7. Chapter 9 – The 12th Man

Chapter 9

The 12th Man[1]

The Lunar Module (LM) Challenger at the beginning of the first extravehicular activity (EVA) shortly after touchdown at 01:55 p.m. EST on December 11, 1972. In the background at right is the eastern slope of the South Massif. To the left of the left-most LM strut in the distance is the small hill, Bear Mountain. Note the line of deep footprints and dark spray pattern on either side of them crossing the view in the foreground (cf. Fig. 9.11 from LRO for overhead views of similar tracks). (Partial pan of NASA photos AS17-147-22516, -22517.)

Day 6 – After Landing

The Challenger first contacted the lunar surface in the valley of Taurus-Litrow with one of its four, six-foot long collapsible probes attached to each landing pad. So, in that respect, Apollo 17’s first word on the Moon was my call out of “Contact” when the blue CONTACT light above and to the right of the DISKEY illuminated (See Appendix A, December 11).

My immediate “STOP – PUSH!” call was a reminder to Cernan to shut off the Descent Engine. Cernan responded, and we dropped to the surface with a thump and slight rocking motion.

“ENGINE STOPPED!” I confirmed, as Challenger dropped that last few feet to the lunar surface.

“ENGINE ARM – [OFF], PROCEED [on DISKEY], COMMAND OVERRIDE – OFF, MODE CONTROL – ATT[ITUDE] HOLD, PINGS – AUTO.” I quickly read off several, rapid-fire, post-Contact checklist actions necessary to insure that Challenger was in a safe condition for any possible early abort. Cernan took the necessary actions without comment as I watched carefully. Cernan recalls only silence after touchdown;[2] however, in fact, we continued to be busy following the procedures ingrained into us by many, many simulator runs.

“Okay, Houston. The Challenger has landed!” were Cernan’s first words from the valley.

“Roger, Challenger. That’s super!”

*****

The relentless clock moved on. The elation of a successful landing and anticipation of all that was to come spread through Challenger’s cabin by look and action. We rushed to safe the spacecraft systems and impatiently awaited the words that would direct us to proceed with the planned mission or, heaven forbid, send us immediately back into orbit because of some technical problem that violated a Mission Rule or otherwise threatened our lives. The relative security of Challenger now seemed as confining as a classroom on the last day of school. A familiar, yet still untouched, field area beckoned.[3]

Looking ahead, over 45 years later, I am certain that descent to the surface of Mars will not have Mission Rules that require “aborts to orbit” and a return to Earth. Engineering and operational designs will permit if not plan for “aborts to land.” I cannot imagine that a Mars crew would be required to come home without landing after the time and expense to fly to get there. Rather, once on the surface, they would take time to analyze and deal with any issue that was of immediate concern. If necessary, and after significant delays for roundtrip transmissions, prolonged discussions about the problem, telemetry indications, and the best plan going forward would take place with Mars Mission Control.

*****

“Okay, Parker valves…,” I called out as I reached up to cycle 8 RCS QUAD switches in front of me from the ON position to OFF and then back to ON. These switches were positioned to the left of my window and the black and white “eight ball” Attitude Indicator (FDAI) and controlled 32 fuel and oxidizer valves leading to the 16 RCS jets. The Parker valves could isolate the RCS jets from their fuel and oxidizer supplies. As a result of early shock tests, concern had been raised that a Parker valve might close with the shock of landing. As far as anyone knows, that never happened, but to make absolutely sure that the RCS jets all had access to propellants, I cycled the switches the first thing after landing. Meanwhile, Cernan had a chance to get all excited without me fully joining in.

“Boy, you bet it is, Gordo…[Jack], boy, when you said shut down, I shut down, and we dropped, didn’t we?

“Yes, sir! But we ‘is’ here, man, is we here! …How does that look?” I asked, pointing to the DESCENT ENGINE fuel and oxidizer indicators.

“That looks good.” Cernan said. We had landed with almost two minutes of hover time left. That may not seem like much, but it would have been plenty if, at the last moment, he had to maneuver to an alternate touchdown location.

“[RCS] Pressures look great. Tank 2 is down just a little from before,” I replied, pointing to the two needles on the RCS tanks pressure gage.

“Okay, Engine Override is OFF,” Cernan confirmed my earlier call out and verified that the MODE CONTROL switches for PINGS and AGS were in ATT[ITUDE] HOLD and AUTO, again, in case we had to leave quickly using either control system.

“[RCS] Manifold [pressure] is great. Manifold is right on. Go to JETS [on your TTCA],” I read, referring to Cernan’s left hand controller.

“Okay. I am [in] JETS.” This needed to be in JETS, meaning RCS control, rather than THROTTLE where it had controlled thrust of the DESCENT ENGINE. If we aborted, the thrust direction of the Ascent Engine would be controlled by the orientation of the Ascent Stage as the Ascent Engine, unlike the Descent Engine, had a fixed nozzle rather than one that could be adjusted (gimbled) automatically or manually.

“Okay. That [Cue Card] side’s complete,” I said.

“Houston, you can tell America that Challenger is at Taurus-Littrow,” Cernan suggested, referring to Evans in orbit above us.

“We’ll do it.”

“Hey, Challenger; this is America. I heard you all the way down. That’s great! Beautiful!” interjected Evans. He had remained in line-of-sight radio communications all through Challenger’s descent and landing.

“Ron, I had the meatball all the way,” Cernan added, speaking as one former carrier pilot to another and referring to the visual aid on a carrier that assisted in landing. He meant that he had been right on track all the way to landing, choosing to ignore the high rate of descent that might have resulted in a “wave-off” had he been landing on a carrier with enough fuel to try again. The actual touchdown on the Moon, however, was perfectly executed.

“Beautiful!” responded Evans.

“Jack, are we going to have some nice boulders in this area.”

“Okay. The old [16-mm sequence] camera’s off,” I said, ignoring Cernan’s premature look at where we hoped we would be able to explore

“Okay.”

Continuing with the Post-Touchdown Checklist, I reported, “LANDING RADAR [CIRCUIT] BREAKER, OPEN. Checking the [Ascent and Descent] water [tanks]. …And, Gordy, [looking at] ASCENT TANK 1…We started out a little low [and] it’s still… [in the] same place. That’s [the tank for] water.”

“Roger, Jack,” replied our CAPCOM for descent and landing, Gordon Fullerton. Without reporting verbally, I also cycled the Ascent Helium Monitor switch, to be sure the tank’s pressure sensor was working, and checked the Ascent and Descent propellant temperatures. We would watch the Descent propellant temperatures until given the okay to vent those tanks.

[The Ascent Engine, on which we now depended to get back home either urgently or after completing our exploration, was designed and manufactured by Bell Aerosystems Company under the close supervision of George Low and C. H. Bolender in the Apollo Spacecraft Program Office. The engine’s inheritance goes back to Bell’s RM-81 engine for the Agena rocket, derivatives of which were used in many early unmanned and manned (Gemini) spaceflight programs. In the case of the Lunar Model’s Ascent Engine, however, the engine’s injector used on Apollo 9 (LM-3) and subsequent missions, and manufactured by Rocketdyne, had entered the main stream only about nine months before Neil Armstrong’s first landing on the Moon. Uncertainties in 1968 related to failures in tests of the original Bell injector prompted the substitution of an alternative injector.[4]]

“Batteries’ [voltages] look good,” I reported.

Then, with the immediate checklist items taken care of, I took my first real look at Taurus-Littrow… “Oh, man!! Look at that rock out there!” I probably had just noticed a large, ~3m high boulder directly west and near the site I eventually would choose for the ALSEP deployment (see Figs. 9.1-9.10 for my first views of the lunar surface). This boulder later would be called “Geophone Rock” because it was near the line of geophones I deployed as part of the Active Seismic Experiment.

Fig. 9.1. This first view looking almost due west from the right window of Challenger after landing in the Valley of Taurus-Littrow shows the relatively undisturbed surface, the ALSEP deployment site near the large boulder (Geophone Rock) in the middle ground, and West Family Mountain in the distance at the head of the valley. (NASA Photo AS17-147-22469).

*****

My first view out the triangular window in front of me, looking west to northwest to east along the valley and across to mountains over 1600 meters high, encompassed only about a quarter of the panorama we expected to have outside the Challenger. Only later, when I could walk a few tens of meters away from Challenger, did the full and unexpected impact of the remarkable setting hit me: a brilliant sun, brighter than any desert sun; fully illuminated mountain walls outlined against a blacker-than-black sky; and our beautiful, blue and white marbled Earth, with its desert accents, hanging over the imposing South Massif. And we were there and were part of it, if only temporarily.[5]

Fig. 9.2. The adjacent view shows in the distance West Family Mt. (left), Family Mt. (middle), and the beginnings of the slopes of the North Massif at right. (NASA Photo AS17-147-22470).

*****

“Absolutely incredible. Absolutely incredible,” expounded Cernan.

“I think I can see the rim of Camelot,” I told Fullerton so as to help them locate where we had landed.

“Roger.”

“Epic moment of my life,” said a now introspective Cernan.

“Where’d you land? You never let me look outside at all,” I joked. “Hey, you can see the boulder tracks (on the North Massif)!” (Figs. 9.3-9.4)

Fig. 9.3. Continuing to the right of the previous views, more of the North Massif is visible. Hanover Crater, mentioned later in text, is the small, bright spot just to the right and above the large central fiducial cross and next to a light-colored fault scarp the turns northwest along the lower slope of the North Massif. (NASA Photo AS17-147-22471).

“Okay, Gordy,” Cernan prodded. “We’re standing by for your GO [to STAY]. We look good. We’re looking good onboard.”

“Okay. You’re looking great here so far.”

“There are boulders all over those massifs,” I observed, a little surprised that the pre-mission photographs had not shown they were there in abundance. The high sun angle of those photographs limited shadow definition, however.

Fig. 9.4. Further to the right striations, boulders and boulder tracks are visible on the slopes of the North Massif. In this view, the slopes are ca. 3.5 km away. (NASA Photo AS17-147-22472).

“God, look at that propellant,” Cernan exclaimed. “We could have gone all around and looked around.” Certainly, the 117 seconds of hover fuel we ended up with made it more than comfortable for landing; however, Cernan was joking about flying around the area.

“We should have hovered around a little bit; gone and looked at the Scarp,” I said, joining in the fun.

Fig. 9.5. Returning to the west, these next views show the areas closer to the spacecraft. The bright aureole surrounding the LM shadow is a result of intense direct back-scattering of sunlight from the very fine-grained, fluffy upper surface (fairy castle structure) of the impact pulverized debris (regolith) that covers most of the Moon. (NASA Photo AS17-147-22473).

Fig. 9.6. As the view moves away from the anti-solar direction, back-scattering lessens and surface features become more apparent. (NASA Photo AS17-147-22474).

Fig. 9.7. In this next view it is clear that, although the surface is relatively level near the spacecraft, there are many small, shallow craterlets and boulders scattered about. (NASA Photo AS17-147-22475).

Fig. 9.8. This image, just past the northerly direction, shows the furthermost view towards the east on this side of the spacecraft without disembarking. Very oblique views of Henry and Shakespeare Craters can be seen above the vertical reaction control thruster (also see Fig. 9.4). (NASA Photo AS17-147-22476).

Fig. 9.9. The last two views in this and the next photo return to the area under the LMP window next to the right side of the LM. (NASA Photo AS17-147-22477).

Fig. 9.10. Similar to Fig. 9.9. (NASA Photo AS17-147-22478).

“No, thank you,” Cernan replied, changing his mind while I laughed. “I like it right where we are. …Okay, Gordy. While you’re waiting on that GO, I shot for a spot, around 2 o’clock from Poppie. There’s a number of boulders out at 12 o’clock from Poppie, and I really think I’m probably not more than about 100 meters out in front of it, and slightly to the north. Actually, I may be a little bit closer to Trident than I expected Poppie to be. I think I’ve got Trident right out the left window. And our first cut at the mobility around here in the Rover [indicates] it ought to be super.”

Okay. Sounds good,” responded Fullerton. Understandably, due to the similarity of many craters, Cernan had lost track of landmarks as we came in and the actual landing point ended up about 100 m north and 20 m west of Poppie, or 230 m west and 60 m north of the planned, pre-mission landing point.[6] (Fig. 9.11)

Fig. 9.11. (Upper): Lunar Reconnaissance Orbiter Camera view of the Apollo 17 landing site in the valley of Taurus-Littrow with a resolution of about 0.5 m/px. (Lower): The same with several features identified with labels. Note the location of Poppie Crater, south of the spacecraft. To vary the sun angle, see the LROC website[7]. (NASA LRO NAC image M168000580R).

“But I tell you, the Massifs and Bear Mountain are two different products (types of features).”

“Sure look it, don’t they?” I agreed. …Of course, they’re different slopes, too.” In looking at surfaces from a distance on the Moon, slopes relative to the Sun have to be taken into account when comparing different features. Future studies would indicate that, indeed, Bear Mountain is made up of material much different than the North and South Massifs.

“I think you’re looking, probably…that may be Rudolph, right there, Jack, out your window. …I was looking more at those boulders [during landing] and trying to stay in the spots in between them than I was…[looking at any] relationship to that crater.”

“Yeah, you did great, Gene. …Man, there was practically no dust, just a little bit of a film. You had the ground all the way to the ground.”

“Yeah. I could call touchdown on the shadow. Look at that… [We’re] Really here!” Cernan’s comment on the obvious brought a laugh from me.

“Okay, Gordy, Cernan said, impatiently. We’re hanging in for your GO.” Flight Controllers in Mission Control would take some time to make sure that all the systems and consumables we would need for three days in the valley showed the stability they wanted before making that “GO” commitment.

“It better be a GO!” I said, emphatically.

“Check everything again. Let’s just double check.”

“Okay,” I replied, having continued to do this since landing.

“That hasn’t changed,” I said, probably pointing to the Ascent Engine fuel and oxidizer tanks pressure and temperature indicators on Panel 2 in front of me, above my Attitude Indicator.

“Okay, that’s good.”

“The [Ascent Engine] manifold [pressure] hasn’t changed. The RCS [pressure] hasn’t changed. Ascent water hasn’t changed. The batteries haven’t changed.”

“Oh, my golly!” Cernan exclaimed as he looked outside once again.

“Only we have changed,” I mused.

“You know, you can’t see into Camelot, Jack; that rim is Camelot out in front of us. …We got enough room to deploy three ALSEPs out there.”

“Yeah.”

Challenger, you’ll be glad to hear you’re STAY for T-1.” T-1 constituted a pre-programmed launch opportunity at about 17 and a half minutes after start of Powered Descent that would let us catch up with America while it was still more or less overhead on its current orbit, but leaving our area, rapidly.

“Gordy, you’re a smooth talker, you know it? We are STAY for T-1.”

“Okay, [Jack]. You can forget all I told you about Verb 22 Noun 46.” This comment related to changing the DAP (Digital Auto Pilot) configuration in case of a failure of the PNGS MODE CONTROL switch.

Challenger, understand [your are] STAY for T-1. Good.”

“What was that?” I said, laughing at an unexpected transmission from Evans to Mission Control. I had assumed that he was long gone from direct communications with us.

“Okay. Let’s find out where we are [in the checklist],” Cernan said. “ENGINE STOP is RESET.”

“Okay,” I acknowledged, “the AGS is ready for us if we need it.”

“Okay. I need a P12 time [from Mission Control] as soon as I get [VERB] 60…”

“Okay.” P12 was the PINGS normal Ascent program and VERB 60 would display attitude error rates on the FDAIs (eightballs) if we had to fly a manual ascent.

“Okay, Gordy. You’re looking at NOUN 43. Copy that down, Jack, right here.” NOUN 43 provided the PINGS estimate of our landing point latitude, longitude, and altitude.

“Okay,” Fullerton responded. “We’ve got it.”

“20:21 [latitude] and 30:75 [longitude], and I’m going to P12…Okay, [Jack]. I need a P12 time from you…”

“Okay.”

“For T-2?”

“For T-2, the time is 113 [hours]…” I took the T-2 time from what we had copied from Fullerton just prior to Descent when they had a good handle on America’s orbit and state vector.

“Okay, [got it].”

“14 [minutes].”

“14.”

“24 [point] 91 [seconds].”

“2491.”

“Yes, sir,” I confirmed as Cernan completed the entry under my watchful eye. If we ever had to leave Taurus-Littrow unexpectedly due to some problem, the PINGS and AGS programmed to put us into an orbit below America’s so that our greater orbital velocity would let us catch up.

I can’t feel any difference between one-sixth g and anything else right now,” Cernan commented.

“Well, you still got your restraints on,” I replied with a laugh.

“Okay. [T-2 time is reading] 113:14:24.91. You happy with that?”

“That looks good, sir.”

“Okay…I got to change these numbers [in NOUN 76]. …You didn’t get an update on Noun 76, did you? …I don’t think so.”

“No. No.” I agreed, referring to ascent variables of downrange velocity relative to the landing site, radial velocity relative to the Moon, and cross-range distance relative to America’s orbit.

“Okay…,” Cernan said, looking at numbers in NOUN 76, “5515…Hello, Gordy. How would you like me to handle R-3 [Register for cross-range] of Noun 76?”

“Stand by. I’ll come back to you.”

“Okay…Oh, that [Landing] Radar performed super!”

“How was the view on the way down, Gene?” I asked with a laugh.

“You know, after we pitched over, I was just looking for a place to land, [so] I’m not sure. I just didn’t want to hit one of those boulders out there- which would have been as easy…And look at that. Look at right in front of us. I didn’t want to land there either.”

“I see that one right in front of us.”

“You see that? Now that’s a hole!” Cernan is referring to a nearby, relatively shallow crater. With the low sun angle for landing and our descent at a planned higher angle, he could see boulder and crater rim shadows during descent. Once on the surface, however, our line of sight was below the sun angle and we could not see the shadows looking to the west.

“Oh, the hole. I can’t see the hole…”

Challenger, Houston. R-3, cross-range, is okay as is.”

“Okay.”

“Okay,” I alerted Cernan. “We’re coming up [on T-2]…”

Taking my cue, Cernan called, “We’re in posture for a T-2, Gordy.”

“Roger.”

“Okay. I can see the Scarp. I can see Hanover. Good thing we didn’t plan to go to Hanover,” I added, laughing. “It’s steep [over there].” Hanover consisted of a sharp, relatively fresh-looking impact crater just east of where the Jefferson-Lincoln Scarp turns across the lower slopes of the North Massif. Early in the traverse planning for exploration of the valley we had discussed trying to get to Hanover as a possible way to gather information about the origin of the Scarp; however, the team decided not to try to attempt to reach it due to the required driving distance and time, the steepness of the slope to get there, and the high probability that debris from the slopes above had covered any outcrop (Fig. 9.3).

