Stand-Up EVA (original) (raw)

Corrected Transcript and Commentary Copyright © 1996 by Eric M. Jones.

MP3 Audio Clip( 15 min 31 sec ) by David Shaffer

106:41:15 Allen: And, Falcon, you are Go for depress.

106:41:20 Scott: Roger; understand Go for depress.

[Readers should note that, according to the Apollo 15 Final Lunar Surface Procedures document, Dave and Jim had planned to start the SEVA at about 106:10. Consequently, they are about 30 minutes behind the nominal timeline.]

106:41:27 Scott: Okay, we're down almost to 5 on the gauge.

106:41:32 Irwin: Okay.

106:41:33 Scott: CB(16), ECS: Cabin Repress, open.

106:41:36 Irwin: Cabin Repress coming open. (Pause) Open!

[By opening this circuit breaker on the panel ( CB(16) ) at Jim's right shoulder, they are preventing any possibility that the ECS will try to repressurize the cabin once they open the dump valve.]

106:41:42 Scott: Okay, overhead or forward dump valve Open, then Auto, at three and a half (psi). (Pause)

[Jim will open the dump valve in the hatch until the cabin pressure drops to 3.5 psi. At that point, he will close it by going to the Auto position so that they can monitor the response of the Suit Circuit to the reduced cabin pressure.]

106:41:51 Irwin: Going Open.

106:41:53 Scott: I'll call you at 3.5.

106:41:54 Irwin: Okay.

106:41:56 Scott: 4.5, 4.0. Mark; 3.5.

106:42:02 Irwin: Okay, back to Auto.

106:42:06 Scott: Verify cabin pressure 3.5, LM suit circuit lockup at 4.3. Okay, the LM suit circuit about 4.5 (psi). (Pause) And it's (pause) stable. (Pause)

106:42:33 Scott: Locked up?

106:42:35 Irwin: Yeah, it looks like it's locked up.

106:42:36 Scott: Say again?

106:42:37 Irwin: Yeah.

106:42:38 Scott: Okay, overhead...I mean, forward dump valve to Open and verify LM suit circuit 3 (garbled, but undoubtedly '3.6 to 4.3').

106:42:44 Irwin: Okay, I'm going Open. (Long Pause)

106:43:00 Scott: Okay, coming off the peg. (Pause)

106:43:09 Irwin: Ready to turn the card?

[Rather than using the Surface Checklist Book, they are using a large cue card which they have mounted on the panel in front of them.]

[Scott - "The Cue Cards were a major and formal part of the procedures and of the checklist system."]

106:43:11 Scott: Yeah. (Pause) (Garbled) (Long Pause)

106:43:32 Irwin: I'll hold it if you'll push it on there.

106:43:34 Scott: Okay. (Pause)

106:43:39 Irwin: Okay, hatch opening.

[This is the overhead, docking hatch normally used in orbit for transfers between the LM and the Command Module.]

106:43:41 Scott: Okay.

106:43:42 Irwin: "Partially open the overhead hatch."

106:43:44 Scott: Okay.

106:43:45 Irwin: I'll read to you.

106:43:47 Scott: Okay, go.

106:43:51 Irwin: "Partially open the overhead hatch." (Pause)

106:44:02 Scott: Okay. (Pause)

106:44:06 Irwin: Is it open, Dave?

106:44:08 Scott: Well, I guess. (Garbled) Okay, it's partially open.

106:44:12 Irwin: Okay, I'm going to go Auto on the dump valvehere.

106:44:15 Scott: Okay.

106:44:17 Irwin: Okay, I'm Auto on the forward dump valve.

106:44:19 Scott: Okay.

106:44:20 Irwin: Okay. "Overhead hatch: full open and latched."

106:44:22 Scott: Okay, coming full open. (Pause)

[Jones - "Did the hatch swing down into the cabin and, if so, was it hinged at the back?"]

[Scott - "Yeah, and there's a latch at the back (of the cabin) that locks it in, as I recall. This was a very easy procedure, relatively speaking, and it's interesting, when we got into it, how straight-forward it was - almost to the extent that the LM almost might have been designed to do this."]

[Jones - "I'll have to ask why the 16 and 17 crews didn't do it."]

[Scott - "I don't know, but it was easy to do and I thought we got a lot of benefit out of it."]

106:44:29 Scott: Move over some, Jim?

106:44:33 Allen: Dave and Jim, Houston.

106:44:37 LM Crew: Go ahead.

106:44:38 Allen: Roger. Endeavour places you very near November Crater; very close to November Crater.

106:44:47 Scott: Okay. A little short (that is, east), huh? (Pause)

106:44:54 Allen: A little short and a little north.

[A detail from Pan camera frame 9377, which will be taken in about one hour, shows the LM on the northwest rim of Last Crater. November is the sharp-rimmed crater farther east. The planned landing spot is just off the bottom of the image, about 200 meters south of the southern rim of Last. Stephen Tellier has provided a higher-resolution detail of the area immediately around the LM.]

106:44:55 Irwin: Okay, Dave, you got the hatch open?

106:45:01 Scott: Okay. (Garbled). Forgot about the LCG (garbled) ISA. (Long Pause)

[The Interim Stowage Assembly (ISA) is a set of cloth bags on a frame that fits over Dave's wall-mounted PLSS immediately behind his flight station. An ISA can be seen on the left at Neil Armstrong's back in Apollo 11 training photo KSC-69PC-319. The dialog suggests that Dave has caught his LM hoses on the ISA. The LCG is a mesh garment which, during the EVAs, the astronauts wear over their long-john underwear. The LCG has a network of thin tubes woven through it. Water is circulated through these tubes and carries away excess body heat. A document that Dave found for me in early 1996 indicated that he and Jim did not wear their LCGs during the descent or the SEVA. This leads Journal Contributor Ken Glover to suggest that the LCGs were stowed in the ISA, making it bulky enough to snag Dave's hoses.]

106:45:28 Irwin: Push them (possibly Dave's hoses) out of the way?

[After opening the hatch, Dave will sit on the engine cover and reach up to remove the docking drogue. Once he removes the drogue, he will hand it to Jim who, in turn, will put it on the floor on the left side of the cabin. Here, Dave may be getting himself into position on the engine cover. His hoses come across the cabin from the ECS which is behind Jim's station.]

106:45:29 Scott: Yeah. All right, give me a little...

106:45:35 Irwin: What do you want me to do?

106:45:36 Scott: Nothing.

106:45:37 Irwin: Okay. (Pause) Okay, are you sitting up there now?

106:45:46 Scott: Yeah, just stand by. (Long Pause) Okay. (Pause) Okay, overhead hatch is open and latched.

106:46:45 Allen: Roger.

106:46:46 Irwin: Okay. (Reading) Sit on the engine cover, facing forward, unlock the drogue, and rotate counter-clockwise to release.

106:46:52 Scott: Okay. (Pause)

106:46:58 Irwin: (As per checklist) I'll block the sun from impinging on the instrument panel.

106:47:03 Allen: Well done, Jim. (Pause)

106:47:11 Irwin: (I'm a) shadow device. (Long Pause)

[Jones - "Why was it necessary to shade the instrument panel?"]

[Scott - "So it won't get too hot. It wasn't really designed to take the heat."]

106:47:24 Scott: Okay, Jim. Drogue's coming out.

106:47:28 Irwin: (Garbled) helmet.

106:47:31 Scott: Yeah. You're breaking up again.

106:47:32 Irwin: I just (garbled).

[Dave is probably handing the drogue to Jim.]

