that we will be able to see the Earth at Station 2 in spite of its location at the base of the South Massif.
“That is a high mountain!” I exclaimed.
“Jiminy Christmas! Listen, if the Earth goes behind it (the Massif), we’re changing Station 2,” Cernan said with a laugh. He probably meant to say “Jiminy Cricket,” an expression that gained popularity with the character by that name in the Walt Disney movie Pinocchio.
“Gonna be nip and tuck, pardon the expression,” I said. “Okay. As we get closer, actually, we’re out of the block area. And that blocky region of 5 percent may have been just associated with that [75 m diameter] crater. I still see no lineations, although…
“Look at these wrinkles (on the Massif), though, Jack…”
“Yeah. I was talking about the mantle.” In fact, LRO images show very broad scale lineations, created by a subtle ridge and trough system that extends perpendicular to the base of the Massif. These lineations probably are the result of the movement dynamics of the light mantle avalanche.
“But you’re right about [wrinkles] on the Massif,” I clarified.
“The same wrinkled lineations we saw sloping uphill to the west on the eastern half of the Massif are still very evident at this Sun angle,” Cernan added.
“Okay, Seventeen, and we’re estimating that you should be there within about 5 minutes to meet the walk-back constraints.
“Come back up!” I asserted as Cernan headed to the left of some large boulders that we would refer to as Station 2.
“Bob, we’re almost ready to park.”
“Well, I wouldn’t have gone so far as to say that (“ready to park’),” I countered. “We’re getting close.”
“I’ll give them their 5 minutes. We’ll make it by then,” he said with assurance.
[As we were farther from the Lunar Module than any previous mission, Parker had expressed a “walk-back” concern related to the very conservative Mission Rule to deal with a full Rover failure at the end of our investigations at Station 2. This walk-back constraint assumed that, if the Rover failed completely at the end of our Station 2 activities, that we could return to Challenger at a rate of 2.7 km/hr and at a metabolic rate of 1290 BTU/hr (versus 1000 BTU/hr on the Rover). Implementation of this Rule, therefore, would be based on Mission Control’s estimate of consumables remaining in our PLSSs. This estimate included a balance between the walk-back use of oxygen, cooling water, and battery power. An alternative contingency assumed a PLSS cooling water failure but with an operating Rover. A PLSS cooling water failure would require the use of the Buddy SLSS hook-up between the two crewmen. Cooling water from the good PLSS then could be shared during the drive back to the Challenger. Mission Control assumed that both a Rover failure and a PLSS cooling water failure would not occur. If such a double failure took place, a traverse of some 9.1 km (7.6 km straight-line) walk back to the Challenger would have been very marginal and probably would have required eventual use of oxygen from the OPS for cooling. On the other hand, if Cernan and I could coordinate our strides, we probably could have approached the 2.7 km/hr walking rate]
“Bob, the boulder tracks [down the Massif] are really just chains of small craters, for the most part,” I noted.
“I don’t think they can tilt the television camera high enough to see the top of the Massif,” Cernan speculated. “Jack, we’re on the edge here, but I don’t know. Is that the [place]…? Well, let me go up here.”
“No, you’re doing great,” I said.
“We’re 071 (bearing), 8.9 (distance), and 7.4 (range).”
“See, there’s Nansen off to my right now,” I said to encourage him to keep the course he was on.
“Yeah, I just want to make sure that I’m not driving down a hole here, …which I am, but…I don’t want to drive down [into] Nansen.”
“No, you won’t,” I assured him. “The [east] end of Nansen is over there near those blocks— right over there. …Look at those blocks! Unfortunately, the good boulder tracks are over into Nansen.”
“Going down here very slowly,” Cernan said as he eased into the trough at the east end of Nansen.
“I think [putting a] station just about anywhere near the big blocks,” I hinted, “would be a good Station 2.”
“Yeah, that’s where I’m going to put it. …Yeah, that’s where we’re going to make Station 2; right up there.” Instead of trying to direct Cernan to do various things related to geology, I would usually just express an opinion, and he generally, but not always, would follow that course.
“What? Straight ahead?” I asked, just to be sure.
“Boy, you’re looking right into Nansen,” Cernan said with amazement. Actually, post-mission analysis indicated that we parked about 30 m inside the east rim crest of Nansen. (cf. Fig. 11.26 with Fig. 11.24↑).
Station 2 – South Massif
Fig. 11.26. Planimetric drawing showing the general layout of Station 2 on the slope of the South Massif but within the Nansen Crater moat.
“Yeah. We’re right where we wanted to be for Station 2,” I informed Parker. “And it looks like a great place. Big blocks. It looks like quite a bit of variety from here. Different colors, anyway. Grays and lighter-colored tans.”
“Okay, Jack, I’m going to do a 180 (degree turn) and park the Rover at 045.”
“There’s a blue-gray rock and a lighter-colored tan rock,” I stated as I surveyed the site from the Rover while Cernan evaluated the best place to park.
Fig. 11.27. The steeper portion of the Nansen trough looking west. The trough continues to the right and becomes shallower at its easternmost extent where the LRV is parked (see Fig. 11.28↓). (Combination of NASA photos AS17-137-20938, -39, -42).
“See where they (Mission Control) can look in here (Nansen).”
“Are you going to park it?” I asked, wanting to get off as soon as possible.
“Right on the other side of this little crater heading . …Okay, Bob you ought to have us again— 045 (bearing), 9.1 (distance), 7.6 (range). Are you reading, by the way?” Cernan asked as he adjusted the low gain antenna.
“Roger. Reading you loud and clear.”
“Okay. Let me get [my seatbelt] undone here,” he continued, as I dismounted. “Amp hours are 98 [and] 98. Batteries are 90 and 112 [degrees], and the motors [are]: forward left is off-scale low and right is 340. Forward (actually left) rear is off-scale low, and right is 240. I expect we’ve got a bad meter. Actually, Cernan has misread the gauges and will correct things later.
Fig. 11.28. The eastern extent of Nansen beyond boulder 2 in the foreground. Note the LRV parked at right on the shallow inner slope of Nansen. (cf. Fig. 11.26↑). (Combination of NASA photos AS17-137-20951, -53, -55).
“Copy that on the 340. And you want to give me the bearing one more time there, Gene. All I got was the distance [driven] at 9.1… and the range [is]?”
“Yes, sir. Zero-point-one, 9.1, 7.6 (range). We are right at Station 2.” This range equated to a net speed from the SEP transmitter near Challenger of about 6.4 km/hr.
For some reason, reading the gauges continued to be a problem for Cernan. A 045 heading meant he had a glancing sun on the console and that may have been the problem. I largely left the Rover housekeeping up to him while I reconnoitered the area for sampling opportunities.
“Look at Nansen!” I exclaimed, impressed by its depth relative to the rest of the South Massif trough. “My goodness gracious.”
Without letting us get the lay of things around Station 2, Parker began to spout recommendations. This was the beginning of a period of friction in communication, activity sequence, and judgment between him and me. He seemed to forget why we just drove over an hour to get to the foot of the South Massif. “When you’re at the station, here’s a couple of things we’d like for you guys to look at in the [housekeeping] overhead. In addition to them, we’d like the TV lens to be dusted, in addition to the regular dusting— that’ll take the lens brush, remember.”
Ignoring Parker for the moment, I asked Cernan, “Can you try to tighten that [camera handle for me]?”
Not to be deterred, Parker continued, “You might check the low-gain antenna elevation to make sure it’s at 45 degrees. We think you commented on that, and I think you’re right now looking at tightening Jack’s camera handle.”
Changing my mind as Cernan worked on aligning the high gain antenna, I overruled Parker. “I’ll work on that (handle). Gene, you go ahead with the other [stuff.]”
“Okay. Yeah, we are at 45 degrees (low-gain antenna elevation), Bob. Let me check it. I’ll lose the comm on you a second. I’ve got to turn it towards me. …Mark it at 045.”
“And, Seventeen, …Jack, we’d like you to check the SEP [receiver]  for us. I suspect we’ll have to turn it off and open the mirrors and dust them.”
“Boy, when you get this (TV) picture…” Cernan said, referring to the view they would have, “You[‘ve] got high gain.”
“Roger. Thank you. We have TV. … Geno, we did not get a good bearing from you guys. We might also check the LMP’s camera.”
“Okay. I’ll give it to you again. …071 is the bearing [to the SEP transmitter].
“That’s (camera handle) fixed.” I had taken my camera off, set it on the Rover seat, and re-tightened the handle screw as tight as I could. “Oh, you mean [frame count] for pictures?”
“142 [frames] on the LMP’s camera. The [SEP receiver] temperature is 105.”
“Roger. Let’s turn off the (SEP) power and the recorder, open the blankets, and dust it.”
“[SEP] Power’s off; blankets are open; and, Gene, you’ll have to dust it.” He had the only brush, of course.
“I’ll get it. I’ve got a lot of dusting to do here, Jack.
“Okay. …Let’s see what we’ve got to do,” I said, looking at my Cuff Checklist.
“We’ve got a lot of housekeeping to do right now,” Cernan replied.
“And, Jack, I presume when I told you, you turned off the receiver, didn’t you? Not just the DSEA (Data Storage Electronics Assembly)?” We would eventually bring the DSEA back to Earth with us.
“That’s affirm. I turned off both switches.”
“That’s what I thought. Thank you.”
“Oh, my scoop! My scoop just came off [the extension handle]! That’s interesting. I’d better check the rake. [Scoop] vibrated loose, I guess.” Both the scoop and the rake had the same push-and-rotate spring loaded ball connector that apparently could vibrate loose, particularly if dust were beginning to work its way into the connector. Fortunately, the scoop, on its extension handle and in a clip on the Gate, did not bounce off during our drive.
“I’ll get (open) the battery covers,” stated Cernan.
“Okay; and Jack, …we’d like to get an EMU check on you,” Parker requested, ignoring that I was working on the scoop and rake.
“And, Jack, we’d like to go to India (AS17-138) on the (camera) magazine for you…”
“Okay, magazine India,” I replied. “My goodness, we’ll never get started,” I griped, as I stuck my scoop in the regolith while I went into the seat compartment to get magazine India. All these added housekeeping requests frustrated me as they delayed getting to the reason for both taking the time to drive here and significant risk of being seven and a half kilometers from Challenger.
“Man, we are down in a depression,” observed Cernan… “Look at where we came down [here], Jack. And that was just one of the hills. Got to go back up and then down some. …Hey, thank you for that fix on the fender, by the way, because I’d hate to see what it would look like without it…”
“…And John [Young] suggests that we might just check it momentarily while you’re here to make sure it’s still holding on good and tight— both the clamps and the tape.”
“Yeah, that’s on my list [of things to do],” Cernan replied. “…If it (the fender) stayed on through that ride it may never come off! Have you got a lens brush in there [under the CDR seat], Jack?”
“Yup,” I acknowledged as I exchanged film magazines and put the India dark slide in magazine Golf (AS17-135) I had taken off my camera.
“Well, hold it a minute. I’ve got to get this SEP. Do you want me to dust the SEP, is that what you said?
“Do you want the covers open?”
“They should be open and dusted,” I confirmed.
“Okay. The SEP is open. It’s about 100 degrees.”
“105 [degrees].” I had reported this earlier.
“105? Okay. And it’s dusted.”
“Here’s your lens brush; if you need it.” I leaned across the Rover seats.
“Okay, thank you. My camera [lens] look all right to you?… Let me get yours; lean over here, and I’ll get yours.”
“Okay. I’ll [let you] get mine, too…”
“And, Jack,” called Parker, “we’re suggesting that you’re getting a little warm. Maybe INTERMEDIATE cooling might help.”
“Bob, I feel the same way; but I want to get this camera fixed, …I mean, [get] the film changed.” Once I had attached the new film magazine to my camera, I advanced the film a few frames to make sure photographs would begin beyond any exposed film.
As Cernan dusted the lens of the TV camera, already transmitting to Earth, he jokingly asked, “Can I change your oil?” The question harked back to the time of full service filling stations when attendants cleaned your car windows and asked if they should check the engine oil level. Times surely have changed.
“Oh, thank you, Geno. It looks much better…”
“How about any other service I can be?”
Interrupting this jocular exchange, I said, “Okay, Houston, the number of blocks plotted on the map are not nearly enough.” I finally could start planning our sampling operations. “In the greater than 1-meter range, there are many hundred blocks on the Massif flank of Nansen (that is, on the south side of Nansen) and up around Station 2, where we are. There are only one or two blocks on the light mantle side of Nansen. It looks as if the [blocky] material in the bottom of Nansen is overriding (younger than) the light mantle materials of the north wall (of Nansen). That’s just an impression. They’re (blocks) slightly lighter albedo than the north wall of Nansen.”
“Copy that, Jack. Looks fantastic up there.”
“And I suggest that we do our raking…That’s right, [Bob]— I just told you everything you can see— [I suggest that we do our raking] fairly close to the Rover to get sort of the general population of talus material coming off the Massif…”
“Bob, on my mark,” Cernan began, but then interrupted himself. “…I’ve got everything: hammer, gnomon, film. Okay. MARK it; you have a gravimeter measurement going.”
“The blue-gray rocks are breccias,” I reported, having moved off the light mantle unit, on to the side of the Massif, and into the block field we would sample. “They’re multilithic, gray-matrix…matrix [dominated] breccias, I guess. There are fragments in them, but it doesn’t look like more than about 10 or 15 percent fragments.” I used these estimates of the percent of fragments in the breccias versus the amount of matrix to help distinguish between various boulders. “Fragment” meant those clasts large enough to be distinguished easily from the matrix, say a few millimeters or larger. I suspect that these estimates may be biased toward the larger sized fragments.
Fig. 11.29. Boulder 1 at Station 2 showing apparent layering/foliation that, along with its petrolographic characteristics, makes this boulder unique among those investigated and sampled at the bases of the South and North Massifs. Its bluish-gray color and low albedo suggest that Boulder 1 came from a similar outcrop about 1500 m, vertically, above Station 2. The near-field projecting layers are roughly 30-50 cm thick. I am investigating the northern side of the boulder at far right. (NASA Photo AS17-137-20900).
“Some of the light-colored fragments seem to have very fine-grained dark halos around them,” I continued. “The zap pits [in the matrix] do not have white halos, so I suspect they (the matrixes) are not [coarsely] crystalline. They might be the vitric or glassy breccias. At least, the one big rock we have here.” The absence of white halos indicates that the clasts and matrix are both rich in minerals containing magnesium and iron.
“There’s a very rough foliation in them (the blue-gray breccias)— and I’m not sure— it’s shown by the elongate knobs on the [boulder] surface. It looks like a fracture (shearing) foliation of some kind.” (Fig. 11.29)
“Jack, that rock has almost got to have come down [from outcrops], don’t you think?” Cernan bent back some to get a view of the upper reaches of the South Massif.
“Oh, no question about it,” I replied, certain that gravity operated on the Moon as it does on Earth. “I’ll bet you it’s the same as the blue-gray rocks we see up higher. Here’s some more blue-gray ones over here.”
“Let’s start taking [samples]. …Oh, yeah. Look at the size of some of these light fragments in here.”
“Yeah, but it still…looks like they’re dominantly matrix [dominated] breccias,” I concluded. “There are light-colored fragments, and they may be crystalline…” I leaned closer for a better look. “They are [crystalline]. They’re very light colored; they look like the shattered anorthosites. They have white halos [around zap pits]… I think that’s what those fragments are.” This is a good example of how field geologists use whatever direct or indirect information is available to identify rocks, minerals and textures and to correlate between similar rocks and minerals at different locations. In this case, I had already learned that white halos around “zap pits” indicated the presence of crystalline plagioclase, based on my close examination of the relatively coarse-grained gabbro boulders near the Challenger.
The first boulder at which I stopped became known as “Boulder 1”. I selected it for sampling because of its apparent heterogeneity as a friable, roughly-layered (foliated) breccia and the apparent resemblance to the blue-gray outcrops we could see high up on the massif. The photographs of Boulder 1 (AS-138-21029-35 and AS-137- 20900-09; Fig. 11.29↑) show that 30-40 cm thick irregular, knobby layers are separated by 5-10 cm of less resistant and less knobby zones. We had no trouble in collecting a series of samples across the layers. These samples later became the focus of a consortium study in which I participated, called “Consortium Indomitable,” and led by John Wood of Harvard’s Smithsonian Astrophysical Observatory.
“Jack, let’s get a piece of this one (fragment) right here.”
“It’s the biggest one here.”
“Set her (the gnomon) up,” I directed. “This is the blue-gray [breccia] variety, Houston.
“I’m going to take that little knob off up there.” Cernan declared his intentions without giving me the chance to work out an appropriate sampling strategy for a possibly multi-compositional, layered boulder. Nonetheless, we eventually sampled four of the major zones. I began to modify his approach, as he had picked the next to topmost zone to sample first.
“Okay; well, you can work that block over [its full width.]”
“We can get several examples,” I added. “We ought to sample across that layering— that foliation.”
“One comment,” Cernan broke into the sampling process giving me the opportunity to look more closely at Boulder 1. He basically repeated what I had observed earlier while housekeeping tasks around the Rover distracted him. “When you look down into the bottom of Nansen, it looks like— I guess, [this] would sound obvious— that some of the debris that has rolled off of the South Massif covers up the original material there that covers the north wall of Nansen. There is a distinct difference. You’ve got that very wrinkled texture in the north slopes of Nansen, and you’ve got the South Massif debris (boulders) in the south slopes of Nansen. And the debris, of course, overlays the north-slope (wall). And all the rock fragments, all the boulders that have come down, are all on the south side of the slope (walls) of Nansen.”
[The training program in field geology I had put together for the post-Apollo 11 missions (Chapter 2) emphasized, among a number of other basic observational techniques, how to organize your thoughts by deciding which material lay on top of other material, that is, what is the apparent relative age sequence of various materials. Cernan’s description of Nansen shows the positive effects of that training. At other times, his more rambling descriptions are hard to follow.
Cernan’s note of the “wrinkled texture” on the north wall of Nansen related to the broad, ridge and valley physiography of the surface of the light mantle. With a wavelength of about 100-200 m, this physiographic texture shows particularly well in recent LROC images and apparently developed along the flow direction of the fluidized avalanche. Some of the more narrow ridges and valleys on the north rim of Nansen appear to join in local “V” shapes that point consistently opposite the apparent flow direction, suggesting flow around buried obstacles. Some back flow of avalanche material is suggested by a lobate scarp across the floor of Lara, a ~700 m diameter crater buried by the avalanche. Rough estimation of the depths of post-avalanche craters, a few of which expose underlying dark mantle, indicates that the light mantle thickness varies from more than 3 m in the northwest to more than 6 m in the southeast across the body of the unit that is within about 3 km of the base of the South Massif. The maximum flow distance was about 5 km with thinning toward the distal plumes. Recent examination of LROC images also has disclosed that the main body of the light mantle partially overlies a significantly older and darker (more mature) light mantle unit (See Chapter 13). This discovery, in turn, makes it improbable, but not impossible, that ejecta from Tycho triggered either avalanche. Faulting related to the formation of the Lee-Lincoln Scarp appears to be the more likely trigger of the avalanches (Chapter 13).]
“Okay, Houston. I take back what I said about no [zap pit] halos. There are light— not very sharply light— but light halos around zap pits in the matrix. The matrix [zap pit impact] glass is dark, and it seems to have a greenish cast; but it’s very dark.” These two observations indicate two things: first, the matrix is finely crystalline, and, second, the matrix contains some iron and/or magnesium-bearing minerals.
“Oh, look at that blue!” exclaimed Cernan. “Look at the white fragments in there.” Some of the more coarsely crystalline plagioclase clasts appeared bluish, as some varieties of plagioclase often do.
“Let me come and help you there [with that sample].”
“Man, there’s some boulder rolling rocks here, Jack,” he said with a laugh.
“Okay, don’t wreck the fillets [with your boots]. There’s an overhang we’ve got to get into.” I had been hoping for an opportunity to sample regolith that had been protected from the solar wind and this overhang looked promising. An exposure age on the regolith would give a measure of when the boulder rolled into position. The overhang’s shadow also constituted a possible cold trap for volatile elements that might migrate there through the transient lunar atmosphere.
“Okay; [bag number] 514 (72235) is the [knob],” I began, but then looked at the fresh surface of the rock Cernan had broken off. “Okay, I’ll take it back (my previous statement about the breccias). On the fresh surface, these look like fragment [dominated] breccias although the fragment size is fairly small. There are dark gray fragments and the light fragments we talked about. The gray ones are very fine-grained and dense, although I see flashes that indicate they may be crystalline. The light-colored fragments are [crystalline] as I described earlier, I think…[the sample is in bag] 514.”
[Post-mission examination of 72235 (Fig. 11.30↓) revealed a very heterogeneous, multi generational, laminated breccia, much as I described, with its light-gray matrix appearing to be similar to that in 72275 (see below). Most of the material in the sample is fine-grained crushed plagioclase (over 80%) mixed with small amounts of basaltic and olivine-pyroxene-rich clasts. This material is aggregated as light and dark, irregular and discontinuous, marbled layers. Dark layers appear to be impact melt breccias and are significantly finer grained than light colored, more clast-rich layers. The dark layers also contain small patches of Ba-rich intergrowths of quartz and K-feldspar referred to as “microgranite”. One portion of the crushed feldspar from 72235 contains about 17 ppm iridium, probably derived from an impacting asteroid.]