“Look at the boulder, halfway up the hill,” Cernan said looking through window in front of me at the slopes of the North Massif, almost due north of the Challenger.

“Yeah…, the boulder tracks; they’re beautiful,” I replied, figuratively licking my geological lips.

“It’s sitting right there in the end of the track,” Cernan added.

“There are tracks all over that hillside.”

“There’s a boulder [that] came right down to the [valley] surface there. See it?”

“Yeah.”

“That one (a boulder track) went right through that little crater…”

“Yeah.”

“Sitting right there for us to sample. Look at it.”

“Yes, sir.” Cernan had noticed the large boulder that would be a major objective of our activities at Station 6 on the third day’s exploration traverse. I was absorbing the fact that, with these boulder tracks, we could actually sample specific outcrops (I sometimes would refer to these as “source crops”.) on the 2000m high slopes of the North Massif. In 2010, LRO photography showed that the two large boulders we sampled on the third day had rolled from outcrops about 500m apart in elevation.[8]

“I’ll bet Bear Mountain and the Sculptured Hills are the same [types of materials],” speculated Cernan. The Sculptured Hills, out of view to the south of the North Massif, have a distinct crosshatched, hill and swale physiographic character compared to the more jumbled surfaces of the Massifs.

“Yeah. Well, the [overall] slope’s different [on the Sculptured Hills]. We’ll have to look at it from outside. You may be right.”

“Now [looking only at Bear Mountain] I see why they call them ‘sculptured’. My god, they’re so hummocky that there’s shadow all over them.

“Yeah.”

“God, there are some holes and rocks around here. Who told me this was a flat landing site?”

Joking with this hotshot pilot, I responded, “It is flat! For crying out loud. What do you want? An airtight guarantee?”

“Let’s see,” Cernan observed from the attitude indicator in front of him, “we got about 2 degrees left (roll) and about 5 degrees pitch-up.”

“We’re about what? About 100 meters from Trident?” I speculated. This estimate turned out to be pretty close. In addition to looking at the distant geology of the North Massif, I had been trying to figure out exactly where we had landed relative to the nearby named features.

“Yeah, less than that. I think Trident’s right here,” Cernan said, continuing to confuse Trident with Poppie.

“Our (LM) shadow’s about 100 feet (long), Geno, I think,” I stated, using a figure I had asked to have before the mission.

“Yeah, we’re only about…Yeah, less than 100 meters then [from the crater].”

“It doesn’t look that long, but it is…” All the lunar astronauts found it difficult to estimated distances in this unfamiliar terrain, lighting and clearness. I therefore had asked our support people to calculate some shadow lengths for our landing sun angle and to be ready with other lengths should I need them.

“God, there are some holes I’m glad I didn’t land in around here, I’ll tell you… Now, if you look at the (South) Massif, Jack. I don’t know if you can see it over here. You see, …they’re almost like a series of linear boulder tracks, but they come crossways down the slope. So it looks like there may very definitely be some jointing.  …There’s outcrop on top the Massif, too.” Cernan has observed the apparent cross-hatched texture of many lunar slopes that has been duplicated as possibly being the result of lighting on the cratered surface of those slopes[9].

Oh, it sure looks like it…[is] gray outcrop,” I agreed. “It’s a bluish gray compared to the brown- or tan-gray of the [outcrops on the North Massif side.”

Cernan continued, “And a lot of that “outcrop” down on the bottom is boulder.”

“Yeah.”

“Do you know what that reminds me of, way up on top…that outcrop? It reminds me of Sunset [Crater] a volcanic cinder cone near Flagstaff, Arizona) where you could just get a little piece of outcrop around the cone.” About five weeks earlier, Cernan had seen basalt splatter layers around the rim of a volcanic crater near Flagstaff, Arizona where we had our last field simulation during training.

“That’s right,” I agreed as to the slight similarity in appearance but a very different geologic context.

“Okay. Let’s see what we’re doing,” Cernan said, remembering that we had not been given the GO to stay on the Moon. “We got 3 minutes for T-2. Let’s take another check.”

“Okay. I just looked at them,” referring to the condition of the various systems we would need to leave. In fact, part of the reason I had not joined vigorously in Cernan’s look around the valley was that monitoring Challenger’s pressures and voltages had consumed much of my attention. I wanted to be sure nothing was happening to the Challenger that would cause us to lose our chance to leave Challenger for the lunar surface. The other reason for my terse comments was that I was assimilating as much as I could of the visible geological features in preparation for actually going out to study them.

“Okay. Ascent (stage) looks good. …Gordy, I noticed something ever since we’ve landed. The Descent Engine oxidizer quantity went from 7 or 8, and now it’s down to 2, and the fuel has stayed constant.”

“Roger.”

“And the Quantity Light came on somewhere, I believe, after we landed,” Cernan added.

“Yeah, it did,” I agreed. “I noticed the Quantity light also. I was thinking ‘REG light’, though, when I saw it.” This is the kind of dynamic situation where we would have been waiting for some other confirming indication that we had a problem, either onboard or from Mission Control. Since they did not call out a problem, we continued with the landing. Obviously, we did not run out of oxidizer, so our assumption that it was a sensor problem was correct.

Challenger, we’ll have a story on that [Quantity Light] for you later. We don’t think we were really low level.”

“Okay, Cernan replied. “It doesn’t make any difference now, Gordy; except to talk about when we get home.”

“Roger.” The Ascent Engine fuel and oxidizer tanks only provided an “Ascent Quantity Caution” light if either quantity dropped below that necessary for 10 more seconds of burn time.

And we’re 2 minutes and counting to T-2,” Cernan reminded everybody.

“Roger.”

I pushed the decision-making a little harder with, “We better hurry if they’re going to give us the GO. …How about some water?”

“Yeah, you can zap me.” Cernan referred to the water gun that dispensed about an ounce with each trigger pull. We had a self-sealing port in our helmets that allowed the barrel of the gun to be inserted for a drink.

“Oh, I tell you. That’s something everyone’s got to do once in their life,” Cernan continued to express some wonder that he had landed on the Moon. A mutual friend once had told me that, after becoming an astronaut, Cernan had said that there were two things he wanted: a son and to land on the Moon. Now, he had accomplished one of those goals.

“We’re not going to have much time for T-2,” I urged.

Challenger, Houston. You’re STAY for T-2, and GO for the DPS (Descent Propulsion System, pronounced “dips”) VENT.

“Okay,” we said in unison. Venting the fuel and oxidizer tanks of the Descent Engine by venting pressurizing helium would prevent those tanks from rupturing while we were on the Moon. Having toxic hydrazine and nitrous oxide around would not be good for us or for the samples we would take from the area.

“Okay. Understand. Stay for T-2, and GO for the DPS VENT. Let me get out of [P12]. …Okay, we can’t hack that. I’m going to get out of P12.”

“Excuse me, Gene,” I interjected, and pointed to the post-landing, Lunar Surface Checklist.

“Okay. You can un-zap that water, if you’d like. And let’s go off VOX. Let’s go on PTT. Tape recorder, OFF.” Prematurely, Cernan wanted to leave voice actuation (VOX) for communications with Mission Control and go to manual or push-to-talk (PTT). A big blue PPT button was on the oxygen hose going into the suit so it often became keyed as we move in the cramped space of the cabin. This resulted in some inadvertent, random communications. Our other PPT button was on the right hand attitude controller as also is normally its placement in airplanes. Cernan also wanted the on-board tape recorder (DSE) off. This meant that for the time being, unfortunately, there would be no record of our conversations unless we contacted Fullerton directly. We would turn the recorder back on as we made ready for the first excursion to the surface so that Mission Control could monitor all our preparations.

But before leaving VOX mode, however, I reported, “Regulator 1 is CLOSED, Houston; OXIDIZER [and] FUEL VENTS coming OPEN.” Being close to the Flight Controllers at the LM CONTROL console in Mission Control, I always wanted them watching over my shoulder when going through critical functions.

“Roger.”

“MASTER ARM – ON,” I directed Cernan as per the Checklist. “MASTER ARM’s coming ON,” I repeated as Cernan enabled the pyrotechnic system that would open the tank vents.

“Okay, Gordo,” Cernan said. “I got two good [System Armed] lights.”

“Roger.”

“DESCENT VENT – FIRE,” I called as Cernan threw the switch that would fire the small Apollo Standard Initiator explosives in the vent lines. These ASIs, as they were often called, had a remarkable record of success and served as the standard initiator for most if not all explosive cutters throughout the Saturn V and the two Apollo spacecraft. ASIs would be used again whenever we separated from the Descent Stage upon leaving Taurus-Littrow.

“Okay. MARK it. We did not hear anything on that one, Gordy.” This surprised both of us, but then we still had our helmets on.

“Roger.”

“Pressure’s coming down, though. Pressure’s coming down,” I reported as I monitored the tank pressures.

Okay,” I said as I began the post-VENT checklist items. “MASTER ARM – OFF…

“Jack, do we need to wait for the pressures to come down?”

“We’ll monitor oxidizer pressure until 20 to 40 [psi], and then OX VENT – CLOSED…fuel pressure to less than 8 [psi]…[then] FUEL VENT – [CLOSED]… DESCENT QUANTITY LIGHT…[I mean] REG LIGHT, excuse me, …MODE CONTROL, TWO [switches] to ATT HOLD.”

“Well, we just keep going, I guess, Cernan said. “Yeah. Hey, we can press on…

“Verify INVERTER 2 is selected,” I continued, now off VOX; however, I used my PPT button to keep Mission Control informed of where we were in the Checklist. “Okay…Okay. Now wait a minute. Here we go. Let’s get that. Go up here [on the Checklist], first…because I haven’t selected it (INVERTER 2)…”

“On Panel 11, INVERTER 1 – OPEN and DECA POWER – OPEN,” I read.

“Okay.” These actions took power from the Descent Engine Control Assembly that, of course, we no longer would need.

“Gene, you read the Checklist for what I need to do on my side,” I suggested.

“Okay…ASCENT ECA CONTROL [circuit breaker] – CLOSED.”

“ECA CONTROL is CLOSED.” This put the Electrical Control Assembly for the Ascent Engine temporarily on line while I re-configured the Ascent Batteries.

“They want Descent BATTERY 3 back ON.”

“3 is back ON.

“[ASCENT] BATTERIES 5 and 6 – OFF/RESET. Check that the talk-back is barber pole.”

“BATTERY 5 is OFF/RESET, and it’s off the line (barber pole]. BATTERY 6 – OFF/RESET, and it’s off the line.” As we were now cleared to prepare the Challenger for its time on the Moon, baring any unexpected problems, the Ascent Batteries could be taken off line.

“INVERTER 2 CIRCUIT BREAKER – IN.”

“INVERTER number 2 breaker is IN. …INVERTER 2 [selected]. …Let me check the voltage. Voltage is great. …Okay, Keep going.”

“On Panel 16, PQGS circuit breaker OPEN…and DESCENT ENGINE OVERRIDE CIRCUIT BREAKER – OPEN.”

“[PQGS…and] DESCENT ENGINE OVERRIDE’s OPEN.” PQGS referred to the Propellant Quantity Gaging System for the Descent Engine.

“ASCENT ECA CONTROL CIRCUIT BREAKER – OPEN.”

“ASCENT ECA CONTROL’s OPEN.”

“CWEA (pronounced “seewee) circuit breaker – OPEN then CLOSE and check Descent Regulator light – OFF.” CWEA stands for Caution and Warning Electronics Assembly.

“CWEA…CYCLED. Both lights are out.”

“Okay…Verify Cabin Pressure.”

“Cabin pressure is good.”

“Okay…PRESSURE REGULATORS A AND B to CABIN.”

“And then, (Pressure Regulators) A and B going to Cabin…A is to Cabin. B is to Cabin.” This action insured that the cabin pressure would be maintained at 4.8 psi.

“CABIN GAS RETURN VALVE – PULL-EGRESS.”

“PULL-EGRESS. RETURN is EGRESS.” Now, we are setting up the suit oxygen circuit so that we can take our helmets off.

“CABIN REPRESS VALVE to AUTO.”

“REPRESS going to AUTO…Stand by for a noise. There you go.” A little gas always went through the valve with this change, making a sharp noise. “It’s in AUTO.” If anything should happen to the integrity of the cabin, re-pressurization would now be automatic and would give us time to put our helmets back on. “Okay. Now it’s your turn,” I said, taking the checklist from Cernan. “Verify…,” but before I could get started, something, possibly ice, that was ejected from this valve, located in the hatch, caught my eye. “Wonder where it’s going?” I wondered. “Out, I guess.”

“Jack, did you select Inverter 2?”

“Inverter 2 is selected.”

“Okay. And DECA POWER – OPEN…And guess what? Take your helmet and gloves off.”

“Next, we put the SUIT DIVERTER VALVES to IV (intravehicular), that’s horizontal, and stow the restraints…”

About five minutes later, Cernan called Mission Control, saying, “Okay, Gordy. We’re on page 1-1 (of the Lunar Surface Checklist). Helmets and gloves are off. Diverter Valves are IV (Intravehicular).

“Okay. We’re right with you.”

Next on the flight plan, Cernan began to undertake a star sighting in order to make sure the guidance platform of the PINGS had the best information possible about our position in space as well as relative to the orbit and state vector of Evans in America. He again would use the Challenger’s one power Alignment Optical Telescope (AOT). Being only one power, the AOT could not provide as accurate alignment as America’s Sextant; but it would still be good enough for any possible emergency departure.

“And you’re looking at NOUN 20,” Cernan told Fullerton. NOUN 20 provided Mission Control and us with the current alignment of the platform from which they could calculate any drift that had occurred due to the dynamics of Powered Descent.

“Window shades are going closed,” I told Cernan and Fullerton. This was to cut out as much light as possible and allow Cernan to dark-adapt for the star sighting. Without the collimation provided by the telescope’s tube, and its elimination of reflected light from the lunar surface, star sightings still would not have been possible. This is the same effect that allows one to see stars from inside a deep well during daylight on Earth.

Then I added, “I’m using it [the corner of the window shade] instead of a light switch because I’ve got it [the light switch] covered up [with gear].” I needed some light to work with the AGS keyboard and numerical display or Data Entry and Display Assembly (DEDA).

“Gordy, you got NOUN 20?” Cernan asked, referring to the current guidance platform yaw, pitch and roll angles off the Inertial Data Coupling Unit (ICDU).

“That’s affirmative. We copy Noun 20.”

“Okay. Jack’s going to pick up the AGS [alignment information] – on the right side of that [Checklist] page – and I’ll park the [rendezvous radar] antenna [out of the way of the star sighting].”

“Roger.”

“P20’s (Rendezvous Navigation) in work. Correction, P57’s (Lunar Surface Alignment of the PINGS guidance platform) in work,” Cernan reported. Why Cernan made this slip, I have no idea. The PINGS’ P57 program would be used to realign the Challenger’s platform, using a determination of the local vertical (gravity vector) followed by incorporating star sighting data using the AOT.

Challenger, Houston,” called Fullerton. “Your DPS Oxidizer Pressure is 40 (psi) or less. You can close it.”

For the next three minutes or so, while Cernan waited for the PINGS to update its knowledge of the gravity vector, he talked continuously to Fullerton, polishing up his memory of the flight into Taurus-Litrow and the landing.[10] He particularly remarked how much the Landing and Ascent (L&A) terrain model we trained to in the Lunar Module Simulator looked like the real thing.

With this long soliloquy and Cernan’s emphasis on the L&A, I could not resist commenting, “Gordy, this is the LMP. Let me say that the inside of the spacecraft looked just like the simulator.”

“Very good, Jack.” I am not sure either Cernan or Fullerton appreciated this attempt at humor at Cernan’s expense.

“Another interesting thing, Gordy,” he continued, all the way through PDI prior to pitchover, Jack and I had the real America – or the other America [meaning the United States of America] – right smack out the front window all the way down, which was pretty spectacular.” I actually could only see the Earth when Challenger was rolled left prior to pitch-over.

“I bet it was. And you can consider yourself STAY for T-3.”

“Thank you, sir. You’re getting smoother all the time. If you’re happy with Noun 22, I’ll PRO(CEED).” P57 began with choosing the REFSMMAT option in the second register of NOUN 06 so that the alignment would be referenced to the landing site. PROCEED on this entry showed that we would specify the alignment technique to be used, both local gravity and a star would be measured, the REFSMMAT would be defined, and the PINGS had a stored, post-landing attitude for the Challenger. A second PROCEED began the measurement of the local gravity vector and a course alignment of the platform, shown by a NOUN 20 display of ICDU angles. The NO ATTITUDE light on the DISKEY flashed ON and OFF, twice, as expected. Hitting KEY RELEASE gave a NOUN 04 measure of the Navigation Error Angle for local gravity relative to the current PINGS alignment. For comparison with a second gravity measurement, we recycled with a VERB 32 entry and then read off another NOUN 04 Gravity Error Angle. Another PROCEED gave Houston a look at the new NOUN 22 ICDU Angles that included the gravity measurement. NOUN 22 provided a look at what the gravity alignment had determined and the PRO Cernan requested would accept use of that information by the guidance system.

“Stand by one. …You’re clear to PRO,” Fullerton reported after consulting with Willard Presley at the GUIDO console.

This PROCEED told the PINGS to accept the gravity alignment and began the star alignment sequence with a NOUN 70 request for a star number, in this case star number 52 (Dubhe). PROCEED to NOUN 79 gave the cursor and spiral angles in the AOT for the designated Forward (2) AOT detent and a second PROCEED put us in a VERB 52 (cursor) or VERB 53 (spiral) flashing with NOUN 71 for marking. For a lunar surface alignment, Cernan turned the AOT’s Reticle Control Knob until the Y cross-hair touched Dubhe at which point he would enter the angle displayed in the reticle counter into the VERB 52 register of NOUN 71. Then he moved the reticle until the spiral touched Dubhe and entered that reticle angle into the VERB 53 register. After four such marks on Dubhe, Cernan hit PROCEED to get out of NOUN 71 and go to NOUN 05 for the calculated Angular Difference relative the old platform alignment.

About this time, I contacted Mission Control about communications. “Okay, Gordy. I had the angles matched on the Steerable High-gain Antenna and went to SLEW, and it [the signal strength] held for a few seconds and then dropped off.”

“Okay. It looks pretty good. You might try to peak it up just a little more.”

“No,” I said when Fullerton did not understand that the Steerable Antenna had lost lock, “we’re on an Omni[-directional antenna] now.”

“Rog.”

“I’ll try the Steerable one more time here. …Okay. We’re on the Steerable, and I’m not going to touch it…It’s [on] STEERABLE and it’s [on] SLEW, and I got 3.8 [carrier signal strength].

“Okay. That looks good to us, Jack. …Jack, we’d like you to verify the tape recorder, OFF.”