106:47:34 Scott: Why don't you...Wait, wait. (Watch out for the) utility lights. That a boy. Okay, you got it?

106:47:39 Irwin: I've got it. (Long Pause)

[Scott, from the 1971 Technical Debrief - "(Getting the drogue out) was very similar to the one-sixth-g airplane exercises we had."]

106:47:52 Irwin: Okay.

106:48:01 Scott: Give me the next step (in the procedure). (Pause) Go ahead, Jim; read the next step.

106:48:15 Irwin: I know. Just a (garbled).

106:48:16 Scott: Oh. (Pause)

106:48:27 Irwin: Okay. (Reading) "Stand on the engine cover."

106:48:32 Scott: Oh, okay. Why not?

106:48:34 Irwin: Get to work.

106:48:35 Scott: Very easy.

106:48:37 Irwin: Master Alarm.

106:48:38 Scott: (Garbled) (Pause) Turn up the...The Annun-Num lights there.

[The brightness of the Annunciator/Numerics lights on the control panels can be adjusted.]

106:48:48 Irwin: Don't see anything.

106:48:51 Scott: Oh boy, what a view. (Pause)

[Scott, from the 1971 Technical Debrief - "When I stood up in the top hatch, I found that, because of the one-sixth gravity, I could support myself on my elbows without having to stand on anything, and get fairly well out of the hatch."]

[Including the suit, Dave's mass is nearly 300 pounds (135 kg). However, in the one-sixth gravity, his weight is 50 pounds (23 kg).]

106:48:56 Irwin: Okay, there's nothing to go along with that Master Alarm.

106:48:59 Scott: Okay...

106:49:00 Allen: Falcon, select (water) separator number 2, please.

106:49:02 Irwin: Everything's looking good. (Hears Allen) That's water separator 2?

106:49:10 Allen: Roger, water separator 2, Jim.

106:49:13 Irwin: Okay, can you...(Stops to listen to Allen) Okay; stand by, Joe.

106:49:19 Allen: Roger. (Long Pause)

[The flow of oxygen through the Suit circuit is driven by a fan and, at one point, flows through a centrifugal water separator which removes excess moisture. The water separator normally spins at 2400 revolutions per minute but, for some unknown reason, has slowed to 800 rpm, triggering the Master Alarm.]

[As indicated in the Apollo 15 Mission Report, "Cabin atmosphere is cooled and passed through one of the water separators where condensed water is separated by centrifugal force and picked up by a pitot tube. The water is then piped from the pitot tube, through a check valve, to the water management system where it is used in the (spacecraft) sublimator. Cabin humidity was high before the SEVA and, because the water and structure were cold, the line between the water separator pitot tube and the water management system was cold. Under these conditions, water would condense on the outside of the line and, when the cabin was depressurized for the SEVA, the water on the outside of the line would boil, freeze, and sublime, thereby freezing the water in the line. Analysis shows that as little as a 0.01-inch film of water on the outside of the line will freeze the line at cabin depressurization. Freezing within the line will cause the separator to slow down and stall because of excess water. Separator 2 had not been used. Therefore, no water was in its outlet line to freeze. Consequently, it operated successfully when activated. Analysis and tests have shown that freezing of the line will not damage any spacecraft hardware."]

[Jim will now put the backup separator on line. They will operate Separator 2 for about an hour before switching back to Separator 1, which will then run properly for the rest of the mission. See, also, Houston's preliminary explanation at 107:22:23.]

106:49:31 Irwin: Stay there, Dave; I'm going to give them Sep 2.

106:49:33 Scott: Okay, go ahead. (Long Pause)

106:49:42 Irwin: Okay, I have Sep 2 selected, Joe.

106:49:47 Scott: Will you reset the Master Alarm, Jim?

106:49:49 Irwin: Yeah.

106:49:50 Scott: Okay.

106:49:52 Allen: Roger, Jim. We think you may be pinching hoses back there somehow.

106:50:01 Scott: No, they all look clear, Joe.

[During our Apollo 15 review, Dave and I had an extended discussion about the reasons for doing the SEVA.]

[Scott - "One of the drivers in the whole plan of the mission was (24-hour) circadian rhythm. But let me give you a little background. I got this great training. I can't tell you how good it was that I got all these things as we went along. After Test Pilot School at Edwards, I went into a subsequent school called the Aerospace Research Pilot's School, and that was more of a kind of Space Cadet kind of thing. Great flying. Pressure suits. F104s to 100,000 feet. It was great. I mean, that was the Right Stuff stuff. But, in that course, there was also an excellent academic program, and an Air Force Colonel named (Robert S.) Buchanan was running it, who was really quite bright, forward thinking."]

["The program, in that form, only lasted maybe five or six classes before the Air Force decided, essentially, to get out of space. They canceled the MOL (Manned Orbiting Laboratory, a small space station), canceled the X-15, and canceled the Dyna Soar. The Air Force went and buried its head in the sand. But during the process of the build up in '62/63, they sent us to Brook Army Medical Center in San Antonio for two weeks of what I would call physiology. Two weeks to teach us to be a doctor. And, at the time, the thought was, when you get into space and your buddy has appendicitis, you're going to have to perform an appendectomy. No, I don't think anybody would ever do that. But, you got to remember, at that time there was a lot of mystery about the body and space. I mean, the Mercury guys hadn't even eaten anything, yet, in zero-g."]

["So, there was all this mystery, and they sent us to this school. Which was marvelous. It was probably one of my best academic experiences, by a long shot. I guess we had about ten hardened fighter pilots with the (reluctant) attitude 'Okay, we'll go down there and go learn about medical stuff'. The school was handled so well, and the instruction was so superior, that the fighter pilots, instead of going to the bar to drink beer at night, went home and studied the books. We took monkeys apart. We even observed a real autopsy. I mean, boy, we got exposed to the whole nine yards. So that was, in my view, one of those learning experiences from which I benefited later on. I got aware at that time of circadian rhythm and what it does. Not that we had any course in it, but I learned that you're not quite as good when you're off your cycle. You can tell me it doesn't bother you, and I'll believe you. But, if you were to put an athlete to test in the Olympics, the guy on his circadian rhythm is going to be better than the guy who is not on his circadian rhythm. Not by much, but if you take the Olympics as an example, a hundredth of a second and you win."]

[Jones - "So you'd better get to Barcelona a week or two before your event."]

[The 1992 Barcelona Olympics had taken place only a few months prior to this discussion. Also, see the discussion following 138:20:37 for an explanation of the expression 'the whole nine yards'.]

[Scott - "Absolutely. I'm convinced of that. And I could see it in my own performance, after I had gone through this course and become aware. I learned that I didn't want to take my buddy's appendix out because, holy cow, look what can go wrong when you do that! And that's when I started jogging - which I still do - because I got to see them pull a heart out and I got to see what it looks like when you haven't taken care of yourself. When you're not a doctor and you don't have that inclination, those things really stick with you."]

["So I got sensitive to circadian rhythm, and I can tell you, from my performance - and I think in Jim's and Al's, too - if you're on the circadian rhythm, you're that much better. So I figured that, when you went to the Moon, you want to be absolutely on. So, one of the things we did, for the mission, was to schedule the mission on Houston time. And, to do that, you had to do something (because landing time was dictated by lighting conditions). Now, as you mention (in the Apollo 15 Summary), we had been awake for 11 hours when we landed and would have had a 26-hour day if we tried to do a full EVA. So that was a contributor, too, to the decision. I don't know which was the main driver. But I do know that, in all the discussions of mission planning and flight planning, a consideration - not a dominant consideration but a vote with some weighting - was, hey, let's be on Houston time, because we're going to be better. Or Cape Time, but not twelve hours off. If you're twelve hours off, you're not going to sleep well. You're just not going to be there. So this Stand-up EVA, among other things, was a result of mission planning and what are you going to do when you get there."]