Fig. 11.30. Lunar Receiving Laboratory images of breccia sample 72235 from Boulder 1, Station 2, as unpacked, showing the marbled character of samples from this large boulder. C1 circled in the bottom photo marks a small clast of KREEP-rich norite. (KREEP = material rich in potassium, rare earth elements, and phosphous with significant thorium.) The reference cube is 1 cm on a side. (NASA photos S73-23590, -585).
“[Lets get] this other one [from higher up],” suggested Cernan.
“[Jack,] if you could tear yourself away in the middle of that sometime to give us an EMU readout, we’d appreciate it,” Parker’s annoying request came in the middle of our first real geological sampling activity for this EVA. “We haven’t gotten that from you yet on the EVA.”
“Okay. I’m [busy]. Stand by. Cernan’s got a rock to go [in a bag]. …That’s from up higher?”
“That’s a little higher,” confirmed Cernan. “See that chop [mark] up there?”
Fig. 11.31. Photo of re-assembled pieces of rock sample 72275, a polymict breccia. The numbers are sub-sample identifiers. The cube at right is 1 cm. (NASA photo S73-16077).
“Okay,” I began again, “The first rock was from about— [that is,] 514— was from a meter above the base of the rock; [bag] 515 (72275) is from about a meter and a half. …Here, can I get this in your (SCB)? …Can you get some (samples) on either side of those two now?”
“Yeah.” I was trying to make sure Cernan used the hammer to obtain samples from each of the major layers exposed on the boulder.
[The post-mission examination and analysis of 72275 found that it was equally as complex a breccia as 72235, with light-colored clasts and breccia patches mixed with clasts and stringers of dark, fine-grained microbreccia. Plagioclase-olivine-orthopyroxene (olivine norite) clasts dominate (~50%) with abundant plagioclase in the very fine-grained matrix. Portions of the light-colored, friable matrix have porosities up to 30%, suggesting near surface aggregation of Boulder 1. There is one large clast of crushed anorthosite (Fig. 11.31↑, lower left).
A cosmic ray Kr exposure age determination for 72275 gave 52.5 ± 1.4 million years.]
“Your [SCB’s] open,” I warned as I dropped the samples in Cernan’s SCB on the left side of his PLSS. “I’ll leave you open for a minute,” I added, knowing we would get several more samples at this boulder.
“Well, okay. Just so they don’t fall out. Am I (the samples) in?
“No. Let me get this other one. …Okay, go ahead.”
“Let me try [to get a sample] from back here,” Cernan said, temporarily forgetting to finish sampling the boulder.
“Of course, that’s a north/south overhang,” I responded to remind him that we wanted a north-facing east-west overhang for continuous protection from the Sun. Such an overhang would be found at Station 6 on EVA-3.
“Yeah. That one?
“Yeah, you’re facing right into the east [and the sun].”
“Yeah, yeah. I don’t know if I can get a piece back here or not,” Cernan commented, going back to the boulder.
“How about right where you [are]? …Yeah, [right there].”
“Right here? I can get that,” confirmed Cernan.
“Yeah, that’s good. Oh, beautiful!” I exclaimed, pleased with the piece he knocked off with the hammer. “[It] hit the gnomon.”
“Well, I already… It (the gnomon) didn’t move. It just tilted it.”
“This it?” I asked, pointing with my scoop.
“Yeah, that’s it right there. …Let me set my working tool (the hammer) down here.”
“Got a bag?” I asked as I picked up the sample in my scoop.
“Coming right up.”
“Boy, that dust [on the rock],” I noted. “Once you get it on there, you might as well forget it (looking at the fresh face). …494, [bag] 494 (72215) is from a half a meter above the base of the rock…”
Fig. 11.32. Rock sample 72215 showing patina and zap pits. (NASA photo S73-23569).
[“Consortium Indomitable” concluded that 72215 is a hard, gray polymict breccia with many different types of clasts. Its mineral clasts indicate that it was derived by impact from a source rock composed of plagioclase and olivine (troctolite) and dark, very fine-grained recrystallized melt-breccia. Like 72235, sample 72215 also contains about five percent fragments made up of quartz, potassium feldspar, and Fe-rich pyroxene— that is, a KREEP-rich granite.
The cosmic ray Kr exposure age measures 41.4 million years, about 10 million years less than for 72275. This difference may be due to 72215 being partially shielded by the mass of Boulder 1 versus 72275 coming from near its top (see Fig. 11.35↓).]
“And these are samples from across the layering…” I continued. “These are samples from across the foliation. …What do you think, [Gene]? Can you get that one up there?” I asked pointing to another zone in the boulder.
“Yeah. I might either get that or this other piece up here. Without busting my butt.”
“Well, don’t take any chances,” I cautioned.
“Yeah, I’m not going to,” Cernan assured me. “How about this one? Here’s a whole big piece.”
“Okay. That’s a good representative fragment.”
“Can you get it?” Cernan asked, handing me the hammer.” I can’t reach it without my camera hitting (the boulder). That’s a football-size fragment.”
“Okay, this next sample,” I began, but then asked Cernan, “Can you get a bag out, and we’ll try to put it around it, [that is,] around the end. …Bob, it’s (the boulder) highly variable. This [next sample] is a light-matrix breccia; whereas the other three fragments were dark-matrix or dark-fragment breccias. The big rock [I just knocked off] is a light-matrix breccia with dark fragments, and it’s the one that has the (zap pit) halos around the light fragments. And that’s in 495 (72255), barely. It’s (the sample) not even in it (the bag). It’s just…[the] 495 [bag] is wrapped around it (the sample).”
“It’s (the bag) not going to stay,” concluded Cernan.
Fig. 11.33. Rock sample 72255 from the lower part of Boulder 1 (see Fig. 11.35↓). Most of the right side is freshly broken from the boulder. (NASA photo S73-23729).
“It’s not going to stay, is it?” I agreed.
“No. Well, …it’s a football-size fragmental rock.”
“Why don’t you see if you can stuff it in there…with the bag down,” I suggested.
“Yeah, we’ll be able to identify 495 when we get back. Okay, it’ll stay.”
“Is the bag on it now?” I asked to make sure.
“Well, yeah. …It’s on it, facing down.”
[Post-mission examination of 72255 indicated that it, like other Boulder 1 samples, consists of a hard matrix containing a highly variable mix of clasts, dominated by various dark, and crushed rock types. One of these dark clasts, that investigators called “Civet Cat,” is plagioclase-orthopyroxene rock (norite) that has relict indications of slow crystallization at depth within the lunar crust. (Fig. 11.34) The Rb-Sr isochron age for this clast of 4.08 ± 0.05 billion years may show either the crystallization age of the original norite parent or, more likely, to a partial reset of that age by subsequent impact events.
Fig. 11.34. Lunar Receiving Laboratory image of breccia sample 72255 from Boulder 1, Station 2, showing the sawn face towards the viewer, including the 2 × 2.5 cm cross-section of the “Civet Cat” clast of norite (plagioclase and orthopyroxene). (NASA photo S84-37180).
Based on the samples, Boulder 1 turned out to be comprised of impact-generated breccias made up of a wide variety of different types of rock and mineral fragments (polymict breccia). Extremely fine-grained to finely granular material makes up 40-70 percent of the matrix of the samples. Almost half of the volume of the matrix consists of fragments of plagioclase, olivine and pyroxene. Plagioclase is twice as abundant as the other two minerals combined, explaining the noticeable light halos around zap pits I had observed. The matrix also contains thermally metamorphosed fragments of Mg-suite rocks, including coarse-grained gabbro (Ca-plagioclase and pyroxene), troctolite (Ca-plagioclase and olivine) and granite (quartz and potassium feldspar). Of particular interest are zircon (ZrSiO4) crystals from 72215. 41 Pb-Pb ages determined on these crystals range from 4.3-4.4 billion years, matching the oldest zircon ages measured on Earth. This range of ages spans the ~4.35 Ga concentration of ages of many Mg-suite rocks (Chapter 12) and may be related to the effects of the impact formation of the Procellarum Basin.
The extreme heterogeneity and friable nature of Boulder 1 are unique among boulders of impact breccias we examined and sampled at this station and later at Stations 6 and 7. “Consortium Indomitable” concluded that two distinct breccia associations exist in Boulder 1. In the first, crushed basalt is interlaced with a light-gray, plagioclase-rich matrix into a relatively friable breccia. In the second, crushed anorthositic rock is interlayered with a hard, dark gray to black fine-grained matrix of microbreccia. The Consortium concluded that materials in Boulder 1 record two major impacts, the younger of which had created the friable breccia and incorporated the older, hard microbreccia.
In retrospect, sampling of Boulder 1 may have been biased toward the more coherent materials that better resisted micro-meteor erosion and therefore formed the knobs on the boulder that were easier to break off. (Fig. 11.35↓) On the other hand, some of the more friable breccia obviously adhered to the Boulder 1 suite of samples. As Consortium Indomitable recognized, this friable breccia formed the host material of the more coherent components. A rough, eyeball estimate of the differential micro-meteor erosion of the surface of Boulder 1, using our photographs of the sampled area, suggests that about 10% of the boulder consists of the more friable form of breccia. Further consideration of Boulder 1 in the overall context of the stratigraphy of the massifs and origins of various breccia units we sampled is given in Chapter 13.
An impact event on the higher slopes of the South Massif exposed Boulder 1 between 40 and 50 million years ago, as indicated by cosmic-ray Kr exposure ages of about 41 Myr for 72215, 44 Myr for 72255, and 52 Myr for 72275, and a 41 Myr Ar exposure age for 72255. That same event probably caused Boulder 1 to roll to its present position, after the light mantle avalanche occurred 75-107 million years ago, as indicated by a comparison of boulder exposure ages and light mantle crater count ages (see Chapter 13). The younger boulder exposure ages, in turn, indicate that the light mantle avalanche carried away many if not most of the pre-existing talus boulders then in place at the base of the South Massif. These older boulders, due to their small surface area to mass ratio, would have sunk to the lower portions of the fluidized and flowing avalanche.]
Fig. 11.35. Boulder 1, Station 2 at the base of the South Massif, showing the locations of the four samples obtained there. The near-field projecting layers are roughly 30-50 cm thick. (Modified from ).
Parker came in with a question from the Science Back Room: “Do you guys see any tracks coming down to these boulders? Do you have any feeling that you can place [the source of] these that way?”
“Bob, unfortunately, no,” I answered. “The main tracks are out into Nansen, and I don’t think we can get over there.” This repeated what I had said earlier as we drove up to the site.
“Okay; that’s those biggies that we see on the maps, huh?” Parker wondered.
“Yeah. Coming up [to Station 2], I was looking,” I said, “and there are no obvious tracks coming down here.”
“Watch your shadow, Jack,” Cernan said as he took the after photos that would document exactly which samples we gathered.
“I’ll get it. Wait a minute; that gnomon is probably not… Well, that’s right; you got stereo earlier.”
“Yeah, I reset it,” Cernan noted.”
“The gnomon was moved a little between the samples,” I reported as I started to take some after sampling photographs. “Do you need to take a vertical pan?” I asked Cernan.
“Yeah, I’ve gotten it all. I’m getting it all.”
“You getting the flight line? I’ll get a flight line this way. …Post-sample flight line, [complete].” When a boulder or feature could not be photographed with two stereo frames, we used a sidestepping, “flight line,” procedure to provide several photos that give full stereo coverage.
“Okay, Bob. I’m on frame count 42. …Did you get a locator from here, Jack?”
“Yes. …Okay. I got flight line [of Boulder 1] on the north-south trend (AS17-138-21030-35); Gene got east-west (AS17-137-20903-09).”
“You going to get that sample under there?” Cernan inquired, referring to the east-west overhang regolith sample.
“Yeah, we got to get the soil,” I concurred.
“There may be an overhang. And look at that, that rock is fragmented (split); let’s see, it’s southeast-northwest. There’s a split.”
“Yeah, that one right over there is okay,” I said, pointing to another overhang. “Hey, did you want to get [a photo of] this?”
“Yeah, I’ll get that.”
“You got it?” Cernan asked as I reached under the overhang with the scoop.
“This is a fillet from underneath the rock,” I reported to Parker.
“Roger. And an update on the rake samples when you get around to it. We’d like to get one up on the massif slope as much as you can, if you can get over to it. And then the second one down near the Rover.” This was good advice, but his timing relative to our other activities left something to be desired.
“Okay, Bob,” I continued. “This fillet is [from] up underneath an overhang. I got it from about…oh, a third of a meter under an overhang. And it’s the upper 3 centimeters of soil… [Gene,] I got to get uphill from you a little bit [to put this in your sample bag]. …That’s good.”
“And it’s bag 496 (72220-24)” noted Cernan.
“Now let me get one out away from the overhang a little bit,” I said, wanting to get an exposed sample for comparative analysis.
“You think that’s permanent shadow?” enquired Parker.
“No,” I answered. As the overhang faced east, some illumination and solar heating would reach the regolith for a few hours after every sunrise.
“No,” confirmed Cernan. “It’s facing east.”
“And [here is] a [control] sample down to a depth of about 5 centimeters,” I continued, “about two-thirds of a meter from the boulder, on the south side, is in 497 (72240-44). …Now, let me get a skim sample, Geno.” The skim sample of the upper few millimeters of the surface would contain the most recent solar wind effects for comparison with samples taken more deeply.
“Okay, …I got to take a set of [after] pictures after that, by the way. Show where they [the Boulder 1 sample locations] are.”
“I can piece them into my flight line stereo,” I said, meaning that the previous flight line stereo would serve as the before photos.
“Okay. They were in both of the before pictures on those rocks,” I added.
“Okay, [this is] about a centimeter-deep skim,” I reported. “Careful,” I added, as I tried to dump the skim sample in a bag Cernan held.
“You’re in a hole. You better come out,” he suggested.
“Yeah. …Boy, that’s hard on the hand (controlling the scoop) even in one-sixth g.”
Looking around, Cernan said, “And I didn’t park that Rover in a very good spot for them to watch what’s going on, I guess; but that was the heading.”
“Oh, shoot. They’re missing all of it.”
“We didn’t work in the right spot; that’s all,” he added as a joke.
“Every now and then we get a peek at you guys,” Parker said, “but only every now and then.”
“Sorry, Bob.” Although sympathetic, I certainly did not want the TV camera operation to dictate where we sampled. Thermal control of the Rover batteries and the TV electronics required parking as we did. If I had picked a boulder that could be seen on TV, we would have missed what turned out to be a unique mix of impact breccias among all the boulders we sample at Taurus-Littrow.
“Oh, wait a minute,” Cernan remarked as his bag dispenser came loose.
“You know, that’s the way it happens,” I sympathized.
“Okay. It’s back on.”
“Skim sample bag number, please,” Parker requested.
“Okay, Bob,” Cernan responded. “I missed that. I didn’t give it to you; but I think… Well the next bag I take out, you can check the num[ber]. …Well, wait a minute, I’ll do it for you.
“No. That’s okay. I suspect it’s 498 (72260-64).” Parker knew the bags came off in numerical order.
“I’m almost positive it was 498,” Cernan agreed.
“Okay. We’ll put that down.”
[No detailed post-mission analysis has been undertaken of the mineral and rock fragments in the regolith samples taken near Boulder 1 so it is not known if mercury or other volatile elements have been concentrated in the shadowed area. Regolith sample 72220-24 may have been only partially shielded from direct sunlight, although such exposure only would have lasted during the first few degrees of the rising, glancing Sun. 72220-24, 72240-44 and 72260-61 have intermediate to intermediate-high Is/FeO maturity indexes of 58, 59 and 64, respectively. The thorium and Rare Earth content of all three samples, the partially shaded sample, the reference sample 72240-44 and skim sample 72260-61, suggest that they have been derived largely from the micro-meteor erosion of Boulder 1.]
Fig. 11.36. A down-sun overhang view of boulder 1 as described in text. The four rock samples 72215, –35, –55, –75 were taken from the left side of the boulder (Fig. 11.35↑). (Combination of NASA photos AS17-138-21036, -37).
“Okay, Bob, looking at the blocks directly down-Sun,” I observed, “the gray-matrix breccias seem to be fragments, or schlieren (elongated groups of related fragments), anyway, within the white-matrix breccias. …And I got a couple pictures down-Sun to show that texture.” Although obviously discernible to my eye, the differences between the two types of breccias appear to be obscured in the photographs (AS17-138-21036-37) by the ubiquitous brownish patina present on all surfaces. My brain, obviously, was filtering out the effect of the patina. Special contrast and color balancing of digital images may make these structures more apparent.
“Okay. And one thing we’d like to do would be to sample a variety of blocks, in terms of looking at differences in the blocks… from block to block.” Parker, or whoever asked for this to be said, forgot that we planned to do just that.
“Rog,” I responded containing my annoyance. “We’re going to do that. We’re going after a lighter-colored block, now. …Are you going up there, [Gene]?” I asked to be sure.
“Yeah.” He headed towards what would be called Boulder 2.
“Okay; and if you’re going up the Massif, why don’t we try and get the rake sample up there now. When you finish these rocks.” Parker, again, tried to insert too much control into our more spontaneous and on-the-spot approach to dealing with what we could see needed to be done.
“Hey, Jack. …Jack, don’t come up here unless you bring the rake. It’s a long trip. No sense coming up here twice. I can go get this sample. I’d get the rake, if I were you. Don’t walk back up twice.” Now, I had Cernan wasting my time.
“Well, I don’t…,” I said, thinking that I had already told Mission Control that near the Rover would be a good spot for a rake sample. “I’m not sure they’re going to gain anything by coming up to the top [where you are]. …Okay? You’re not going to gain a thing, Bob,” I said as I turned back toward the Rover. “You’re still on the talus (eroded material at the base of a mountain)… You guys [aren’t here.] Oh, well.” I gave up wasting time arguing and began to think about other things. “The rims of the small craters in the talus are softer than the normal (surrounding) terrain,” I said, going back to observing. “My foot goes in maybe 10 cm where normally it only goes in a centimeter.”
“Okay. As long as it’s above the break of the slope, Jack, we don’t have to get very far up the slope.” Parker and company finally got the point.
“That’s right!!” I exclaimed, really put out with what seemed at the time to be unnecessary interference and waste of time going back to the Rover when I felt that I should have been examining the boulders. The Flight Director should have realized that the inputs to Parker were causing a loss of efficency as well as being repetitive.
As I grabbed the rake from its clips on the gate of the Rover, Parker decided to add insult to injury with, “And, Jack, since you’re back at the Rover, how about giving us a Grav reading before you leave.”
“Because I’m late sampling, that’s why. But I’ll do it anyway. …Okay, 670, 155, 201; 670, 155, 201.” This reading would have been provided before leaving Station 2. The Principle Investigator, Manik Tawani, probably was anxious to see how much change there was from the readings near the Challenger, and, in retrospect, I can understand that.
“Okay. Copy that, Jack. Press on.” I momentarily forgot to retrieve the scoop from where I had stuck it in the regolith at the back of the Rover and lost more time going back to get it. I am not a happy geologist at this point. It turns out, in my wish to get on with the boulder sampling, I was wrong about the rake sample. We ended up getting two important rake samples, one up the slope and one by the Rover, and they were very different (see below).
Meanwhile, Cernan has reached Boulder 2. “Okay, Bob, I’m at another boulder up the slope here. It looks quite similar to the one we just sampled, except there is a lot of flake fractures on it. Non-uniform, non-directional, but quite different, at least from that other rock, in terms of its fracture pattern. The [internal] texture looks to be quite similar. Boy, I’m glad I don’t have to walk to the top of this thing (the South Massif).” When I finally could look at Boulder 2 up close, I would find that Boulder 2 actually is very different from what was implied by Cernan’s description.
“Hey, look, Gene, on these rake samples, there is just no point in carrying a rake all the way up here…because all we needed was a break in the slope.”
“Negative, Jack, as long as you’re above the break…in slope; that’s right.” Parker tries to recover.
“Well, that’s all right. It’s being done; but let’s watch those kind of calls please.”
“They can’t appreciate the toughness of going up this slope, though. We can; we’ve got to tell them that.”
“Well, we did [tell them].” Instead of trying to patch things up between Parker and me, Cernan should have listened to me, earlier.
“Yeah, that’s what we were saying,” Parker continued to beat this horse. “Don’t go above just at the base of the break in the slope, Jack. Don’t climb all the way up there with it.”
“Oh, relax!” Frustrated, I let my temper show. Parker just did not know when to shut up. I had told them soon after I began to reconnoiter the area that we should get the rake sample near the Rover that we parked above the talus toe off the Massif. Someone had not listened or was not screening all the requests coming to the CAPCOM console. In retrospect, I should have not listened to their original request to take the rake up the slope. Take a geologist to the Moon and then ignore his judgment. On the other hand, the final location of the rake sample, higher up the slope and away from the effects of any shedding off the boulders, removed all doubt as to its position on material currently working its way off the Massif.
“Okay, we’re all set, Bob,” Cernan claimed. “No problem…”
Climbing the slope toward Cernan, scoop in one hand and rake in the other, I first used some two-footed hops and then walked upward and across the increasingly steep slope. As I climbed, I continued to observe and plan. “We want to get away from that big rock [for the rake sample] because it’s (the rock) probably [is] shedding. …Hey, that’s a different [type of] rock, Gene.” As I drew closer, I saw evidence that the rock, Boulder 2, was much more obviously crystalline and uniform than Boulder 1 and did not have any of the overall foliated or layered aspect.
“Yeah. Well, it looks like the same texture, but it’s got that flaky fracture pattern all over it. I’m going to get a [flight line] stereo while I’m at it.