“Yeah, that’s verified, Gordy. …Gordy, how does the fuel vent look to you?”

“Okay. Looks like 8 (psi) to us. You can go ahead and close it (the vent).”

After about five minutes, Cernan called Mission control concerning his work with the P57. “Gordy, I guess I’m puzzled on that one. I had the right star. You see anything we did wrong?”

“Stand by. We’re checking. …Gene, our only guess is that you might have loaded NOUN 88 [star parameters] wrong. We’d like you to start over, and we’ll watch you real close again.”

“Gordy. Listen, I think we know what we did. We loaded Spiral for Cursor, and Cursor for Spiral. How would it be if we went through the P57 again and…I guess we got to do it all over. Those old numbers are no good anymore.” Cernan had mixed up the VERB 52 and VERB 53 entries.

“Okay.”

“I’m sure that’s what we did. We loaded Cursor for Spiral, and Spiral for Cursor.” I am not sure why Cernan kept saying “we”. Normally I would have helped him by running the computer during a P52 or P57 alignment, in this case, I had been working on other things during this P57 alignment.

“Okay. And it’s our fault, too. We should have watched that. …Jack, this is Houston. We do have the pre-PDI AGS cal[ibration]numbers. You won’t need to read them to us.”

“Okay.” I had been going through recording various AGS alignment data, consisting of Addresses for Landing Azimuth Angle (047, 053) and x, y and z Gyro Drift Component Coefficients (544, 545, 546). A calibration of the Gyro and Accelerometers followed with an entry of +60000 in Address 400 and entry of the various ascent target parameters related to our landing site (224, 226, 662, 673). I then monitored Address 400 over the next five minutes until it changed to 00000, indicating that the calibration was complete. At that point, I recorded the new Gyro Drift Component Coefficients displayed in Addresses 544, 545, and 546. If these values had changed more the 2.0 degrees per hour, the AGS would have been considered unusable. In this case, the change had not even come close to this limit.

“Gordy, you going to want a recycle on this gravity measurement? I doubt if it the [PINGS] will need it.”

“Stand by…No…no recycle necessary this time through.

“Okay.”

“Gordy, ED Batts are 37.2,” I reported.

“Gordy, let me comment about the handling of the bird. After you once fly it [the LM] around in orbit a little bit, you get accustomed to the thrusters, and it came back to me quite a bit from [Apollo] 10, anyway. And you get a feel for acceleration and deceleration as well as the attitude-hold capability. And, really, the response, even with a heavy descent stage near the surface, is phenomenal. Responded exactly in the direction I wanted, held attitude very good. And, let me tell you, the LLTV [Lunar Landing Training Vehicle] played no small part in this landing as far as I’m concerned.” As an aviator myself, I can understand Cernan’s desire to debrief his piloting of the Challenger; but some of his prolonged statements were eating into our productive time on the Moon.

“Roger, Gene,” Fullerton replied.

[In December 2008, I helped stimulate the scheduling of a day-long discussion on lunar landing training held by the Constellation Program’s Altair Lunar Lander Project Office. The lead participants in this discussion of the experiences and opinions of Apollo Commanders consisted of Neil Armstrong, Gene Cernan, and John Young. Dave Scott (Apollo 15 Commander) provided written comments as well. Pete Conrad and Alan Shepard, Commanders of Apollo 12 and Apollo 14, respectively, were deceased. The main question asked of the three Commanders at this meeting was, “Does lunar landing training need to include a single pilot active training craft comparable to the Lunar Landing Training Vehicle (LLTV) used for Apollo.” As a Lunar Module Pilot, I acted as a more-or-less objective commentator on what the other three said.

At this meeting, Cernan stated emphatically that he “tuned out Jack’s read-out of data from the computer” as he flew toward a landing. This incredible statement probably came from the macho fighter pilot side of his memory, as it just could not be true in reality. In fact, Neil Armstrong’s comments following Cernan’s contradicted the latter on this point.[11] In the relevant portion of his book, “The Last Man on the Moon,” Cernan also comes close to saying that landing on the Moon required only his skill and daring but still includes a number of relevant quotes of the altitude and velocity data provided verbally from several thousand feet altitude to touchdown and which, by implication, he relied on to make the landing.[12] In reality, a shared approach to flying the Lunar Module, with the Commander clearly having the final responsibility, had been developed over many years by extensive interactions between guidance and navigation equipment and software designers as well as flight controllers and astronauts.[13] Critical analysis and confirmation of landing techniques came largely during Flight Operations Planning Meetings, chaired by Howard W. “Bill” Tindall.[14] Commanders and Lunar Module Pilots then worked out the details of information transfer as required by different phases of the landing sequence and as needed to meet the individual preferences of Commanders. The refinement of this interaction between Commanders and LMPs went on from Apollo 11 through the 15 months Cernan and I had trained together in Lunar Module simulators for Apollo 17.

A number of unique factors about the lunar surface and the design of the guidance and navigation system required that the Apollo Commanders use the information provided verbally by the Lunar Module Pilot. First, no familiar visual landing references relative to actual size exist out the window by which altitude and rate of descent can be judged – landing radar gave us these two critical parameters through the computer display that the LMP monitored and, in turn, gave verbally to the Commander. Second, in the last 100 feet or so, dust streaming away from the descent engine nozzle gives a false impression of flying backward and, again, the landing radar provided actual forward and backward and sideways velocities through the PNGS computer display. Commanders generally wanted one or two feet per second forward velocity at touchdown and could only get confirmation of this from the LMP without taking their eyes away from the landing scene. And third, the Lunar Module’s windows had no heads-up display of information needed for landing, and all Commanders soon learned that looking into the cabin for that information from instruments on the near-window panel raised the risks to unacceptable levels. In fact, the only flight information available to the Commander in his field of view consisted of an etched grid display on the inside and outside of his window called the Landing Point Designator. After pitch over at 8,000 feet, coordinates displayed by the computer, and given verbally to the Commander by the Lunar Module Pilot, allowed the Commander to determine the point ahead on the surface where a hands off, automatic landing would occur. Then, if desired, the Commander could “re-designate” the computer’s landing point by “clicking” his right hand controller forward or back or right or left so that the computer’s landing point determination coincided with the planned landing location or one deemed best by the Commander.[15]

So, in the final analysis, the Apollo Commanders depended on location, altitude, altitude rate, and forward and lateral velocity information given verbally by the Lunar Module Pilot, to make a safe landing. In the future, this information might well be provided by a heads up display in the Commander’s window with a back-up display in the Pilot’s window, but that was not available in the Lunar Module. The inherent difficulties of lunar landings, however, will not change and almost certainly will benefit from two pilots working together as they did in Apollo.]

Cernan stayed quiet for a few minutes while he redid the P57 alignment. “Okay. NOUN 22 again. I’ll go ahead and torque them.” Cernan means that he will tell the PINGS to realign the platform based on the new information once Mission Control agrees.

“Okay. Go ahead,” Fullerton replied after checking with the GUIDO console and who were watching our telemetry.

After a redo the star sightings, Cernan said, “Okay, Gordy. It’s a little better.”

“Rog. Looks good.”

“Okay, there’s NOUN 93 [gyro torquing angles].”

“Okay. Torque it.”

With the new alignment in the PINGS, I entered Address 400+30000 in the AGS so that its strapped down gyros would be aligned with the PINGS before power-down. I also entered Address 413+10000 in order to store the Challenger’s azimuth in the AGS. The AGS now was ready for any emergency liftoff that might be required over the next three days.

Challenger, Houston. We’re standing by for the [PINGS computer memory] dumps.”

“Jack, verify that TELEMETRY is HI.”

“Verified.”

“Okay, Gordy…Coming at you. Mark it. It’s on the way,” Cernan said as he entered VERB 74 to initiate the 42-second E-Memory dump.

Preparations for Exploration

Four days and eighteen hours since leaving the Kennedy Space Center, Apollo 17’s crew began to configure Challenger’s cabin for a three-day stay in the valley of Taurus-Littrow. We never received a formal “STAY” authority from Mission Control; however, the continued work through the Lunar Surface Checklist made it clear that we would begin the preparations for a full three days of exploration.

At this point, we are about thirty minutes behind the planned timeline. Cernan, however, continued to relive the landing and touchdown.

“Gordy, one other thing about the landing. I saw the [CONTACT] light, I think. And I heard Jack call it – the CONTACT light. I think I waited about a second and hit the [ENGINE] STOP button. She shut down immediately. And, of course, you could feel the fall. I don’t really feel we fell that much, but it was quite a change in acceleration at that point.”

“Roger, Gene.”

“And I guess I had, from what I would guess, a foot or two per second forward speed on that one.” Of course, I had told him that based on the Radar data in the PINGS.

“Okay. Sounds good.”

“And let me know when I can have the computer, please.”

“Okay. It’s your computer. …And I’m standing by with [IMU] parking angles when you’re ready to load them [in the computer].” These angles would position the Inertial Measurement Unit (IMU) of the PINGS in its least stressful passive position for the three days it would be powered down.

“Okay. We’ll be ready in a second.”

“Go ahead with the angles,” I called when I had a pen in hand.

“Okay. These are the IMU parking angles. Plus 295.86 [for X]. …I see you (Cernan) loading the [Rendezvous] Radar [parking angles],” Fullerton interrupted himself. “Do you just want to load these [IMU numbers] or write them down?”

“Go ahead. I’m writing,” I answered.

“Okay. Y will be plus all zeros. And [Z will be] plus 084.14. Over.”

“Okay. NOUN 20 will be plus 295.86, plus all zeros, plus 084.14.”

“That’s correct.”

“Okay, Houston. I’m going to power down the AGS, if you’re willing.”

“Not yet, Jack. We’d like you to read out 047 and 053 to us.” These Addresses gave the sine and cosine of Landing Azimuth Angle, respectively.

“Okay. You want the new ones?” These registers in the AGS had been changed by my just completed AGS realignment to the PINGS.

Cernan, not paying attention to what I had asked Fullerton, interjected with, “Okay, Gordy. If you’re happy with NOUN 22, I’ll Enter them.”

“We’re happy.” This quick response meant that Thorson at LM CONTROL had given Fullerton thumbs up from across the Control Room, satisfied with the results of Cernan’s second try at a P57 alignment of the PINGS.

“Okay. And it just dawned on me. I’m sorry about the zero on the NOUN 69.” This apology caused me to laugh for some reason. Cernan had initially miss-entered the Landing Site Correction numbers for downrange, out of plane, and altitude Mission Control had given us during Powered Descent.

“That’s okay. You’re forgiven.”

“I appreciate that.”

Meanwhile, I had called up AGS Registers 047 and 053 for Thorson at LM CONTROL, watching over both the PINGS and AGS by way of telemetry.

“Okay, Jack. We got 047 and 053.”

“Okay. Am I GO to pull the [AGS Circuit] Breaker?”

Breaking in again after entering VERB 41, NOUN 20 to set the IMU parking angles Fullerton had given me, Cernan asked, “Jack, give me those angles you just copied down.”

“NOUN 20 will be X plus 295.86, Y plus all zeros, Z plus 084.14.”

Cernan then verified those angles had been accepted with a VERB 16, NOUN 20 entry and asked, “Okay. Are you happy with NOUN 20?”

“Okay. We’re happy with NOUN 20, and you’re clear to power down the AGS.”

“Okay,” I acknowledged. Cernan also went to P06 on the DISKEY, the program that powered down the PINGS.

“Gordy, the breakers are coming OPEN on [Checklist pages] 1-4 and 1-5.” This reconfiguration of the two circuit breaker panels began the full power down of the Challenger.

“Roger.”

“Gordo, we’re on [page] 1-6,” Cernan reported.

“Okay. Thank you.” This began about ten minutes of setting three pages of switch positions that reduced power consumption minimum required for our stay on the Moon. At the same time, we set switches in the positions necessary for any emergency departure should that become necessary. ECS valves and communications switches were configured in preparation for beginning to work with the EVA Preparation Checklist as soon as we had our first meal on the lunar surface.

“Okay, Houston,” I finally called. “We’re at the bottom of [page] 1-8, and I’m standing by for your lift-off times.” These times represented when we would have a normal Ascent and Rendezvous with Evans should we lose communications and some degrading condition in the Challenger required our departure over the up-coming 12 hours. I pulled out the Data Card Book, opened it to the pre-prepared page, and began to copy.

“Okay, Jack. Lift-off time for rev 15 is 116:55:51; 16 is 118:54:28; 120:53:04; 122:51:40; 124:50:17; 126:48:53. Over.”

“Okay. Starting with rev 15, 116:55:51; 118:54:28; 120:53:04; 122:51:40; 124:50:17; 126:48:53.”

“That’s a good read-back.”

After we stowed the armrests under the hand controllers to a vertical position to get them out of the way, Cernan reported, Gordo, the PLSS is against the hatch, and we’re installing the BRA.”

“Roger on that.” PLSS stands for Portable Live Support System (pronounced “pliss), in this case, mine had been stowed on the floor between us for launch and landing. BRA was the politically incorrect name we gave to the two large pouches of loose webbing that we temporarily hung across the front of the cabin. The BRA gave us a place to put helmets, gloves, and other loose items until they were needed as we prepared for the first EVA.

Challenger, Houston. We’ve got three questions for you to help pin down your exact position, any time it’s convenient. Maybe when you’re taking the out-the-window pictures. Over.”

“Okay, Gordo,” Cernan responded. “I think we can give it to you. Why don’t you wait? We’re just getting the mag[azine] bag out and jett[ison] bags out from behind the engine cover here, to give you an idea where we are[(in the checklist].”

“Okay. No hurry at all.” The Science Back Room and the traverse planners wanted very much to know exactly where we landed even though it would make little difference in our actual activities. I am sure the media also were asking the same question of Public Affairs. Answering it, however, would continue to use up some valuable time, and we landed close enough to known features that implementing our exploration plans should not be a problem. Later analysis of photographs showed that Cernan had landed us about 100 m north of Poppie and that for the time being he was confusing that crater with the western-most of the three craters that make up Trident (Fig. 9.11).

“Okay, Gene, lets stow the LEVA Bags on the floor – one to your left and one over here to my right. …Now, the two lens brushes go in the Purse.” The Purse was a bag that we hung on the front of the DISKEY to have a place for the temporary retention of small items.

“Got them. …Here’s your LEVA (Lunar Extravehicular Visor Assembly).”

“Now, I need to change the 16mm magazine from O to P with O going into the ISA (Interim Stowage Assembly) top pocket. Can you get that ISA from behind the Engine cover? But leave it on the cover. …While you are back there, leave our backup EVA gloves that are in the ISA behind the Engine Cover…and put the spare LCGs (Liquid Cooled Garments) in the ISA big pocket.”

“That’s done.”

“Next, we need the RCUs (PLSS Remote Control Units) transferred to the LGC bag until we are ready to prep for EVA-1. …And we need the ISA and the hammocks (Sleep Restraints) put above the shelf where the RCUs were stowed.

“Okay.”

“You can come back to the front now and deploy the EVA Antenna.” The handle for erecting the VHF antenna projected down from the cabin ceiling just above the Commander’s station. This antenna would receive our transmissions during activities in the vicinity of Challenger and before we began to transmit directly to Earth through the Rover’s S-band system.

“Wait! If you can reach the bag of film magazines behind the Engine Cover, I will put it out of the way over here on the DEDA. …Thanks. …Now, we need to move four of the jettison bags to the stowage compartment next to you and hang one other on your handhold.”

“That makes sense.” In fact, these were checklist procedures we had gone through many times in the simulators. The procedures were the product of hundreds of hours of trial and error work by the support team and ourselves so that EVA preparation would go as efficiently as possible.

“The 500mm lens and its camera and ring sight go in the Purse… and the Constant Wear Garments go into the camera box. …The Camera Bag goes in the jettison bag.”

“Got them.”

“Finally, and then we can eat, let’s disconnect all the armrests except your right hand one, and put them in the jettison bag.”

With this preparatory work done, Cernan tried again to locate our landing point relative to named craters. After rambling on with bad information for a minute or so, Cernan said, “That’s probably as close as the Navy Captain can ever guess where he is anyway.”

“Rog,” Air Force pilot Fullerton responded with a laugh.

“Okay, Houston,” I reported, “we’re just starting our eat period. Sorry to be a little behind [by about 20 minutes]. PRD readings are [CDR] 17037 and LMP is 24117.” PRD stands for Personal Radiation Dosimeter that we wore, except during the three EVAs, to measure our accumulated space radiation dose.

As Cernan unlatched the food compartment, the pressure from the expanded food bags caused much of our food for the day to explode into the cabin. We sorted the first meal bags out and re-stowed the rest.

“Okay, Jack. We got that. (Long Pause) Would you verify you’re Biomed [sensors are in the]…RIGHT [switch position]?”

“Yeah, that’s verified [RIGHT]. How does it look?”

“Looks good.” Fullerton looked back at Dr. Zieglschmid on the MOCR’s Flight SURGEON’s Console for a visual OK.

“Okay, Gordy. We’re starting to cut into a little lunch here and, if you’ve got any questions, why don’t you come up with them now?”

“Okay. We’re wondering if you can give us estimate of the angular position – clock position – of Rudolph. And can you line up Rudolph with a horizontal feature out beyond it? …I should say ‘horizon feature’ – out in the distance – not ‘horizontal’.”

“Okay. I thought Rudolph was right out there at 3 o’clock. Jack’s looking at it and he said, ‘yes’, that is Rudolph right at 3 o’clock out his right-hand window.”

“Okay.”

“I don’t know if it’ll mean anything to you, but (on) the shadow of the LM, the rendezvous radar antenna is pointing about one-third of the way down from the peak of Family [Mountain] And that, I know, is pretty gross [as an estimate]. And, Gordo, I must be right here abeam of Trident 1. The only reason I hesitate is that I’m so close; but it’s probably, well I guess it’s close to 100 meters – 80 meters anyway – to where the rim of Trident 1 falls off. And I am abeam of the center of Trident 1, and that’s the only possible thing it could be. And that would put Poppie just about where I expected it to be.”

“Okay. …We just want to confirm. You’re referring to Trident 1 as the easternmost part of Trident, is that right?”

“No, sir, Gordo. It’s always been the westernmost part of Trident. The [planned] landing site was on a line between Trident 1 and Rudolph and judging from what Jack’s got out his right-hand window and what I got on my left-hand window we’re right there, except possibly a skosh further south on that line.”

“Okay, understand.”

“And the target point that was in the PINGS was right up where we all had expected it to be, about halfway between here and what we’re calling the rim of Camelot. We can’t see into Camelot; we can just see the rim of it. It’s several, oh, at least 2 to 300 meters up there, I expect.” Actually the rim of Camelot lies about 800m due west of our position, illustrating the problem of underestimating distances on the Moon due to the lack of atmosphere and familiar size references.”