["A lot of people said, 'Gosh, how can you go to the Moon and go to sleep, without getting out?' Well, Jim and I used to talk about some of these quasi-philosophical things, so we were on the same frequency. Neither one of us thought we'd have any problem. I mean, it is a big deal, but it's also your job. And, if you're tired, you go to sleep. And that's why we slept well, I think. I slept well; I think Jim slept well. Remember, 'sleep' was an essential element of a J-mission. But, getting to the Moon and doing a Stand-up EVA took the edge off."]

["The SEVA was a marvelous and useful experience for a lot of reasons. One of our problems at Hadley was that the resolution of the Lunar Orbiter photography was only like 20 meters, as I recall. So they couldn't prepare a detailed map. There wasn't anything to map. The maps we had were best guesses. And we had the radar people tell us before the flight that there were boulder fields - massive boulders - all over the base of Hadley Delta (where they planned to drive on both EVAs 1 and 2). Just boulders everywhere. And the photography people said "No, there aren't, but we only have 20-meter resolution, so we can't be sure.' So another reason for the Stand-up EVA was to look and see if we could drive the Rover. Because if there were boulder fields down there - and nobody could prove there were no boulder fields - it changed the whole picture. And if you had rocks the size of those in the Rille (that they saw from Station 2 near St. George Crater on EVA-1), you can't drive the Rover there. No way. So, another reason for the Stand-up EVA was to look, because we didn't know what we had."]

[Jones - "I had never heard that."]

[Scott - "And that's another one of the parts of the methodology, and all the people who had roles. The reason that came up was because the radar guys briefed us, in one of our geology sessions. The radar people came in to tell us what they saw on the surface. And the discussion had nothing to do with driving the Rover; it had to do with geology. Which is another benefit from the interdisciplinary interaction, when you have people who are sensitive to all issues listening to other issues. So, when somebody tells me from a geological point of view there are a lot of boulders down there, and I have to drive the Rover, I'm sensitive to that, and I say, 'Wait a minute, man! If you're telling me there are boulders there, I can't drive my Rover.' So that's why that whole method of bringing this all together was so valuable, in my view."]

[Jones - "Did you get a distinctly better view of the countryside in the SEVA rather than out of the windows?"]

[Scott - "Oh, yeah. Oh, without a doubt. The windows are very restrictive. And the SEVA, boy that was a rush. To be able to stand there and just look at all that stuff. I mean, that was just a mindblower to be able to just stand up there and gaze around and report what you saw, knowing full well that the Lee Silvers and the Gordon Swanns and the guys in the Backroom are listening to every word."]

[Jones - "Salivating"]

[Scott - "Oh, yeah. Because they did that on our field trips. And we had to push pretty hard to get the SEVA. We had to convince a lot of people that it wasn't dangerous. 'Cause, at the time 15 went, you were beginning to have this apprehension in the system, because the reason for Apollo was to send people to the Moon and bring them back. 'We've done that; so, let's stop now, because we've already taken the risk and we're ahead.'"]

[Jones - "And we've had one close call, already, with Apollo 13."]

[Scott - "Yeah, and maybe we ought to not do this any more. So, you start getting this - and I don't know how to describe it, but I was aware of it as missions went on - this apprehension. 'Don't do anything wrong. Let's get it over with.' It's sort of fingernail (biting) time. So, when we broached the idea of a SEVA, it was poorly received by management. 'You what?! What are you talking about?' And we had to push pretty hard to get it."]

[Jones - "Were they concerned about getting the drogue and the hatch all put back together again properly."]

[Scott - "Well, yes. But that was pretty well put to rest because it was very simple on the LM side. But still, there was always a question about screwing up the hatch seal...A lot of things could go wrong; and management had to make a trade-off of risk versus gain. You don't want to take unnecessary risk; and, if you do take a risk, you want to make sure you get something out of it. Fortunately, we had a bunch of people in the world of geology who supported us, who said "yes, that will be useful geologically.' And we could justify a lot of it based on the Rover driving. The probability was we wouldn't (find boulders), but the possibility was there. So we could justify it from a lot of reasons. Timing, geological productivity, hazard avoidance driving the Rover. Getting familiar with the situation, which is always good. There were a lot of reasons and, obviously, we finally got it justified."]

[Jones - "One of the obvious benefits is that you had a stable platform for the 500-mm camera lens. The pictures you took of the North Complex during the SEVA are the best ones you took. You get a little better perspective from up on Hadley Delta; but, boy, the ones you took during the SEVA are nice steady images."]

[Scott - "Yup. And the 500 is another story. Again, it comes from geology. On a field trip, we asked 'why not take a telephoto of this'? 'No telephoto cameras on Apollo.' 'Well, can you put a telephoto lens on a Hasselblad?' 'Gee, I don't know. We'll look.' 'Yeah, you can, but it weighs a pound and something.' 'Well, so that?' 'Well, you can't use it on the Moon.' 'Why not?' 'Oh, you'll never be able to hold it steady on the Moon.' 'Why not?' So we spent a lot of time and energy justifying the 500-mm lens. And the final trade-off was in abort propellant. They reduced the amount of abort propellant on the landing by whatever the mass of the telephoto lens was. And Rocco Petrone (the Apollo Program Manager) made that decision. We had to push very hard to get a 500-mm lens. There was a lot of skepticism on whether it would be useful at all. And we were always pleased that it was useful. But, gosh, you go out in the field with a bunch of geologists and you can't get to the mountain and it becomes obvious that a telephoto picture is a lot better than nothing. And yeah, we got some great pictures, because it was pretty easy. You point the dude and you've got a great scene out there to take pictures of."]

[Jones - "Did you have a gunsight on yours?"]

[Scott - "The ring sight. Yeah."]

106:50:05 Irwin: Okay, Dave, you ready for me to hand you the map?

106:50:07 Scott: Yeah. I can see Pluton and Icarus and Chain; Side, of course, St. George, Window, Spur.

[Pluton, Icarus, Chain, and Side are craters in the North Complex. St. George is a very large crater on the north west flank of Mt. Hadley Delta, and Window and Spur are smaller craters on the flank of the mountain farther to the east. See the pre-flight map showing crater names and, as well, Pan Camera frame 9377, which will be taken in about an hour on Al Wordon's next pass over the landing site. The lighting on 9377 is, of course, virtually the same as what Dave is seeing during the SEVA.]

106:50:27 Scott: Beautiful!

106:50:28 Allen: Fantastic.

106:50:29 Scott: Okay, let's get a good fix; hand me the compass there. (Long Pause)

[Scott, from the 1971 Technical Debrief - "(I had a) very good vantage point, primarily because we landed on a topographic high. This proved helpful; subsequently, when we were great distances from the LM, many times we could locate it."]

[In Houston, the Flight Director is informed that, if the SEVA extends past 106:58, it will eat into the rest period.]

106:50:44 Irwin: Dave?

106:50:45 Scott: Okay.

106:50:48 Irwin: Want the map?

106:50:50 Scott: Just the Sun compass first. Let's get a pick on our position. (Pause)

[Jones - "Did the Sun compass have a little gnomon/shadow device so that you could get it properly aligned?"]