“Yeah…” As Cernan takes his before stereo photos, I stick the scoop in the talus regolith and begin to examine Boulder 2. (Fig. 11.37).
Fig. 11.37. Boulder 2 at Station 2 showing its more uniform nature relative to Boulder 1. The black vertical oval denotes the rock sample 72315 (see Fig. 11.38↓) and the horizontal oval is rock sample 72335 (see Fig. 11.39↓). The deployed height of the gnomon is 62 cm. (NASA Photo AS17-137-20914).
“This [set of photos] ought to cover any samples I take off of that thing. …I’m going to get myself a zap of cold water… Man, we’ve got to be a million miles away from the LM.”
“Okay, this is a crystalline rock, Houston,” I begin as I lean close to Boulder 2. “It’s got nice white halos around the zap pits. The [centers of the] zaps are not dense black glass, but a dark greenish…[that is,] a very dark greenish-gray.” The greenish color of the zap pit glass indicated iron-magnesium minerals in the rock.
“Are those halos or fragments?” asked Cernan.
“No, they’re halos. Well, there are fragments, I think, also. But, right now, [I think] it’s fairly crystalline, but it is heterogeneous. Matter of fact,” I add with a laugh,” there’s a big fragment of a porphyry [looking rock] caught up in this thing, I think.” I had noticed what appeared to be a fragment or clast with two distinct crystal sizes, but use of the term “porphyry” implied that it had an igneous origin— something not known at the time. By using the term “porphyry, “I was trying to describe a texture. The two crystal sizes also could have resulted from crushing or recrystallization of an earlier, more uniformly textured rock.
“Did you get a locator, by any chance?” asked Cernan.
“I haven’t done a thing.” The rake sample disagreement had disrupted our whole routine, as I should have arrived at Boulder 2 at the same time he did.
“Okay. Well, I want to start taking some [samples],” Cernan declared.
“Gene, we got to get some of that.” I pointed to what I had called a porphyry.”
“That’s what I want. That’s where I’m going right now.”
“And there’s a chunk [sticking out] there we can get,” I added. “That’s a big fragment within this crystalline rock, [that is,] an inclusion.”
“Take a picture of that (fragment) and then your locator, I’ll get it (the sample).” Cernan handled the hammer most of the time when we needed to break a sample off. His large hand gave him a better grip on the handle than I could manage.
“Go ahead [and sample]. I’ve got it (the locator). Got it (the sample)?” I asked.
“Yeah, I’ve got it.”
Fig. 11.38. (top photo): Outer surface and (bottom photo): edge of rock sample 72315 from Boulder 2, Station 2 (see Fig. 11.37↑ for location on the boulder). In this color photo the patina on the outer surface is obvious— note micrometeorite pits with halos in the upper photo. Several dark clasts are visible in the lower photo. The scale is in cm. (NASA photos S73-16656, -660).
“Beautiful. Looks like a porphyry!” The key to my repeated use of the term “porphyry” related to its texture of larger crystals in a finer grained matrix. I am sure the geologists in the Science Back Room assumed I might have found an igneous rock.
“Boy, it does look like a crystalline rock,” Cernan said.
“Looks like an andesite porphyry is what it looks like.” My use of “andesite” along with the textural term “porphyry, probably confused people even more, as “andesite” is the name used for a type of terrestrial lava of an intermediate silica content between rhyolite and basalt. Again, as a field geologist, I am saying what the rock “looks like”, based on experience, and not what it would turn out actually to be when looked at more closely in the laboratory.
“[It’s] got some very large crystals in there. They’re very reflective, elongated crystals,” described Cernan.
“It’s a relatively angular inclusion,” I added in slightly slurred speech, probably due to being slightly out of breath from my climb. “It’s about a half a meter in size, and it’s a square cross section. Well, it’s irregular; but generally square [in] cross section. It’s in bag 516 (72315), and it looks like it’s a high feldspar rock. It may be an anorthositic gabbro, but it does look like a porphyry.”
“There’s a big chunk (feldspar?) where I’ve got [the sample]. …I can’t get it out, though; it’s buried in the rock. …Oh, a half-an-inch [long], elongated. …I can’t see whether they are colorless or not, but they are certainly reflective crystals. See that up here? See right there?” Cernan asked me.
“And then in the big [surrounding] rock,” continued Cernan, “you’ve got massive things— like this big fragment here— that’s 5 inches across.”
“Well, that may be a spall point (area), Gene; that’s a lighter color, in general, because of a zap or something [removing the patina].”
“Let me get some more samples off it (the main boulder).”
“Yeah, we need to get some of the host rock here.” I tried to get Cernan’s focus back on the essential samples from Boulder 2.
“Okay. We’ll get a piece here.”
“Okay, …now, you’re still sampling the one we just got.” Cernan apparently had not understood that we had just sampled what appeared, at the time, to be an inclusion in Boulder 2. “So we’ll get another one [of the same inclusion].” I had to go with the flow as he had the hammer. “Okay. The same kind [of rock as the last sample]” Then I noticed that this sample also had the contact of the inclusion with the host. “The contact of that (inclusion with the host) rock looks like it might be finer grained, but it’s about the same. …[Sample is] in 517 (72335). That’s the inclusion side of the contact. …Keep going after the other one (the host), Gene, I’ll get this in your bag.”
Fig. 11.39. (upper photo) The exterior and (lower photo) interior surfaces of rock sample 72335 (see Fig. 11.37↑ for location on Boulder 2). The micrometeorite pits with halos are evident in the exterior patina in the upper photo. (NASA photos S73-16247 and S73-23543).
“Bob, you could probably see this rock if you look over this way. We’re high enough.” Cernan’s concern for TV coverage always exceeded mine.
“Yeah, we saw it, Geno,” responded Parker. “Quite a sight; quite a goodie.”
“Okay. Let me see if I can’t get this one here. There it is.” Cernan finally had knocked off a piece of the Boulder 2 rock that hosted the apparent inclusion.
“Okay. The host rock for the inclusion,” I began to describe the sample, “which appears to be also crystalline but may be a re-crystallized rock of some kind, …[possibly] metamorphic… [It] also looks like it’s [has a] high plagioclase [content]— high feldspar, anyway. That’s in bag 518 (72395). And that was a fairly loose but in-place fragment along a fracture zone.”
“Will you hold this a minute?” Cernan asked, handing me the bag he held so that he could reach higher on the boulder. “I’m going to try to get the rest of it up there.”
“And for your thinking in the next few minutes,” interjected Parker, “you might also factor in the question the Backroom raises about taking 10 minutes out (of) Station 4 and adding it into this station, given the wealth of interest that seems to be occurring here. You might think about that. You haven’t been to Station 4, so it’s a little hard to judge. But if you think 10 minutes can be very profitably spent, you might as well do that.” Little did we know what would greet us at Station 4 and how much we would want that 10 minutes back. I also was thinking, “Why can’t he not interrupt so much?” and then went on with my discussion of Boulder 2. “This is a medium-green anorthositic gabbro, and it looks like it has some pastel-green olivine crystals in it.”
“I can’t get any more of that,” Cernan concluded.
“Did you get it (the higher sample)?” I asked.
“I can’t get any more of it, Jack, up there. I can’t reach it.”
“Okay, and that small chip of that [higher sample] is in 519 (72375). It’s the same host rock, much like the previous sample,” I concluded.
“There’s a good sample for you. And another chunk of the host… Oops, be careful,” I said to Cernan as he started to drop the sample.
“It’s still there [in your glove],” I told him.
“Yeah, I’ve got it.”
“I need to get rid of this [sample bag],” I declared, meaning I needed to put 519 in his SCB. “It’s in there. I haven’t closed your bag (SCB), yet, …And we’ve got to get one soil sample up the hill here…” Then, I remembered, “Oh, we’re going to get [it with] the rake [sample]…”
“We ought to get a soil sample, though, up here, so…” Cernan may have forgotten that we get a soil sample with each rake sample.
“We’ll get the rake sample right over here on this slope [and away from boulders].” I asserted.
Cernan still worked on getting another chip of Boulder 2. “Where did that thing go, Jack?”
“Right here,” I said, having watched the chip fly into the regolith near the boulder.
Parker again: “Was that last sample in 518, as well?” He probably meant to say “519”.
“There it (the chip) is. That’s it right there.”
“No. We haven’t put it in [a bag], yet,” I told Parker.
“Bob, that will go in 499 (72355),” Cernan reported.
“Can you get it?” I asked Cernan as he took hold of his tethered tongs. “Okay…” Then I summarized for the Science Back Room. “Bob, this is a fairly uniform-looking rock. It does have some widely spaced fractures across it. It’s clearly crystalline and has crystalline inclusions (clasts) in it.” By “clearly crystalline” I meant that I could see the reflections from the fine crystals in the matrix.
[Boulder 2 turned out to be very different from Boulder 1. It would be classified as an impact melt-breccia of relatively uniform texture and composition. The very finely crystalline and vesicular matrix had formed from a melt that had incorporated many different mineral and rock fragments. Post-mission examination indicated that 72315 (Fig. 11.38↑) probably originally consisted of a coarsely crystalline anorthositic gabbro related to the Mg-suite of lunar rocks. The proportions of the mineral and rock clasts suggest that the protolith (original rock) consisted of a layered, coarse-grained anorthosite that also included units of gabbro (plagioclase and pyroxene) and troctolite (plagioclase and olivine). The protolith had been crushed as well as partially melted and mixed by impact so that some large crystal fragments stood out in a very fine matrix, giving the rock a porphyry-like appearance.
The vesicular, very fine matrix of Boulder 2 consists of interlocking crystals of plagioclase, pyroxene, olivine and some pyroxene and ilmenite, the latter mineral containing laths of plagioclase and rounded grains of olivine. The matrix surrounds local vugs that are lined with course, euhedral plagioclase and brown pyroxene, indicating that the vugs were originally fluid-filled vesicles (bubbles) and that the rock remained hot enough for sufficient time for their wall minerals to grow into the fluid.
The young ~0.27 ± 0.05 Myr exposure age for 72315, based on cosmic-ray tracks, exposure to solar flares, and micro-meteor impact crater counts, indicates that what I initially thought is an inclusion was the result of a large, relatively fresh spall that removed most of the normal patina and long-term exposure evidence from the rock surface. The spall left a visually, sharply contrasting line against the rest of the boulder. This relatively fresh, roughly rectangular spall area can be seen on the right in Cernan’s down sun (zero phase) photograph of the southeast face of the boulder (AS-17-137-20924) and the contrast in density of micro-meteor halos is obvious in the “contact” sample shown in the upper photo of Fig. 11.39↑.
Fig. 11.40. The black arrow points to the rectangular spall area on boulder 2. (NASA photo AS17-137-20924).
As I expected at the time, post-mission examination of 72335 showed it to be much the same as 72315 described above, but without as diverse a fragment population. Its matrix also looks to have crystallized from an impact melt.
Post-mission examination of 72395 indicated a close similarity to the two previous samples from Boulder 2 except for the presence of many very small vesicles. These vesicles further support the interpretation that the matrix of the rock crystallized from an impact melt. As with the vesicles in lunar basalts, no evidence yet exists as to the nature of the vesicle filling fluid; however, this lack of evidence implies a non-reactive fluid, possibly hydrogen and/or carbon monoxide.
Fig. 11.41. The location of rock sample 72395 is marked by the white oval. (NASA photo AS17-137-20912 is the base photo).
72395, the largest sample taken from Boulder 2 (Fig. 11.41), from a point well removed from the spall I initially had thought was an inclusion, has an exposure age of about 27 Myr, in contrast to and supporting the ~0.27 ± 0.05 Myr old spall interpretation for 72315. The impact or seismic event on the slope of the South Massif that caused Boulder 2 to roll to the Station 2 site appears to have occurred significantly after that associated with Boulder 1. As with Boulder 1, Boulder 2 probably was dislodged from higher up the slope, well after the light mantle avalanche but too long ago for its track to have survived (See discussion in Chapter 12, Station 7). This experience with sampling a probable young spall area on Boulder 2, rather than a large clast, constitutes a reminder that continual micro- and macro-spalling of boulder surfaces produces minimum exposure ages rather than giving the actual length time of original rock exposure.]
“Here, Jack, …might get the soil from around that thing (Boulder 2).”
“Bob, both rocks look like they might be in the anorthositic class…of rocks. It’s just that [this] one has the appearance of being a finer grain matrix. Looks like a porphyry in the boulder.” A later determination of the plagioclase content of both 72315 and 72395 at ~56% supported this field impression.
“Your bag is still open part way, too.” Cernan alerted me to a loose cover on my SCB.
“And a reminder,” Parker said, “as you photograph it (Boulder 2), to remember that the photograph in the southwest quadrant there will be the best ones. Around the corner on two sides there will be the best ones to show the structure through the whole rock.” This “reminder” got us into a classic illustration of someone who was not on the spot trying to second-guess those who are.
Fig. 11.42. Lunar Receiving Laboratory images of impact melt breccia sample 72395 from Boulder 2, Station 2, as unpacked and dusted (top = exterior surface; bottom = interior face). Consistant with this sample’s exposure age of ~27 Myr, and that of 72315 of about ~0.27 ± 0.05 Myr years, the visual density of light colored zap pits appear to reflect qualitatively the exposure age difference. Studies of these two samples might put limits on the age at which saturation by micro-meteor impacts occurs (steady state between formation and distruction plus obsuration by patina formation). (NASA photos S73-23979, -23983).
“Yes, sir,” I responded and then had a second thought as the southwest portion of the boulder was in shade and up the slope. “Oh, the southwest [you say]?”
“South and west?” Cernan suggested as clarification.
“South and west. Yeah,” I started to agree.
“No, the west’s in shade,” I countered.
“No, no. You mean the…south and east, [don’t you?]”
“Southwest,” insisted Parker. “Roger. The southwest face, …or it faces not quite south.”
“Okay.” Cernan rightly decided to ignore the whole discussion and take pictures all around the illuminated portion of Boulder 2. “I’ve got a stereo [of where we sampled]. I’ll just continue my stereo around here… Hey, Jack, you can get way under there, and I know you could get soil.” He had noted an east-west, north-facing overhang. “I don’t know how long it’s been shadowed, but it’s been shadowed as long as this rock’s been here.”
“Okay. I’ll do that,” I replied.
“Way out under there. I’ve got to stereo this one. I’ve already got it.”
“Well, I’m getting it from this way,” I stated, “and they like that. Did we kick any dirt in under there?” Regolith exposed to the sun would contaminate the shadowed sample.
“No, I don’t think so” Cernan said. “Go way down in there [for the sample]. Let me get a couple of after pictures. Yeah, we want to get two sides of these rocks, and you can see their structure…”
“I’ve got that [after picture], Gene. …I took those. I took that stereo.”
“Okay, and if I could remind you guys to get a pan,” Parker interjected, “from up there before you leave the high uphill area there. There’s no point in climbing up there twice. Remember?” he added, sarcastically.
Ignoring Parker, Cernan asked, “Did you get under there [for that shadowed sample]?”
“I think so.”
“Yes, sir, Bob,” Cernan agreed on the panorama. “How much time we got here now?”
“Okay, [Gene]. You got your [sample] bag?”
Parker broke in with, “We got 12 or 13 minutes left at this station; unless you take that extra 10 minutes that we were offering you.”
“Let’s take it, Bob,” said the Commander.
“We got to get the rake [sample],” I reminded everyone.
“Let’s take it (the extra time),” Cernan repeated, “we’ll need it.”
“Okay. Let me try again (to get the sample under the overhang),” I said. “…I don’t know whether I can or not.”
“Do you know how far under you’re getting, by any chance?” Cernan asked.
“Yeah… I got under an east-west [north-facing] overhang about 20 centimeters. …Way back…quite a ways back; it goes even farther, but that’s about as far as I can reach back and [still get a scoop] sample. …That’s in bag 500 (72320-24).” I am surprised I did not immediately obtain a control sample of nearby, illuminated regolith. No harm done, as the rake sample 1 kg of regolith could serve as a control.
[Post-mission analysis of the thermo-luminescence spectrum of 72320 suggested that the sample had been only partially shaded under Boulder 2; however, as I said during sampling, this was a north-facing, east-west shadowed location. If the 27 Myr exposure age of Boulder 2 is correct, 72320 was in permanent shadow for that period of time. A portion of this sample has been kept frozen for future analysis, but will be provided for study in the near future (2019).
The agglutinate concentration of 72320 is 45.3%, similar to other soils at Station 2, and it has an intermediate-high Is/FeO maturity index of 73.]
“And, 17,” Parker called, “if you want to take a minute, you might look up in the sky and notice that our [TV] camera is taking a beautiful picture of Mother Earth.”
“Isn’t that pretty over [the Massif]? …Can you see the Massif, too?” asked Cernan.
“Now we’re coming down to look at the Massif,” replied Parker. “Had a beautiful picture of the Pacific there. Ed (Fendell) finally found it (the Earth). Now we see the Massif.”
After stowing bag 500 in Cernan’s SCB, I told him, “Okay,” so he knew he could move, again.
“And, Bob, I took an after picture of where Jack just got that soil sample under the rock from; and I’m on [frame] 60.”
“Are you through with the gnomon?” I asked Cernan.
“I’ll set it (the gnomon) up for the rake [sample].”
“I’ll go up there and get a pan, Jack.”
“Okay. You get that pan…”
“I didn’t get that soil bag number, Jack,” Parker said to me when he should have asked Ray Zedekar at the EVA console behind him.
“We’ve been here. …500,” I answered, anyway. …We’re on a pretty good slope, Geno.” I was trying position myself for the rake sample.
“You betcha. And do I know it.”
“Hey, …Bob, how long have we been at this station?” I asked as I stuck the scoop in the regolith and took up the rake.
“You’ve been here about forty minutes right now. Can you believe it?”
“Is that right?” I said in disbelief that it had been that long.
“And we’re going to give you that extra 10 minutes out of Station 4,” Parker added. “That leaves you about 20 minutes; then you’ll have to be moving.”
“Boy, this pan (AS17-137-20926-56) may be looking right smack in the sides of the Massifs. Only way you can get it is to lean back, and I can’t lean downhill.” (See Fig. 11.27↑, Fig. 11.28↑ for part of Cernan’s pan).
While Cernan struggled to get his color panorama, I took several down sun photographs of the rake site before taking the sample (AS17-138-21043-46). These before photographs indicate that the surface of the slope regolith does not have the pronounced raindrop pattern we had noted on the valley floor. Although lighting in the photographs may be a factor, slow movement of material down-slope may be at a rate sufficient to eliminate the small micro-meteor and micro-seconary ejecta craters that produce this pattern.
Fig. 11.43. The rake area a few meters from Boulder 2 at upper left. The sample scoop and gnomon are at right. The partial bootprint at lower right shows just how soft the regolith is in this location as noted earlier in text. The “raindrop” effect is practically non-existant compared with the valley floor near the SEP site (Fig. 11.5↑). (NASA photo AS17-138-21046).
“Hey. Watch out for that crater behind you there, Geno,” advised Parker, watching on TV.
“I’m standing in the crater so I can get level,” he replied, showing human innovation at its best. He is standing about 10 meters up the slope from Boulder 2.
“Yeah, we see that.” No boulder tracks to either Boulder 1 or 2 are visible in these photographs, indicating that impacts have destroyed such tracks within the minimum exposure age of 27 million years for Boulder 2.
“Well, I have some good pictures of Nansen, anyway, and, …you know, I look out there, I’m not sure I really believe it all.”
I absorbed the scenery without comment, feeling under constant time pressure to explore new things as much as possible. “Bob, my down-Sun pictures on the rake were taken at f/8. I’m sorry.” They should have been at f/11 so they will be somewhat overexposed.
“Okay, copy that. We’ll take it into account.
This [raking] isn’t an easy [task]. …Okay, I got to get out of my shadow or I can’t see what I’m doing…”
“I’ll be right down there to bag that rake [sample] for you,” Cernan alerted me as he finished the panorama and took photos of the Earth over the South Massif (AS17-137-20957-9). Unfortunately, for his main panorama, Cernan did not reset his camera from 15 to 74 feet, leaving the far field in the photographs badly out of focus. He had reset the focus for the Earth pictures. (AS17-137-20960 and -20961 are particularly good. Fig. 11.44.)
“I got to get it (the rake sample) first,” I warned, conscious of the difficulties of working the rake on this steep slope. I selected a rake sample site about five meters away from any large boulders, and with no significant boulders upslope. I had to rake uphill, toward the Massif, with the rake at my left side so that my shadow fell to the west. I pulled the rake uphill as far as I could than then hopped up a foot or so to pull it farther. I then would step downhill into the just raked area and start another swath. I went through this procedure several times, shaking the fine material out of the rake basket, frequently. The sampling sequence finished with just dragging the rake up hill for a couple of meters.
Fig. 11.44. The Earth over the South Massif and Boulder 2 at Station 2 in the valley of Taurus-Littrow. Although the background looks level, it is actually the very steep Massif slope of about 26°. For comparison, the Earth’s elevation is ca. 44°. Asia and the western Pacific Ocean are in view in this image of a waning Earth. In contrast, at this point in its monthly orbit, a waxing Moon also would have been at half phase as seen from Earth. (NASA Photo AS17-137-20960).
“Man, I tell you,” Cernan said with a laugh as he came to join me at the rake sampling location. “Can you come downhill in a hurry. Going uphill is a nice job. …Bob, I’d say we can meet our walkback constraints, if anyone’s interested.” He felt that he could move at the assumed walk-back speed; however, he had not done nearly as much walking/skiing as had I. With that experience, I already felt that the walk-back constraints were too conservative, particularly if we used the cross-country (Nordic) skiing motions described previously.