“Okay, what o’clock position is…the nearest part of the rim of Camelot? Or maybe…it’s better to define the south rim. Can you see the south rim of it? “

“12 o’clock [for the near rim]…Yeah, Gordy, [we can see the south rim] but it blends in so well; all we’re seeing is an undulating high [slope] as the rim. And to the best of my knowledge, we’ve got…the east rim right at 12 o’clock.”

At this point, I stopped eating and added, “Hey, Gordy, right at 12 o’clock, also, is a boulder that’s at least 3 meters (high) and maybe 5, and I wouldn’t be a bit surprised if you can find it (in the overhead photography). It’s on a line between us and the intersection of the South Massif and the [West] Family Mountain horizon. Just slightly left of that line or south of that line. And that boulder ought to show up on your best photography…” Then, using my knowledge of the about 30m length of the Challenger’s shadow, I added, “And that boulder’s at least 200 meters away.”

Cernan and Fullerton then got back on the question of where we were relative to Trident and Poppie. The real answer would come later. In fact, a few minutes later, Evans said to Mission Control, “Hey, I think I can see a light spot down there on the landing site where they might have blown off some of that halo stuff. It’s between Sherlock and Camelot.” He gave map coordinates that put us on the north rim of Poppie and confirmed this on later orbits. For some reason, neither the Science Support Room nor Public Affairs picked up on this accurate placement of our landing point.

“Okay. That’s all the questions now. Enjoy your dinner.”

“Houston,” I reported. “I have calmed down, but be advised that our dinner is corn chowder.” This comment refers back to the corn chowder that earlier had created bad intestinal gas during the flight to the Moon.

“Roger.”

“He went to Captain’s Mast for eating that the other day,” Cernan commented.

In addition to corn chowder, my first meal on the Moon consisted of frankfurters, white bread, chocolate pudding, and re-hydrated orange drink, tea and lemonade. Cernan had selected the same menu plus some partially dried apricots.

“Gordy…Houston, Seventeen. Houston, how do you read Challenger – or whoever we are?” While I ate, I took the opportunity to look at the geological features near the landing point (Figs. 9.1 to 9.8).

“Whoever you are”, you’re loud and clear.”

“I took the [Leitz 10×10] monocular,” I began, chewing on some extra bacon squares, “and looked at some large boulders at our 12 o’clock position. They’re probably on the order of a half-meter to 2 meters, buried but without strong filleting. …And most of them that I could see had the same mottled light-gray and medium-gray texture, and it looked like there’s a lineation in it. And whatever the mottling is, it’s on a grain size or fragment size of a few centimeters, and it looks as if it’s very uniform in that mottling; that is, there’s one fragment size.”

“Okay,” responded Fullerton. This mottling turned out to be because of the disruption of a thin, brownish, glassy patina by solar wind sputtering and micro-meteor impacts. Both, in turn, produce a high temperature plasma that condenses as the aluminum-silicate glass forming most of the patina. The brown color of the patina, which darkens with age, comes from extremely small (“nanophase”) particles of metallic iron embedded in the glass. Reduction of iron in silicate minerals by sputtering and at the point of mirco-meteor impact produces the metallic iron.[16]

“There are a few [boulders] near one crater out at 12 o’clock),” I continued, “[that are] dark-gray rock that may be glass coated. Matter-of-fact, one of them looks like it’s right at the rim [of that crater] and might have been part of a projectile that made the crater.”

“Roger,” replied Fullerton. A secondary crater, that is, one made by a piece of ejecta from another impact, are usually irregular in shape and may have the boulder that made the crater inside the crater or at its rim. The apparent glass on the boulder I was looking at suggested that it had been thrown into the valley by an impact some distance away.

“The large boulder that I mentioned that’s several meters in diameter; …I’m not even sure it’s a boulder. It does have a well-developed fillet [of soil at its base]. It’s highly fractured. It looks like the fractures generally are north-south. At least we can’t see end-on into the fractures. And it’s too far away to be sure, but it looks like it’s mottled also, although there did appear in the monocular to be a more heterogeneous mottling. It might be a breccia (rock composed of fragments of other rocks).” This boulder, later known as Geophone Rock, turned out not to be a breccia but rather a basalt lava boulder with small, smooth-walled holes or vesicules that contained a gas when the rock was molten. …That boulder ought to be very close to the ALSEP site.” I eventually selected an ALSEP deployment area about 40m north of this boulder.

“Roger.”

Cernan then jumped in with some additional comments about what we could see from the Challenger’s windows. “Gordo, in reference to these boulders [Jack referred to], everywhere I can see out of my left window and out ahead of me – in referring [particularly] to that boulder Jack’s talking about which is just a little bit on my side at 12 o’clock – it appears that the dark mantle has filleted and, for the most part, has covered part of, or is up on top of some of, the crevices and the crannies in the boulders themselves, with the exception of – well, I’ll take that back – even the very small ones.”

[Cernan’s observations here and, for the most part, throughout our stay in the valley illustrate the intensive nature and success of the simulation-based field geological training program I proposed to Alan Shepherd in 1968. This training began with the enthusiastic acceptance of Jim Lovell and his Apollo 13 crew, but with some feedback into Apollo 12.[17] (Ironically, Cernan’s training as Back-up Commander of Apollo 14 was the least intensive of the Apollo 13 through 16 missions, due to a lack of interest, ironically by Shepherd, Commander of Apollo 14. On the other hand, Cernan was a quick learner during Apollo 17 training.) Had most of the professional pilots who landed on the Moon, and who observed it from lunar orbit, not responded well to this training, the scientific return from all the lunar missions would have been far less than the extraordinary scientific benefits that still flow from Apollo exploration.]

At this point in the mission, the field geology team as well as the crew had the working hypothesis that the dark mantle, to which Cernan referred, consisted of young volcanic deposits, probably explosively generated volcanic ash and debris or what geologists call ”pyroclastics”. Cernan’s exposure to the filleting effects of recent pyroclastic eruptions during training on the island of Hawaii probably influenced his description of what he saw from the window. Of course, the spray from nearby meteor impacts and impact erosion of the host boulder constitute other sources of fillet material on the Moon as well as the possible effects of regolith entrained by the Descent Engine exhaust close to the landing point.

“I’d say (that) boulders of the size Jack’s talking about – anywhere from 1 to 2 to 3 meters – that are visible through the surface, [make up] a very small percentage [of the surface], but when you look at them at our level, it looks like they are quite populous. I’d say there are maybe about 25 of them in view between myself and where the horizon falls off down away from us towards the South Massif. The area back [southeast] towards Station 1, at least the other side of Trident, looks like it’s more heavily strewn with some of these filleted and partially-mantled large fragments.”

“Roger, Gene.” Later discoveries at Shorty Crater[18] and the analysis of samples of regolith show that dark pyroclastic material, indeed, once blanketed the region; but this dark material had been largely mixed into the regolith over the 3.5 billion years since the last eruptions occurred. Any filleting was impact generated; but, of course, we did not know this at the time of our first view from Challenger’s windows.

Cernan continued: “To say that there is a boulder, as such, actually sitting on the surface, I really can’t find one, unless they’re around some of these very small and possibly younger craters. But I think for the most part everything is somewhat mantled.”

Okay,” responded Fullerton. Buried and partially buried boulders prevail as a normal characteristic of the regolith everywhere on the Moon. This results from the very low frequency of impacts with enough energy to excavate below the regolith and eject boulders on to the surface. Subsequent impacts that move only regolith, or break up ejected boulders over tens of millions of years, tend to bury or at lease significantly fillet those boulders exposed at the surface. Certainly, any boulder at the surface that had formed a depression around it when it landed at least would be partially buried as redistributed regolith gradually filled the depression.

I broke in at this point. “Gordy, I think maybe the predictions of a fairly thin regolith were good. I have a crater at about, oh, 130 feet (from the LM). It looks like it’s not more than a meter deep. …It’s very fresh, has a bright halo around it, and it’s very rocky in its interior and has some rocks that are at least 10 or 20 centimeters in diameter on the rim. It looks like it’s penetrated into some much rockier substrate than what we’re seeing on the surface. The surface [fragment population] itself looks like, oh, probably 15 percent fragments greater than half a centimeter [in average diameter].” This interpretation did not hold up when I examined the crater, directly. The fragments turned out to be impact compacted regolith (regolith breccia) like what we would see at Van Serg Crater.[19]

“Okay, Jack.”

“I don’t see any general size sorting,” I continued, meaning the fragment population appeared to have a random frequency of sizes. Actually, my statement about the lack of “any general size sorting” is misleading. A form of sorting in the regolith has taken place. As the impact commutation process takes place, it produces mature regolith in which the proportion of fine fragments increases with decreasing grain size down to a size of ~64 and then the proportion of fine fragments decreases from that size on down.[20] “I do have a crater out here that’s maybe a meter in diameter – fairly fresh, although not bright halo[ed] – that has not penetrated to blocky material. And it looks like that the saturation crater size is very small in the area we can see; that is, there don’t seem to be any old or very subdued craters. …Well, let me think about how to put that again. It’s obviously saturated with craters a few centimeters in diameter, but when you get bigger than that, there seems to be more of a clear [frequency] distribution rather than a saturation [crater size].”

“Okay,” Fullerton acknowledged. Crater saturation is reached at a crater size when each new crater destroys craters its own size.[21] As there are exponentially more small impactors than large, saturation occurs first at small diameters, moving over time to larger and large craters. Everything being equal, saturation crater size is a measure of the age of a specific surface; however, everything may not be equal, particularly over relatively small regions. The frequency of impacts may vary with time, ejected or eruptive material may bury or partially bury craters, seismic events may degrade craters, or some original materials may preserve craters better than others.

While we continued to eat, Cernan began a several minute long description of the view shown in Figs. 9.4 to 9.8. Eventually, Fullerton interrupted him, saying, “Challenger, Houston, over…We’re about 12 [or] 13 minutes behind the timeline for starting cabin preps. And [the] Backroom (Science Support Room) is enjoying your descriptions, but we think we’d rather you press on with the preps and get ready to get out for a really good view. Over.”

“Okay, Gordy. We’re doing this and eating too. We’re trying to do them both at the same time, and we are pressing. Just want to say one other thing about the [South] Massif. I can see a couple of places where very small craters have penetrated the Massif – craters maybe a meter or 2 in size, some [possibly] 5 meters – and there’s a lot of rock debris around them, which tends to [make me] believe that there is very little, if any, soft covering on that Massif.”

“Roger.” Cernan’s description shows the payoff of the many geology discussions on impact cratering we had during training. Here, Cernan probably describes craters on the steep, ~26° slopes of the South Massif from which most regolith apparently has been stripped by the debris avalanche that formed the Light Mantle – a further indication of an avalanche-based origin for that material.[22]

I took a moment from my eating to add some potential planning information for the third EVA. “Gordy, just a couple more words about the North Massif. It looks like a good distribution of boulder tracks [on its slopes]. Many of the boulders are accessible. The tracks can be traced up at least to mid-slope. That’s at my 3 o’clock position. And occasionally, at that mid-slope position, particularly northwest of Henson [Crater], you can see abundant boulders suggestive of outcrop. That’s something that we had missed seeing on the pre-mission photos. And [they, the boulder ledges, aren’t] as abundant as on the South Massif, but there are apparent ledge formers [there at] about mid-slope. …Okay, Gordy. There’s also a few very bright sparkles from the [near regolith] surface – not abundant, but a few.” I apparently picked up reflections from the abundant glass beads present in the valley regolith.

Challenger, Houston. I’m going to hand you over to the good Dr. [Robert] Parker here. Have a good trip outside there.”

“Gordy, thank you,” Cernan replied. “You do outstanding work and we sure do appreciate it, Babe.”

“My pleasure.”

*****

Completion of the first phase of human exploration of the Moon, as unfortunate as that end would be, constituted the primary goal of the Apollo 17 Mission to the valley of Taurus-Littrow. Apollo 11 and 12 achieved all the initial Cold War objectives of the United States. A lack of historical perspective by political leaders and the media, beginning in the late 1960s, had forced the limitation of post-Apollo 11 lunar explorations to just six additional missions[23], five of which would have successful landings.

The valley of Taurus-Littrow lies significantly north of the area explored by previous missions, being located 600 km north of Tranquillity Base. Most importantly for science, the valley provided the then most accessible three-dimensional exposure of many aspects of lunar geology. Our observations, orbital and geophysical sensing, sampling, and photography of the geology exposed in the valley would focus on gathering new knowledge and answering questions about the origin and evolution of the Moon raised by previous field observations and photographic and sample analyses.

All of lunar exploration, that of Apollo and that in the future, has its primary scientific justification in gaining an understanding of the early history of the Earth and other terrestrial planets. On Earth, that history remains largely unavailable due to the intense geological activity that has taken place over the last 3.8 billion years. Internal geological forces on the Moon, on the other hand, have been largely quiescent during that immense expanse of time. The Moon, therefore, provides earth scientists with a record of the environment of the inner Solar System during the first 800 million years of Earth history, a period known as the “Hadean Eon.” These 800 million years included the time when the molecular precursors to life developed on Earth and possibly on Mars.[24] By the time Apollo 17 arrived in Taurus-Littrow, we knew this period on Earth had been extraordinarily violent – impact basins and craters had formed on all four terrestrial planets as well as the Moon. Even with the remarkable results of Apollo investigations, a great deal more information remains to be gathered before the all the important details of Earth’s early history will be revealed.

*****

The primary objectives of the first period of ExtraVehicular Activity (EVA-1) for Apollo 17 consisted of raising the American Flag at a sixth location on the Moon, activating the Lunar Roving Vehicle (LRV), deploying the many components of the Extended Apollo Lunar Scientific Experiment Package (EALSEP), but always referred to as the “ALSEP”)[25], and exploration of as much of the floor of the valley as time permits.

With the ALSEP deployed, we would get down to the real business of exploration. Plans for that exploration rested on the then status of lunar science and its relation to the geological features and interpreted history of the region in and around Taurus-Littrow. Apollo 15 and Lunar Orbiter imagery (Fig. 9.12a,b) formed the foundation of photo-geologic mapping related to Taurus-Littrow. We also depended on the extrapolation of the results of observations and sample analysis coming from five previous Apollo missions.

Fig. 9.12a. A part of the Apollo 15 panorama camera image P-9290 of Tauris-Littrow Valley and surrounding regions that provided the basis for planning for exploration by Apollo 17. The frame is from orbit 16 when the CSM was at 106 km altitude and the solar elevation was 39°; west is at top. (NASA photo AS15-P-9290).

Fig. 9.12b. Part of an earlier Lunar Orbiter IV frame showing the valley. The photo was taken in May, 1967 at an altitude of 2722 km, more than 25 times higher than the Apollo 15 CSM. The sun angle was 66°; west is at top. (NASA photo LO-IV-078-H3).

[By December of 1972, the lunar science community thought it had developed a general understanding of the broad history of the Moon except for how it actually originated as a planet-like body orbiting the Earth and what was the absolute timing of the major basin forming impact events that had disrupted the lunar crust prior to about 3.7 billion years ago. 45 years later, far more analysis and thought has significantly modified that original understanding and added many more questions; however, the planning for exploration of Apollo 17 was necessarily based on what was then thought to be either true or uncertain.

Most in the lunar science community agreed that radiometric dating of some Apollo 15 impact breccia samples showed those materials had cooled no earlier than about 3.85 billion years ago[26] and probably recorded the age of Imbrium, one of the youngest basin forming impact events; but other than that, only the relative sequence of basin formation had been determined by photo-geological mapping. That mapping showed that at least 50 major basins (>300 km in diameter) formed before Imbrium, but only one, Orientale, formed after Imbrium, Therefore, the questions of “When did the 50 or more major basins form?” and “Where did the Moon come from?” remained to be answered with direct relevance to the early history of the Earth. Many other more detailed questions about lunar history also existed and were integrated into the plan for exploration of Taurus-Littrow.

Lunar photo-geologic mapping relies heavily on the geological “law” of superposition, first articulated by Nicolas Steno in 1669,[27] that is, a distinct feature lying on top of another distinct feature is the younger of the two features. Such mapping had shown that the Serenitatis Basin is older than a Imbrium,[28] and we hoped to determine how much older by sampling the material that forms the 1600-2100 m high massif walls of the valley, presumed to be ejecta from the Serenitatis Basin. As the Serenitatis impact event created the valley of Taurus-Littrow after ejecta from that impact had been deposited,[29] it was possible that even older materials could be sampled at the base of these mountains.

In addition to dating the Serenitatis event, high expectations existed for obtaining samples in Taurus-Littrow that would provide additional insights into the nature of the lunar crust and expand our knowledge of lunar volcanism. In the case of lunar volcanism, it was thought that very young deposits of volcanic ash might be encountered. Few expectations had developed, however, for gaining new insights into the origin and very early history of the Moon, but surprises awaited us. (See the Introduction to Chapter 13 for more details on the status of lunar science prior to the mission of Apollo 17.)]

Preparation for Stepping on the Moon

Before we could begin to evaluate the accuracy of the geological history of Taurus-Littrow, and perhaps add additional insights into the evolution of the Moon and Earth, we had to prepare to exit the Challenger into the vacuum, heat, and dust of the lunar environment. This we began to do about four days and 19 hours after leaving Earth.

With dinner over, we began to stow all the loose items in the cabin that we would not use outside and get the two Utility Lights and their wires out of the way behind the AOT. Also, I set up the Sequence Camera to monitor activities outside the right hand window during the first part of EVA-1, setting the aperture at f8, shutter speed at 1/250 of a second, and a frame rate of 6 fps.

Bob, we’ll give you a call in a minute,” Cernan reported. “We just made a couple of suit adjustments.” We had put on our pressure suits about eight and a half hours earlier, prior to activating the Challenger. This had given us time to evaluate how they fit. It became clear that some minor increases in leg length would make them a little more comfortable because of a gain in spinal cord length after several days of exposure to weightlessness.

Okay. Copy that.” Our EVA CAPCOMM was Robert “Bob” Parker, one of the second group of scientist astronauts, selected in 1967. Although Bob was to be our lunar surface activity CAPCOM, he also had been assigned the role of “Stoney” at Launch Control (Chapters 4 and 5) and had regular duty as CAPCOM during our flight to the Moon. Prior to becoming an astronaut, Parker graduated from Amherst College, received his PhD from Caltech in astronomy, and ultimately became a professor of astronomy at the University of Wisconsin-Madison. He had a weird, sometimes cutting “Caltech” sense of humor that probably resembled my own more than I ever wanted to admit. It was testament to the perseverance, dedication and abilities of many of the scientist astronauts that they handled assignments like this as well or better than the pilot astronauts. Bob eventually flew as a Mission Specialist on STS-9 and STS-35 Space Shuttle flights.