[Scott - "It was a card on which a circle was drawn with the highlights of the topographic features, the mountains around and the angles and a little flap that you would raise and align with the Sun so that the shadow fell within the marks on the map. And that would orient the card to where it should be and then you could look out at the mountains to see if they lined up. It was a backup navigation system for the Rover. If your Nav system didn't work and you couldn't see the LM, you could align this Sun compass with the mountains and you could point your way home. Great little device. Cheap. A piece of paper. Clever. I don't know who came up with it and, in fact, I often wonder did the other guys carry the same thing on the subsequent flights. (They did not.) It was a great get-me-home device."]

[Jones - "The attitude that the 16 and 17 guys had - which I think grew out of your experience - was that they had plenty of recognizable horizon features and could use those to get close enough to find the LM. You more or less knew where you were, relative to the LM, and drove toward the appropriate horizon feature and there you were."]

[Scott - "I think that's probably true."]

[Jones - "And it's not like there are a lot of Rover tracks around, either."]

[Scott - "We'll get into the Rover track thing but, prior to the flight, nobody had ever been over the horizon and there was a lot of discussion on the Nav system. And that ended up with the single-string gyro system, which worked pretty well."]

[Journal Contributor Rob MacLachlan notes that in NASA-ese 'single string' refers to a non-redundant system.]

[Dave Scott commented in a December 2004 e-mail, "Not only was the sun compass a backup to an unproven -for A-15 - single-string nav system on the Rover (i.e. if the nav system failed, or in our case, since the first use, if it were not accurate), the sun compass could have been essential in the event of a time-critical return to the LM. Perhaps the following rough example will illustrate our thinking before the mission - and why a very cleaver chap came up with the sun compass. A simple piece of paper - the stiff back of a checklist - reduced the overall risk of the surface expedition. Why not? The only additional weight was the bubble level and the ink!"]

[We return to the 1992 mission review.]

[Scott - "There was a lot of discussion of the kind: if you're over the hill, do you always stay on a route that you go back on your tracks, or do you circle around? Well, we planned to loop around and come back. But there was some uncertainty as to whether you could get yourself pointed toward where the LM was. You might get pointed but it wouldn't be directly at the LM and you could essentially circle the LM, never seeing it because you're over the horizon - because we didn't know what 'over the horizon' meant. If your sitting on the Rover - or even standing - you're relatively low and somebody calculated that you don't have to drive very far to go over the horizon. And, if you're doing a looping exercise, we had contemplated before we went that you could get lost in terms of circling the LM, always being over the horizon and never finding it. Not that you couldn't eventually find it - you probably would - but you might run out of oxygen or water before you got there. So one of the reasons for the Sun compass was to ensure that we had some fairly well defined capability that somebody had practiced with on the Earth. And it was pretty clever. It gave us another backup. Then, when we got there, we found out it wasn't hard and the Nav system on the Rover worked great."]

[Jones - "There's enough topography that you just get up on a high place and, bang, there it is."]

[Scott - "It wouldn't be bang, even thinking about it now. If you're offset in your alignment, the distant features look the same. So if I'm out 5 kilometers and offset two kilometers and if the horizon's a kilometer and a half, and I head for a mountain which is 15 kilometers away, I'll pass right by the LM and never see it. Because, if I'm heading direct for the mountain on a parallel path that's over the horizon, laterally, I'll go by the LM and never see it. You do have that problem, because the horizon drops off so quickly on the Moon. I'd never really thought that much about it, but that would be an interesting exercise for somebody."]

[During the second Apollo 16 traverse, John Young and Charlie Duke drove south of the LM to Stone Mountain and, on the return journey, looped around to the northwest to visit some sites that were west of their outbound track. Part way back, the Nav system stopped working - probably because a switch was accidentally reset. Young could see Smoky Mountain on the horizon north of the LM but could not see the spacecraft and, in order to intercept his outbound track, aimed the Rover a little farther east than planned. As they got close to where they thought the LM was, they topped a ridge and the spacecraft was right in front of them.]

106:51:07 Irwin: And, actually, at this Sun angle, Joe, there's no direct sunlight coming into the cabin.

106:51:10 Allen: Roger, Jim; understand. (Long Pause)

106:51:25 Scott: Okay, hand me the big overlay map, Jim.

106:51:28 Irwin: Okay. (Pause) Let me know when you're ready for the camera

106:51:41 Scott: Okay.

106:51:42 Allen: And, Falcon; Houston. It looks like water separator 2's holding up fine.

106:51:49 Scott: Okay. Good, Joe. (Long Pause) Okay, Joe, our bearing to Icarus is 338.

106:52:18 Allen: Copy. (Long Pause) And, Dave, be advised we're going to be hustling you along here. We think we know pretty well where you are (based on Al Worden's observation), so maybe we shouldn't spend too much time just on location.

[Note that Joe makes this transmission on his own initiative, conscious that the Flight Director wants to keep close to the timeline.]

[In principle, these bearings can be used to triangulate an accurate LM location. However, since there is no doubt that they are relatively close to the planned landing site, the remaining uncertainty will not cause any revision in the planned EVA-1 traverse. Note that, at a distance of 4 kilometers, which was typical for these sightings, an error of one degree would translate to a LM location uncertainty of 70 meters.]

106:52:53 Scott: Okay. (Pause) Another quick one. Bennett Peak is 255.

[Bennett Peak - more usually Bennett Hill - was named by the crew for guidance expert Floyd Bennett, who designed their descent trajectory.]

106:53:04 Allen: Roger. (Pause)

[In Houston, the Flight Director tells Joe that Dave should get one or two more bearings. "It won't take long to get 'em."]

106:53:11 Irwin: Hey, Dave; and (as per checklist) the first camera work (that is, the first photographic task)'s with the 60-millimeter lens.

106:53:14 Scott: Okay.

106:53:15 Allen: Rog, Dave; maybe one more bearing.

106:53:20 Scott: Okay, coming up. (Pause) Make Hadley Delta at about 182.

106:53:27 Allen: Roger.

[Because all of the features mentioned are fairly large, Dave must be sighting on some predetermined points.]

106:53:29 Scott: Here you go, Jim. (Handing down the compass)

106:53:33 Allen: (Passing on a request) And, Dave, a bearing on a close feature if you can identify it, please.

106:53:39 Scott: No, I can't right now, Joe.

106:53:42 Allen: Roger.

106:53:43 Scott: I'll get on with the photography here.

106:53:45 Allen: Roger; we agree. (Pause)

106:53:54 Irwin: Okay, you want 22 frames in the stereo pan, Dave.

106:53:59 Scott: Right.

[This black-and-white pan (assembly by Dave Byrne) includes frames AS15-85-11353 to 11382.]

[The f-stop settings used relative to the direction of the Sun are shown on decals mounted on the tops of the film magazines. 'HBW' is High-Speed Black-and-White and 'HCEX' is High-Speed Color Exterior.]

[The current time is 0028 GMT/UTC on 31 July 1971. The solar azimuth and elevation are 96.4 and 13.4 degrees, respectively.]

106:54:03 Allen: And, Dave, while you're firing them off there, does the trafficability look pretty good?

106:54:12 Scott: Yeah, it sure does, Joe. The largest fragment I can see right now on the surface (near the LM) is probably about 6 to 8 inches; however, inside the walls of Pluton, there's some pretty big chunks.

106:54:33 Allen: Roger. (Pause) We'll worry about those when we start driving in Pluton.

[Frame AS15-85-11359 shows these boulders. They are about 3500 meters from the spacecraft.]

106:54:38 Irwin: Dave, can you see the edge of the rille?