“Okay. I expect it’s all downhill from here,” joked Parker.
“Well, no, sir,” corrected Cernan. “Not exactly [downhill]. …That’s why I said we could meet our walk-back constraints.”
[The walk-back constraint, in the highly unlikely case of a complete Rover failure, assumed that we would have the oxygen and cooling water necessary to sustain 2.7 km/hr at an average metabolic rate of 1290 BTU/hr for over an hour of walking with a 20% margin of safety. This presumably would get us back to the Challenger with enough consumables to close out the EVA. Had the walk back been less than an hour, the assumed numbers would have been 3.6 km/hr and 1560 BTU/hr. I am certain that Cernan and I also would have carried the samples in our SCBs with us, as well as the SEP recording tape and the tongs, hammer and scoop for use on a revised EVA-3. In retrospect, Cernan could have carried the rake to give him the extra stability that the scoop gave me (ski pole principle).]
“Can you guys see the LM, or are you too far down to see the LM?” Parker asked.
“Oh, no. The LM is over about three rises in the Scarp before we can even see it.” Cernan’s estimate probably was about right if you included the trough we were in.
“Okay, I thought that might have happened.”
“I’m not even at a level of the last hill (north rim of the trough) we came over. …I don’t know if you’ve looked up that way (with the TV).”
“Roger. We had a feeling for that. I was just checking.”
“We can meet them (walk-back constraints), but I wouldn’t stretch them.” In actual fact, this was a judgment call that neither of us would want to test.
“Gene, you got a bag?”
“Yes, sir. Right here. How you doing?”
“My hands are getting tired.”
“Yeah. Bag 501 (72535-39, 45-49, 55-59),” Cernan reported as I took a last swath. “No, there aren’t a lot [of rocks]; but that’ll fill up a bag.
[Post-mission examination of the bag containing 72535-39, 45-49, 55-59 disclosed it contained fifteen fragments of impact breccias: a mixture of nine blue-gray breccias (similar to Boulder 1), five green-gray breccias (similar to Boulder 2), and one light-gray breccia (extremely fine-grained impact melt). As I had selected a rake sample site carefully, this distribution of breccias probably represents the relative quantities of the various rock sources above us that feed the slope of the South Massif.
72535’s exposure age of 107 ± 4 million years lies at the upper end of the range of other exposure ages that limit the timing of the light mantle avalanche. Crater count data from the surface of the light mantle suggest a younger, more likely age of about 75 Myr (see Chapter 13). Also, continuous micro-meteor erosion, however, would bias 72535’s exposure age downward, so its actual exposure age would be greater than 107 Myr, including any pre-avalanche exposure.]
“[Is] this [a] kilogram-of-sample site, too?” I asked Parker.
“I’ll have to look [at the checklist],” Cernan answered first. “I think so. I think they all are, aren’t they?”
“Practically,” I agreed.
Finally, Parker answers. “And this is one that we would like to get the kilogram of soil from Jack.”
“Okay. I’ll use my scoop for that.” The scoop weighed less than the rake.
“Bag 501,” Cernan repeated
“Okay, what do we have left [to do] here?” I asked myself as much as anyone.
Looking at his Cuff Checklist, again, Cernan noted, “We want to get a [pan]. …I got the high pan.”
“I don’t know how we used up all the time, but we did,” I mused.
“Okay, [on] my pan, by the way,” Cernan reported, again, “I got extensive vertical (downward) coverage down into Nansen, Bob.”
“Well, the soil’s getting into my [scoop hinge],” I observed, trying to adjust the angle of the scoop on the extension handle.
“I don’t know where the hour went that it took to drive here.” Cernan joined me in my musing.
“Maybe time’s different in space. ‘Adventures in space and time.’ ” I am not sure why this quote came to mind unless it had seeped out of the classic 1960s BBC series “Doctor Who” that I have no recollection of ever watching.
“We changed 2 hours and 40 minutes. I don’t know whether that makes us older or not.” Cernan refers here to the launch delay that resulted in our mission clocks to be set ahead by about that amount.
“Ooops…” I utter as I lost part of the soil sample out of the scoop. “Awrrrrrr…”
“Try again. I got half of it. [Actually] I got three-quarters of it. [bag] 502 (72500-05), Bob, will be the kilogram.”
“And that’s a sample down to about 5…about 4 centimeters,” I added. “Don’t get [the bag] too close to your camera, [Gene]. …[Now you’re] okay.”
[Post-mission examination of 72501 indicates that the 90-150 µm fraction contains about 35% agglutinates and has a low-intermediate Is/FeO maturity index of 35. This relatively low maturity, as compared to maturity indexes more than twice as high for regolith forming on the surface of the light mantle (see below), may be the result of continuous impacts upslope that add low maturity material to the sample site. 72501 also consists of 2% non-impact glass (volcanic ash) and about 3.3% basalt fragments. The presence of this glass and basalt in the Station 2 regolith gives a rough indication of the rate of impact redistribution of regolith within the valley. Volcanic glass and basalt, of course, are major components of the dark mantle. The nearest significant impacts into dark mantle since the light mantle avalanche occurred lie about 2.5 km to the east. About 5% of the Station 2 post-avalanche regolith, therefore, has been derived from sources at least 2.5 km distant in 75-107 Myr since the youngest avalanche took place (see Chapter 13).
Comparison of sample 72501 with North Massif sample 76501, suggests that mineral fragment-rich, lithic-clastic eruptions of fine debris from within the crustal mega-regolith preceded each regional eruption of mare basalt (Chapter 13). Old North Massif regolith is rich in mineral fragments, whereas post-avalanche South Massif younger regolith is rich in impact breccia fragments. ]
“Oh, that’s a ‘big bag full’. Want to put it in mine?” Cernan said, quoting a nursery rhyme and thinking that my SCB might be getting heavy.
“It’s all right. I can’t feel it (the weight). You might as well [keep using it].” In one-sixth gravity, the bags never became heavier that about 5 or 6 moon-pounds and, in addition, were supported by suit pressure.
“How’s your cooling?” Cernan asked. “Okay?”
“Cooling’s fine. My hands are tired.”
“Well, that’s natural.” Cernan showed little sympathy.
Parker came on line, again. “And guys, do you see any more different blocks up there that are worth sampling before you go on down on to the flats [near the Rover] and sample the light mantle?”
“We haven’t had a chance to look around any more than you’ve heard,” I replied. “You want a rake in the light mantle here (near Station 2)?” I asked this question, knowing full well that I wanted such a sample to compare with the one we just obtained on the post-avalanche slope of the South Massif.
[The comparison of rake samples would give an indication of whether the avalanche was fluidized to the point that fragments had been sorted according to size prior to final settling. In a gravity field, larger fragments settle in fluidized media faster than finer ones due to their smaller surface area to mass ratios. I expected that we would find fewer fragments on the surface of the light mantle in a rake sample comparable to 72500. Also, I expected that larger and larger, and therefore deeper, impact craters in the light mantle would excavate larger and larger boulders. In addition to the boulder concentrations on the rims of craters I had already observed during the drive to Station 2, the two rake samples would test these two related hypotheses.]
“We want a rake [sample] in the light mantle,” answered Parker. “You might as well get that down by the Rover later on.”
“Get an after [photo],” I said urgently as Cernan began to move away from the rake sample site. “Get an after, Gene. (Calling after him) Gene, get an after.”
“Got it, got it, got it, got it.”
Parker again began to try to do our thinking for us. “Then you might look around…for a couple of documented samples there, up on the slope of the Massif, before you move down the flatter, light mantle areas by the Rover. Just do the other sampling.”
“We will,” I acknowledged, again exasperated with this lack of confidence in us doing the job we were here to do.
“Okay, Bob. Jack got the befores on the rake and I got the after [photos].”
“Okay, Bob, here are two rocks side-by-side, a meter or two in diameter. And one is the anorthositic gabbro [like Boulder 2], if I can use the term; and the other is that two-cycle breccia [like Boulder 1].” I also might have said that these were green-gray and blue-gray breccias, respectively.
“Man, that’s the way to come downhill.” Cernan had started to move toward the Rover.
“Just don’t stub your toe,” I said, visualizing one of us doing cartwheels down the slope.
“Yeah, that’s the way to come downhill,” he repeated.
“Set up right there (Boulder 3). Let’s get that…let’s get that big clast.” As I had begun to move toward the Rover, my eye caught sight of a large, light greenish fragment in a boulder of blue-gray breccia, causing me to skid to a stop and move a few meters back up the slope.
“There’s a fracture right in there [where] I want to get the [sample]… Oh, the clast!” Cernan suddenly saw what had brought me to a skidding stop.
“Yes, sir. Good eye, good eye,” enthused Cernan.
“Big white clast in the two-cy[cle]…[that is] in the [blue]-gray matrix breccia,” I reported to Parker as I stuck the scoop in the ground to take a down-Sun before photographs of the Boulder (AS17-138-21047-49).
Fig. 11.45. The blue-gray Boulder 3 with the large white clast at left that I discovered on the way back to the LRV (see Fig. 11.26↑). This image illustrates how my eye-brain combination instantaneously looked through the brown patina on the rock to note that the clast is greenish white beneath that patina. See also next photo below. (NASA photo AS17-137-20963).
“Good eye! Man,” Cernan repeated. “That’s a prize. Let me get this [gnomon] over here so I can [get the stereo befores]” (AS17-137-20963-64).
“I think you can even get it [with the hammer].” I meant that the surface of the clast showed enough undulations that Cernan could chip pieces off.
Fig. 11.46. A close-up of Boulder 3 showing the chipped white clast (sample chips 72415-18). Some much smaller chip fragments lie on the soil next to the tongs that Cernan used to keep the focal distance constant. The area of the host rock that was also sampled (72435) is seen as the darker gray area at the left edge of the boulder not far from the clast sampling area. (NASA photo AS17-137-20968).
“I can get both sides [of the clast]. I want to get this big [piece] …Yeah, I think I can get that. I’m going to try.”
“Oh. I can’t believe the trouble I have with f-stops. Okay.”
“Now, I want to try to take this piece off first.” Cernan begins to hammer, still not quite hitting the easiest places to chip.
“Pretty hard, isn’t it,” I sympathized with his initial lack of success.
“That boulder’s going to roll. Man, that is hard. There’s the same clast over there. …That clast is soft!”
“Can you use your blade end?” I suggested, aching to do it myself.
“Yeah. Yeah, let me get that little piece, anyway, to start with.” With this swing, a small chip came off.
“Got it,” I said as I picked up the first chip with the scoop.
“There’s two more pieces.”
“Okay.” I watched closely to keep track of where the chips flew, accelerated by the impact of the hammer blade.
“Before we cover them up, let’s get them. I got to get a sample of that mother [host] rock.” Cernan is remembering his training. …“Okay, there you go. The other one’s right there…”
“Okay.” I again used the scoop to skim the two new fragments of the clast off the surface where they had flown.
“Now, Let me see if I can’t get a sample [of the host]…”
“Want to try to hit that (clast) one more time,” I asked. “I think we’ve got another one coming there.”
“There’s another little one…”
After scooping up the final chip, I looked more closely at the now fresh face of the clast. “That looks almost like a rhyolite from here. I don’t believe it, though.” Again, I was describing what the rock looked like, not what I thought it actually was. Volcanic rocks called “rhyolite” often have a distinctive color and texture. They are light-colored and may have two distinct crystal sizes, that is, some larger crystals in a fine-grained matrix (porphrytic texture). When examined back on Earth, this “rhyolitic texture” is caused by selective crushing that left some grains distinctly larger than most of the others.
Cernan has been beating on a projection of the main boulder. “No, that’s not going to come off.”
“I think that’s it. Got a bag?” I asked. Cernan handed me a bag, and I handed him the scoop containing the chips.
“Okay, this is a fine-grained, but crystalline, white clast in the [blue-]gray breccia; and it’s mixed with soil. We had to pick up a little soil. [Bag] 503 (72415-18).” (Fig. 11.46↑)
“I guess they’re all there, aren’t they?” Cernan asks as he pours the chips into the bag I have opened as wide as possible.
“I think they are,” I replied. “There are three clasts, anyway. …[I mean] three fragments that we got off [the clast]. Chips.”
“Let me get a piece of the rock it’s in,” continued Cernan. “And I’m going to take a close-up stereo of that [clast].”
“Okay. Don’t get it (the host) [too close to the clast]. Okay.”
This time, Cernan hammers on a projecting knob of the Boulder 3 host and a nice sample comes off with his third hit. As the fragment flies slowly left, he grabs at it, misses, but deflects it into my left wrist and from there onto the ground. (Fig. 11.46↑)
“See it?” he asks me.
“Yeah… See it? You hit me with it!”
“Well, I tried to catch it. …Bob, you still there?”
“Roger. Still there. Listening with great delight.”
“Look at the size of the piece that came off there, though, Jack.”
“I got another piece of it up here,” I noted.
“And I’d roll that downhill…”
“Okay, the host rock for that inclusion of white material will be in bag…what is it (the bag number)?” I inquired.
“[Bag] 504. Two chips with soil…” This time, Cernan holds the bag and I pour. The regolith with this sample has the number 72430-34.
“getting heavy?” Cernan still shows concern about the weight of my SCB.
“What? The bag?” The suit supports this weight so it would only affect my overall workload rather than being something I would notice, directly.
“No. Just the scoop [feels heavy]. …I wore my hand out holding that camera together coming out here.”
“Just make sure they’re (SCBs) closed so they don’t [lose samples]. …We’re getting some samples this time,” Cernan declares, possibly remembering how few we obtained overall on the EVA-1. “I want to get an after [photo], and I want to get a close-up stereo of that [clast]. And I’m going to get some pictures around this block, too. …There’s an after and now I’m going to get sort of a close-up stereo around it (AS17-137-20965-73). That ought to do it.” The best of these after photographs (AS17-137-20968) shows the clear distinction between the light colored clast and the blue-gray matrix as well as the sharp difference between a freshly broken rock surface and the brown patina of impact glass on an exposed surface (Fig. 11.46↑) Enlagements of this image not only show the “rhyolitic” texture of the clast but also the vesicles present in the freshly exposed blue-gray breccia.
[See Fig. 11.46↑. (72415) of Boulder 3 at Station 2 was found to be a light colored crushed dunite clast in blue-gray impact melt host (72435). The fresh surfaces where samples were obtained stands in sharp contrast to the original surface that is covered by a light brown patina produced by space weathering effects (Chapter 13). Enlagement of the fresh, blue gray surface to the right of the dunite clast, shows a number of small vesicles indicating an immiscible fluid was present in the impact melt that enclosed the clast (Chapter 13). Isotopic and textural evidence indicate the dunite clast, and a troctolite sample from Station 6 (76535) were both part of magma ocean cumulates that once resided near the base of the lunar mantle, probably as much as 400-500 km below the surface (Chapter 13).]
“Hey, Bob, while he’s [Gene] doing that, there’s a real good example of a pit-bottom crater up here even on this talus slope. I’ll try to take a stereo of it.” I took three shots, hopping downhill a little between each.
“Okay, Jack, that sounds great,” acknowledges Parker. “I guess there’s always a problem of getting the in-place glass, if you think that’s appropriate at this point. Word along those lines, though, is we’d like to have you in the Rover moving in 11 minutes; so it’s probably not appropriate at this time on that.”
Fig. 11.47. My 3-photo pan of the pit crater just east of Boulder 3 (see Fig. 11.26↑). Note the slope! (NASA photos AS17-138-21050-52).
“Okay, there isn’t any glass in [the bottom of] this crater. You can see it with your TV. …It’s just bigger than the average crater. And it still has that pit, the pit being about a third of the inner diameter of the crater. …Make it a fourth of the rim diameter, that’s easier.” This crater was several meters across with the pit being about one meter wide (Fig. 11.47).
“Jack?” called Cernan, as I headed back to Boulder 3.
“Can I look at that [boulder again,] closely?” I wanted to get a closer look at the white clast in Boulder 3.
“Look at what?”
“Hold the rake a second,” I requested, now using the scoop and my hand on the boulder to get my helmet visor as close as possible.
“We got to be moving in how many minutes, Bob?” asked Cernan, having missed Parker’s statement to me.
“We’d like to have you moving in one-zero (10) minutes, which means: allow the usual 3 or 4 or 5 minutes for close-out before that time.”
“Okay, we’ll get hustling.”
“Okay, Bob,” I began, “that white-colored inclusion we sampled looks like a strange…”
“Look out, Jack,” interrupted Cernan. He stood just uphill from Boulder 3, and after a couple of kicks, got it to roll over twice. I tried to help it roll farther, to little effect as it hit a rise in the slope.
“It’s the old boulder-rolling trick,” Parker jokes, recalling similar activity on some of our training trips.
“How about getting a soil sample under there?” This is a good call by Cernan as an exposure age on the boulder can be compared with such an age on the sheltered regolith beneath it.
“Don’t hit the Rover,” Parker advised, in good humor.
“Get that sample under there, Jack, …under that rock.”
“Okay. Got a bag?”
“Got a bag.”
“The soil from right underneath the rock— down to about 4 centimeters [depth]— in 505 (72440-44).” Cernan stayed above me, causing me to reach higher than usual to dump the scoop into a bag… “And I’ll try to skim it here a little, too, …[and] get the upper centimeter.”
“Bob, this big white clast,” Cernan states, “I’m not sure there aren’t some smaller ones in some of those other big boulders. That’s just an intuitive guess.”
“Oh, there are [more clasts],” I confirmed.
“But we never saw any as obviously big and gross as this one,” added Cernan. “Fact is, [in] this particular boulder I photographed, I had three of them (clasts) other than the one we sampled. …And that’s 505 and 506 (72460-64), in that order…on the soil [samples].”
[No effort yet has been made to measure and compare the exposure ages of Boulder 3 (72435) and the regolith beneath it, that is, 72440 and 72460. The intermediate-high Is/FeO maturity indexes of the two soil samples are about the same, 68 and 71, respectively, with corresponding agglutinate concentrations of 41.7 and 43%, again showing a close correlation between these two maturity variables. Analyses show no anomalous volatile element concentrations in these soils. The relatively high maturity versus that of the rake sample regolith (low to intermediate maturity index of 35 with agglutinate of 35%) documents the younging effect of down-slope movement of newly exposed material. It also indicates that the soil under Boulder 3 has not been exposed to the addition of such less mature material since it rolled into place. The high maturity of the soil under Boulder 3, however, indicates a long period of maturation after the light mantle avalanche took place and before Boulder 3 rolled into place. This observation is somewhat surprising due to its location being on the slope where younging would have been expected. It may be that such younging is very slope angle sensitive, with the slope at Boulder 3 being less than at the rake sample location about 20 m farther up the side of the massif.]
“And by now, probably the best thing for you guys,” Parker said, “to do is to go back to the Rover and pick up the rake sample. …Go ahead, Jack.” Parker apparently realized I had been interrupted.
After Cernan put the two samples in my SCB, he turned to retrieve the gnomon, and I said, “I’ll get it (the rake).”
[Continuing to speak about the clast in Boulder 3, I headed for the Rover using my low energy skiing motion while Cernan moved more rapidly downhill with his preferred hopping gait. As I arrived at the back of the Rover, I held the scoop in my left hand with the handle forward. This was misoriented relative to putting the scoop on the gate with the scoop end up, so I just tossed it up, rotating it clockwise like a baton, caught it, and inserted it in its clips on the gate. You take advantage of any opportunity not to move the suit very much and, as things fall slowly in one-sixth gravity, tossing objects up to change their orientation or to change hands makes a lot of sense.]
“That white clast,” getting back to what I started to talk about before rock rolling intervened, “I looked at it [closely], and it has light, pastel-green, fairly-rounded crystals in a fine-grained white to light pinkish-tan matrix. And you can figure that one out. Looks like olivine [grains] in something.”
“Roger on that. Sounds like a rainbow.”
“It might be a [dunite]. …No, the colors aren’t that distinct [as a rainbow], Bob. I’m just giving you shades” (Fig. 11.48).
Fig. 11.48. Lunar Receiving Laboratory image of cataclastic dunite sample 72415 from Boulder 3, Station 2, as unpacked and dusted. Note the coarse grains of olivine in a much finer matrix of crushed olivine and minor other minerals. There is mineralogical and isotopic evidence that this rock initially was formed ~4.45 billion years ago, near the base of the lunar magma ocean and possibly once resided as deep as ~500 km beneath the current lunar surface (Chapter 13). Chips of the large white clast are shown in the lower photo. (NASA Photos S73-27577, S73-17969).
[Sample 72415-18 (Fig. 11.48, lower), indeed, turned out to be a dunite, with rounded olivine mineral clasts in a fine-grained matrix of olivine and very little else. Some olivine is associated with a symplectitic (worm-like) intergrowth of Cr-spinel and Ca-clinopyroxene. Differential crushing of olivine crystals give the clast the appearance of a being porphyritic (granoblastic texture in cataclastic rocks). Initially, this sample was assumed to be from the Mg-suite of lunar rocks. New petrographic and isotopic analysis, however, suggest that this dunite may have originated as part of the initial cumulate of the magma ocean. Overturn of the mantle appears to have brought some cumulates close to the base of the crust and to where large basin impacts could excavate fragments from them (see Chapter 13). This sample may have originally accumulated and stabilized mineralogically as much as 500 km below the surface of the Moon.