Apollo 17, Houston.”

“Go ahead, Bob,” Cernan answered.

“Okay, Challenger; we’ve just lost about 16 dB (decibels) on your high-gain signal strength there. We’re wondering if you happened to hit the switch there, has it moved, or could you give us a check on it?”

“We’re nowhere near it. Stand by one.”

“And, Challenger, that should be a Pitch of 21 and a Yaw of minus 45 [on the S-Band Steerable Antenna].”

“Plus 21 and minus 45; Rog…Bob, [give Jack] about 2 minutes here.”

“Okay.”

“Bob, this is Jack. On that High Gain [antenna], I’m up close to 3.9 (signal strength) now, which is better than when we landed. Do you want me to do anything to it?”

“Stand by on that,” Parker said, looking over at Jack Knight, now manning the LM TELEMU console. With a thumbs-up from Knight, he came back with “…Leave it alone. It seems to have gone away, Jack. It may have been a ground problem. …Did you guys adjust it, Jack?”

“Yeah, Bob,” I said, thinking he asked if we were adjusting something about the suits. “We had to fix the drink bags and a couple other things.”

“No. Did you guys adjust the high-gain antenna?”

“No. I didn’t touch it.”

“Copy that.”

“Buddy SLSS’s in there?” I asked and then answered. “No. That’s over there.” The Buddy SLSS (Special Life Support System) consisted of a hose that we could attach between our suits that would allow both of us to use one PLSS if the other had failed.

“And, Challenger, we have you hot miked,” warned Parker.

“Huh?” I grunted. I may have been leaning against my Push-to-Talk switch on my oxygen hose.

“Gene, next is putting the 500 mm camera together,” I began again with the EVA Prep Checklist  “…Let’s see, …take the tape off the Hasselblad and its lens, attach the 500 mm lens and the ring sight, and install black and white magazine R. …Here’s mag R. It was in the LCG (Liquid Cooled Garment) compartment.” This telescopic lens and camera would be used largely to photograph inaccessible areas of the Massifs.

“Next, we load up the ETB (Equipment Transfer Bag). You ready?”

“Stand by…okay,” Cernan replied, as he repositioned himself in the cabin.

“First on the list comes the Cosmic Ray Experiment. It should already be in there.”

“It is.”

“Then the Buddy SLSS, …the 500 mm camera, …your 70 mm camera with color mag A…”

“Where are the film mags?” Cernan asked.

“All extra mags are over here in the Right Hand Stowage Compartment. …Here you go…mag A. …Next, we need a sample bag dispenser bracket for the camera, color mags B and C, black and white mags G and H,” I continued, handing him the necessary film magazines. “…Now we need the two lens brushes. They’re in the Purse. …Here’s the [25 feet of] duck tape from my Stowage Compartment; our ONE pair of scissors,” emphasizing “one” in reference to the pair of scissors we had left in the Command Module after Evans had lost track of his (Chapter 7). “I hope Ron is happy with our other pair. …Now we need the Rover Sun Compass, Map Holder, and LRV Checklist. …Can you reach them? They are in the Aft Flight Data File.”

“Got them.”

“ …And get the EVA-1 maps and Horizon Return Chart from the Forward Flight Data File along with the Map Ring. …After you get those into the ETB, you want to put the EVA-1 Preparation and Post Card where we can get to it?”

Challenger, Houston. Over.”

“Go ahead, Bob.”

“When you guys get to the top of page 2-5, and I assume you’re down still in (loading) the ETB from what your comments were on the hot mike there, when you get to the top of page 2-5, we’d like you to put both DEMAND REGs to EGRESS. Over.”

“Okay, Bob. Will do. We’ll give you a call as we go along.”

“Roger. Thank you.”

“Hey, Bob,” Cernan added, “while I’m thinking of it, we’re working with one pair of scissors down here. We’re going to take them out with us in the ETB. You might make a point of reminding us to bring them back.”

“I copy that. Never did find Ron’s, huh?”

“No, sir, and I couldn’t just leave him up there starving to death.”

“Roger on that.” Each of us had a pair of scissors that normally traveled with us, individually; but Ron lost his in America’s cabin on the trip out. Cernan and I kidded him unmercifully on the way out and back about losing his scissors in a very small spacecraft. More seriously, a number of items in the surface timeline on the surface were based on having two pairs of scissors. One pair could be in the cabin and the other pair left outside – largely as a contingency tool for cutting Duck Tape – and then not have a worry about remembering to bring a pair back after each EVA. We finally decided, generously, of course, to leave one pair with Ron so that he could eat. You needed the scissors to cut open the plastic food bags.

By the way, how’s he doing?” Cernan asked.

“Stand by…” “[Mattingly says] your buddy is doing great; and the [lunar radar] Sounder is also doing great, which is a surprise, I guess.” Navy Commander and test pilot, T. K. Mattingly, always Ken to me, was CAPCOM for Evans.

“I’m glad to hear that,” Cernan responded. “That [Sounder update] was no surprise, Bob. We wouldn’t have taken it if it wasn’t going to work.”

“I thought about that after I said it.” Parker had been closer to the technical uncertainties and testing of the Sounder than we had been. With his typical lack of political sensitivity, he admitted to his surprise.

“Bob, I just turned the Urine Line Heater, ON,” Cernan reported, after also closing the URINE LINE circuit breaker. The heater kept urine from freezing while it flowed to a holding tank in the Descent Stage. This and other reports before we went back on VOX for communications gave Mission Control a fix on where we were in the Checklist.

“Copy that.”

“And the physical status of the crew is excellent, by the way.”

“Beautiful. The [Flight] Surgeon’s happy.”

At this point, I attached the line for lowering the ETB to the surface to its handle and put this bag out of the way in the corner of my station in the cabin. This line has the archaic name of Lunar Equipment Conveyor (LEC) that harks back to Apollo 12 when Conrad and Bean thought they needed a conveyor and pulley system to get equipment to the surface. I clipped page 2-3 of the Lunar Surface Checklist over the AOT. This one page of procedures provided a transition to a one-man EVA in case of a PLSS failure, something we both never thought about again.

“Say, Bob, we’re at the top of Page 2-5, and I forgot what it was you wanted me to do up there.”

“We’d like you to have DEMAND REGs, both of them, go to EGRESS, please.” This step somehow had been left out of the Lunar Surface Checklist, but had been picked up by the team supporting LM CONTROL. These pressure regulators had been placed in the CABIN position prior to Powered Descent Initiation and left there until this point.

“Yes, sir,” Cernan said, and I changed the position of PRESSURE REGS A and B on the panel behind me. “Okay, they’re EGRESS now.”

“Okay, thank you.”

“This will be fun, Gene. We get to empty our urine bags. Here comes the Urine Dump Line – you first.” The Urine Line could be attached to a port in the right leg of the suit. With the cabin pressure higher than the line pressure, the Urine Collection [and] Transfer Assembly (UTCA) could be drained. Afterwards, the suit port was capped to keep it clean during the EVA.

“My turn. …Not very satisfying, huh? Don’t forget to turn the Urine Heater OFF and open the Urine Line Heater circuit breaker.”

“Okay, Bob, we’re in the middle of the first paragraph at 115:15 in the timeline.”

“Okay; copy that.”

“Okay, Jack, let me check your [suit] zippers and verify that they are locked shut. …You’re okay, now check mine.”

“You’re good. …My suit gas connection plugs are out and in the Purse, …and I have my suit Relief Valve in my pocket.”

“I’m the same.”

“Now you need to get your [EVA] boots, Purge Valve, and boot donning lanyard from the aft stowage area. …Give the valve and lanyard to me, and I will put them in the Purse. …Okay, now get out your OPS (Oxygen Purge System).”

“CDR’s OPS 5800 [psi],” Cernan reported.

“Okay; we copy 5800.” The OPS (Oxygen Purge System) consisted of 5.7 pounds of high-pressure oxygen that would be mounted on top of the PLSS before donning. A hose from the OPS 3.7 psi pressure regulator connected to one of the two oxygen inlet ports of the pressure suit. The other inlet port connected to the main, re-circulated PLSS oxygen supply. If a problem arose with the normal oxygen flow or cooling supplied by a PLSS, the OPS’s supply could be initiated by a cable actuator mounted on the side of the RCU (Remote Control Unit) that, in turn, would be attached to a bracket on the breast of the suit. If more than small amount of makeup oxygen were required, or if a significant leak appeared in the suit, or if the PLSS oxygen fan (pump) failed, the Purge Valve (flow regulator), in one of the two exhaust ports of the suit, could be activated to allow either 4 or 8 pounds per hour to flow through the suit. A red ball on a short cable attached to the Purge Valve’s redundant locking pin made it easy to find and grip without seeing it if purging were required. In the extreme case, the OPS would give about 30 minutes of oxygen and some cooling. Removing and using the other OPS from the second PLSS would provide another 30 minutes of oxygen. The combination of using the second OPS and the Buddy SLSS for cooling and/or makeup oxygen to get back to Challenger, and then using the first OPS to get into the cabin and hooked up to spacecraft oxygen and cooling, should cover any reasonably plausible single PLSS failure of oxygen supply and/or cooling.

“My turn,” I said and replaced Cernan in the aft part of the cabin. I un-stowed my boots and Purge Valve and stowed my IV (IntraVehicular) pressure gloves where my boots had been. Then, I un-stowed my OPS. While I did this, Cernan donned his EVA boots.

“LMP’s OPS is six thousand plus,” Cernan reported after I handed him my OPS.

“Copy that, Jack.”

“Okay, Hank.” Cernan was getting even for Parker’s misidentification of his voice. Our voices, after being clipped in the high and low frequencies by the communications system, resembled each other, particularly during short transmissions when context and speaking style were not evident.

“Both [OPS] regulators are reading slightly under 4.0 [psi],” I added. This pressure lay in the upper range of what was expected.

“Copy that, Challenger,” Parker said cautiously, probably not knowing who had spoken.

“Bob,” Cernan said. “The URINE LINE HEATER is OFF and the URINE LINE breaker is OPEN, and we are down to applying anti-fog [to the inside of the helmets].”

“Copy that, Challenger.”

Next, we put the maintenance kits for the suit in the Purse, for ready accessibility, and temporarily stowed the LEVAs, helmets and EVA gloves in an Interim Stowage bag to keep them out of the way. We both attached our watches and a mirror to the EVA gloves at this time. The wrist mirror will allow viewing of the outlets and inlets on the suit and the controls on the bottom of the RCU.

“Bob, the BRA (Bag Restraint Assembly) is stowed.” The BRA consisted of two mesh sections that we used for temporary stowage of the helmets.

“Copy that, Challenger.”

“We’re starting PLSS donning on the LMP, Cernan reported.”

“Roger. Copy that.”

“Gene, UNLOCK the Forward Hatch Handle before we start PLSS donning. It will be tough to get to, later.”

“…Got it.”

“Okay, I’ll read you though this,” Cernan said. “Set your PLSS on the mid-step below the Engine Cover.”

“Boy, that is certainly easier than in the LM mockup! One-sixth gravity is a wonder.”

“Okay, grab your OPS and check for any decay in OPS regulator pressure.”

“No decay.”

“Un-stow the OPS oxygen line and the antenna lead. …Attach the OPS to the top of the PLSS, including the antenna lead.”

“Stand by. … Okay, that’s done.”

“Verify the ice sublimator exhausts are clear.”

“They’re clear,” I said.

“Un-stow the straps and hoses and remove the electrical connector dust cap.”

“Done.”

“Verify that your AUXILIARY H2O, DIVERTER VALVE, OXYGEN AND PRIMARY H20 are all OFF.”

“All OFF.” These valve levers all were at the lower right front corner of my PLSS so that they could be accessed while the suit is pressurized.

“Connect battery cable.”

“Connected.”

“Now, verify these are locked: battery connection, …OPS antenna lead, …OPS hose.”

I responded positively to each item he called out.

“Okay, lets get this thing on you. …Have to get these suit hoses above the lower straps. …Now turn towards me…so I can attach the oxygen hoses to your suit. …I have re-verified that the AUX H20, DIVERTER, O2 AND PRIMARY H2O – have remained OFF. …Now, lets connect the upper straps to the suit breast plate.” While Cernan performed these tasks, I kept the PLSS resting on the mid-step of the Engine Cover.

“Now, let me attach your RCU to the breast plate and over the straps. …I’m verifying that the RCU’s PUMP and FAN switches are OFF and the communications MODE SELECT is O.”

“The LMP has got the RCU connected to the PLSS,” I reported to give Parker a check on where we were in the donning process. I had mis-spoken, as the RCU was actually attached to the suit breast plate, not the PLSS.

“Copy that, Jack.” The RCU or Remote Control Unit on my chest had the line connecting it to the PLSS under my left arm. The RCU also serves as a mounting point for the Hasselblad camera and the OPS purge actuator. The controls out of normal view, for which we needed the wrist mirror, consisted of an ON-OFF switch for the PLSS water pump, a MAIN-OFF-MOM talk switch, rotary knob for Mission Control audio volume control, and an independent rotary “blade” on top of the rotary knob for controlling audio volume between the two of us. The “MOM” position provided a “momentary,” that is, a backup “push-to-talk” capability. The top of the RCU showed alarm windows for oxygen, suit pressure, cooling water, carbon dioxide, and whether an OPS purge is needed; a suit pressure and oxygen quantity gage; and a communications MODE SELECT SWITCH.

In addition to the status information available to us, Bill Bates’ PLSS support team in Mission Control would be modeling consumption of oxygen, water and battery power based on the time the PLSS was in use combined with our biomedical telemetry showing heart rate and respiration. The control for the level of cooling desired had been placed within reach on the lower right corner of the PLSS.

“Bob,” Cernan reported.” I’m going to get on a PLSS, now.”

“Okay, Geno. Copy that,” Parker replied. I then took Cernan through the same procedures he had just gone through with me.

“Okay, Gene, set your PLSS on the mid-step, …and check your OPS for any decay in regulator pressure.”

“No decay.”

“Un-stow the OPS oxygen line and the antenna lead, …and ttach the OPS to the top of the PLSS, including the antenna lead.”

“Done.”

“Verify ice sublimator exhausts are clear,” I continued.

“Clear,”

“Un-stow the straps and hoses. …Remove the electrical connector dust cap.”

“Done.”

“Verify AUXILIARY H2O, DIVERTER VALVE, OXYGEN AND PRIMARY H20 are OFF.”

“OFF.”

“Connect battery cable.”

“Connected.”

“Now, verify these are locked: battery connection, …OPS antenna lead, …OPS hose.”

“All three, verified.”

“Turn a little toward me. …Suit hoses go above the lower straps. …Oxygen hoses attached, red to red and blue to blue. …And, AUX H20, DIVERTER, O2 AND PRIMARY H2O are OFF. …Upper PLSS straps to the suit breast plate.”

“Turn more toward me and I will attach your RCU to the breast plate, …There. And it is over the PLSS straps. …Your RCU’s PUMP and FAN switches are OFF. … MODE SELECT is O.”

“Bob. I’ve got my PLSS on,” Cernan said. Donning the two PLSSs took about 22 minutes. “We’re picking it up with verifying the power-down configuration on the upper, right-hand corner of the EVA prep checklist.”

Roger. Copy that.” We now transitioned from the bulky Lunar Surface Checklist to a single, stiff Cue Card for the remainder of the preparations for the first EVA. At this point, we were in the same configuration that would precede the second and third EVAs, so the same Cue Card would be used then.

“Circuit breakers are configured.” In this case, rather than looking at a panel diagram, the individual circuit breakers that should be open for the EVA had white dots on their ends.

“Houston copies.”

“Gene, you want to read this list of COMM switch positions to me?” These settings would set up the Challenger’s communications systems to receive our VHF EVA transmissions and relay them to Mission Control via S-Band.

“Okay, for audio you need S-BAND – T/R (transmit and receive).”

“Okay, S-BAND – T/R,”

“ICS (intercom) – T/R.”

“ICS – T/R

“RELAY – ON.”

“RELAY – ON.”

“MODE – VOX.”

“MODE –VOX.”

“VOX SENSITIVITY – MAX.”

“VOX SENSITIVITY – MAX.”

“VHF A – T/R and VHF B – RECEIVE.

“VHF A – T/R and VHF B – RECEIVE.

“For COMM you need VHF A TRANSMITTER – VOICE.

“VHF A to VOICE.”

“VHF A RECEIVER – ON.”

“VHF A RECEIVER is ON.”

“VHF B TRANSMITTER – OFF.

“B IS OFF.”

“VHF B RECEIVER – ON.”

“B is ON.”

“TELEMETRY BIOMED – OFF.”

“BIOMED is OFF.”

“SQUELCH for VHF A and B goes to noise threshold plus 1 and one half

“…Noise, plus 1 and a half.”

“RECORDER – ON.

“RECORDER – ON.”

“VHF ANTENNA – EVA

“VHF ANTENNA to EVA.”

“UPLINK SQUELCH – ENABLE.”

“ENABLED.”

“Now, read me mine,” Cernan asked, referring to the switches on his Comm panel.

“S-Band to T/R.”

“T/R.”

“ICS (Intercomm System) to T/R.”

“T/R.”

“Relay, OFF.”

“MODE to VOX.”

“I’m in VOX,” Cernan told me, then continued down the checklist without me. “VOX SENSITIVITY is MAX, [VHF] A is TRANSMIT/RECEIVE and B is RECEIVE. …You can open your [AUDIO] breaker and connect to the PLSS comm. …Houston, I guess you heard that.”

“That’s affirm. Loud and clear.”

“Just AUDIO breaker [, Jack]. Your AUDIO breaker, that’s all. Want some help with that?” With the PLSS on my back, I was having a hard time rotating so that I could see the Circuit Breaker panel next to my right shoulder.

“Yep. Do it while you’re facing that way. Just hang them (LM hoses) up. Best time to do it. All you’ve got [left to do] is water. …Okay, Bob. We’re getting Jack up on PLSS Comm, and we’ll be picking it up on the Comm check here on the left-hand column of the bottom sheet [of EVA Prep].”

“We’re following you,” interjected Parker.

“You’re on [PLSS Comm] and locked [, Jack],” Cernan said as I opened the AUDIO Circuit Breaker so I could safely connect to PLSS Comm. “Okay, and you got the cover [over the suit Comm port]? …[Now,] Your AUDIO breaker, CLOSED.

“CLOSED,” I replied.

“Okay, on your PLSS PTT (on the bottom of the RCU), go MAIN; that’s [to the] right. Okay. PLSS MODE A.”

“A,” I confirmed, and began to transmit to Mission Control with my VHF transmission being pick up by the Challenger’s EVA antenna and relayed to Earth via S-Band.

“Tone – ON; VENT FLAG – P,” Cernan said as he continute to read the Cue Card.