106:54:45 Scott: Nope. (Pause)

[Jim is asking about the closest portion of the rille, due west of them. Photo AS15-85=11356 shows a bend in the rille in the direction of Hill 305.]

106:54:51 Allen: And, Dave, while you're swinging (turning) around there, do you know if you can see November (Crater) yet or not?

106:55:01 Scott: I don't, Joe. I better try and get some photos here and then start thinking...

106:55:06 Allen: Roger.

106:55:07 Scott: ...about looking around. (Long Pause) I think, probably, we owe you the photos first.

106:55:23 Allen: Roger. We agree.

106:55:29 Irwin: When you're finished with that, Dave, I've got the 500 handy.

106:55:32 Scott: Okay. (Pause) Okay, Jim. Here's the 80 (sic; means "60").

106:55:48 Irwin: Okay. I've got it.

106:55:49 Scott: Okay. 500, now?

106:55:51 Irwin: Got it. (Long Pause)

[Dave and Jim have three 70-mm Hasselblad camera bodies, where "70-mm" refers to the film format. Two of the camera bodies are equipped with lenses of 60-mm focal length. One is loaded with black & white film and the other with color. The third camera has a 500-mm lens and is loaded with black & white film. Dave has been using the 60-mm B&W camera and has just exchanged it for the 500.]

106:56:25 Scott: Okay, Joe. I'm taking a picture now of that bright, fresh crater just to the south of the rim St. George.

[Dave takes two pictures of the crater: AS15-84-11235 and 11236.]

106:56:42 Scott: And now over to Spur and Window, I believe.

[According to the Apollo 15 Photo Catalog, photo 11237 shows Contour Crater which is high up on the northern flank of Mt. Hadley Delta.]

106:56:44 Allen: Roger. (Pause) (Passing on a reminder from the Flight Director) And, Dave, we're coming up on 15 minutes SEVA.

106:56:54 Scott: Okay. (Long Pause)

[Here, Dave is taking a 500-mm pan of Hill 305 (assembly by Dave Byrne). The frames are AS15-84-11238 to 11241.]

[Jones - "Hill 305 has a number for a name. How come?"]

[Scott - "Probably the elevation of that hill was 305 meters above something, because that's the normal way the Army designates a hill."]

[In June 2003 it occurred to me that a more likely explanation is that the name refers to the azimuth of the summit as seen from the landing site which is, indeed, about 305 degrees (east of north).]

[Next, Dave takes a mini-pan covering the North Complex. These photos are AS15-84-11242 to11246. Dave Byrne has combined low-resolution versions of 11242 and 43 as a portrait of Pluton and frames 11244 to 11246 as a portrait of Chain Crater.]

MP3 Audio Clip( 20 min 46 sec ) by David Shaffer

106:57:23 Irwin: When you finish with the 500, Dave, I have the other camera.

[The third camera has a 60-mm lens and a color magazine.]

106:57:25 Scott: Okay. Try not to hit my foot there. (Long Pause) Looking back into the Sun is almost useless, Joe. Really blots everything out.

[Dave has turned to the east to take a mini-pan of the base of Mt. Hadley (assembly by Dave Byrne). These are AS15-84-11247 to 11249. He will get much more extensive coverage of the mountain from Station 6 on the flank of Hadley Delta during the second EVA.]

106:57:57 Allen: Rog, Dave. Any sign of the big mountain back there?

106:58:02 Scott: Yeah. You can see Big Rock Mountain back there!

106:58:07 Allen: Roger. Copy Big Rock Mountain. (Long Pause)

[Big Rock Mountain is named for Rocco Petrone. Note that, at 106:57:57, Joe was not passing on a question from the Backroom but, rather, was reminding Dave to mention Petrone's mountain.]

[Dave is taking 500-mm photos of Mt. Hadley Delta, starting with the striking feature known as Silver Spur, named for Caltech geologist Lee Silver. These photos are AS15-84-11250,11251, 11252, 11253. Mini-pan assembled by Dave Byrne. Compare the view of Silver Spur in 11250 with the one shown in AS15-82-11121 which taken at Station 9A and has a similar viewing angle but a much higher sun elevation. See, also, a discussion of the appearance of Silver Spur in the Apollo 15 Preliminary Science Report.]

106:58:22 Scott: Okay. Here, I'll give you this one back, Jim.

106:58:26 Irwin: Okay.

106:58:27 Scott: I think we'll get a chance to get a lot more of those (500-mm photos). Okay. Got it.

[Comm Break. Dave now has the camera with a 60-mm lens and a color magazine. The photos in this color pan (assembly by Dave Byrne) are AS15-87- 1175811730 to 11758. David Harland has assembled a high-resolution version of the portion showing Hadley Delta and Silver Spur(1 Mb). Marv Hein has created a VR version of the pan.]

[Frame 11732 shows Hill 305, which is on the west side of the Hadley Rille. ]

[Frame 11747 is a good photo of Silver Spur and the Swann Range, named for U.S. Geological Survey geologist Gordon Swann.]

[Frame 11748 shows Silver Spur. Last Crater is in the foreground, with a smaller, fresh crater in its east wall, as can also be seen in a detail from Pan Camera frame 9377.]

[Frame 11752 is centered on Mt. Hadley Delta; and frame 11753 shows St. George Crater on the northwest flank of Mt. Hadley Delta.]

[In Houston, the Flight Director asks the Backroom to ready their "four or five most pertinent questions" for Dave.]

107:00:03 Scott: Okay, Joe. We've got all the photos. (Handing the camera down) Here you go, Jim.

107:00:07 Irwin: Okay. I got it.

[Next, Dave will describe the scene for the geologists in Houston.]

[Jones - "What is the purpose of the horizon description?"]

[Scott - "Just to describe the general geological setting. What's there, what's it look like, how you relate it from one place to another, are there any surprises, anything that we didn't expect?"]

[Jones - "Is it a way to get you to look at it in a systematic way?"]

[Scott - "Yes, in a sense. But it's a way to explore the area, to go look at it. On field trips, we would often sit down and look at a mountain and draw a map. Just sit there and look at it. And, if you do that, you learn an awful lot. The visual of all this is so important and I thought that was one of the interesting training tools they used with us. Sit down. There's a mountain. There's a lot of things on that mountain. Draw a map of it. And that forces you to put it all down and start thinking about the relationships. So this was to (A) describe what's there and (B) to sort of set the tone, get the geological relationships. What is it we're looking for? What do we see? And you know, thelineations in Silver Spur were something new. That's was the first time anybody had seen that; and they were very dominant, it was very clear."]

[Jones - "No ambiguity about lighting effects."]

[Later, they will see striking lineations on Mt. Hadley which, upon analysis after the mission, seemed to many analysts to be due to lighting effects and not to structure in the mountain. In the case of the Silver Spur lineations, however, Dave was probably seeing actual layering in the mountain.]

[Scott - "That kind of thing. Stand up, what do you see? Are there boulders? What's the general setting? What can you observe that would be useful, so that the Backroom can go think about that overnight and decide if they want to change anything. Maybe they hear something that triggers some linkage to something else. It's a verbal description of what's there. Too bad they can't see the photographs or TV, but it gives everybody a general idea of what the general picture is. And, then, are there any surprises, anything unique which enables to Backroom to think about and maybe tomorrow morning they'll have something to say that they will want to look at as a result of the lineations, as an example. And that goes back to having spent many field trips with those same guys over the hill with Joe Allen playing CapCom. During the field exercise, we sit and we describe the area. So they learn what we mean, and we learn from them what it is we're supposed to be looking for. And it's just a communications linkage that has built up over a long period of time. It's not the first time we've done this. We've done this kind of description many times for Lee Silver, Gordon Swann, Jim Head, etc."]