Making geological sense of the age data from the three boulders sampled at Station 2, however, remains difficult. Many different events appear to be interacting, some of which never provided an opportunity for isotopic equilibration to occur. Perhaps the best anchors for evaluating the various samples are the Rb-Sr crystallization age of the dunite clast in Boulder 3 of 4.45 ± 0.10 billion years as well as the 3.97 ± 0.01 billion year 40-39Ar reset age for that same highly crushed clast.
Post-mission examination and analysis of 72435, the host rock of the dunite clast, indicate that it consists of a melt-breccia with scattered concentrations of vesicles. Besides the dunite, the melt-breccia includes clasts of anorthosite and troctolite. The overall character of the matrix resembles that of the melt breccia of Boulder 2 except for its darker, bluish color. ]
Fig. 11.49. Lunar Receiving Laboratory image of blue-gray melt-breccia sample 72435 from Boulder 3, Station 2, as unpacked and dusted. (NASA Photo S73-16194).
[No exposure age is reported for 72435. This color contrast in melt-breccias also will be visible in the boulders sampled at Stations 6 and 7 at the base of the North Massif.
The Rb-Sr isochron age of dunite clasts in 72435 is 3.77 ± 0.18 billion years with the impact melt matrix showing an older Rb-Sr model age determined for portions of the matrix of 4.01 ± 0.05 billion years. This difference suggests a significant lack of isotopic equilibration. A fission track age of a plagioclase mineral clast was determined to be > 4.05 billion years.]
“Hey, Bob,” Cernan called, “have you panned down into Nansen and seen this rock that’s, oh, 30 or 40 meters from us? To give you an idea of the kind of upslope filleting you have on some of those boulders. …It’s down to your right.”
“We’ll send Ed (Fendell) over there to look at it.”
“Well, I’ll help him [by manually pointing the TV]. I don’t think you got enough time [for Ed to find it].”
“Okay, we’d like you guys to get going on the rake sample. We’d like light mantle on (in) the rake there.”
“Where’s your gnomon?” I asked. “We’ve got to get a rake sample. …I’m going to have to move out here a ways, Geno.” With rake in hand, I headed toward a spot about 40 m northeast of the Rover where the rake sample could be taken well out onto the light mantle.
“Okay. Coming right there, [Jack]. …[Bob,] right there is what I’m looking at [in Nansen].”
“Okay. We’re going to check it out; thank you…”
“And there’s no sense trying to get 500’s up [the slope]. …Well, we’ll see what happens.” Cernan headed toward where I wanted to take the light mantle rake sample. As he moved in my direction, I took a black and white panorama of the area (AS17-138-21053-73). Photograph AS17-138-21072 as well as AS17-137-20976 show the Rover and the Station 2 boulders on which we had worked (Figure 11.50). Additionally, photo 21061 indicates that the raindrop pattern of small craters exists on more or less level surfaces but not on steeper slopes (Chapter 13).
Fig. 11.50. Photograph from the location of the second rake sample at Station 2, showing the Lunar Roving Vehicle with the area of Station 2 behind. The large Boulder 1 sits to the right and down from the central reseau mark. An equally large Boulder 2 is directly to the right of that mark. The much smaller Boulder 3 is midway between Boulder 1 and the Rover. The crater I photographed in Fig. 11.47↑ is at the end of the 3 boulders leading up and left from the LRV, its identifying boulder on the south rim easy to spot in both photos. The planimetric map of the area is in Fig. 11.26↑. No boulder tracks have been identified that lead to these boulders from higher on the South Massif. Each of the splashes of light color on the background slope indicates locations of a relatively young impact craters. (NASA Photo AS17-138-21072).
Fig. 11.51. The same view from nearly the same spot taken by Cernan a few minutes earlier (my tracks are not yet in the scene at left, cf. Fig. 11.50 above). (NASA photo AS17-137-20976).
[The abundance of boulder tracks on the flanks of the North Massif, as well as tracks to boulders in Nansen, shows that tracks to the sampled boulders existed at some time on the slope of the South Massif above Station 2. Unfortunately, neither the photographs we took of the South Massif nor any LROC images, show tracks leading to the area to the east of Nansen where we established Station 2. The avalanche that formed the light mantle erased all pre-avalanche tracks above that location. Post-avalanche tracks have been lost due to regolith redistribtuion by impact and gradual down-slope movement of that regolith. Comparison of boulder exposure ages and the tracks leading to the Boulders at Stations 6 and 7 suggest that tracks on the massif slopes will be largely erased within about 50 million years or less (See Chapter 13) or somewhat greater than the lowest exposure ages of the boulders sampled at Station 2.]
“Okay. Also, there’s no time to get 500’s either, unfortunately,” Parker repeats. “We’re planning [adding this] on Station 4, which will be a better perspective distance anyway.”
“Yeah, I was going to say there’s no sense in trying to get them up the Massif; I don’t think you’ll see anything up there [because of the angle]. …You getting your pan?” Cernan asked, switching his attention to me.
“Where do you want it (the gnomon)?”
“Well, right over there where there’s some fragments. And you get the…”
“I’ll get the before [photo] and the locator (AS17-137-20974-75),” Cernan said, reading my mind.
“Okay, and then I’ll get the down-[Sun]. …[Its even] tiring to take pictures.” Here I am, exploring the Moon for heaven’s sake, still complaining about tired hands!
Fig. 11.52. Cernan’s “before” of the 2nd rake site. The locator photo is Fig. 11.51↑. (NASA photo AS17-137-20974).
“Yeah. Let me tell you, you just got to think an order of magnitude bigger [time for tasks] than what you’re normally are accustomed to thinking.”
“Okay, pan’s complete,” I reported.
“Let’s get the rake sample so we can move on. …Bob, I couldn’t get those 500’s anyway. It would require me to pitch up (lean back) too far, and there’s no way I could do it.”
“Okay. No, we’re definitely not in favor of that, Gene,” Parker agreed, “at this area.”
“I know. I’m just mulling it over, but there really isn’t any way I could get them.” One way would have been for one of us to hold the other as he leaned back or just to take the camera off the RCU, but neither of these ideas occurred to anyone at the time.
I took this rake sample by going forward a few steps, dragging the rake for about two meters for each swath. “Boy, I tell you…”
“How are your hands? Let me rake that a little bit,” Cernan offered.
“Well, it’s all right,” I said, “there just aren’t any rocks. Should have brought the scoop and used the old shovel trick.” “The old shovel trick” consisted of using the scoop as a shovel to fill the rake.
“There’s a couple; keep going. …There sure aren’t [many rocks], are there?”
“Okay, do you have any feeling [that] you have that hard layer underneath there like you did yesterday,” asked Parker, “when you raked at Station 1, Jack?” This was a good question from the Science Support Room. Unfortunately, I never made any comment about it as I collected the sample.
“There’s one (rock) under the gnomon you can get,” Cernan suggested; however, one point was to see how many rock fragments turned up randomly in a given area.
“Several I thought were rocks turned out to be clods,” I observed.
“Yeah, that’s what most of them are is clods. How do you get clods if it’s never been wet? You’re not getting any. You’ve had three in there ever since the last four scoops (swaths).”
“There just aren’t many.” I stopped at this point to pour the few rocks in the rake into a sample bag Cernan held out.
“507 (72735-38),” he said.
“Okay, copy 507, very few [rocks].”
“Three rocks. …Yeah, you got about four rocks about 2 inches and smaller,” counted Cernan.
[Post-mission examination of 72735-38 confirmed that the light mantle rake sample consisted of only four breccia samples in contrast to the fifteen collected on the lower slope of the South Massif from similarly sized areas. This difference supports the hypothesis that the light mantle consists of the remains of a fluidized avalanche of regolith that flowed off the side of the South Massif (See Chapter 13). As a fluidized avalanche moved, fragments would tend to be sorted by size with larger sizes moving toward the bottom of the flow and finer fragments concentrating toward the top based on their surface area to mass ratios.
Rake sample fragment 72735 has received considerable interest. It has unusually high concentrations of rubidium, zirconium and trace elements as well as a small amount of K-feldspar. Olivine and pyroxene contain about 15-40% iron component. All of this suggests a strong association with the KREEP suite of lunar rocks that in turn appear to be related to the residual melt of the lunar magma ocean (urKREEP). No 39-40Ar age date has been obtained other than this sample’s latest reset age appears older than 3.85 billion years.]
“And let me get the down-Sun which [also will be an after photo]. …And we want to get the soil.”
“Okay,” Parker repeated, “let’s just get the soil and…press on. We’d like to move in 3 minutes, 3 minutes.”
Okay. …You got it (the down-Sun picture)?” asked Cernan.
“Okay. Let me put this in your bag (SCB) and… Forget the soil.” This command from Cernan surprised me.
“Forget the soil?” That would make the rake sample much less valuable.
“He wants us moving in 3 minutes. So let’s go.”
“Well…” I said with uncertainty. Clearly, Cernan had assumed the role of a Commander, responding to what he thought he had been ordered to do by Mission Control.
“No, get the soil, guys. Get the soil. Don’t forget the soil; get the soil.” Parker broke in, possibly realizing that he had interrupted the normal rake sampling procedure, prematurely.
“Yeah, we want it,” I said, reinforcing Parker’s request.
“I’m sorry, I thought you said to skip it.” Cernan apparently had misheard “just get the soil” as “forget the soil.”
“Got your bag?” I asked him.
“May be a little messy.” I warned.
“That’s all right…”
As I poured the kilogram sample into the bag, I said, lightly, “One-scoop-Schmitt, they call me. That’s good.”
[Except for the paucity of large fragments, post-mission examination of 72701 disclosed that this portion of the light mantle regolith near the massif mostly contained material similar to that of the South Mantle slope, including about 3.4% volcanic glass and 1.7% basalt in the 90-150 µm fraction. This also is comparable to other Station 2 regolith samples. Agglutinates are 43.6%, a value that corresponds well with an intermediate-high Is/FeO maturity index of 61. The light mantle 72701 maturity index of 61 is puzzling and shows that comparisons of one maturity index with another must be viewed with caution. As discussed below, other surface regolith samples from the light mantle have significantly higher maturity indexes than 61.]
“You’ll have to start putting some of these samples in my bag,” suggested Cernan. “You’re getting a full bag for Christmas here.”
“Is it (the SCB) so full we ought to change it?”
“Yep. Let’s do that after we get to the next station, though.”
“Well, okay.” I sounded hesitant, as I did not want to take a chance that samples might bounce out on the drive to Station 3.
“We ought to start moving out of here.”
“Yeah, let’s go,” I agreed, and started to ski rapidly to the Rover.
“Let me get one after [photo] of the area.” Cernan had lost his concern for the time.
“[The area] that we messed up.”
“Beautiful station, guys; just simply beautiful. Almost deserves a Falcon code,” added Parker.
“Man, I’ll tell you,” Cernan agreed, now hopping, then skipping the 40 m back to the Rover. His progress over relatively level terrain was significantly slower compared to my skiing gate. Then he laughed at the reference to the Navy’s Falcon code system. “Falcon 109 (beautiful!). I couldn’t help that, Bob; it’s just too beautiful.”
[Falcon codes were developd by military pilots’ codes as a means of passing rude comments over the radio, but in this case, Cernan apparently usurped “Falcon 109” as a compliment to the activities at Station 2. Falcon 109 actually meant something else, entirely.]
“Hey, Jack,” Cernan continued, “will you look where we kicked up this stuff. There’s some light [material]. …Well, I can’t see it now, I’m looking…”
“I can see,” I confirmed, having noticed this earlier but had neglected to mention in the rush to finish at Station 2. “There’s a light-colored fragmental [layer] I think we break into.”
“Yeah, we kick it up.”
“They’re light-colored clods.” I am glad Cernan mentioned this, as I probably would have forgotten it. Later, I would note that the upper couple of centimeters of the light mantle are significantly browner than what lay below. This upper zone probably shows the depth of new regolith development since the light mantle was deposited 75-107 millon years ago (Chapter 13).
“And,” Cernan went on, “when I was walking uphill [near the boulders], I really wasn’t sinking in, probably, more than an inch or two.” Although not totally clear, this observation may relate to sinking in more deeply on the light mantle and be related to a much higher content of fines near the surface of the light mantle as compared to the more fragment-rich regolith on the slope of the South Massif.
“You want to take this bag (SCB) off of me?” I said, forcing the issue of protecting the samples we had gathered from the potential of the SCB coming open during our next Rover traverse.
“I’ll get one out [from under the seat]. …We can use this one (SCB-4).”
“Yeah. Because we want to get rolling…”
“Okay, Seventeen, there’s a couple of things here, while your getting undone there.” Parker then gave us a much too long a list as we were busy doing other things in preparation for leaving Station 2. “There’s our housekeeping to close out. Change those bags. We’d also like to get the SEP turned on, and you might read us the temperature when you turn it on. And other than that, stowing the TV and low-gain (meaning to say “high-gain”) antenna and you’re on your way. We’ve taken care of the gravimeter already.” Parker should have waited until we had finished with what we knew was required to see what we might have missed.
“Did our [gravimeter] reading change much, Bob?” Although not pertinent to the field activities under way, my curiosity had gotten the best of me.
“Which one?” Parker thought I might be thinking of the non-functioning ALSEP gravimeter rather than the TGE. Due to the press of leaving Station 2, this question never had an answer and probably did not need one at this time.
[The preliminary TGE gravity readings between the Challenger and Station 2 decreased by about 25 mgal with the value of gravity at the landing site determined to be 162,694.6 ± 5 mgal. This determination assumes a 1 km thick basaltic block in the valley with a 0.8 gm/cm3 greater density than the underlying breccias of the massifs.]
“[Gene,] Make sure that’s (SCB-8) locked on there (the gate),” I warned.
“Yeah, it is locked; [and] make sure the cap’s locked,” he said to himself. …Okay, bag 8 is on the gate, and Jack’s getting bag 4. …Boy, I know my camera’s going to be [dusty]…”
“You copy on the SEP receiver turn-on and temperature?”, repeated Parker.
“Right,” I said.
“Is my bag (SCB) closed?” Cernan asked me, then, responding to Parker, “We got that, Bob.”
“Your bag is closed.”, I told Cernan.
“Okay. Seventeen, take all that back, we’ve just had a change of heart back here. And we’re not going to turn the SEP ON, just cover it up. And you might give us a temperature reading as you go by; that’ll help us think what to do with it.” Unfortunately, the SEP receiver had run hot during its operation out to Station 2, and Mission Control hoped that it would cool down if left off and covered for another hour or so. Our return as far as Station 3 would cover ground for which we hoped we had out-bound data, so leaving the SEP off would not lose much information, provided it recorded data on the traverse to Station 2 as, indeed, proved to be the case.
“It’s (SEP temperature) about 98,” I reported – a drop of 7 degrees since we arrived at Station 2.
“Copy 98; then leave them (the switches) both OFF…”
“Seventeen, John (Young) and Charlie (Duke) are kind of advising you to put that full SCB(-8) underneath the seat to make sure the top doesn’t bounce open and lose some of those rocks.” Excellent advice. I should have thought of this, given my earlier concern about samples bouncing out with it mounted on my PLSS.
“Well, you can’t take better advice than from those who have been here!” replied Cernan… “Their advice has been pretty good, so far.”
“I won’t pass that on to them. I think they [might be hard to live with].”
“These [tool gate] locks are clamming up, Jack. I can’t unlock that one now. …Can you lock that one? …They’re all getting sticky.” Cernan refers to the clamps on the gate that hold the various tools in place. Very fine dust has worked its way into the moving parts and had begun to jam their movement.
“That one [for the SCB] just didn’t want to work any more,” I replied.
“Let me see.”
“It isn’t moving either way,” I added.
“This one was sticky, too. Let me see.”
“Out’s OPEN, right?” I asked to be sure I remembered correctly.
“Out is OPEN, yeah,” agreed Cernan. “Let me try once more, if I have to [I’ll hit it with the hammer].”
“Here I got it,” I said as I applied even more force with my hand.
“Okay, those are really getting dusty. I’ll hit those with a dust brush next time around.”
“Charge that time up to John and Charlie!” I exclaimed as I carried SCB 8 to my seat. Of course, it was the right thing to do. “…Okay. What haven’t we done?” I was glancing at the Cuff Checklist for the end of Station 2 activities.
“Okay. I got to get the (TV) camera,” replied Cernan. “Okay, Bob, I’m taking your [TV] camera,” he warned Mission Control.
“Okay, looks like it’s in the right place,” Parker replied as Fendell had pointed the camera down and aft. “You won’t have to turn it around. Good coordination.”
“Yes, sir. Okay,” Cernan said, looking at the Checklist. “We read the TGE. I’m going MODE 1 [on the LCRU].
“Roger on that. Okay; we lost the picture,” acknowledged Parker. “…And give me a call when you guys get rolling. …And we’d like frames [count] when it’s convenient on you guys.”
“Okay, Bob. …LMP is at 46,” I responded, having jumped into my Rover seat while Cernan dealt with the TV and LCRU. At this point, Cernan took a photograph of the right rear of the Rover that provides an excellent picture of the replacement fender after about 9 km of use (Fig. 11.4b↑).
“And CDR is at – if I stop long enough – 113. …Oh, look at that! Boy, I tell you…” We took one last look at the Earth over the Massif behind us.
“Okay, Geno,” I directed, based on referral to the diagram in my Cuff Checklist, “more or less follow our tracks back until we get over the big hump (main scarp) and then we can start picking our way to (Station) 3. I’ve got 3 pretty well spotted.”
“Okay; low-gain is set, and heading about 035. …Oh, let me set this thing out of the way again. This has been giving me more trouble.”
“What’s that? The hammer?”
“Yeah, the [hammer] handle.”
“Oh, getting caught in there?” I realized that the hammer handle projecting out of his right calf pocket was hitting the bottom of the console between us.
“Okay, Bob. We’re ready [and] we’re rolling. You need any [Rover system] readings?”
“No, no readings called out. And when you get going, I’ll give you a little advice on what we’re going to do on the way to Station 3.”
Traverse to Station 3
We started EVA-2 three hours and 12 minutes earlier, putting us about 20 minutes behind the planned departure time. We still had plenty of walk-back margins, but this deficit would impact the times we would have for future stations.
“Well, let me tell you a few things first, Bob.”
“Okay, start telling me.”
Increasingly, I tried to let Parker know without showing obvious discord that his interruptions distracted us from the job we had come to do. It interfered a lot with recording information about the geology. I could not take written notes, so everything had to be verbalized. At other times, he interrupted the flow of my investigations as well as Cernan’s activities spelled out in the Cuff Checklist. Cernan never seemed to recognize these problems, probably being conscious of the fact, as a pilot and Commander, that scientific results were not his prime responsibility. He clearly showed more interest in the activities of exploration than in the results of exploration. My aim, in turn, focused on maximizing results.
[Clearly, I had an unexpected problem with Parker’s disruption of thought processes as well as his lack of recognition of when on-the-spot exploration decisions need to be made. In spite of all our field exercises and related simulations, he seemed to forget when exploration of Taurus-Littrow was actually taking place that we could evaluate any given situation with more information related to field decisions better than he could. In his defense relative to the conduct of his role as CapCom, Parker seemed to feel that his job consisted more of managing the EVA activities than of maximizing the return from having two human explorers on the lunar surface. Like Cernan, as an astronomer, Parker did not have a vested personal interest in the scientific success of Apollo 17, although, clearly, he hoped for the best return possible. Also, Parker often had to do his job, rightly or wrongly, without seeing what we were doing at any given time, unless Fendell had directed the TV coverage to monitor our actions. If TV coverage had been more closely directed to our activities, Parker could have used more discretion in interjecting himself.
In the “Lessons Learned” category, the Flight Director should have been exerting control over Fendell who seemed to spend a lot of time only looking at things that interested him, although it is possible that the Public Affairs Officer was communicating with him on these matters. The field training never had a TV camera in operation or this problem might have been identified and rectified before flight. I monitored the EVAs on Apollos 15 and 16 in Mission Control, but I do not recall noticing during these missions that Fendell did not follow the human action with the TV camera. This might partly be the consequence of the valley of Taurus-Littrow being a more spectacular scenic area than either the Hadley or Decartes landing sites explored by those previous missions. Fendell should have been directed, however, to be more supportive of the need of Parker and others working the EVAs in Mission Control. In turn, these individuals should have insisted, through the Flight Director, that he do so.]
“I think those two [major kinds of blocks],” I began only to be interrupted this time by Cernan, repeating his previous call.
“All right. Those two major kinds of blocks that we sampled there— about the [only] two varieties we saw in the area— it’s a long extrapolation I realize— but they do resemble in color, and I believe in texture, the blue-gray rocks and the light-tan rocks up on the Massif. So I feel confident that— fairly confident— that we sampled at least the two major units visible from a distance in the South Massif.” The question remaining, of course, was which block source lay above the other.
“Excellent. Excellent.” Our CapCom just could not shut up!
“I think that there is some, [that is,] a lot of post-mission work to be done on correlating the angularity (surface irregularities) and possibly even the albedos of the rocks we sampled with those on the Massif. We should have good pictures of both from a distance and up close.” Boulder 1’s highly irregular and roughly layered shape contasts sharply with the smoother and more uniform shape of Boulder 2.
I tried to continue. “So we may be able…”
“Okay,” Parker interrupted, again. “I’m reminded…that extrapolation is the nature of our art,” This time, his interruption, however clever he may have thought it was, kept me from finishing whatever thought I wanted to record.