“Got a weak tone and a VENT FLAG – P,” I noted.

“Okay.” This tone and flag indicate that the pressure sensors work and that my suit is not yet pressurized.

“Got a good tone right now,” I said.

“PRESS FLAG – O; and O FLAG”

“O and…”

“[O2 Should be only] momentarily.”

“…O2 [FLAG] still there.”

“Okay, PLSS O2…”

“It’s (PLSS O2 FLAG) gone,” I interrupted.

“What’s your PLSS O2 pressure gauge?”

“The O2…”

“Give Houston a call and give it to them,” Cernan suggested.

“I’m reading 100 percent, Houston.”

“Roger, Jack. And we’re reading you slightly garbled but loud.

“Well, you’re loud and clear, Bob.”

“Okay, Jack. You got that, and I’m reading you. How you reading me?” Cernan asked.

“You’re loud and clear.”

“We will not un-stow the [PLSS/OPS] Antenna. You are a skosh garbled, but very readable…” Had I been unreadable, we would have temporarily un-stowed the PLSS antenna. “Okay. Stay where you are. I’m going to get mine. Okay. Audio breaker is…

“Open your AUDIO breaker, Gene, and then I will connect you to PLSS comm.”

“[Now,] your AUDIO breaker, is CLOSED,” I said, working Cernan through getting on PLSS communications. “And put both your VHF A and B to OFF,” “Okay, on your PLSS PTT go MAIN. “…Okay. PLSS MODE B.”

“B. Okay. I got a tone.”

“VENT FLAG – P.”

“I got a VENT FLAG – P.”

“Pressure FLAG and O2 [FLAG] momentarily.”

“Pressure flag, and I still got an O2 Flag.”

“Off with your tone.”

“The tone is gone. The O2 flag cleared.”

“PLSS O2 quantity?”

“…I’m reading 100 percent.”

“Okay.” Minimum quantity limit was 85%. I don’t remember what we would have done if one of our quantities was below that limit; possibly delayed the first EVA and gone through a recharge procedure as we would have to do after any EVA. Alternatively, to stay closer to the overall timeline, we might have transitioned to a one-man EVA and concentrated on deploying the ALSEP, only, leaving all exploration to the second and third EVA’s after both PLSSs had been recharged to full capacity.

Note crewman in Mode B,” Cernan read from the Checklist, “that’s me, cannot hear Houston. Houston, broadcasting in the blind; 100 percent [oxygen] on the CDR.”

“Roger, CDR. Houston reads you loud and clear.”

“I read you loud and clear, Gene. How me?”

“I’m reading you loud and clear.”

“Okay.” I acknowledged.”

“Give me a call again.”

Okay. How do you read, Gene? 1, 2, 3, 4, 5.”

“Give me again.”

“1, 2, 3, 4, 5.” Part of the problem here may be that Cernan also hears me through the air as we have not put our helmets on, yet.

“I think so. I can’t [be sure]. Okay. I’m reading you. Okay. “PLSS. LMP go B [mode].”

“Going B. (Pause) Try that. B…”

“Okay. How do you read me, Jack?”

“You’re loud and clear, and I got a tone.”

“Okay. Give me a short count once [more].”

“Counting. 1, 2, 3, 4, 5.,”

“You’re great.”

“Okay.”

“I had a tone, too. I still got a Pressure and a Vent Flag. …And, Houston, how do you read the LMP?”

“Roger, LMP. We read you loud and clear.”

“Okay, Bob. I’m reading you loud and clear, and he’s (me) not reading you in this mode. How me?”

“I read you loud and clear also, Gene.”

“Very, very, good. We’re both going AR, now. Let’s go.”

“Okay.”

“Ought to get a tone.”

“I didn’t, but my Vent Flag did clear.”

“There it is. Tone and a Vent Flag.”

“There’s my tone and Vent Flag,” I confirmed.

“Okay, Jack. The wheel is Houston and the blade is me. Hello there, Houston. How are you reading CDR?” The wheel-like adjustment on the RCU controlled our audio volume from Mission Control, while the blade-like adjustment on top of this rotary wheel controlled audio volume between the two of us.

“Read CDR loud and clear. And, for your information, your TM (telemetry) on the PLSSs looks good.”

“Okay. …How do you read, Houston? This is the LMP.”

“Houston reads LMP loud and clear now. You’re much clearer than you were before, Jack.”

“Very good.”

“Okay. Jack, we gave them our [oxygen] quantities already; so, SQUELCH, VHF B LMP, FULL DECREASE..”

“SQUELCH B is to FULL DECREASE, huh?” The unresolved mysteries of communications continued.

“That’s affirm.”

“Okay. It’s FULL DECREASE.”

“Okay. On [Panel] 16, leave that [Liquid Cooled Garment] PUMP breaker CLOSED.”

“Okay.” We had Challenger’s LCG pump off during the PLSS checkouts. Now, we would use LM cooling until we were ready to depressurize the cabin and vacuum sublimation of ice would become effective for PLSS cooling.

“Oh, that’s cold; but that’s good. Okay. On [Panel] 16, ECS, CABIN REPRESS – CLOSED.”

“Is that a verify?” I asked as it was already CLOSED.

“That’s a verify.”

“It’s CLOSED.” This would allow us to re-pressurize when we returned.

“SUIT FAN DELTA-P [

[CB] – OPEN.” The sensor powered through this circuit breaker regulates the pressure in the Suit Loop. “Fan” referred to two air pumps in the Suit Loop across which the Delta-P would be measured.

“DELTA-P [CB] is OPEN.”

“And SUIT FAN number 2 [CB] – OPEN. SUIT FAN number 1 circuit breaker remained CLOSED for the time being; however, this would test the redundant circulation system.

“[Number] 2’s OPEN.”

“Okay. And I’ve got Suit Fan number 2. There’s a MASTER ALARM. …Okay. And I heard it (Fan 2) run down. …I don’t see a… No, there’s not an ECS CAUTION [light] until that thing (Fan 2) runs down in about a minute or so. We’ll watch for that.” We are disconnecting from and powering down the cabin ECS system for both our absence and to minimize power use during that time. The Caution and Warning System would warn us that both fans were not operating and was expected.

“SUIT GAS DIVERTER – verify PULL-EGRESS.”

“DIVERTER is PULL-EGRESS.” Now, we were back to ECS valve changes that I had to make on the panel behind my LMP station. This action shut off the flow of oxygen into the cabin.

“CABIN GAS RETURN – verify EGRESS.”

“RETURN is EGRESS.” Now, cabin oxygen could no longer flow into the suit loop.”

“SUIT CIRCUIT RELIEF – verify AUTO.”

“RELIEF is AUTO.” This regulator prevented pressure in the suit loop from exceeding 4.3 psi by venting excess oxygen into the cabin.

“OPS CONNECT. You ready?” Cernan asked.

“Yep,” answered the astronaut-cowboy from Silver City.

“SUIT ISOLATION VALVE – ACTIVATE OVERRIDE.”

“OVERRIDE.” This cabin valve normally would be in the SUIT FLOW position. It includes a pressure sensor that, in the event of a significant pressure drop due to a suit circuit malfunction, would automatically put the valve in the SUIT DISCONNECT position. By manually disconnecting the suit from the suit circuit, we could remove Challenger’s inlet and outlet oxygen hoses and replace them with the OPS and PLSS hoses.

Disconnect your LM O2 hoses,” Cernan read.

“LM O2 hoses are disconnected.”

“And they’re stowed, right?”

“Right.” I had hung the two hoses behind my right shoulder.”

“Connect OPS O2 hose to PGA (suit), BLUE TO BLUE.” PGA stands for Pressure Garment Assembly, and we almost never referred to the suit in this way except in the Checklists. All input connections are colored blue and outlet connections are red.

“Where is it?” I said as I could not see the connection below my neck ring.

“It’s sticking right. …Turn around. No, that’s not right.”

“No, that’s the water [inlet].”

“Could you turn towards me a little bit?” Cernan asked. “Turn to the left. There you are, because I got to…Okay. Here it comes, right here. OPS hose under [your arm]. No, right here.”

“Here it is,” I declared having finally put my finger on the right inlet port.”

“Let me get it. I’ll get it under your electrical cable. …Because you’re going to want a Purge Valve [next to the hose] in a minute.” The Purge Valve would allow me to intentionally open a hole in the suit for OPS oxygen to flow through, if the PLSS circulation failed. “That is locked and the lock-lock [on the suit port]. …Move your arm.”

“This [part] is up [for access]. Did you do that?”

“I will in a second…Move your arm. I can’t see.”

“I’m trying to.” Maneuvering and lifting arms, even un-pressurized, was a challenge in these close quarters.

“We’re right here,” Cernan said, pointing to the Checklist. “Okay? And I’m going to Connect OPS hose to PGA BLUE TO BLUE, [and] retrieve Purge Valve [from the Purse]. Let me give you a Purge Valve, and I’ll pick that up, Jack. …The cockpit’s just as small as the mock-up [where we practiced]. …Here you are. You verify it’s (Purge Valve) in LOW [FLOW]. [Yes, that’s right,] LOW”

“It’s in LOW.”

“Slip to the right just a skosh.”

“Yeah; slipped it to the right just a skosh.”

“Oh, man, that’s easy.”

“Whee,” I exclaimed, laughing. “Pin’s installed.” This is a one inch-long Latching Pin on the other end of the short cable with the red ball. The pin kept the Purge Valve from being activated, unintentionally.

“And I might be an iceberg when I get out there, but it’s going to feel good.” We were pre-cooling our bodies, the water-cooled underwear (LCG), and the suit for 15 minutes or so we would have between disconnecting from LM cooling and having the cabin depressurized enough for the PLSS sublimator to be effective for cooling.

“Okay. It’s (the Latching Pin) in.”

“My Purge Valve’s [set to] Low [FLOW], locked,” Cernan said, “and the Pin’s in. …Want some help with that? I want to take a look at it.”

“There’s the old MASTER ALARM,” I called out, unnecessarily.

“That should be the [second] WATER SEPARATOR.”

“Yeah.” We had turned the two Separators in the Suit Loop off earlier, but it took about three minutes for the sensor to find that out. This possibly was longer than normal, but may have been slowed by the reduced gravity.

“It (the water separator light) is ON,” Cernan noted. This light is one of two ECS caution lights and below the O2/H2O Quantity Monitor rotary switch that is below my attitude indicator. These lights warn of off-limits in CO2 concentration as well as the water separator.

“Yeah. It’s (Purge Valve) barely on. …You’re going to have to push my lock-lock [on the Purge Valve] down.”

”I’ll get it,” Cernan said.

“I don’t know why, but [I can’t feel it like in training],” I commented.

“Why don’t you check mine, too,” Cernan replied. “Let’s see it. I’m going to have to check you anyway.”

“See if I can turn it this way,” I said

“…That’s why; because it wasn’t locked,” Cernan realized. “Is that where you want it; facing down or in? You don’t want it there, do you?”

“No, I don’t want it there,” I said, emphatically. “Must have had it in the wrong [orientation]. …Thank you.”

“Is that the way you want it?” Cernan asked.

“Yeah.”

“Okay. It’s there,” he said.

“Good.”

“The lock-lock is down, and it’s verified LOW [FLOW] and the pin still is in. …Look at mine while you’re there,” Cernan requested.

“Okay. It’s facing in. Lock’s in. Stand by, …it’s LOW [FLOW] Pin’s in; it’s good,” I confirmed.

“Let me get this thing right here,” Cernan stated. “Reach that (OPS) hose for me under my arm. …Put it under the electrical cable.”

“Okay,” I agreed. As I recall, we had not figured out the importance of proper routing of all the hoses and cables in training, maybe because Earth gravity or repeated use took out most of the elastic memory that would be in a new OPS hose.

“I think that’ll be better, isn’t it?” Cernan asked.

“Yup. …It’s there and locked.”

“Verify lock-lock.”

“It’s locked.”

“Okay.”

“And the [dust] cover is going on [over the Purge Valve],” I told him. This cover made sure that dust would not bind the actuator, if needed.

“Okay. …Look pretty good under that [cover]?”

“Yeah, it does,” I assured him.

“That’s fine.”

“Good. Okay. You’re covered.” In actual practice during an EVA, we would have helped each other activate the OPS purge if needed.

“I think we’re getting to our favorite part here,” Cernan then said with a laugh, as we prepared to put the helmets and gloves on and pressurize the suits. This would make it triply difficult to move around in the cabin as well as accelerate the heat build up when we went off LM cooling. “Purge Valves are installed on both. PGA DIVERTER VALVE; put it VERTICAL.”

“It’s VERTICAL,” I confirmed. This valve position put all the PLSS oxygen flow through the neck-ring. The horizontal position would have diverted some flow to the torso to help remove sweat moisture; however, the LCG cooling was so effective that we never needed that function. It would have been used, of course, if the LGC system failed.

“Commander repeat [OPS connect]. That’s done.” Cernan had read an instruction in the Checklist that we had performed, already. We had decided in training that it worked better for us to do the OPS CONNECT procedures together. “ ‘Drink’, Cernan read. “Let’s take a drink, and close the DESCENT [STAGE] WATER.”

“Okay.”

“My [EVA] Meal is already prepared,” Cernan said, referring to the fruit stick in its holder near the neck ring. “And drink and position mikes [as well]…”

“Oh, those little [head] covers are next,” I said, referring to the helmets.

“[I’ve] had enough water today [that] you could say you ‘discovered’ me. I’m ‘water on the Moon’,” Cernan joked. “…Okay. Let’s turn the DESCENT WATER – OFF and let’s stow this [Water Gun] and [hose].”

[“Water on the Moon” had not been proven until investigators in 2008 found water inside the orange volcanic ash we would sample on EVA-2; and water was detected in the ejecta plume of the Lunar Reconnaissance Orbiter’s LCROSS 2010 impact into a permanently shadowed crater wall at the South Lunar Pole.[30] The discovery of increased concentration of hydrogen toward the lunar pole by the neutron spectrometer team on the Lunar Prospector mission, however, had led to intense speculation that water-ice existed at the lunar surface along with solar wind hydrogen.[31] It is not yet certain that the water released by LCROSS and sensed by the LRO instruments originates from indigenous sources or from cometary impacts and/or solar wind proton interactions with the lunar regolith over hundreds of millions of years. Indigenous lunar water will be considered in Chapter 11 in connection with Station 4 discoveries at Shorty Crater.]

“Okay. (DESCENT) WATER’s going OFF…DESCENT WATER’s OFF.” This valve, directly behind my station, controlled access to the water tank in the Descent Stage.

“Position your mike. …Okay, mikes are good. …Top of the page [on the Cue Card]. Before we turn the {PLSS] fans on, let’s make sure we’ve got [everything right]. …All I’ve got hooked here is the [LM)] water. Those cables (hoses) are all stowed. They’re not in your way, are they?”

“No, not in my way,” I replied.

“[They look] Pretty good. Let’s [try putting them more out of the way].

“[This water hose could go over here,] though,” I suggested. “Do you want to put this [hose over there]?”

“Yeah. …That’s probably a little bit better.”

“Seventeen, Houston. Over.”

“Go ahead, Houston.”

“Roger. We’re still seeing the Commander’s Suit Disconnect Valve’s in CONNECT.” Parker meant to say Isolation Valve.

“How’s that?” I responded, puzzled, but reaching around to my left, I moved Cernan’s SUIT ISOLATION VALVE to DISCONNECT.

“Yep, there it goes,” verified Parker. “We got it. Thank you.” In going through the earlier OPS CONNECT procedures together, I had neglected to disconnect Cernan’s suit when I disconnected mine. Had we followed the Checklist sequentially as written, with me first and then Cernan, this would have not happened. Good catch on LM CONTROL’s part, as we would have otherwise had oxygen flowing into the cabin when we started to depress for the EVA. The open suit circuit would have been caught then but would have delayed things a bit.

“Okay,” Cernan went back to the Checklist. “We got to get the PLSS fan on. Don’t forget that’s [on PLSS] battery power. [Now,] We can don our helmets, check our drink bags, [for position], don our LEVAs, [put] protective visors [down], [and] secure our tool harness. …Our O2 umbilicals are already stowed. CDR’s under the handhold. Verify the following. Now, where we pick up our…”

“Have to put the helmets on [first], I think.” Helmets consist of a clear Lexan globe with back padding as an inside head rest. The LEVA (Lunar Extravehicular Visor Assembly) fitted on top of the helmet and provided a gold plated sliding cover for the front that cut out most solar UV radiation and a shield above the eyes for shade from direct sun light. The LEVA also gave additional passive thermal protection to the head.

“Okay, yep. Then we pick up our gloves.”

“I reckon.” Why I engaged in this “Ah shucks” dialog, I have no idea.

“Yep, there it is,” Cernan said, joining in. “Okay. Well, let’s do one at a time here.”

“That’s (helmet) mine.”

“That’s yours? Okay. Do you want to turn your [PLSS] fan on for circulation?”

“Well, I guess I better. Fan’s ON,” I said, using the switch on the RCU.

“I’ll pull this (fruit stick) out just to get it out of your way.”

“Okay…”

“All your candy bars and lemonade, and all that jazz are all clear. Water [nipple, too], I should say…” The fruit stick consisted of about ten inches of dried fruit mixed with a high calorie binder and enclosed inside a long, narrow bag. You had to learn to pull enough of the stick out of the bag with each bite so that you could take the next bite and not lose the stick down in the bag. The water nipple allowed drinking by sucking from a flat quart bag that was attached inside the suit, just below the neck-ring.

Cernan then helped me seat the helmet on the neck ring and rotate it so it locked in place with a sharp click. “Mmm. That sounded good,” I said.

“Try it. Okay? It looks good here, Jack…[Do you] want your LEVA?”

“Guess so,” and he began to place the LEVA over my helmet.

“Okay. Enjoy it in there; you’re going to be in there for a few hours.”

“Can’t think of any place I’d rather be right now,” I responded.

“Sounds like you’re in there, too. Oh, [LEVA’s] too far back? Okay, that’s better…I’m freezing my “you-know-what” off!”

“Me, too,” and we both had a good chuckle.

“Does that look lined up to you?”

“Looks pretty good.”

“Okay. Let me [work on the back of the LEVA a little]…”

“Wait a minute,” I said.

“Let me get this [back flap] down [and] around. Okay. That’s around behind you; thermally protected back there. That’s below the OPS hose.”

“Right now, I’m hoping to get out of this [cabin and get] warm,” I commented with a laugh.

“Okay. You’re thermally [isolated]. …Let me double-check that. The helmet is locked. Your visor is locked. It’s one thing you don’t want to lose among some others. …Okay, you want to give me a hand?”

“Not particularly,” I answered, referring to the difficulty of working in the cabin, wearing a pressurized suit.