["The guys in the Backroom probably got more out of it than we would just reading it, because they're in the interpretation phase and their job is to know the area very well and quickly start making interpretation so they can take the next step in the exploration and get more out of what we're going to try and do."]

[Jones - "They've been staring at the available photographs for months - if not years."]

[Scott - "Yeah. They're experts and they can read into this, perhaps, things that can give them an insight into what's going on and enable them to decide, maybe, that we ought to go do something on the first EVA that we hadn't planned. That's one reason I thought it was a pretty valuable exercise, because it gives everybody a chance to settle down. It's the first hit in the ball game. (Mixing metaphors) It's the first basket. It's the first inning and, when it's over, everybody settles down and starts thinking about what's really there, start focusing about the geology. It gives everybody a running start. And actually, it gives us a fourth period of exploration. Because we've gotten past the initial start-up, and the initial overhead. You know, when you get into these things and you start going in geology, you've got a lot of buildup time, a lot of overhead time. Get people working together, get people thinking together, get people focused on what's there, and this gets all of that for you, free. Which means that now, when we get out tomorrow on the Rover and start going, everybody's up to speed. We're into the second inning or the second quarter and the system becomes more efficient."]

107:00:09 Scott: Okay. And let me start by 12 o'clock (west), Joe, and I'll go around real quick. On the far distant horizon, apparently across the rille, I can see - just about our 1 o'clock, now - a very large mountain, which I'd have to callHill 305.

107:00:31 Allen: Roger.

107:00:32 Scott: And all of the features around here are very smooth. The tops of the mountains are rounded off. There are no sharp jagged peaks or no large boulders apparent anywhere. The whole surface of the area appears to be smooth, with the largest fragments I can see are in the walls of Pluton. There are no boulders at all on St. George, Hill 305, Bennett (Hill), or, as far as I can tell, looking back up at Hadley. Hadley's sort of in the shadow.

It's a gently rolling terrain completely around 360 degrees; hummocky, much like you saw on 14. The ridge line across the rille, from Hill 305 around to 1 o'clock, seems to be slightly lighter in albedo, with some white marks from craters - recent craters, apparently. Bennett Hill also has a lighter-colored albedo. One face of it - that facing the Sun, now - is almost completely white.

As I come around to my 2 o'clock, the horizon is really the Northern Complex. I can see, as I mentioned before, Chain, Icarus, and Pluton are very rounded, subdued craters. It looks like the southern rim of Pluton is on the same level as our location here. The northern rim is somewhat higher. I'd say - distances are difficult - but maybe 50 meters higher. I can see the scarp on the other side of the north rim of Pluton. All of it very flat, smooth, and gently rolling.

The inside walls of Pluton are fairly well covered with debris; fragments up to, I'd estimate, maybe, oh, 2 to 3 meters. Irregular (distribution); no layering; just sort of scattered around, and maybe the walls have 5 percent (of the surface covered with) fragments.

[According to the caption to Figure 3-19 in the Apollo 15 Preliminary Science Report, the largest boulder visible in Pluton is about 20 meters across.]

As I look on around to the north, Mount Hadley itself is in the shadow, although I can see that the ridge line on the top of Mount Hadley. It too is smooth. I see no jagged peaks of any sort. The hill I would call number 22 on your map - in the far distance - also looks smooth (and) rounded; no prominent features. I'll skip the distant field around to my 6 o'clock, because it's all in the shadow. And looking into the Sun, of course, obliterates almost everything. As I look on down to my 7 o'clock, I guess I see Index Crater (almost certainly Last Crater) here, (in) the near field. But, back up on Hadley to the east...Hadley Delta, why, again I can see a smooth surface. However, I can see lineaments. I'll take a picture for you. There's some very interesting...Take Silver Pass (sic) and look at 13 on your map. I can't tell whether it's 13 or 16, right now, because of the Sun. But there appear to be lineaments or lineations running...(correcting himself) dipping to the northeast, parallel (to each other). {See photos AS15-87-11748 and AS15-84-11250.} And they (meaning the lineations) appear to be, maybe, 3 percent to 4 percent of the total elevation of the mountain, almost uniform (spacing). I can't tell whether it's structure or internal stratigraphy or what. But there are definite linear features there, dipping to the northeast, at about, oh, I'd say 30 degrees.

And, as I look up to Hadley Delta, itself, I can see what appears to be a sweep of linear features that curve around from the western side of Hadley Delta on down to the (Silver) Spur down there. And they seem to be dipping to the to the east at about 20 degrees. These are much thinner lineations on the mountain than I saw before. These probably are less than one percent of the total elevation of the mountain. The craters on the side of Hadley Delta are rather few. Around Window (Crater) and Spur (Crater), those that you see on your maps are the only ones I can see, and there appear to be, oh, about a dozen up in that particular area. I might associate those with the Secondary Cluster (also known as the South Cluster, a group of craters possibly created by the impact of ejecta from the craters Aristillus and/or Autolycus which are 150 to 300 km north of Hadley), if I took a guess at it. I see nothing that indicates any flow down - or a landslide - down Hadley Delta, only some subtle changes in topography. There's one bright, fresh crater right next to St. George on the eastern side which is almost white in albedo; and it's got an ejecta blanket about a crater diameter away. How are you copying so far?

[While Dave talks, the Flight Director asks the Backroom if they need any comments on the near-field and, in particular, comments about the planned ALSEP deployment activities. The Backroom tells Flight that they would like some additional description of the area around the LM but, otherwise, probably now have everything they need. Dave's comments are, of course, being recorded for the Backroom's consideration during the rest period.]

107:05:54 Allen: Superb description, Dave! Got every single word. Beautiful. And we'll ask you to hustle on around and give us something on the near-field, plus a comment on ALSEP deployment possibilities. Superb communication, though. Beautiful!

107:06:11 Scott: Okay. Coming on around to St. George, it again is a very subtle old crater, but in this case, I can see some lineaments dipping to the west at about 20 degrees, parallel to the rim of the crater. These, too, are very small, less than a percent, and continuous (and) parallel. The rim of the crater is very subdued and smooth. Coming around, I'll just take a quick look at the near field for you here. It's all generally the same. The crater density is, I'd say, somewhat higher than I expected. Sizes are mostly less than about 15 meters. The only large crater that I see is what I believe to be Index back here - (at) about 8 o'clock - and it has a very subtle rim, almost no shadow in the bottom of it. I think that's one of the things that was deceiving on the descent. There are very few deep, dark craters in the area (that is, craters with shadows in them).

The distribution of fragments appears to be less than 2 percent (coverage of the surface). On the surface, they vary from about centimeter in size up to, maybe, 3 or 4 inches. Most of them appear to be angular. I see some white ones. I can give you some more of that out of the window (after the SEVA). Trafficability looks pretty good. It's hummocky; I think we'll have to keep track of our position, but I think we can manipulate the Rover fairly well in a straight line. And I can see the base of the (Apennine) Front. As near as I can tell...As a matter of fact, I think I see where the Front runs into the level ground, where we get that 5-degree inflection. I see no boulders over there, whatsoever. Looks like we'll be able to get around pretty good.

107:08:00 Allen: Roger, Dave. We copy.