“Ha-ha-ha-ha-ha-ha.” Cernan thought this was funny and only made me even unhappier with both him and Parker.
“And, Bob, I’m not going to [ever be able to finish]! …How am I on the film?” I apparently just gave up trying to insert my thoughts. I suspect I was going to speculate on being able to correlate the blocks we had sampled with the outcrops visible on the slopes of the South Massif.
“Oh, my golly! Look at that valley!” Cernan exclaimed as we climbed out of the Nansen trough. A great, eastward view of the valley of Taurus-Littrow lay before us.
“I think you’re doing fairly well, now, [on film].” Parker at least heard my question about film. “And before you guys get too far, a couple of comments we want to do on the way. There is a Rover sample stop in your checklist, it used to be at 073 (bearing) and 6.3 (range); it’s the first thing there, halfway out to Hole-in-the-Wall. And we’re now going to have that Rover sample stop at 078 and 7.0. That should be along your tracks going home. So, about 078 and 7.0, we’ll have the Rover sample stop. And the gravimeter people have won today, and we’re going to stop and get off the Rover and get a gravimeter reading at that location. We’re taking out (time from) some stop, I’m not sure quite where. And right now, Jack, you’re right-on on the film, says a little note in front of me.”
“Okay. I’ll take [traverse] pictures, then.”
“Bob, we’re on the top [of the Nansen rim],” reported Cernan, “coming off the highest lobe of the Scarp looking back into the valley. And it’s quite a scene back there, but we still cannot see the LM. …That may be it. I don’t know.” The Nansen rim actually consists of the rim of the moat or linear depression that lies along the north base of the South Massif. In referring to the “highest “lobe” of the Scarp,” Cernan may have been referring to the highest longitudinal ridge that we came over. Usually, we used “lobe” to refer to the northeast projecting rounded ridges that define the scarp where it crosses the valley floor.
“Hey, turn a partial pan [with the Rover],” I requested. “I know it’s into the Sun.”
“Wait a minute. Wait a minute. Okay. Let’s take one from right here. I want the whole thing (the whole valley)… You ready to start?”
“Yeah, I got it.”
“Start taking. Take the whole thing.”
“Go ahead,” I instructed.
“[Have to] get around this crater.”
“I got a pan down the valley. This is just going to be right into the (Sun)…”
Fig. 11.53. Two frames from the LRV pan I made shortly after we left Station 2 on the way to Station 3. (Top): a view NE towards the Wessex Cleft showing the paucity of boulders in the near field. (Bottom): The view NW towards the Lee-Licoln Scarp on the North Massif with Hanover Crater just visible above the ridge to the right of the central cross. (NASA Photos AS17-138-21095, -21090).
“Yeah. Don’t take that one. Get it up as we come around. You get it?”
“There we go.”
“Okay. That’s the one we want. And you got the valley?”
“Yeah. Keep going. …Keep turning around over there, and I’ll get that Scarp. That’s beautiful.” I referred to the Scarp snaking across the valley, up the North Massif’s lower slopes, and then bending off to the northwest.
“Isn’t that something? Man, you talk about a mysterious looking place…” The non-geologist found Taurus-Littrow “mysterious” even after at least dozens of field trips and training exercises in spectacular geological locations on Earth. Geologists don’t normally think of natural features as “mysterious” but rather as presenting opportunties to understand further how nature works.
Referring to the partial panorama of the valley I just took (AS17-138-21075-92), I suggested, “They can cut some frames – [cut] some parts of those pictures out – and make a nice photograph, [including] TV camera, maps…” As a consequence of the glare and Rover motion, my panorama of the valley did not show much except for the relative paucity of boulders around craters in the near field as compared to craters in the dark mantle. (Photographs AS17-138-21093-95 show the lack of boulders around craters in the light mantle). The human eye and brain do much better than the camera in integrating what can be seen in spite of the glare of the sun; but only the person on the spot benefits directly from those mental images, unfortunately.
Then, I went back to geological observations. “Okay, looking at the light mantle: No more comments except that, by that rake sample, and just looking [around], there certainly are fewer [rock] fragments [at the surface] than we saw at Station 2 [on the massif slope]. The main thing that we can tell [that is different] about the light mantle, and when we’re on it, of course, are the light-colored craters. The fresher craters all appear to be light colored. As they get older, the albedo goes down (lower) and, potentially, have been dusted with material from the dark mantle or from other sites. Either that or it’s just the [result of] lunar patination that we’re all familiar with.”
[Post-mission considerations and discoveries have provided an explanation of observations related to crater albedo. The addition of ejected dark mantle material probably adds 4-6% volcanic glass plus basalt, as discussed above. Another process may be of equal or grater importance. As the surface of the light mantle ages, solar wind sputtering and micro-meteor impacts cause it to darken. Each process results in the high temperature melting and volitalization of silicate grains at the surface of the regolith. A high silica and alumina glass condenses from the plasmas so produced and coats exposed particles. In addition, each micro-meteor melts material at the point of impact. During these processes, iron oxide in minerals reacts with solar wind protons (FeO + H+ = Fe°+ OH–) with the formation of extremely small particles of black metallic iron (nanophase iron) in the glass. These processes also create the thin brown glass patina that covers rock surfaces (see Fig. 11.38↑ upper, for example). Impacts of larger objects penetrate the developing, brownish surface regolith zone of the light mantle, currently a few centimeters thick, exposing lighter colored material underneath. This gives each fresh crater wall and ejecta apron a higher albedo than the surrounding, more mature surface (Fig. 11.54↓).]
You know, it’s a shame,” mused Cernan. “They could have had TV coming down here because my heading isn’t going to change much at all. The high-gain could have been on the whole time.
“Bob, none of the craters out here in the light mantle appear to show bedrock,” I continued. “Almost all of them are instant rock craters.” Most of the fragments in the ejecta of these craters consist of regolith compacted into chunks of breccia at the instant of impact.
“Say, Bob. Give me that bearing and range again for the [Rover sample] up on the hill.”
“7.0 [km]; right here,” I told him.
“078 (bearing) and 7.0 (range),” Parker added, belatedly.
“How about 071 and 7.0?” queried Cernan. “Will that do?”
“Yeah. I think that that will be enough to hack it.”
“Well, if not, we can go down there [to 071].”
Fig. 11.54. This partial LRV pan I took just after we left Station 2 shows that we are on the light mantle. Note all the bright whitish circles and ellipses of craters on the South Massif and also just ahead of the rover. The boulder above the TV camera is sitting on the rim of a large, light colored crater. (NASA photo AS17-138-21102).
“No, no, no. Good Lord!” exclaimed Parker. “Stay on the road you’re on.”
“Well, I’m not on any road,” Cernan countered, “but I’m stopping here.”
“I thought you guys were making a road.” Parker should have known, that in new country, one pass makes a track, two passes over the same track makes a trail, and a “road” requires multiple passes over the trail.
“071. …Let me turn it (the Rover) off. …9.8 (distance) and 7.0 (range).”
“And the Rover [roll and pitch] numbers should be fairly flat for the ole gravimeter,” Parker reminded us.
“Uh, oh.” I noticed that the Rover had a pretty good tilt to it.
“Well… That means we have to change [position] here,” decided Cernan.
“Hey, right over here to my right [looks good],” I told him.
“Maybe it’s the best we can do, but it’s still going to be on a slope.”
“Well, I’ll level it off [with a wheel] on a [crater rim],” improvised Cernan. “…[I’ll use that one just ahead].”
“Yeah; go ahead,” I agreed. “I’m off [the Rover]. Do you see [the crater I mean]?”
“Yeah, I see it. Right there.”
“On the rim of that crater that’s built up a little bit?”
“Right up here.”
“What’s your [roll]?” I asked. “Can you tell your roll?
“Okay, now that’s about zero [roll] right there.”
“What’s your roll?” I wondered, again, as the Rover looked tilted to me.
“Let me turn this (Rover power) OFF. Boy, this roll indicator isn’t very [responsive]. …Oh; [roll is] zero.”
“Zero?” I sensed that we had noticeable roll in spite of this reading.
“I’ll punch it (the gravimeter) [when you get off]. You’ll change it (the roll) as soon as you get off.
“Now it’s zero.”
“Oh, you got to get off anyway,” I told him, as there should be no Rover motion during the TGE reading.
“Do I have to get off for this?” Cernan asked, reluctantly.
“Roger. Both of you get off.” Parker confirmed what I told him.
“[Rover] gravimeter reading [requires you get off].”
“Why should I have to get off?” Cernan may have been tired.
“So you don’t move the ole gravimeter,” Parker argued.
“Think you can hold still?” I asked Cernan.
“Yeah. I’ll hold still.”
“No. Negative on that, Gene.”
“[Gene,] give me your [Rover] sampler ‘cause that’s the other thing I have to do.
“Yeah. We’ll get Rover samples, at least,” Parker added.
“Unless you need me off?” I am not sure why Cernan kept arguing instead of just getting off the Rover. It is possible, I guess, that the side-slope activity at Station 2 had aggravated the pre-mission crew vs. support team baseball injury that hyper-extended a tendon in his right leg. He had kept the seriousness of this problem hidden from almost everyone else including me.
“Roger. We want Gene and Jack both off.”
“Well, if you need me off, [it’s too late]. Jack just punched it (the TGE).” Actually, I had waited to see what he would do.
“Okay. Hold still,” I commanded. “They don’t know anything about your PLSS noise.” We had not tested whether vibrations from the PLSS pumps and fans would disturb the TGE measurement.
“I better get off,” he concluded.
“Yeah, I think you oughta,” I agreed.
“Gene, we’d like both of you off,” Parker repeated.
“071, 9.8, and 7.0, Bob.” Cernan repeated what he had already given them about our position, trying to cover for the time he had wasted arguing. “Don’t push it yet. …Did you?”
“Okay. Go ahead and push it,” Cernan said as he alighted from the Rover and took the 500 mm Hasselblad out from under his seat.
“Let me wait until it (Rover movement) settles down here.”
“This thing (the 500 mm) is all [set up], isn’t it?” Cernan asked. “This thing doesn’t change.”
“No, that [setting] should be good,” I confirmed
“Yes, it does change.”
“[Cycle the camera shutter] A couple of times.
“Cycle it a couple of times.” I repeated.
“No, the settings.”
“Oh, I don’t know. …Yeah, they’ll change [depending on Sun angle].” Okay. …Quiet Rover. Gravity. MARK it.
“Say, Bob, I need a quick f-stop for the 500.”
“It’s the same film [as in my camera],” I reminded him.
“Stand by,” Parker said again.
“Hey, Bob,” I called, can I punch it (the gravimeter) again?” The TGE numbers indicated disturbance by Rover vibrations.
“Ah… Yeah. Go to STANDBY and then punch it again.”
“You don’t have to wait for it to time out, do you?” I wondered. “…MARK it.”
“And, Geno, f-stop for the 500 millimeter should be the same as for the 70 [mm Hasselblad].”
“And, Jack, I presume you’re getting some Rover samples here off the Rover.” This time I just ignored Parker for thinking that I would just stand around while the TGE did its thing.
[For reasons that are not clear, Cernan appeared to have lost focus on what was required for both the TGE measurement and the 500 mm camera. This occasional loss of focus on what was important to the moment marked his career as a pilot and astronaut (see Chapter 2).]
“Bag 30 Easy (73120-24).” This sample consisted of light mantle surface material representative of the general area. I must have felt more rested, as I started to use phonetic letter designations, again.
“30 Easy,” Parker acknowledged. “Are you guys finding much in the way of rocks here?” Parker apparently had not heard my previous remarks on this subject.
[Post-mission analysis of the 90-150 µm fraction of 73121 showed ~4.7% volcanic glass and no basalt particles. Relative to ~4.3% volcanic glass and no basalt particles in the light mantle regolith (72701) near Station 2, this similarity in components of dark mantle suggests a relatively uniform flux of post-avalanche ejecta from the dark mantle in spite of the closer proximity of 73121 to dark mantle (~500 m vs. ~2500 m). ]
Fig. 11.55. One of the pair of stereo photos I took of the small pit-bottom crater from which I picked up sample 73131. (NASA photo AS17-138-21096).
“I’m looking. I’m going to get you some instant rock out of a small pit crater. …[I mean] pit-bottom crater.” No breccia fragments from the Massif could be seen. Before I took the instant rock (regolith breccia) sample, I took stereo photos of the crater (Fig. 11.55).
“Bob, up to frame count 36 [on the 500 mm] is the outcrop— or boulders— at the top of the South Massif.
Fig. 11.56. Part of Cernan’s pan along the top of the South Massif with the 500 mm lens, showing boulders, but no tracks interspersed amongst bright patches (craters). (Composite of NASA photos AS17-144-22005, -06, -07, -08).
[Unfortunately, Cernan’s coverage of the South Massif did not include Station 2. The areas above Station 2, however, do not show any indications of boulder tracks that might relate to the boulders we sampled. Boulder tracks also appear to be absent on the slopes of the Sculptured Hills above Station 8 that we would visit on EVA-3. These 500 mm photographs (AS17-144-22003-35; see Fig. 11.56 for a partial pan from 4 of these photos) should be merged with overhead images obtained by the Lunar Reconnaissance Orbiter (LRO) and used to map apparent outcrops on the Massif slopes. Such maps may give a clearer picture of the internal structures of the Massifs. The photographs of the Sculptured Hills east of Wessex Cleft (AS17-144-23033-35; see Fig. 11.57↓for a composite of these photos) suggest that a contact exists along the higher portions of the mountain. The apparent contact separates a lower, light-gray, boulder-strewn surface from a higher, much lighter gray, relatively smooth surface. This possible contact will be discussed later in Chapter 12 in relation to Station 8 at the base of the Sculptured Hills.]
“Bag 31 Easy (73130-34),” I reported. “Instant rock out of a 2-meter [diameter] pit bottom crater— off the inner wall. …Well, let’s make it 30 centimeters down from the rim.” My stereo pair of photographs of this crater (AS17-138-21096-97; see Fig. 11.55↑) show that the “instant rock” or regolith breccia fragments produced by this small impact into light mantle material concentrate on the walls of the crater and its pit. Some such fragments are scattered on around the crater out to a distance of about a crater diameter; however, no concentration exists at the crater rim immediately outside the wall. I did not report or see any impact glass in this crater.
Fig. 11.57. Composite of the three 500 mm photos of the Sculptured Hills just past the Wessex Cleft off the frame at left. (From NASA photos AS17-144-23033, -034, -035).
[Post-mission determination of the 22Na-26Al cosmic ray exposure age of 73131 placed the crater (Fig. 11.55↑) age between 100 and 600 thousand years and adds some indication of the rate at which fresh appearing craters degrade. The absence of observed impact glass in the crater, suggests that such glass disintegrates in no more that a few 100,000 years. The fragment I had sampled also disintegrated prior to examination on Earth, showing the fragile nature of some, so-called “instant rock”, that is, regolith breccia.
The low Is/FeO maturity index of 16 for this clod taken from about 30 cm depth in the light mantle is inconsistent with its moderately high agglutinate content of 32%. The Is/FeO index for the Station 2 light mantle rake soil sample, 72701, is 61, 45 points higher, and for Station 3 light mantle sample 73121 is 78, 62 points higher. The low maturity index of 16 for impact breccia 73131 may indicate that impact shock has partially disturbed ferromagnetic ordering of nanophase iron particles on which maturity index measurements depend.]
Fig. 11.58. Photo of the area (lower left) where I saw orange reflections coming from the mylar on the LCRU blanket on the front of the LRV at upper right. (NASA photo AS17-138-21099).
“Okay, Seventeen. We’ve got about 30 seconds left for that gravimeter reading. You want to start finishing up your tasks and getting back toward the Rover.”
“Okay,” I replied.
“Okay, Bob,” Cernan reported as he continued with the 500 mm photography of the valley walls. “And through frame count 57 are the North Massif from part of the western portions to part of the eastern portions.”
“Here’s something different,” I broke in. “Here’s a little… A chunk of yellow-brown rock that apparently has several spots behind it, probably indicating direction from which it came… Oh, no… What is that? That’s a reflection,” I said with a laugh. “That really fooled me. A reflection off the [Rover orange] Mylar. Crazy,” I continued laughing. …Well, what the heck, I’ll sample it anyway.” I suspect my face was red at my sampling of a reflection. My black and white stereo pair of the reflection (AS17-138-21098-99) shows only a faint indication of what I had seen.
“And, guys, we’re ready for the gravimeter reading. And we’d like a frame count on you, Jack. I guess if you’d prefer…”
“Let me get my [low-gain] antenna set so,” Cernan said. “It’s not quite [pointed at you]…”
“Is it (the TGE) through reading?” I asked, still holding the two Rover samples.
“Yeah, it’s through reading,” Cernan assured me as he adjusted the antenna. “[You’ll] probably read us better now, Bob… I’ve got [500 mm] photos of Family Mountain and some of the hills way off to the right (north) of Family Mountain (AS17-144-22036-45). I’m at [frame count] 67 on the 500, and I’ll give you the reading on the gravimeter.” (Fig. 11.59)
“Well, you were reading [our transmissions] at probably a 90-degree low-gain angle.
“We’ve been reading through the LM also.”
“32 Easy (73150-56) is just another small fragment [with some soil], I informed Parker. The maturity index for this “reflection” sample is 68.
“[Gene,] you know what I need?” I had realized that the Rover sampler had only one more Dixie Cup in it.
Fig. 11.59. (upper): (West) Family Mountain at the southwest entrance to Taurus-Littrow valley. (bottom): (Old) Family Mountain at the northwest entrance to the valley. For a discussion on the naming of these two mountains, see ALSJ. (Composites of NASA 500 mm photos A17-144-22036,-037,-038 and 144-22045,-042,-043).
Ignoring me, Cernan read off the TGE numbers “670, 123, 501; 670, 123, 501.”
“Okay. Copy that, Geno,” Parker replied. “And we’re ready for you guys to go on at your earliest convenience.”
“Do you want me to load the LRV sampler?” Without waiting for an answer, I told Cernan to “Go ahead” and get a Dixie Cup dispenser from under his seat.
“Yeah, There you go.”
“And, Jack, is that your last LRV sample bag?” Parker asked.
“I only had one left, but it’s (the sampler) loaded [again[ now.”
“We’re buttoning up,” reported Cernan.
“And if you don’t have one left for that sample at Hole-in-the-Wall, Jack, we’d like you to get a new set of sample bags.” Parker had not understood that I had reloaded the sampler.
“We got it,” I told him.
“Okay. Got it. …And still understand that thirty-two Echo was your last sample.”
“Thirty-two Echo,” I repeated. “Got three [samples] here. …Oh, oh,” I said as Cernan fell onto the surface getting into his seat. “[You] okay?” As Cernan’s bad leg was his right leg, and he would need to kick that leg up and to the right to land on his seat, it may be that his damaged tendon was indeed causing him some pain. On EVA-3, he tripped at Station 6 crossing a slope with his right leg uphill, and then fell again next to his side of the Rover at Station 8 and needed my help to stand up due to being parked on a slope. As Cernan never called attention during the mission to his tendon issue, this is speculation on my part some 50 years later. I knew that he hurt himself at the baseball game, and used a crutch for a few days afterward, but I only became aware of the seriousness of the tendon injury in 1999 with the publication of his book.
“Need some help?”
“Nope. I’ve got the Rover.” He reached up and grabbed the Rover frame to help stand up.
“Was that me?” I asked, thinking I might have distracted him as I put the Rover samples in the console’s SCB.
“No. …That was interesting. Bob, about 2 inches below the surface here, you run into that blue-gray (light-gray) material down there and it’s in little clods, and it breaks apart in your hands.”
“Yeah, that’s right,” I said as I went over to help him. It appeared that the thin regolith on the light mantle had developed on material that is slightly indurated and breaks into irregular, roughly tabular fragments.
[The slow settling of very fine, slightly cohesive material in a post-avalanche, degassing medium may have partially indurated at least the upper portions of the light mantle deposit. This also is suggested by the relatively high reflection of 12.6 cm radar detected by the Mini-RF system aboard the Lunar Reconnaissance Orbiter.]
“Did you get some of that in your Rover sample?” Cernan asked.
“No, but I got it out of that instant rock crater.”
“We oughta…just grab a quick Rover sample, and we’ll take off.” Then he laughed. “That was a pretty interesting episode,” referring to his fall.
“Yeah,” I agreed, adding, “well, you know, we haven’t been trenching like we should or we would have…”
“We would have found it [earlier],” Cernan finished my thought.
“But, really those craters are giving us the same information: that there’s a light-colored material underneath.”
“Okay, Seventeen, we’re ready for you guys to move on and we’d like to eliminate the Rover sample at Hole-in-the-Wall.”
“Okay, Bob. We’re getting on now. …We got on a minute ago,” Cernan added with a chuckle, meaning he was on but fell off.”
“And, do I understand that these Rover samples, Jack, are in your pockets?” Parker asked to be sure the EVA console in Mission Control could keep track of the sample inventory.
“No. They’re in the [SCB] bag on the Rover…[along with Bag] 40 Yankee (73140-46). …That’s light-colored soil from a depth of about…. It’s mixed with a little of the upper surface [material], but [it’s] mostly light-colored soil from a depth of about 15 centimeters.” I had used my foot to dig a rough trench down to about that depth.