“Oh, man,” Cernan exclaimed as I started to drop the helmet over his head and everything else. “Where did that come from?”

“Watch your nose, drink bag, candy bars, popcorn!” I joked. With audible clicks, his helmet locked into place.

“Squeeze hard back there.”

“Want your fan [on]?” I queried.

“Yep.” So I moved the Fan switch on his RCU to ON.

“Looks good,” I observed after double-checking the seating of the helmet ring on the neck ring of the suit.

“Okay. I can hear the fan running. Oh, man. Whew!” Cernan exclaimed, smelling the chemical odors inside of the suit. “Looks good here.”

“Yeah. That’s all right [about those smells].”

“There you go,” he acknowledged.

“It’s new. Never been used before!”

“Make sure that [LEVA] flap in back goes below that OPS hose,” Cernan directed.

I took care of the flap and then asked, “Want to put your protective visor down? Yeah, if you got that thing all [set]. …You got it all down?”

“Yep. You happy with it (the LEVA flaps) back there?”

“Yes, sir. You’re nice and protected,” I assured him.

“Okay.”

“Good Velcro. …Okay. You’re all covered here.”

“Okay. Not my other one, is it? No.”

“No.”

“Okay. Ohhh!” Cernan said, looking at the Checklist. “I think we’ve got to get tool harnesses here. ‘Don LEVAs.’ Look at that scratch right in the middle of that thing. Okay. ‘Don LEVAs and lower protective visor.’”

“Okay.”

“ ‘Secure harness and self-doff straps.’ Okay. Stay where you are. …Can’t miss it. …Okay.” The self-doffing straps, to be used in case the other crewman cannot assist for some reason, secured with Velcro to the side of the LEVA. If pulled, the tool harness would be released, too easily it would turn out. “ ‘Stow the LM O2 [hoses]. And comm [cable].’ Okay. …They’re all stowed; everything except [LM] water [hoses], right?”

“Verify the following: ‘Check your helmet and visor.’ Okay. You check me. I’ll read them. ‘Helmet and visor, aligned and locked.’”

“That’s locked,” I verified.

“O2 covers all locked. There’s a peek at them.”

“That’s locked.”

“Purge Valve. Everything down there?”

“That’s locked; that’s locked.” Two locks had to be checked on the Purge Valve, the Valve itself and the Release lanyard.

Comm Carrier.”

“Stand by, …That’s locked,” I continued.

“Diverter Valve is vertical.”

“Comm is that way. Diverter Valve is vertical.” Again, this put all oxygen flow to Cernan’s helmet.”

“One more time,” Cernan declared, verifying my setup. “Your helmet is locked; purge valve, locked. …Yep. That’s (O2 connector) locked; that’s (water connector) locked; that’s (comm connector) locked. And, let me see, …let me see! Yes sir, and that’s locked. Don’t let anything to chance, today. And the Diverter Valve is vertical. Comm – you checked [mine], too?”

“Yes, sir.”

“Verify your old white dots [on your circuit breaker panel],” I said.

“Okay. Old white dots, …my old white dots, …look good to me.” All circuit breakers that should be OPEN during the EVA had white dots on them, making it much easier to verify what should be OPEN and CLOSED.

“[Can you] move a little? I asked” I needed to turn to my right more so I could see Panel 16 and verify the positions of the circuit breakers.

“Yeah, I’ll move.”

“Okay.”

“Got it,” Cernan said. “…I’m going to miss Danny [Schaiewitz] being out there to hand us those light PLSSs.”

“That’s right…” Danny worked for the PLSS manufacturer, Hamilton-Standard, and, along with many others, managed our equipment during EVA training and tests.[32]

“You want it (EVA Prep Cue Card)?” I asked.

“Okay. I want the EVA decals [checked], also, Jack.”

”Yup.”

“White dots plus decals,” Cernan repeated.

“Rog.”

Okay, Bob, we’re turning the [Cue Card] page [over],” Cernan informed Parker and Mission Control.

“Roger. We’re right with you,” replied Parker.

“ ‘Don EV gloves’,” I read

“Okay; on [with the gloves]…”

“Is that it? That’s it. ‘Don EV gloves.’ Doing a little greasing in here.” Cernan used a hand grease to minimize abrasion from flesh rubbing on the inside of the rubber glove. I wore thin nylon glove liners that, I believe, proved to be more successful. We both ended up with chaffing, but Cernan’s was significantly worse that mine.

“And make sure your Wrist Locks are LOCKED. Glove Straps adjusted and cover the Wrist Rings!’ Golly! …I sure missed hearing it (wrist lock) click, but they are locked. One of them is, anyway. …Okay, Jack. I verify, “…Cernan paused because I was laughing. “What?” he asked.

“Guess what?”

“They don’t go on any easier in one-sixth g, do they?”

“They (glove tie-straps) break just as easily, too,” I added.

“Okay, I’ve got my one glove locked,” Cernan reported. “…One of the old dust covers [on]”

“I never had that (tie strap break) happen in training; you did.”

“It’s (his glove) locked,” Cernan finally confirmed. “That’s about as locked as it can go. Boy, I’d hate like the devil to have that (glove lock ring) pop open. Okay; that’s very good. You want me to help you with one, or can you get it?”

“Well, I don’t know. I’ve only worked on one so far,” I replied.

“I’ve got a free hand before I grease it up.”

While he helped me, I said, “I broke that one (strap)…”

“I’m telling you, from the looks of that soil out there, that drill may have a job ahead of it.”

“Yeah,” I speculated, “I didn’t have a chance to mention that. I don’t think the regolith is very thick, and I think you’ve got rocks below it…” This prediction proved totally wrong for most of the valley area.

“You got that [glove on]?”

“Well, how does it look?” I asked

“Let me take a look. …No.”

“Didn’t make it, huh?”

“Yeah, well, let me… Hold your hand up here,” Cernan asked, hold it up here.”

“Looks good on my side,” Cernan declared. “How is your side?”

“Good over here.”

“Let me pull this [wrist cover] down for you,” Cernan offered. “Okay?”

“Thank you,” I said.

“Get the old other hand…”

“Okay. That’s locked…”

“And my other glove is locked,” Cernan said and then continued, laughing, “Now, for the fun in back. Oh, me; oh, my.” Here, he is referring to getting his glove strap tight.

“I think I got it! I think I got it,” I mimicked, thinking of Professor Higgins in “My Fair Lady.”

“Pull it and let go. Isn’t that the word?”

“That’s what they tell me. Want me to get it?” I offered.

“I got mine. …No, I got it. [Have you] verified yours [is] locked?”

“Yes, sir.”

“Both my gloves are verified locked. …How does that grab you?”

“Okay; feels good,” I answered.

“Is your mirror on tight enough?” Cernan asked, referring to a small metal mirrow on my left wrist that allowed me to see the front of the suit and the controls under the Remote Control Unit on my chest. “[Cuff] Checklist on tight enough…That’s the best I can do; I guess.”

“Okay.”

“Now what?” I asked as Cernan had the EVA Cue Card in his hand.”

“Wrist rings are covered. ‘Note if PGA biting…’No, mine’s all right. Your’s okay?”

“No; it’s fine.” The “biting” comment referred to the possibility that the pressure in the suit might decrease due to carbon dioxide removal before we went on PLSS oxygen.

“Okay. ‘LGC (Liquid Cooled Garment) cold as required.’ We been on cold all this time, right?”

“Yes.” We stayed as cool as possible by circulating Challenger’s cooling water through our underwear until the last moment. The PLSS cooling system would be ineffective until its sublimator was exposed to vacuum. That would mean about 15 minutes until the cabin became fully depressurized and PLSS cooling became effective.

“Okay. Guess you can open that [LGC PUMP] breaker, and I’ll stop shivering,” Cernan said with a laugh.

Okay.”

“And, we can disconnect the LM water hoses. Let’s help each other with those, so we don’t screw up the other hoses.”

“[LGC] breaker’s open,” I reported

“Okay.”

“Let me turn around this way [toward you].” I said as I turned toward Cernan so he could get to my cabin water hose and disconnect it.

“Okay. Go ahead and I’ll…”

“You want to get mine or you…?.” I asked.

“No, I’ll get yours [first],” stated Cernan.

“Okay.”

“First of all I’m going to take that (LM water hose) off. …Okay. Now let me get your other one [from the PLSS]. There it is. Okay. We did this before. Stand right there. …It’s locked, Jack.”

“Okay.”

“It is locked,” he verified. [I’ll] get the [dust] cover on…Okay. The cover is on. Okay. Yours off?” Cernan meant his water hose that I was now disconnecting.

“Get that in a second,” I said.

“Yours (PLSS hose) was just laying there, too.” The hoses were stiff with their packing memory.

“Okay. Hang on,” I said, impatiently.

“I’ll push towards you…” He was trying to make it easier. “Make sure that thing (inlet) falls in the hole, because yours didn’t right away. …Did it fall in?”

“Yeah. Yeah, it’s in the hole. Okay.”

“Dust cover on?”

“Dust cover’s on,” I confirmed.

“And my PGA is going to start biting here if we don’t get going…Okay. ‘PLSS DIVERTER…’ I’ve got to turn my oxygen on a second, Jack.”

“Yeah, so do I….”

We both began to feel around the RCU, again getting used to where the various controls were positioned, with Cernan saying, “That…That…There it is. Okay. It’s ON…”

“[O2 switch is] a little hard to get it off, isn’t it,” I said.

“Yeah. Okay. Mine is back OFF.”

“Yeah, mine is [too].”

Cernan went back to the EVA Cue Card. “‘PLSS DIVERTER VALVE – MIN; verify.’” This valve was on the lower left, forward corner of the PLSS.

“Mine’s MIN.” This setting on PLSS cooling would keep water flowing through the LCG, but would not add water vapor to the cabin and slow the depressurization.

“‘PLSS PUMP – ON.’ That’s [moves] to the right [on the RCU]. ‘PRESSURE REGS A and B, EGRESS.’ I think we’re already at Egress.” Fullerton had told us to put the REGS at that setting almost an hour and half previously.

“Pump’s ON. We’re in EGRESS.”

“Okay, my pump’s ON. I can feel it running.”

“Keep talking,” I prompted. I was getting impatient to get outside.

Pressure Integrity Check. Okay. “PLSS O2 – ON.” You ready for this?”

“I hope so,” I said, referring to this necessary but time consuming test of the suits.”

“PLSS O2 – ON. Mine’s ON. ‘Pres[sure] Flag and O2 Flag [will] clear [at] 3.1 to 3.4 [psi].’ Okay. I’m coming up. I know that…Gee, it’s 10 minutes to 6 at home,” Cernan observed, looking at his NASA issue Omega Speedmaster wristwatch. “I’m still coming up (in pressure).”

“Keep coming up. Just got mine (PLSS O2 switch) on.”

“Oh, okay. Well, I’m ahead of you then…The PRESS FLAG will clear [at] 3.7 – correction – 3.1 to 3.4 [psi].”

“What do you (the Checklist) want me to do when I’m pressurized?” I asked, as Cernan was holding the Que Card.

“Well, we want to make an integrity check.”

“Yeah; but then what?”

“Can you reach those (LM) water hoses right there? By chance? Before you get too hard? …Stow them out of the way. …When you get up [to pressure]. …Okay. PRESS FLAG cleared on the commander. …Okay. The O2 FLAG did not clear. I’m at 3.8…Okay. O2 Flag cleared on the commander.”

“Still got an O2 Flag on the LMP,” I noted, but my PRESS FLAG had cleared.

“Okay, you’re not up [to 3.1 to 3.4psi] yet; I suppose.”

“No.”

“Okay,” Cernan acknowledged. “I’m going to take my PLSS O2 Off for one [minute]. Counting 1 minute… 57. Let me know when you’re up, Jack, and I’ll give you a minute hack.” The one-minute test provided a check on any leaks in the overall suit system.

“Okay. I’m clear [on the O2 FLAG],” I reported.

“Okay. You up [to pressure]?”

“Yep.”

“You can turn your PLSS O2 off any time. Let me know when. Can you reach it? If you can’t, I’ll get it for you,” offered Cernan.

“Why don’t you get it,” I said, after finding I was unable to bend my arm enough to reach my RCU in these cramped quarters. Outside, I could throw my arm up into a shoulder joint detent and then reach across to the RCU.

“…Mark it.” Cernan timed the test on his wristwatch.

“Okay.”

“You’re on the 30-second mark, and I’m on the minute mark.” Cernan had his timing reversed, as he was ahead of me.

“Okay, and I’m at 3.8,” I observed.

“I’ll give you a hack when… I’m coming up on 45 seconds. …Okay. I’m one minute; I’m going back on [with O2]. Okay, Houston. Commander went from 3.8 to about 3.67[psi]. I’ll get yours on when you need it on, Jack.” This drop showed a normal change due to breathe-down and residual filling of small, isolated portions of the suit.”

“I copy that, Commander.”

“And we’ll pick Jack up here in about 10 more seconds.”

“Okay. “

“Okay, Jack. I’m turning on [your O2]. Did you mark it?”

“Okay, Houston; 3.8 to 3.6[psi]. …Hello, Houston; you copy the LMP?’

“Roger. Copy the LMP…”

“Standing by for your Go for DEPRESS,” Cernan stated.

“Okay, …and Challenger, You’ll be glad to know you are GO for DEPRESS.”

“Thank you, Robert. I understand we are GO for DEPRESS.”

“That’s affirm.”

“Okay, Jack,” Cernan said, getting two steps ahead of the Checklist. “Can you reach the FRONT [DUMP] VALVE, or do you want me to [get the OVERHEAD DUMP VALVE]?”

“Well, let me turn around here.” I needed to turn about ninety degrees left from my front-facing position to get my right arm free so I could squat and both see and reach the valve on the forward hatch.

Before I turned, however, Cernan went back to the Cue Card and said, “Okay, on [circuit breaker Panel] 16… First, around on 16, CABIN REPRESS – OPEN.”

“Okay; [on] 16, …Circuit breaker is coming open.” This prevents automatic re-pressurization when the open hatch valve begins to lower cabin pressure.

“Okay, and CABIN REPRESS VALVE – CLOSED on the panel [behind you].”

“Okay. The valve is closed,” I reported after turning to my right and pushing sideways against the front panels so I could see and reach the valve.

“Okay. If you can’t reach it (the valve ion the Forward Hatch), I guess I can.”

“I just had a momentary tone.”

“So did I. I got it, too.”

“Okay.”

“I think it was when you closed the REPRESS VALVE. …Can you reach it (the Front Hatch valve)? If not, I’ll reach the overhead one.”

“I think you better reach the overhead one.” In suited training in the one-g mockup, I could bend the suit and reach the Forward Hatch Valve without any great effort; however, in one-sixth gravity on the Moon, the lessened weight of the suit made this much more difficult. Cernan, on the other hand, only had to raise his arm to reach the Overhead Hatch Valve. Raising his arm, nonetheless, required some maneuvering, as I was facing him at this point and he needed to turn to face the rear of the cabin.

“Slip over to your right [toward] your window. …Some more. …Let me turn here. …Wait a minute, I got to turn [to reach the overhead valve].”

“Okay. How far down are we going to take it? 3.5 (psi), right?” I asked.

“Yeah, wait a minute. I’m not there yet.”

“Well, I just want to make sure that I’m watching (the cabin pressure gauge).” Once the cabin pressure reaches 3.5psi, Cernan will put the Overhead Dump Valve in AUTO. In that position, it will only open to relieve pressure if the cabin goes over 5.4psi. Our suit pressures will go up at first, due to normal delay in regulator response, and then they will slowly decay. If this all happens as planned, it will be another good check on the integrity of the suits.

“Okay; now. Okay, [overhead] coming open. You ready? You reading the checklist?”

“Stand by: [DUMP VALVE] – AUTO. [CABIN] REPRESS [valve] is CLOSED,” I read.

“Say when.”

“Okay.”

“You ready?”

“Wait a minute; wait a minute; wait a minute.” Cernan was getting impatient while I made sure everything was right by the Checklist.

“Okay.”

“Got the wrong place [in the Checklist]. ‘OPEN, then AUTO at 3.5’ [for the Overhead Valve],” I read again to remind us. “Okay; go ahead [and OPEN].”

“Here it comes. I can see daylight through it (the Valve).” At this point, we are running about 20 minutes behind the Timeline.

“Okay, it’s (cabin pressure) coming down. …That’s 4 [psi]. Stand by.”

“Mark. 3.5,” I called.

“It’s (overhead valve) OFF.” Cernan meant AUTO rather than OFF.

“And your cuff gauge should not be below 4.6, and mine’s at…” I told him.

“Mine’s at 5.0,” he interrupted.

“[Mine’s] 5.1. …Okay. The suit circuit is locked up at 4.5,” I reported. We already had disconnected from the Challenger’s suit circuit when I had closed the SUIT ISOLATION valves. With the SUIT CIRCUIT RELIEF valve in AUTO, that circuit would bleed down to about 4.3psi. Meanwhile, we would wait for the suit pressure to decrease, as we used up oxygen and carbon dioxide was extracted by the PLSS’s LiOH canisters. “We’re at 3.5 [psi cabin pressure] and holding. And I’m decaying. I’m below 5.”

“So am I,” Cernan confirmed.

“Verify that; okay?”

“I’ll start my watch,” he said.

“We verify and we’re counting,” interjected Parker, looking over our telemetry shoulder.

“Watches started.”

“Okay,” I said, going back to the Checklist. ” ‘Overhead or Forward DUMP VALVE – OPEN’.”

“Okay. Here it comes [OPEN].”

“And it’s (pressure) going down.” This began the official start of the EVA-1 even though we had been on PLSS oxygen, power and water for almost ten minutes. Now we had fully transitioned to a new spacecraft: the A7LB EMU or Extravehicular Mobility Unit, better known among the operators as “the pressure suit” and among the public as “the space suit”.

You going to want me to put this (Forward Hatch DUMP VALVE) in AUTO afterwards or not? …[Move] So, I can turn around, Jack.”

“Stand by.”

“[Leave it in] OPEN”, I said.

“…leave it OPEN?”

“Leave it OPEN,” I repeated.

“No, we don’t [put it in AUTO], because then we don’t want that hatch to get closed…” Cernan finally remembered that, even though we could dump pressure from the cabin from the outside, this OPEN position of the valve would keep any pressure build up in the cabin from making it difficult to open the hatch at the end of the EVA. “…I got to turn around here. Oh, boy! …Boy, you sure get heavy (stiff) at 5 [psi], don’t you?” Suit pressure still needed to bleed down to its eventual working pressure of 3.7 psi. “Okay. Where are we [in the checklist]?”

“We’re right here, huh?”

“What that was… What’s cabin [pressure], Jack?…Do you read, Jack?”

“Jack, this is Houston,” Parker called, realizing that I was not transmitting.