107:08:05 Scott: And as far as ALSEP deployment...Ha! Unfortunately, looking straight ahead (that is, directly away from the Sun) in zero-phase, it's washed out somewhat, but if there's continuity of the surface that I see in our general position, I don't think we'll have any trouble taking the ALSEP out 300 (meters) or so and placing it. I just noticed a couple of items on the far side of the rille on the flat horizon, Sallyport West there. Looks like a couple of very large boulders on the horizon. Just unique; two of them. They're quite bright and quite sharp. I cannot see Hadley C at all, as we thought we might be able to. Bennett Peak is about all I can see in direction of Head Valley.

[Hadley C is a 30-km-diameter crater southwest of the landing site. Head Valley, named for Brown University Geologist Jim Head, the west running portion of the rille below St. George Crater.]

[Scott - "A sally port is the archway or passageway through the academic buildings at West Point. That's where they post your grades. So, I remember we named this Sallyport West as a familiar term to the young cadets who go through the sallyport on the way to and from class and stop and look at their grades at the end of every week. A memorable place."]

107:08:51 Allen: Roger, Dave. Is that down towards Head Valley?

107:08:53 Scott: Trafficability up...(Stops to listen) Right. Yeah, that's correct. And the trafficability up to the Northern Complex looks the same. I see no large boulders. The slopes go up maybe 5 (to) 10 degrees at the most. And beyond that, all the terrain looks pretty smooth. I can see some young, fresh craters in our vicinity, which are sort of interesting in that there's some very small debris in the crater itself and on the rim; and it's somewhat lighter gray than the general surface - the debris being on the order of, oh, centimeters or so, but quite young and fresh.

[This debris is probably what is know as regolith breccia or, more descriptively, "instant rock". In a small, high velocity impact, some of the target soil is compacted into very weak, rock-like fragments. The Apollo 17 crew sampled large pieces of regolith breccia at Van Serg Crater, a relatively large impact in what may have been an exceptionally deep blanket of soil. During the third Apollo 15 EVA, Dave and Jim will sample regolith breccia at their first stop, Station 9. See the dialog and discussion following 165:05:05.]

107:09:47 Scott: And I see - at 3 o'clock - a very deep crater, old crater, smooth. But I can't even see the bottom, and it can't be more than, oh, 60, 70 meters away. I think that's one of them I was avoiding on the way in. That very well may be November (but is not).

107:10:05 Allen: Roger, Dave. And how far away do you think that might be. It sounds very exciting.

107:10:15 Scott: Joe, distances are very deceiving. I'd guess maybe 60, 70 meters. There's another somewhat deeper one just to the north of that. It looks to me - and Jim had the same impression looking out the window - that we're much closer to Pluton and St. George, and all that stuff, than we expected to be.

107:10:40 Allen: Roger, Dave. We (actually, Joe himself) think it just may look closer to you. Sounds like we're in business, old friend.

[Pluton is north-northwest of them and St. George is south-southwest. They can't both be closer. As with all the other crews, Dave and Jim are being deceived by the completely unobscured, exceptionally clear, sharp view. On Apollo 12, Pete Conrad and Al Bean saw a large boulder out to the west and were quite convinced that it was a few meters high and a couple of hundred meters away. It was actually about 25 meters high and 4.5 kilometers distant. For some reason, Jack Schmitt seemed to have less trouble with distance estimates than the other astronauts. His estimate of the size and distance of Geophone Rock, a 3-meter boulder about 200 meters west of the LM was very accurate.]

[Scott - "I'm sure you've discussed distances with the other crews. Everybody had problems with distances, but I'll throw my two cents in. There's nothing of scale which is familiar. There are no trees; there are no cars; there are no houses. And, as an example, we all know what size trees are in general. There are no trees and there's nothing in the landscape that has any familiarity. There's no hook. So, when you look out there, you see boulders but you really can't tell whether it's a large boulder at a great distance or a small boulder nearby. If it's very nearby, it's easy because you can run out along the ground and start calibrating your eyes (because of changing parallax). If you're looking close to the LM, you know what three or four inches are. But, as you start going out, you start losing your perspective because there's nothing to measure out there. And that's why everybody had these problems. On 14, they kept going and going (thinking they were getting close to the summit of Cone Crater Ridge). It's because you just can't tell. There's no atmosphere, so there's somewhat of a difference in terms of how you see distances. There's a magnification effect of sorts. It's a very interesting phenomenon that everybody gets fooled on these distances. You try to visualize based on what you know the distances are. We sort of knew how far Pluton was and I sort of guessed at what the boulders were, but that was a real guess. It becomes a real problem in those situations in which you don't have anything that you grew up with, in a sense."]

["(Man-made) tracks help you a lot. Once you have some Rover tracks you can start seeing things. As an example, up on the side of Hadley Delta, looking back at the Lunar Module, boy it was small! (Without haze, it looks closer and smaller than it really is.) But it (knowing how big the LM really is) gives you a scale of how far away it is. Five or six kilometers. And when you're on the Moon, boy, that's a long way away. And then - I remember this - I took a 500-mm photo which is my favorite photo of the whole mission (AS15-84-11324, taken from Station 6 at about 144:50:48). It shows the LM from the side of the hill (Mt. Hadley Delta); and, in the background is Pluton. And if you look at how small the LM is and how big Pluton is, you get an appreciation for how giant that crater is. The other part of the SEVA which I thought was beneficial...If you think about it, it was a full half-hour of geology. Equivalent to anything we did on the surface except move. It's the same kind of thing we did on the side of the mountain; it's the same kind of thing we did at every stop. When we got off the Rover, we surveyed the area and discussed it; we took photographs and whatever. So, it's actually a free (that is, zero cost) half-hour in terms of the exploration because it doesn't cost you any backpack time. It doesn't cost you anything but the clock-running time, which you're spending on the surface anyway."]

[Jones - "And little bit of oxygen from the depressurization."]

[Scott - "But that's internal oxygen, of which you have plenty. So, in terms of productivity of the mission - how many hours of geology do you get to spend for hours on the surface - it really adds to the total picture. I'm surprised the other guys didn't do it. Maybe management didn't want to do it. You can tell they're anxious for us to get back in. And I know what the backrow's saying,: 'Okay, Okay. Get on with it. Get on with it. To heck with this geology stuff. Get them back in and get on with the real mission.' That's what they're doing. They're getting nervous when we're out there. But I think it was a productive period."]

[Jones - "It's interesting that you brought up the influence of atmosphere or the lack thereof on the distance estimates. Jack pointed out that distance perceptions out here in the desert West, where the air tends to be pretty clear - where you don't have all that salt and moisture and what have you - is different than it would be in the East where the air tends to be hazier. Haze actually helps you calibrate the distance in a subconscious way."]

[Scott - "He's right. And you get the real difference on the Moon. Even in seeing - in being able to visually identify features with your eyes, how good are your eyes, how can they transmit images to your brain is so much better on the Moon than anybody can believe. And that's why, when people say 'What was it like?', I can't tell you what it's like because there's nothing on the Earth that compares with it. There's no way to describe it in any terms I've ever found - even through (science fiction author) Arthur Clarke, who does a wonderful job. I've never read anything that can adequately describe how well you can see. Whatever that means. It's crisp, and it's clear, and it's distinct, and it's definitive. And when you look off to Pluton and you see the boulders on the side of Pluton, boy they are definitive."]

[Jones - "They're right there; they have sharp edges."]