[Post-mission analysis of the 90-150 µm fraction of 73141 from about 15 cm depth added more information about the distribution of dark mantle components on to the light mantle. This sample contained only 1.2% volcanic glass and 2.6% basalt particles. This is in contrast to 4.7% volcanic glass and no detected basalt particles for surface sample 73121 in the area of the trench site. The low content of volcanic glass would be expected in recently deposited light mantle and could be either original to the South Mastiff regolith that supplied material for the avalanche or came as the result of sampling contamination from the new regolith on the upper surface. The presence of a basalt component in 73141, on the other hand, indicates that some introduced basalt particles probably existed in the South Massif avalanche source regolith but were preferentially sorted by density and/or volume/mass differences from the finer material closer to the surface of the avalanche. The presence of small quantities of crushed basalt in sample 72275 from Boulder 1 at Station 2 indicates that some of the basalt particles in the pristine light mantle may have been derived from the South Massif breccias during pre-avalanche regolith formation.
The Is/FeO maturity index for 73141 is an intermediate 48, closely matching its agglutinate content of about 32%. These indications of maturity may be roughly those of the pre-avalanche regolith on the slope of the South Massif; however, active redistribution of fine particles of agglutinate during the avalanche may have taken place and thus added to the apparent maturity of this sample.]
“Wonder what I’d do for an encore?” asked Cernan, referring again to his fall that accidentally exposed original light mantle below a thin surface layer of slightly darker regolith.
“It looks like the light mantle in here is covered with dark[er regolith] to a depth of about 5 or 10 centimeters,” I concluded.
[Simulations of the process of regolith formation, as would be expected, show that, with time, the depth of regolith on a new surface increases at a decreasing rate in accordance with an observed exponential decrease in the frequency of large versus small impacts. It appears that a general rate is 0.6 cm after one million years, 1.5 cm after ten million years, and about 4 cm after 100 million years, subject to local variations of several centimeters due to the irregular distribution of impact ejecta. These conclusions roughly match my observation of at least 5 cm of new regolith on the light mantle, if the 75-107 million years estimate of its age is about right (see Chapter 13).]
“You might want to go MIN, Jack, on your [cooling water] diverter,” suggested Cernan.
“Right now, I’m sort of warm.”
“Okay. When we start driving, you might want to go [MIN]. I’m going to zap myself with a [little] cold.”
“I can do it on here [while we’re driving],” I told him.
Fig. 11.60. One frame from the series of a partial LRV pan I made as we left Station 2a (the gravimeter and pit-crater stop) on our way to Station 3. (NASA photo AS17-144-21108).
“Did you take any pictures at all while you were there?” Cernan asked as we started to roll.
“Oh, yeah. I didn’t take a pan. …Why don’t you turn right to [get a pan of the site]?”
“Okay, Bob. If you read, we’re rolling,” reported Cernan.
“Okay. MARK that,” Parker replied.
“Making a right-hand turn for a pan.”
“[Make that a turn to the] left,” I said, changing my mind so that I could minimize the amount of the high-gain antenna imaged in each frame.
“Let me see where we’re going. I [missed that crater,] again. You know, a little more [right] and that hole (crater) would have been in the way.”
“We left some of our litter (the bag for the Dixie Cups replacement). Not a complete pan but it will show the location. …Okay. LMP frame count [is] 80. …Geno, you’re heading for a spot that’s about 080/5.5, approximately.” I called out the next stop indicated on the Cuff Checklist, forgetting that this Rover sample had been canceled in the interest of making up a little time.
The partial panorama at Station 2a (AS17-138-21100-13) continues to document how few boulders lie at the surface of the light mantle (e.g., Fig. 11.60↑). The last of these pictures catches the entrance to Hole-in-the-Wall and the top of the lobe of the Scarp that forms its east boundary.
“Yeah, you guys following tracks home or not?” Parker asked. He did not mean, “home”, but rather meant Station 3.
“No,” Cernan answered. …Do you have an update [for navigation to Hole-in-the-Wall]?”
“…Hole-in-the-Wall should be at about 080 (bearing) and maybe 5.7 (range).” This location was remarkably close to that in the Cuff Checklist, and probably was off, as later Parker would tell us that Station 3 would be 089 and 6.1, respectively. “And we’re not going to stop to get a Rover sample at Hole-in-the-Wall.”
“Okay, that sounds reasonable because it’s just nothing but lots of rolling terrain…” If Cernan meant by this comment that the light mantle out ahead of us looked similar to that which we had sampled, then he was correct. Had there been time, however, another Rover sample would have been statistically valuable, but he probably would not have been thinking about that geological nuance.
“What about Station 3?” he then asked.
Before Parker could answer, I interjected, “Bob, I think we have a good sample of only partially contaminated light mantle in that last Rover sample that Gene accidentally discovered was right under our feet. It’s almost certainly the light-colored material that we’ve been talking about in the walls of the [fresh-looking] craters. And, as a matter of fact, that instant rock sample I took was light-colored and probably represents the same stuff, indurated slightly [by impact].”
“That light-colored mantle has that bluish tint that you saw in those rocks,” Cernan added.
“Yeah,” I agreed. “I still don’t think there’s anything…,” I began, but then had another thought: “We ought to get a core in this light mantle sometime; and probably Station 3 is going to be the place. I hope that’s still in the agenda.”
“Rog. It’s still in the agenda,” answered Parker.
My traverse photographs (AS17-138-21109-42) during this portion of the drive to Station 3 show no significant change in the near absence of boulders on the surface of the light mantle as we approached Hole-in-the-Wall (Fig. 11.61).
Fig. 11.61. View across the surface of the light mantle avalanche deposit, looking northeast. The photograph shows the near absence of rock fragments or boulders across this surface. The dark line to the left of the center reseau mark is the rim of Shorty Crater that would be the subject of Station 4 activities described in Section 2. Between the center and first reseau marks and beyond Shorty Crater, the raised surface of a debris flow from a pyroclastic feature on the slope of the North Massif is visible. Horizon features, from left to right are the North Massif, Wessex Cleft, and the west end of the Sculptured Hills. (NASA Photo AS17-138-21128).
“Say, Bob, can you update the mileage on Station 3?” requested Cernan.
“Okay, you want mileage to it or do you want the range and bearing at it?”
“Well, range and bearing at it, …because Hole-in-the-Wall is fairly nebulous.
“Okay, we’re going to say about 089 (bearing) and 6.1(range) for Station 3.” As suspected, bearing and range had been revised from that in the Cuff Checklist.
“Do you get the feeling that we’re the only ones out here, Jack?” Cernan may have been joking; however, he seemed to be reacting to the isolation that a field geologist takes as normal. “Looking around…”
“…Do you want to give us another range and bearing right now?” interupted Parker, this time breaking into Cernan’s continuing soliloquy about the appearance and remoteness of the valley of Taurus-Littrow. Without waiting, he added, “073 (bearing), 10.3 (distance), 6.6 (range).”
Meanwhile, I kept trying to record observations about the light mantle we moved across. “Bob, I have a feeling that whatever darkens the… Ooh, there’s a beautiful little glass-lined crater…pit-bottom crater. …Whatever darkens the light mantle is not a one-time-only mantling of darker material. It’s something that happens over a period of time, continually, because craters of all sizes and apparent degradation are darkened and there are lighter craters that are light to varying degrees. It seems to be a continuum of albedo change.” This summary covers the visual effect of the gradual accumulation of nanophase iron in near surface regolith.
“You know that little crater on the side of the North Massif,” Cernan said, looking to the north, “that we’re thinking about going to, doesn’t look nearly as light-colored or haloed as it does in (our pre-mission overhead) pictures, does it?”
“You mean Hanover? Yeah. …No…”
“Now, let’s see where we are,” Cernan said to himself. “I don’t want to run into that big crater at the foot of the [Hole-in-the-Wall]…”
“I think you’re almost to the [Scarp] rim,” I warned.
“Yeah, I want to go down here if I can. My tracks are over there to the left, I haven’t crossed them yet.”
“073, 6.3,” I reported to Mission Control. …LMP’s frame count is 86.
“Boy, that’s a sight, isn’t it?” I said, rhetorically. The view from the top of the Scarp toward the North Massif, the Sculptured Hills, and the east end of the valley, indeed, could not help but impress. From this vantage point on the Lee-Lincoln Scarp, trending off to our left and right, we had a full panorama of the high massifs bounding a valley of bombarded, gray plains with interspersed low hills and large craters like Camelot, Henry, Cochise, Shakespear, Steno and Powell. In spite of the brilliant sun on their slopes, the spectacular valley walls were set against a blacker than black sky. Even through the glare of sunlight on our visors, this unique lunar landscape would be embedded in our memories forever.
“That’s spectacular,” agreed the driver.
“I don’t know why something that’s all approximately the same hue should [show so much definition]…”
“The lack of color has got to contribute to the inability to judge distance,” Cernan stated.
“See the lobes coming out,” I stated, “[that is,] lobes coming out from the Scarp. The [southern portion of the] Scarp, rather than being a line in there on the plain, appears to be lobes. I got a couple of shots of that. Whereas, when it gets up on the [North] Massif, it’s a fairly continuous curve; although it does appear to be younger [than the Massif slope]; at least there’s less relief on [top of] it for the first few kilometers of that bend there [on the North Massif].” Traverse photographs (AS17-138-21114-18 and AS17-137-20980) taken as we entered the roughly north-south trending vale of Hole-in-the-Wall give a good impression of the lobes that make up the Lee-Lincoln Scarp; that is, the scarp is not a linear feature except on the side of the North Massif. Also, photograph -21114 shows the strong, nearly horizontal broad lineaments on the northwest flank of the Sculptured Hills that may reflect thick layering in those Hills as discussed in connection with Station 8 in Chapter 12.
Fig. 11.62. One of the traverse photos showing a very noticeable eastward projecting lobe of the scarp crossing the valley (just above the TV camera) as well as a series of horizontal lineaments across the northwestern flank of the Sculptured Hills (also above the TV camera) intersecting a series of diagonal slineaments running down-slope. (NASA photo AS17-138-21114).
[Recent analysis of orbital photographs taken by Evans, stimulated by the much higher resolution images from cameras aboard the Lunar Reconnaissance Orbiter, have improved understanding of the Lee-Lincoln Scarp. The physiographic appearance of the Scarp clearly is consistent with it being the surface expression of a low-angle thrust fault that post-dated both the formation of the valley and its partial filling by basalt. The lobes of the fault we referred to appear to be the collapsed hanging wall of the fault, now covered by light mantle avalanche material. Many other relatively young scarps and wrinkle ridges around the Moon have formed as thrust faults, and may still be forming, as a consequence of the gradual thermal contraction of the Moon. The geology of the Lee-Lincoln Scarp is discussed in detail in Chapter 13.]
“We’re going to have to go down [the Scarp] like the way we came [up],” observed Cernan, “because there’s that big crater down at the bottom, I’m afraid.”
“Yeah, I think we agree with that suggestion, too,” added Parker, having no idea what we were seeing.
“Bob, the so-called Scarp impresses me as less of a scarp than a series of lobes which roughly have a north-south trend,” I noted. “And we’ve been driving over various hummocks within those lobes.”
“I think we made a gross mistake in not trying to let them get TV,” Cernan again commented. “My heading hasn’t changed much at all here. They would have had a spectacular view. Look at it out in that valley, Jack.
“Yeah.” This would have been a good idea for the stops; however, the picture would have been very bouncy, otherwise.
“Good lord!” exclaimed Cernan. “I still don’t know where the LM is. …I see it, I think. The shadow, …[maybe] a blob. It’s the only sharp shadow out there right in the [Sun], …because you sure can’t make out the craters [near the Challenger] from here, can you? Okay, hold on. Over the hill and down the dale. …Man, I tell you, this machine is fantastic.”
“Yeah. Watch it,” I warned with a laugh as our speed picked up to close to 18 km/hr.
“Quite a machine.”
“Likes to spin when you turn going downhill,” I warned him, again.
Fig. 11.63. One of the series of traverse photos I took on the way to Station 3 showing a boulder free landscape over which we are driving. Note the multiple en echelon scarp lobes just above the left portion of the middle line of reseau marks, and the linear continuation of the scarp on the North Massif. The nearest lobe is partially blocked by the high gain antenna and its pointing handle. (NASA photo AS17-138-21119).
“Quite a machine…”
“I think you’ve got something right ahead of you,” I alerted Cernan.
“I got it.”
“See the instant rock [around that crater]?”
“I got it,” insisted Cernan. “There’s that crater [at the bottom of Hole-in-the-Wall]. It doesn’t look nearly as bad from here, but it sure is deep when you get up there. I’ll meander around and over this next little lobe then I’ll head down that next one— the first lobe we came up— and then along it.”
“Okay, there’s Lara, and I think we can see Station . …Watch it, watch it, watch it!” Cernan had turned too sharply for our speed and the rear end of the Rover slid hard to the right.
“Okay, I’m going through it slow.” About time, I thought.
“Beautiful,” I said with a nervous laugh. “I figured we’d buckle the LCRU with that one.” The LCRU hung in the front bumper area of the Rover and might be stressed if we pitched down and up too rapidly.
“I bet they can watch this road [by watching heart rate],” Cernan allowed. “My heart rate just dictates the kind of terrain we’re going over.” Actually, both our pulses were consistently in the 80 beats per minute range during this drive.
“Okay…Houston,” I called after about ten seconds of silence, “we’re navigating and not talking. Sorry. But the light mantle is a uniform surface and I think you’ve heard just about everything we have to say so far.
“Roger. Your comm’s great and you guys are doing [great].”
“The fragment population hasn’t changed, nor has the crater population, as near as I can tell. I hope the LRV photos will give you more details than that…” Traverse photographs AS17-138-21119-30 (Fig. 11.64) cover the entry to and descent in Hole-in-the-Wall. Again, the photographs show no variation in the surface characteristics of the light mantle that covers the Scarp. One indication of the young age of the light mantle surface, however, is the indication that the saturation crater size probably is only a few centimeters. The last several pictures in this sequence include views in the far-distance of Shorty Crater (Station 4) and its smaller companion dark crater to the west.
“Okay, Gene, do you have the target over there, that set of [small craters]…?”
“Yeah, I got to get over to this next knoll and I’m going to be off the Scarp. We’re about three-quarters of the way down. (Pause) Isn’t that sharp shadow out there the LM? See it way out there? Almost under the Sun. It’s got to be. It’s the only sharp shadow out there. Right under the Sun, straight down there.”
Fig. 11.64. Racing down the Hole-In-the-Wall ramp at 18 kph. Again note the relatively boulder-free landscape of the light mantle and the large lobes of the scarp directly ahead of the Rover. The ramp parallels the lobes, and slopes down from right to left. Shorty Crater, Station 4, can be seen in the darker mantle between the right-most reseau marks on the North Massif. (NASA photo AS17-138-21125).
“Okay, I’m going to try to make it down this (pitch). Hold on!”
“This is the one (lobe) we climbed up,” Cernan declared.
“Oh, there’s Nemo [Crater] over there to my right,” I noted.
“Yes, sir, this is the one we climbed up. Would you believe that?”
“Well, I don’t know.” I wanted to see our earlier tracks before agreeing.
“Yeah, I would.”
“The problem is any crater on the side [of the slope]…” I probably had begun to suggest that craters on slopes would age more rapidly that elsewhere due to the down-slope movement of regolith in response to small impacts.
“I think you’re all right,” I agreed as he moved along the side of the lobe.
“We’re all right. I don’t know, that’s got…”
“Keep your speed down because if you have to turn, it doesn’t like it (speedy turn) on a downhill slope,” I advised.
“Man, that’s got to be [the limit in pitch]. …[The] pitch-angle [indicator]’s pegged, and I don’t know what that means. …Okay! Right off the Scarp!” Cernan said with some relief in his voice.
“We’re off the Scarp,” I repeated.
“You guys cut each other out, but I take it that means you’re at the edge of the Scarp,” acknowledged Parker
“We’re off!” I assured him.
“We’re off! We came down!” Cernan seemed to have been concerned about his own driving.
“Hey, will you look at the hill we came down!” exclaimed Cernan. “[Is that the] same one we went up?”
“I’d rather not [look].” Not driving meant that I had less feeling for what the Rover could do than I would have liked. Worry about my comander’s tendency to make rash decisions also was on my mind during the rush down the scarp.
“Oh, I don’t know, I’m impressed. …Okay, now where we got to go? [I’m headed] 345 (degrees NNW), roughly. And we want to go to 087/6.1 (bearing and range)…”
“Okay. You’re… I think you’re headed right…right for where we want,” I said, consulting our map. Due to the Sun being partially behind us and its zero phase-angle lying just to our left, traverse photographs for the remainder of our drive to Station 3 (AS17-138-21131-42) do not give much detail about the surface except there is no apparent change in boulder frequency or surface texture. One picture (AS17-138-21136) (Fig. 11.65) includes Rover tracks from the outbound traverse.
Fig. 11.65. An enlargement showing our outbound tracks running across the frame to the right of and above the TV camera. (From NASA photo AS17-138-21136).
“See that bright crater?” I ask him, pointing off to the left of our course. “You can just start to see Station 3 over there now.”
“Okay, navigation says I’ve got more than 90 degrees (heading from the bearing to the SEP), …[so] I should be increasing range.” “Bob, we’re at 079 (bearing), 11.5 (distance), and 5.7 (range).” A heading to the SEP would have been 79 degrees. As a pilot would do, Cernan has headed so that both bearing and range are increasing toward the assumed numbers for Station 3, while I am just trying to get him to just head directly for the spot we picked out earlier.
“Okay, beautiful, guys. Really going smooth.”
“And I’m headed northwest.”
“Roger. In fact, we understand it’s been going so smooth down here that they haven’t even spilled any coffee in the SPAN room yet this mission.”
“Thorson must not be on duty,” I replied. (SPAN stood for “SPacecraft ANalysis”).
[I spent a lot of time during other missions in the SPAN room, helping with various trouble-shooting tasks. Once, during an Apollo 16 quiet period, I came in and walked behind the row of SPAN consoles that had relatively loose pegboards across the top in front of which coffee cups had been placed. The pegboards had notes on them with various operational documents in front. As I talked to a seated Mel Brooks over his console, someone bumped me from behind, causing me to hit a pegboard, spilling coffee cups down into Brooks’ console. A display of sparks showed that this was not good. Brooks cut power to the console, and I lifted the back of the console to check for damage. In doing so, I started a chain reaction to left and right of falling boards, documents, more coffee into other consoles, and people scrambling to get out of the way of hot coffee. SPAN took a while to get back on line. Dick Thorson’s console (Dick normally would have been in the MOCR, but was between shifts.) was one of those that sustained significant damage. Obviously, I will never live that episode down. 50 years later my Flight Control friends still rib me about it.]
“I’m glad we don’t have any [coffee] sitting on the LCRU!” Cernan joined in the banter, but I am sure he had no knowledge about the incident to which Parker referred. In fact, Parker could have only known about it second hand.
Changing the subject, I said, “Right over there is Station 3, I think. Oh, actually, I guess…Hmm. …I guess they would want it [at the toe of a lobe]. …Is there…? …I can just start to see two craters…that are closer to Lara.” Everything that seemed obvious from higher up now looked different from a horizontal perspective.
“You know what the problem is?” Cernan complained. “I got a full planar view of the high-gain, and I can’t see a thing out there.
“That’s right,” I sympathized.
“Full planar view. All I can do is see underneath it. …Gonna take it (a crater) broadside. See, I can’t see a lot of craters now that they’re out in front [with the Sun behind us]. Oh, I guess I can see them, most[ly]. Here’s a nice sharp little hole; look at that.”
“Yep…Bob, the texture of the light mantle – surface texture – is really no different on the Scarp, on its flank, or out here to the east of the Scarp. Fragment population, crater population, everything looks about the same. If there is such a thing as a light mantle, it seems to be uniform across the Scarp. …There are your tracks. Hey! We crossed somebody’s tracks!” (See Fig. 11.65↑).
“We sure did. We just made a loop.”
“Hope they look like yours,” Parker joked.
“That was at 081 (bearing)/5.7 (range),” I reported. This should have given Mission Control some help on their plotting of our path to and from Station 2.
“Okay, copy 081/5.7. Do they look like your tracks?” Parker could not give up on his joke.”
“Well, here’s another set,” I observed.
“Yeah, this is where we went to the big crater,” Cernan recalled, “and I came southeast in order to get around it, remember? We saw that hole?”
“Yeah.” It was very intriguing to come across Rover tracks we had made a couple of hours earlier.
“Look at that big turn I made. Ha ha!” laughed Cernan. “That was a quick change of mind when we came over that ridge [and saw what was in front of us].”
“Okay, we’re still headed northwest, Bob,” reported Cernan.
“Okay, Bob, I guess one thing we don’t have a handle on yet is – [and] I think we sampled them once in a Rover sample – what are the fragments out here [that are] mixed with the light mantle? …I think I got one [of these fragments] at our last gravimeter stop, a small one, and I guess there’s one other Rover sample, but, at Station 3, we probably ought to make sure we get a representative suite of those fragments.”
[Post-mission examination of the fragment samples collected earlier indicate that most of the fragments are regolith breccias (instant rock) produced by impacts into the light mantle. Actual rock fragments I would gather at Station 3 were at the rim of a crater and probably had originally resided at depth within the light mantle.]
“Roger. Agree to that,” It is not clear how much coordination, if any. Parker did with the Science Back Room to make these calls.
“Hey, Bob, how long have we been out?” Cernan asks.
“Three [hours] plus four five [minutes].”
“Thank you. We’re at 083/5.7.”