“Wait a minute,” Cernan replied for me.

“CDR, we’re not reading the LMP either.”

“Now, how do you read, Jack?” I checked the two RCU MODE SELECT blades and found that Cernan’s was in the B position rather than A. In bending down to work with the front hatch DUMP VALVE, Cernan had inadvertently put his MODE SELECT to B and this inhibited my transmissions.

“Okay. You’re loud and clear.”

“Okay….”

“We got a switch in the wrong place as usual, Bob,” I explained.

“I just hit the MODE SELECT [switch on the RCU], that’s all.”

Okay. We copy,” Parker acknowledged.

“Okay, ‘Partially open the forward hatch’,” I read from the Checklist. “When we can,” I added.

“Okay. Can you zap over to the left as much as you can?” Cernan asked, still trying to get in position for opening the hatch.

“To the right, you mean?”

“Yeah. To the north,” Cernan said, not being able to see that I had moved to face forward.

“To the north.”

“The north.”

“The north.” This comedy routine gave us a good laugh as we waited for the cabin pressure to decrease. “Okay, it’s about 0.2 [psi], Gene.” Full depressurization through the front hatch valve took about three minutes.

“Okay. Let me…”

“You going to be able to get to it?” I could not be any help as the hatch was hinged so that it would open into me.

“Yep,” Cernan affirmed. “You betcha. I’ve come this far. I’m not going to miss getting that hatch open…”

“Hey, something just flew out (the hatch)!” As Cernan broke the seal around the hatch and started to open it, the residual oxygen in the cabin streamed out, carrying a small piece of Styrofoam or bread with it. I was looking out the window with nothing else to do at this point.

“It’s open now.”

“Gosh, look at those trajectories!” I exclaimed with a laugh as condensed ice from moisture in the expanding cabin air and other small pieces of debris left the Challenger.

“Yeah. Put just enough air in here, we’re… Okay; it’s open, babe.”

“Okay.”

“It is open,” Cernan repeated.

” ‘Final Prep For Egress:’ PLSS [sublimator] – PRIMARY H2O.’ I’ve got to figure out how to open that now,” I stated.

“…When you’re at 5 psi, it’s [hard to reach the PLSS controls],” Cernan explained as he also struggled to get to the guarded switch under the right front corner of the RCU.

We never did really train for this in the right way,” I commented.

“Yeah, we did,” Cernan contradicted, but I had no memory of such training, however, particularly at 5 psi suit pressure.

“Okay. My water is OPEN,” I reported.

“And my water is OPEN,” Cernan followed, breathing hard with the exertion. “Okay. Well, let’s see: ‘Rest until cooling sufficient; 3.7 to 4.6 (psi).’ I’m to 4.9; coming down.”

“Yeah, I am, too. Coming down.”

Cernan returned to the Checklist. “CWEA (Caution and Warning Electronics Assembly) status. PREAMPS and ECS [lights should be on]. Can you see that?”

“See a PRE AMPS, and I see ECS. …Barely,” I confirmed, turning my head to the left while facing toward the circuit breaker panel. The ECS caution light came on as the cabin depressurized and the RCS Jets Pre-amplifier Caution Light showed we had powered down the attitude control system. Both these lights were on the Caution and Warning display above the eight ball and at the top of my instrument panel, Panel 2.

“Okay. Water Sep Component Light – ON.”

“Water… Excuse me, Water Sep – [ON].” The water separator used a spinning fan to remove condensed moisture from the suit circuit.

Well, the next thing it says is that ‘Gene gets out’.”

“I don’t see that,” I kidded. We transitioned here to the Cuff Checklists attached to our left wrists.

“That’s what it says on my [Cuff] Checklist.” Actually, at this point, his Cuff Checklist says nothing about his egress and mine says “Assist CDR.”

“Okay. …Good heavens!” I said in mock surprise.

“That means you got to get out of the way so I can open the hatch”

“Well, I’m going to have to turn around [toward you] a little, I think, so I can help you.” With the suits stiffer than normal, I would help Cernan clear the projecting bulk of the DISKEY as he went out the hatch, belly down and feet first.

“Okay. …Boy, beware of that corner.”

“This high pressure…,” I said, sympathetically.

“Yeah. I tell you at four and a half (psi), you’re really pretty heavy (stiff).”

“What was that that came shooting up here? A piece of bread?” I speculated with a laugh. “Would you believe that?”

“Yeah, I’d believe it.”

“Why is our hatch open?” I asked in mock concern. “Somebody opened our hatch! …Are you getting cooling?”

“I’m beginning to, I think. I still got a Water Flag. [But I’m] not hot.”

“Stand by. …How does the water pressure look, Houston?”

Challenger, they’re looking just a little bit low,” Parker responded. “We’re still expecting them to build up. It’s going to take a little while.”

“I’m getting down on my knees out here. How am I looking, Jack?”

“You’re just fine. I’m holding you away from the DEDA…[that is] the DISKEY.”

“I’m going to put this visor down now, I think. …How does that look to you?”

“What?”

“How are my legs? Am I getting out?”

“Well, I don’t know. I can’t see your legs.”

“Oh, okay,” Cernan said, laughing at his question.

“I think you’re getting out though, because there’s not as much of you in here as there used to be. …Oh, hey, Gene, when I get down there, I got to fix your tool harness [on the PLSS]. Hold it.

“Okay. Can you reach it?”

“It’s come off the bottom again.”

“Can you reach it?”

“Well, I can’t do it now, because it’s come off from the bottom. I’ll have to…”

“Oh, [off] the bottom of the PLSS, huh?

“Yeah.”

“Okay. Well, my legs are out. Keep that hatch open.”

“Can you squat down any further, because you’re hooked on… You’re making it worse. …Okay.” The corners of Cernan’s PLSS were temporarily hooked on the frame of the hatch.

“How’s that?”

“Okay. Now, be careful because you might hook it (tool harness) on something down there.”

“Oh, the tool harness?” Cernan asked.

“Yeah. The back. It’s loose on your back; on the back of the PLSS.”

“Oh, man, I don’t like that. Okay. I’ll watch it.”

“Well, I’ll fix it when I get out there.”

“I’m still reading 4.0 (psi). Houston, the Commander is on the porch of Challenger.”

“Roger. We copy you, Commander, and your feed-water pressure is looking much better…now, and you’re probably getting cooling.”

“Okay. Everything else look good to you?”

“That’s affirmative,” Parker replied.

Cernan seemed to have more trouble than I did in getting out of Challenger. Three factors may have contributed to this: He was taller than I, I could open the hatch a little wider, and my suit pressure had decayed more than his by the time I started out. Also, with me in the cabin to observe and assist, there was naturally more conversation about various difficulties.

“Okay, Jack. I’m going to get the MESA.” The MESA (Modular Equipment Stowage Assembly), stowed in the Descent Stage quadrant to the left of the ladder going down, held our various sampling tools, extra food, replacement PLSS batteries, sample bags and boxes, and the detectors for the Cosmic Ray Experiment. Whether anyone ever realized that MESA is the Spanish word for table, I am not sure. The MESA basically was a large box that Cernan deployed on its hinges by pulling a D-ring he could reach while on the porch. Depending on its deployed position, I later will adjust the MESA to a good working height.

“Okay. And I’ll have an ETB ready for you.” As described earlier, the ETB (Equipment Transfer Bag) contain items like cameras and scissors that would be transferred back and forth from the cabin to the surface.

“Oh, man; oh, man; oh, man,” Cernan exclaimed as he reached for the MESA D-ring.”

“Deploy, MESA!” I ordered.

“Okay,” Cernan agreed with a chuckle. “Here it comes. …There she goes, babe.”

“Hey, hey!” As this was the quadrant of the Descent State below my window, I literally had a bird’s eye view of the MESA’s slow rotation out of its stowed position.

“There she is. All the way down, it looks like. Okay. I jettisoned…” Cernan got ahead of himself on the Cuff Checklist. “Oh, you want an ETB?”

“That’s up to you.”

“Yeah.”

“You’re the Commander,” I reminded him.

“I got it! I got it. …And, the [suit] pressure looks like it’s started to stabilize at 3.8. I don’t know whether I’m getting cooler or not, but I feel pretty good.”

“We copy that,” broke in Parker.

“How about a Jett(ison) bag, too?”

“Okay…” The Jettison Bag contained empty food bags and other trash that would be left under the Descent Stage.

Using the lanyard to lower the ETB to the ground, Cernan commented, “Oh, Jack, I could swing it (ETB) over the – it won’t be any problem – over the strut. Okay; and the Jett Bag is swinging free.”

“You mean the ETB.” The ETB had a lanyard to lower it to within reach from the surface.

“ETB,” corrected Cernan. “Oh, man. This (ETB) looks like a Santa Claus bag.

“It is,” I reminded him.

“Oh, boy. There it goes. The Rover looks in good shape.” Cernan could see behind the thermal blanket that covered the Rover stowage location to the right of the ladder. “ETB is down there. …I’ve got all my visors down. Jack, I wouldn’t lower your gold visor until after you get on the porch, because it’s plenty dark out here.” The west facing ladder and front quadrants of the Challenger, of course, were in shadow.

“Okay…Tape recorder (DSE)…is OFF, VOX (VOICE) SENSITIVITY – MAX AND MAX.” I said, finishing off the final items for the cabin that were on the first page of the Cuff Checklist, including another verification that white dots were out on both circuit breaker panels. While near the Challenger, we would be transmitting by VHF into its S-Band communications system.

“I’m on my way [down the ladder],” Cernan reported. “Okay, Houston. The Commander is about three quarters of the way down. …I’m on the footpad. And, Houston, as I step off at the surface at Taurus-Littrow, we’d like to dedicate the first step of Apollo 17 to all those who made it possible. …Jack, I’m out here. Oh, my golly! Unbelievable! Unbelievable; but is it bright in the Sun. …Okay! We landed in a very shallow depression. That’s why we’ve got a slight pitch-up angle. (It’s a) very shallow, dinner-plate-like, dish crater, just about the width (span) of the struts. How you doing, Jack?”

“Fine. Getting the circuit breakers verified.” I also made sure the Utility Floodlights were off and that the Sequence Camera was still running.

“The LM looks beautiful,” Cernan continued. “Oh, do we have boulder tracks coming down [the North Massif]. Let me see exactly where we are. I think I may be just in front of Punk.”

“We copy that, Gene,” responded Parker, “and are the boulder tracks…to both the north and south?”

“On the North Massif we’ve got very obvious boulder tracks. A couple of large boulders come within 20 or 30 feet of the [break in slope]. …Looks like where we can get to them; there’s a couple I know we can get to. Well, the Sun angle is such that, what I saw on the South Massif earlier, I can’t see very well. But, I know there were boulder tracks over there. Bear Mountain [to the east]. …Boy, it’s hard to look to the east. …Bear Mountain and the Sculptured Hills [to the east] have a very, very similar texture on the surface. The Sculptured Hills’ [surface] is like the wrinkled skin of an old, old, 100-year-old man. [That] is probably the best way I could put it. Very, very hummocky but smoothly (evenly) pockmarked. I do not see any boulders up on the Sculptured Hills from here. But it’s awful hard to look to the east and to the southeast.”

“We copy that, Gene. Have you got an LMP with you yet?” I had been quietly maneuvering inside the cabin to get in position to egress to the porch. I took it slow and easy while Cernan talked.

“Well, here come his feet. Jack, let me make sure. …We didn’t have an awful lot of dust on landing; but I can dig my foot in 8 or 10 inches [into the regolith], and I know we’re (the regolith) at least that thick. There’s a small little 1-meter crater right in front of us with a whole mess of glass right in the middle. That’s right in front of the MESA, as a matter of fact. Right where I want to park the Rover. Jack, you’re looking good.”

“Beautiful, guys; beautiful,” gushed Parker.

“I’m going to take a quick look back. I think this is Poppie, and I can give you a real better idea where we are.” Cernan wandered some 30m to the east to get his bearings and try to identify Poppie.

“Hatch is closed, barely,” I reported from the porch.

“Hey, Jack, don’t lock it.” Cernan started the traditional routine about the hatch.

“I’m not going to lock it.”

“We’ve got to go back there. You lose the key, and we’re in trouble.”

“Oh, I’m on the porch!” again, feigning surprise.

“Who said this place was smooth? Oh, boy! There’s a lot of local depressions here I didn’t figure existed,” continued Cernan’s excited commentary.

I took hold of the handrails on the porch and then the smooth sides of the ladder and slid down slowly, not bothering with the rungs, until my left foot touched the surface. The left foot first touched a partially buried boulder under the front landing pad. As I put weight on that foot it slipped down the slick side of the boulder, catching me by surprise and leaving my legs separated much more than normal. The little beads of glass partially coating the boulder had acted like small ball bearings. I was more careful, next time. Looking toward the North Massif, the 12th and most recent man to step on the Moon[33] spoke his immortal first words, standing in the valley of Taurus-Littrow:

Hey, who’s been tracking up my lunar surface?”

(to be continued…)

*****

ENDNOTES:

  1. In the quoted dialog and annotations directly related to the Apollo 17 Mission, black = normal mission activity and commentary with quotes from the NASA transcript of air to ground communications; red = spacecraft anomaly discussions; blue = Earth observations; brown = Lunar Module Challenger discussions; green = Public Affairs Office transcripts or news updates from Mission Control; and purple = lunar observations. Other than their use in the names of spacecraft, italics = onboard recorder transcripts (Data Storage Equipment or Command Module DSE and Data Storage Electronics Assembly or Lunar Module DSEA), and turquoise = probable dialog derived from the author’s memory.

    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. They are also used for parenthetical emphasis of explanatory paragraphs set off from regular text.

    The CMC (Command Module Computer) commands are referred to occasionally 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.

  2. See Jones, E. M., Apollo Lunar Surface Journal, Apollo 17, Landing at Taurus-Littrow, time hack 113:01:58

  3. Adapted in part from Schmitt, H. H., 1994, A Trip to the Moon, in V. Neal, editor, Where Next, Columbus?, Oxford University Press, New York, p. 61-62.

  4. See Encyclopedia Astronautica, Lunar Module ascent engine injector, Details for 1968 May 28, and Details for 1968 Sept. 25.

  5. Adapted in part from Schmitt, H. H., 1994, A Trip to the Moon, in V. Neal, editor, Where Next, Columbus?, Oxford University Press, New York, p. 62.

  6. See Jones, E. M., Apollo Lunar Surface Journal, Apollo 17, Landing at Taurus-Littrow, time hack 113:04:17; Wolfe, et al, 1981, The Geologic Investigation of the Taurus-Littrow Valley: Apollo 17 Landing Site, USGS Professional Paper 1080, USG Printing Office, Washington, p. 9, Figure 6.

  7. The reader can watch the intensity of these markings change by varying the sun angle at the LROC website.

  8. Schmitt, H. H., and M. S. Robinson, 2010, Geology of the Apollo 17 Taurus-Littrow site in light of LRO imagery, Abstract, Geological Society of America Annual Meeting, Denver, CO, November 1.

  9. Batson, R. M., Personal communication.

  10. See Jones, E. M., Apollo Lunar Surface Journal, Apollo 17, Post-landing Activities, time hack 113:23:22.

  11. See also, Hansen, J. R., 2005, First Man, Simon & Schuster, New York, pp. 466-472.

  12. Cernan, E. A., and D. Davis, 1999, The Last Man on the Moon, St. Martin’s Press, New York, pp. 316-318.

  13. Mindell, D. A., 2008, Digital Apollo, MIT Press, Cambridge MA, pp. 181-215.

  14. Woods, W. David, 2008, How Apollo Flew to the Moon, Springer-Praxis, New York, pp. 255-256; Mindell, D. A., 2008, Digital Apollo, MIT Press, Cambridge MA, pp. 170-174.

  15. See Scott, D. R., and A. Leonov, 2004, Two Sides of the Moon, Simon and Schuster, New York, pp. 292-293.

  16. Lucey, P., et al, 2006, Understanding the lunar surface and space-Moon interactions, in B. Joliff, et al, editors, New Views of the Moon, Reviews in Mineralogy and Geochemistry, 60, Chapter 2, p. 61-63.

  17. Schmitt, H. H., A.W. Snoke, M.A. Helper, J.M. Hurtado, K.V. Hodges and J.W. Rice, Jr., 2011, Motives, methods, and essential preparation for planetary field geology on the Moon and Mars Geological Society of America Special Paper 483; 1-15 doi: 10.1130/2011.2483(01); See also Chapter 2.

  18. See Chapter 11, Station 4 – Shorty Crater.

  19. See Chapter 12, Station 9, Van Serg Crater.

  20. Graf, J. C., 1993, Lunar Soils Grain Size Catalog, NASA Reference Publication 1265, Apollo 17 soils, pp. 325-462, PDF download of whole catalog.

  21. Wilhelms, D. E., 1984, The Geologic History of the Moon, U. S. Geological Survey Professional Paper 1348, p. 129

  22. See Chapter 11, Station 2 –South Massif and Station 3-Light Mantle

  23. See Chapter 1.

  24. Schmitt, H. H., 2015. Potential catalytic role of phylosilicates in pre-biotic organic synthesis, Geological Society of America Special Paper 518, pp. 1-16.

  25. NASA, 1973, Apollo 17 – Preliminary Science Report, National Aeronautics and Space Administration, NASA SP-330, Chapters 9-19.

  26. Wilhelms, D. E., 1987, The Geologic History of the Moon, USGS Professional Paper 1348. p. 191.

  27. Steno, N., 1669, Dissertationis prodromus.

  28. Wilhelms, D. E., 1987. The Geologic History of the Moon, USGS Professional Paper 1348. Pp. 64-65.

  29. Lucchitta, B. 1972, Geologic map of part of the Taurus-Littrow region of the Moon, in D. H. Scott, et al, Geologic Maps of the Taurus-Littrow region of the Moon, U. S. Geological Survey Miscellaneous Geological Investigations, Map I-800, Sheet 2, scale 1:50000.

  30. Saal, A. E., et al, 2008, Volatile content of lunar volcanic glasses and the presence of water in the Moon’s interior, Nature, 454, p. 192-195; Colaprete, A., et al, 2010, Detection of water in the LCROSS ejecta plume, Science, 330, p. 463-468.

  31. Feldman, W. C., et al, 2001, Evidence for water ice hear the lunar poles, Journal of Geophysical Research, 106, p. 23, 231-23, 251.

  32. See Chapter 3.

  33. Neil Armstrong became the first man to step on the Moon on July 20, 1969, followed by Buzz Aldrin, Pete Conrad, Alan Bean, Al Shepherd, Ed Mitchell, Dave Scott, Jim Irwin, John Young, Charlie Duke, and, number 11, Gene Cernan.

 

Copyright © by Harrison H. Schmitt, 2018. All rights reserved.