“Well, it (the valley) certainly doesn’t look like the geology of Norway,” I said, with some geological facetiousness, “but it certainly is interesting.” The glacial valleys of Norway are “U” shaped, in general, as compared with the truncated “V” shape of the radially faulted valley of Taurus-Littrow. And, of course, there is no relatively uniform cover of regolith in Norway, although there are patches of glacial till and shoreline soil deposits, nor are small farms nestled at the base of the valley walls on the Moon.
“That must be Lara right there, huh?” Cernan wondered. Station 3 would lie about 100 m down from the east rim of Lara.
“On the left. …You can see the blocks on the other side of her.”
“That’s right,” I agreed. “I told them about those earlier. That’s the only… I think, Gene, you want to bear a little bit…a little bit to the left. See those two craters, two bright craters, that are just this side of Lara?”
“No… well… I’m not [sure]…”
“You’re pointed right…almost right at them, now.”
“Okay, I can barely see them now through that high-gain… But I can see [enough]. …I know where we’re going now.” Cernan was not about to have me drive the Rover from the right seat with my clear view. That is what he should have done.
“Those are the two [craters] I think they wanted us to be at,” I said, “and I think that’s a good choice— if we can get up there.”
“Ah. I want to get some 500s [of] the way that scarp flows up on top of… Well, it looks like it flows up on top of the North Massif. Now it may look like the North Massif may drape material down upon it. Look at that.”
“Well…not really,” I disagreed. “The texture [on the down hill slope of the Scarp] is so different. It just doesn’t look like as old a surface [as the slope of the North Massif].” This observation jibes with my recent identification of “stirred not shaken terrain”  surrounding the Scarp on the valley floor (see Chapter 13).
“But definitely different.”
“Yeah. …Wish they had never said anything about [limiting] pictures, because I’ve tended to not take enough [in order] to do better.”
“Okay, but Jack,” Parker said, “you’re doing quite well in the picture department. …You’re not getting too far behind or ahead [of budget].
“085/5.8,” reported Cernan.
“No, but I mean I’m not sure I’m getting the [photo] coverage I should.” These photographs are an augmentation of the verbal notes I took about the terrain we covered.
“Okay. We’ll look at the frame counts when you get to Station 3.”
“Oop, oop!” I exclaimed as Cernan went through a couple of small craters without slowing. “Oh, there’s another big crater with a pit in it.”
“What was it, 17-1/2 or 18 clicks (km/hr) we hit coming down the Scarp, Jack?”
“I don’t…” I began and then realized what he intended. Cernan wanted the lunar Rover speed record on record. Rather than contradict, I said, “I’m in MIN cooling now.” Actually, we did go well over the 11 km/hr max speed that we had previously recorded.
“Oh, look at that. Wait until you get over here and look at that South Massif.” Cernan was maneuvering to find Station 3.
“Is that [where you are stopping?]”
“Well, I don’t know where we’re going to get a good [spot],” he replied.
“Well, let’s see,” I said, looking around. “You know, that big block up there [on Lara Crater’s flank] might be worth going to.” This block would have been too large to have been covered by the light mantle avalanche; however, it probably would be a block of mare basalt and not as important as getting samples of rocks in the light mantle that would give a more statistical sample of the South Massif. I am glad that this suggestion was ignored.
“087 (bearing) at 5.9 (range). I think that’s the best station we’ve got right here. …Let’s see what’s over on your right. Let’s see if we can get at that Scarp over there.
“I’ve sort of lost track [of the two bright craters].”
“We’re about there,” Cernan concluded.
“I think we expected you guys to be a little bit farther north [along the Scarp],” inserted Parker.
“I think we want to be more to the left.” Why Cernan did not go to the planned 089 and 6.1 spot is not clear.
“We were guessing a heading of 080 for [getting to] the bearing,” Parker tried to explain, “which really kind of says you were going a bit farther north than this.” For some reason, Parker has confused the bearings to the canceled Rover sample stop (080) and Station 3 (089). At this point we actually are almost at the planned location of Station 3.
“Well, there’s that fresh crater, there, Jack.” Then Cernan realizes that Parker has said something confusing. “080?”
“Roger,” persists Parker. “080 is where we think…”
“All of a sudden I’ve lost track,” I admit, thanks to Parker’s confusing direction.
“Standby.” Somebody in the MOCR has gotten Parker’s attention and pointed out his mistake.
“There’s nothing wrong with that except that…I think we ought to go back to that big block.” No one seems to have picked up on my recommendation.
“Heading 080 is [behind us],” Cernan correctly asserted. …Heading north (he means south) is not going to [get us to Station 3].”
“Roger. I just realized that, Geno,” admitted Parker.
“I’m 087 now!” emphasized Cernan, becoming a little irritated.
“Yeah, I realize that, Gene; my mistake. Somebody’s got a wrong thing down here. …That’s the Hole-in-the-Wall [stop]. My mistake.
“I think we need to go back there a little bit,” I said, still trying to get close to the big block near Lara.
“Yeah, we’re at 087/6.0,” Cernan read. “I think that’s probably [close]. Let me get up on the top [of this rise], here.”
“Okay, Seventeen, that’s a great stop. That was my mistake, I was reading the Hole-in-the-Wall coordinate.”
Continue to Section 2: Station 3 – Ballet Crater→
In this chapter, all color-balanced Apollo 17 orange soil and Apollo 15 green soil photographs at Shorty and Spur Craters, respectively, are products of the Tranquillity Enterprises, s.p. photo lab. They were produced under my direction from the unprocessed NASA Johnson Space Center digital scans of the prime Ektachrome SO-368 film provided by Kipp Teague in his Project Apollo Archive. The following information was provided by the photo lab:
“Each image was contrast balanced by histogram analysis, then split into three color channels. Together with feather masks of specific areas, the dominance of the channels was varied to bring out colors already present in the soils until the color distributions matched both Schmitt’s in situ observations and his later visual inspection of the prime film with a 10× optician’s loupe in Houston. The photo AS17-137-20990 served as the principal model because it had the smallest phase angle; hence, had the fewest shadows and gave the brightest colors. No specific colors were added during the processing. The other orange soil photos had larger phase angles with more rock shadows. This shadowing, which increasingly dominated the reflected color rays in those scans, especially in the close-ups of the trench areas in -20987, -20988, and -20989, was compensated for by micromapping their locations. Similar variations were less pronounced in the green soil photos of Apollo 15 because they were all taken with essentially the same large phase angle. The green soil color intensity was matched to that of the contrast-balanced green color chip of the gnomon.
“Software programs used in the production were Adobe Lightroom™, Adobe Photoshop™, and Corel Photo-Paint™. Since these images are derivative works, they have been registered with the U.S. Copyright Office, registration no. VAu 1-341-778 (Oct. 3, 2018).
“Fair use of the images in printed scientific and/or other non-profit web articles, blogs or electronic documents is permitted provided the photos carry a caption which includes: (Copyright © 2018 by Tranquillity Enterprises, s.p. Courtesy of Tranquillity Enterprises, s.p.). However, use in for-profit or fee-paid publications of any kind is restricted and permission to use must be requested from Tranquillity Enterprises, s.p., 445 Fairway Dr., Abingdon, VA 24211 USA. All 31 green and orange soil color-corrected images can be downloaded as a ~108 Mb zip file by clicking here.”↑
In the quoted dialog and annotations directly related to the Apollo 17 Mission, black = normal mission activity and commentary; red = anomaly discussions; blue = Earth observations, brown = Lunar Module Challenger discussions; green = Public Affairs Office transcripts or news updates from Mission Control; purple = lunar observations; italics = onboard recorder transcripts (Data Storage Equipment or Command Module DSE and Data Storage Electronics Assembly or Lunar Module DSEA); and tourquois = probable dialog derived from the author’s memory, checklist requirements, or logical inferences.
In addition, parentheses (-) in the text are used to clarify the meaning of a preceding word or phrase. The use of text inside brackets [-] provides completion of an unspoken transcript thought. Brackets [-] enclosing letters or words quoted from a checklist complete abbreviated words to clarify what the word in question means. Also, double-indented paragraphs that set off explanatory details are enclosed in brackets.
The CMC (Command Module Computer) commands are referred to oc-casionally in text as Pxx (Program i.d. number), Nounxx (data specification), or Verbxx (action number) to be carried out by the CMC when entered by hand. ↑
One purpose of this book lies in the integration of field observations with post-mission examination and analysis of the returned samples. In this effort, the author has drawn heavily on the extraordinary compilation work of the Lunar Field Geological Experiment team (Wolfe, E. W., et al., 1981. The Geologic Investigation of the Taurus-Littrow Valley: Apollo 17 Landing Site, Geological Survey Provessional Paper 1080, US Government Printing Office, 279 p.) as well as that of the Lunar Receiving Laboratory (Meyer, C., 2008. Lunar Sample Compendium) and the Lunar Sourcebook (Heiken, G. H., et al., 1991. Lunar Sourcebook: A users guideto the moon, Cambridge University Press, Cambridge, 736 p).
Some additional data has been found in the Catalog of Apollo 17 Rocks (Joint effort by G. Ryder, C. Neal, and L. A. Taylor, 1993.) Specifically for Apollo 17 regolith samples, the work of Korotev and Kremser (Korotev, R. L., and D. Kremser, 1992. Compositional variations in Apollo 17 soils and their relationships to the geology of the Taurus-Littrow site, Lunar Planetetary Science Conference 22, pp. 275-301) also has been used extensively. For the reader interested in details about specific samples, these references key information to the official sample numbers given in the text of this book.
Some sample data may not have been included in these four compilations. In that case, specific references to the relevant literature are given. Also, Original Rb-Sr age determinations made prior to 1985 have been reduced by factor of 0.979 due to a subsequent change in accepted time constant for 87Rb decay (See Heiken, et al., 1991. Lunar Sourcebook, Cambridge University Press, Cambridge, Table 6.9, p. 229). Similarly, 39-40Ar ages determined prior to 2008 have been increased by a factor of 1.0065 (See Kuper, K. F. et al., 2008. Synchronizing rock clocks and Earth history, Science, 320, pp. 500-504).
It should be noted that, before the advent of laser microprobe enhanced targeting of very small portions of samples, isotopic ages of impact melt-breccias risked including isotopic contributions from clasts of significantly older ages than the crystallized melt. (See Mercer, C. M., Young, K. E., Weirich, J. R., Hodges, K. V., Jolliff, B. L., Wartho, J.-A., and van Soest, M. C., 2015. Refining lunar impact chronology through high spatial resolution 40Ar/39Ar dating of impact melts. Sci. Adv. 1 (e1400050), DOI.10.1126/sciadv.1400050.) Earlier, less precise age determinations, therefore, probably are biased, toward older ages. ↑
Green, R. O., Pieters, C., Mouroulis, P. et al., 2011. The Moon Mineralogy Mapper (M3) imaging spectrometer for lunar science: Instrument description, calibration, on-orbit measurements, science data calibration and on-orbit validation. Journal of Geophysical Research, 116, DOI:10.1029/2011JE00G19. ↑
Pike, R. J., 1974, Depth/diameter relations of fresh lunar craters: Revision from spacecraft data, Geophysical Research Letters, 1, p. 291-294. ↑
Croft, S. K., 1980, Cratering flow fields – Implications for the excavation and transient expansion stages of crater formation, Lunar and Planetary Science Conference 11, p. 2347-2378. ↑
Schmitt, H. H., Petro, N., Wells, R. A., Robinson, M. S., Weiss, B. P., Mercer, C. M., Revisiting the field geology of Taurus–Littrow, 2017. Icarus, 298, 2-33. ↑
Stenonis, N., 1669, Nicolai Stenonis solido intra solidium naturaliter contento dissertationis prodromus, Florentiae: ex topographica sub signo Stellae, an English version by J. G. Winter, The Prodromus To A Dissertation Concerning Solids Naturally Contained Within Solids, Macmillan, New York. ↑
Talkbacks are small, square visual indicators that show either barber pole or gray depending on the status of certain critical mechanisms, e.g., valves and latches. Position sensors on the mechanisms are tied to the talkbacks by independent electrical circuits. If the window shows yellow diagonal stripes (barber pole), then the condition indicates an abnormal or temporary status. If the window shows a solid gray appearance, then the condition of the mechanism is normal or as commanded. ↑
Schaeffer, O. A., and Schaeffer, G. A. 1977, Laser 39-40Ar Ages of Lunar Rocks, Lunar Science Conference 8, Abstract 1269. ↑
Is/FeO maturity indexes are a measure of the ratio of nanophase free iron to the FeO content of a lunar regolith sample (Moris, R. V., 1978, The surface exposure (maturity) of lunar soils: Some concepts and Is/FeO compilation, Lunar Science Conference 9, Geochimica et Cosmochimica Acta, Supplement 10, p. 2287-2297). Maturity indexes also can be found in Meyer, C., 2012, Lunar Sample Compendium and in Heiken, G. H., et al., 1991, Lunar Sourcebook: A users guide to the moon, Cambridge University Press, Cambridge, p. 320. For generalized comparison of different soils, the author has defined the following breakdown in maturity indexes:Relative Maturity Is/FeO Maturity Index
Low 0-20 Low-intermediate 21-40 Intermediate 41-60 Intermediate-high 61-80 High 81-100
Wilhelms, D. E., 1987, The Geologic History of the Moon, United States Geological Survey Professional Paper 1348, p. 129. ↑
Howard, K. A., and Larsen, B. R., 1972, Orbital-science investigation: Part G: lineaments that are artifacts of lighting, in Apollo 15 Preliminary Science Report, NASA SP-289, pp. 25-58 to 25-62. ↑
Simmons, G., et al., 1973, Surface Electrical Properties Experiment, in Apollo 17 Preliminary Science Report, NASA SP-330, p. 15-13. ↑
Graf, J. C., 1993, Lunar Grain Size Analysis – Apollo 17, NASA Ref. Pub. 1265, March 1993. ↑
Speyerer, E. J., Povilaitis, R. Z., Robinson, M. S., Thomas, P, C. and Wagner, R. V., 2016. Quantifying crater production and regolith overturn on the Moon with temporal imaging. Nature 538, 215-218. ↑
Robinson, M. S., personal communication. ↑
Schmitt, H. H., Petro, N., Wells, R. A., Robinson, M. S., Weiss, B. P., Mercer, C. M., Revisiting the field geology of Taurus–Littrow, 2017. Icarus, 298, 2-33. ↑
Schmitt, H. H., and Robinson, M. S., 2010. Geology of the Apollo 17 Taurus-Littrow site in light of LRO imagery. GSA Annual Meeting (abst.) ↑
Basu, A., Des Marais, D., Hayes, J. M. and Meinshein, W. G., 1975, Integrated investigation of the mixed origin of lunar sample 72161, The Moon, 14, 129-138. ↑
Phipotts, J. A., S. Schumann, C. W. Kouns, R. K. L. Lum, and S. Winzer, 1974, Lunar Science Conference 5, pp. 1255-1267; Miller, M. D., R. A. Pacer, M.-S. Ma, B. R. Hawke, G. L. Lookhart, and W. D. Ehman, 1974, Lunar Science Conference 5, pp. 1079-1086; Basu, A., D. Des Marais, J. M. Hayes, and W. G. Meinshein, 1975, Integrated investigation of the mixed origin of lunar sample 72161, The Moon, 14, pp. 129-138. ↑
Heiken, G., Vaniman, D. and French, B. M Lunar Source Book. Cambridge Univ. Press, New York. 354-356, 436-449. ↑
Graf, J. C., 1993, Lunar Grain Size Analysis – Apollo 17, NASA Ref. Pub. 1265, March 1993 ↑
Schmitt, H. H., 2003, Apollo 17 and the Moon, in H. Mark, editor, Encyclopedia of Space and Space Technology, Wiley, New York, Chapter 1, p. 62; Walters, T. R., et al., 2010, Evidence of Recent Thrust Faulting on the Moon Revealed by the Lunar Reconnaissance Orbiter Camera, Science, 329, 936-940. ↑
Schmitt, H. H., and Robinson, M. 2010, Geology of the Apollo 17 Taurus-Littrow site in light of LRO imagery, Geological Society of America, Annual Meeting, November 1, Denver CO. ↑
Lucchitta, B. K., 1977, Crater clusters and light mantle at the Apollo 17 site – A result of secondary impact from Tycho, Icarus, 30, 80-96. ↑
Schmitt, H. H., Petro, N., Wells, R. A., Robinson, M. S., Weiss, B. P., Mercer, C. M., Revisiting the field geology of Taurus–Littrow, 2017. Icarus, 298, 2-33. ↑
Wolfe, E. W., et al., 1981, The Geologic Investigation of the Taurus-Littrow Valley: Apollo 17 Landing Site, USGS Professional Paper 1080, Fig. 72, 55. ↑
The Surface Electrical Properties (SEP) experiment consisted of a transmitter and an antenna placed ca. 175 m east of the LM (where the LRV navigation unit was calibrated at the start of EVA-2) and a receiver and antenna mounted on the LRV. At the various Stations (stops) a signal transmitted through the regolith to the receiver measured the electrical properties of the regolith between the two units. ↑
The Apollo Hasselblad film magazines were identified by letters of the alphabet on small attached labels (Mag. A, Mag. B, etc.). In voice communications, the standard Military (later NATO) phonetic alphabet is used for these letters (Alfa, Bravo, Charlie, Delta, etc.). They were later assigned a numerical number. Magazine I (India) was also Mag. 138. These numbers are used in the photo i.d.’s, e.g., AS17-138-21029. However, I had a tendency to deviate from the standard phonetic alphabet and use ladies’ names instead. ↑
Consortium Indomitable, 1973, The Moon, 14. ↑
Heiken, G., Vaniman, D. and French, B. M Lunar Source Book. Cambridge Univ. Press, New York. 225-228. ↑
Borg, L. E., A. M. Gaffney, and C. K. Shearer, 2015. A review of lunar chronology revealing a preponderance of 4.34–4.37 Ga ages, Meteor. and Planet. Sci., 50, 715-32; Schmitt, H. H., 2016. A continental-scale Procellarum impact’s potential relevance to many unresolved issues of lunar and terrestrial history. Annual Meeting, Geological Society of America, (abstract). ↑
Wolfe, E. W., et al., 1981, The Geologic Investigation of the Taurus-Littrow Valley: Apollo 17 Landing Site, USGS Professional Paper 1080, 57. ↑
Wells, R. A., Petro, N. E, and Schmitt H. H., 2019. Red/Orange Volcanic Ash Deposits on the Lunar Surface Documented in Color-Balanced Apollo 17 Hasselblad Surface and Orbital Photographs Compared with Apollo Panoramic, Metric Mapping, and Lunar Reconnaissance Orbiter Photos. J. Geophys. Res. – Planets, (revision submitted, Aug. 2019). Details of the color-balancing process are given in the Supplemental Information file of this paper. ↑
Ryder, G., 1993, Catalog of Apollo 17 Rocks, Volume 1, Stations 2 and 3, (South Massif), NASA-CR-194854, 72315. ↑
Schmitt, H. H. (2016) North Massif regolith at Taurus-Littrow may contain lithic-clastic volcanic debris erupted prior to mare basalt, LEAG Annual Meeting, Abstract.↑
Schmitt H. H. (2016) Symplectites in dunite 72415 and troctolite 76535 indicate mantle overturn beneath lunar near-side. 47th Lunar Planet. Sci. Conference, Lunar Planet. Inst., Houston. (Abst. #2339). ↑
Wolfe, E. W., et al., 1981, The Geologic Investigation of the Taurus-Littrow Valley: Apollo 17 Landing Site, USGS Professional Paper 1080, 77. ↑
Talwani, M. et al., 1973, Traverse Gravimeter Experiment, Apollo 17 Preliminary Science Report, NASA SP-330, p. 13-12. ↑
Taylor, L. A., 1988, Generation of native Fe in lunar soil, in S. W. Johnson and J. P. Wetzel, editors, Engineering, Construction and Operations in Space: Proceedings of Space ‘88, American Society of Civil Engineers, New York, p. 67-77. ↑
Cernan, E. A., and D. Davis (1999), Last Man on the Moon, St. Martins Press, New York, p. 288.↑
Morris, R. V., 1976, Surface exposure indices of lunar soils:, A comparative FMR study, Proceedings of Lunar Science Conference 7, 315-335; Taylor, L. A., Pieters, C., Keller, L. P., Morris, R. V., Mckay, D. S., Patchen, A. and Wentworth, S., 2001, The effects of space weathering on Apollo 17 mare soils: Petrographic and chemical characterization. Met. & Planet. Sci. 36, 285-299.↑
Schmitt H. H., Petro N. E., Wells R. A, Robinson M. S., Weiss B. P. and Mercer C. M. (2017) Revisiting the field geology of Taurus-Littrow. Icarus 298, 2-33. ↑
Hörz, F. et al., 1991, in Heiken, G. H., Vaniman, D. T., and French, B. M., editors, Lunar Surface Processes, Cambridge University Press, p.89 ↑
Watters, T. R. et al., 2010, Evidence of recent thrust faulting on the Moon revealed by the Lunar Reconnaissance Orbiter Camera, Science, 3129, 936-940. ↑
Brooks, M., 2003, The famous spilled coffee episode, in Liebergot, S., Apollo EECOM: Journey of a Lifetime, Apogee, Burlington, Ontario. ↑
Schmitt, H. H. and Robinson, M. A. 2010, The geology of the Apollo 17 Taurus-Littrow site in light of new high resolution images, Abstract, Geological Society of America annual Meeting, Denver, Abstract. ↑
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