[Scott - "Even though they're at a distance, they're so clear that it's just a spectacular sight. And when you're looking up Hadley Rille, it is so clear it's just mind-blowing. Because we don't know that on the Earth. I know we worked with a little elementary school in LA and the principal, a very forward looking guy, built a planetarium out of an inflatable dome and brought the kids in. And the ones who really came in were the parents because, in south-central LA, you don't see the stars. So, on the Earth, you don't get to see what you get to see on the Moon or in space. It sort of relates to another thing. From orbit, we found out that looking down at Earth from 150 miles or whatever, you can see much better because you're not looking through glue. You're looking down through almost no atmosphere until you get to like 10 or 12 thousand feet. So the acuity is much better. And, on the Moon, it's even better than that. So, some of these distances, we get fooled because there's no relationship. But, at the same time, it is so clear. And that's probably why I say in here, 'We're a lot closer than we thought we were'. It's so clear that you really get fooled. It looks like you can reach out and touch it, because the image is so sharp. 'Cause on the Earth, when you're used to looking at mountains, even, they're far away and your mind sets that scale. We've been doing that for thousands of years. And, all of a sudden, people go to the Moon and the atmosphere isn't there and their scaling goes away. There's no way for your mind to use the experience, the hook, that's in the back of your head. Now you're looking at this crystal clear, crisp kind of scene that's a totally new experience - from the eyes to the brain. It's a remarkable thing, and I've never found any words that can describe it."]

[Jones - "Would it be anything at all like the difference between going to a theater and watching a film projected on a screen - where you're looking at silver grains - versus watching that same film on the tube (television) where you only get six hundred lines per inch?"]

[Scott - "In a relative comparison, yes. But you can't say that the theater would accurately represent what you would see on the Moon. For the degradation, that's probably a good analogy from A to B..."]

[Jones - "And then go to C for the Moon."]

[Scott - "Some of the IMAX stuff is pretty good. It's getting there. It's not there, but I'm sure people will get there (technologically), as we were talking last night. I think with the improvement in optics and computers and enhancement, things that are going on now - I think people will get pretty close to being able to clear out all of the glue that's in front of you. But this visual thing is pretty spectacular on the Moon. On the plus side, it enables you to see more and describe more; and, on the minus side, it probably creates a little more confusion in terms of distances. 'Cause it is so crisp and so clear and you tend to think things...In addition to the fact there's no scaling, this clear visibility and acuity makes you think you're closer than you really are."]

[Jones - "I personally don't have any doubt that you'll get two kinds of adaptation, once you get a base and you get some people who have been there for a while. You get the local adaptation where you know the features, you've been over there to Pluton and you've been over to St. George. Once you've been there, you know how big it is and suddenly the distances are understandable."]

[Scott - "Those distances, because what you'll actually be doing is calibrating your brain. But if you go to a new area on the Moon - new problem."]

[Jones - "But the other thing I suspect will happen is that there probably are clues in the environment. In a broad, general area, the regolith is probably a sort of uniform depth, and there's a certain size of crater that will have boulders on them. And you may learn to recognize..."]

[Scott - "Yeah, I think you probably will. And I don't know how long that will take. I'm not sure how soon the subconscious will kick in and enable you to precisely start making these judgments. One of the things we probably discovered, all of us, is it's really hard to tell how far things are. Pretty soon you accept it and just go on about your business, because it's not that big a deal. It really fooled Shepard and Mitchell, and I can see why it fooled them. I mean, we had that boulder at Hadley Delta (at Station 6A) and, 'Man, it's just right over there. It's right over there. It's right over there. It's right over there.' It's an interesting phenomenon and is an exciting part of the exploration, because you discover these phenomenon. There are no words. Go try it, guys."]

107:10:49 Scott: Yes, it just looks closer, I'm sure. But we are indeed in business. And I think, once we get through here and I hop back down, why, we can talk over more of what I've been seeing up there.

[As noted previously, Joe is taking a great deal of initiative in his communications with Dave and, with only occasional guidance from the Flight Director, is running the SEVA with Dave.]

107:11:03 Allen: Roger, Dave. You're coming up on 30 minutes into the SEVA, and we don't have any more questions. You've answered every one beautifully. Outstanding.

107:11:17 Scott: Okay, Joe. I'll take another quick look around. See if anything looks unique. There's just so much out there, I could talk to you for hours. Do you have any specific questions before we call it quits?

107:11:34 Allen: Dave, we're hoping you will be talking to us for hours about it. We don't have any specific questions right now. We'll think about it and talk to you again, once you button up. Maybe one last look for an ALSEP deployment position. And we've copied that you've gotten both sets of pictures for us.

[This entire transmission earns Joe an "excellent" from the Flight Director.]

107:11:55 Scott: That's correct, Joe. I limited myself somewhat on the 500s, because I think we'll get a chance to take a lot more of those. But I did get the pans for you.

107:12:07 Allen: Roger, Dave. We're quite...

107:12:09 Scott: And the ALSEP...

107:12:10 Allen: ...satisfied and would...would like for you to climb back in now, please.

107:12:15 Scott: Okay. Coming down.

107:12:18 Allen: (On his own initiative) Just out of curiosity, could you see any sign of the South Secondary Cluster?

107:12:32 Scott: There's a gentle rise, just to our south and I don't see anything that's really prominent, as far as elevation. I think the elevations on the models we've been working with were somewhat exaggerated, because I just don't see that much detail looking up towards Hadley Delta (that is, on the plain south of them).

107:12:55 Allen: Roger, Dave. We agree. Sounds like it (South Cluster) may well be hidden behind a shallow ridge there.

107:13:04 Scott: Well, we'll just have to go look for it. (Pause)

[Scott, from the 1971 Technical Debrief - "I might say, in conclusion, that the SEVA was a very useful thing. It gave us a lot of confidence that we could get to the Front with the Rover and also to the rille and the Northern Complex. I felt we had all three of them pretty well in hand for traveling, in spite of the fact that it was obvious that we had not landed precisely at the pre-planned point. At this time, I wasn't sure where we were located. Although I could see prominent features, I was relying on the Sun compass to give us the data for triangulation to spot our point, because there was nothing in the immediate vicinity which was recognizable. I think this was general throughout the rest of the EVAs. The terrain was considerably different than we had been led to believe, because of the lack of high-resolution photography. I think, in retrospect, the enhancement of the photography provided more detail than was actually there and that fooled us a little bit."]

[By now, Dave is probably once again seated on the Ascent Engine cover, facing forward. They are on checklist page Surface 2-4.]

[In Houston, the Flight Director is told that Dave and Jim have used up 15 minutes of their rest period. The flight Director's tone of voice clearly indicates that this is not a concern.]

107:13:08 Scott: Okay, Jim. You want to hand (me) the drogue? (Pause) I tell you, Joe, this one-sixth g is really great. (Long Pause) Okay. The drogue is in. (Long Pause) Okay, the drogue is locked. You want to verify that, Jim? (Pause)

107:14:17 Irwin: I can't see it as well as you can, Dave.

107:14:19 Scott: Okay. It's locked.

107:14:20 Irwin: Okay.

107:14:21 Scott: I'm coming down. (Pause)

107:14:25 Irwin: Okay. We'll close the hatch. (Pause)

107:14:45 Scott: Okay. Hatch is closed. Hatch is locked.

107:14:47 Irwin: Okay. Both dump valves are Auto. That's verified.

107:14:51 Scott: Auto and locked.

107:14:52 Irwin: Okay. Cabin Repress (valve) is going to Auto.

107:14:54 Scott: (Not yet adapted to the cabin light level) Wait, stop.

107:14:55 Irwin: It's Auto. That's verified.

107:14:58 Scott: It's dark in here. Go.

107:15:00 Irwin: Okay, I'm going to push Cabin Repress circuit breaker, if I can turn around here.

107:15:05 Scott: Okay.

107:15:09 Irwin: Okay. Cabin Repress circuit breaker going in now.

107:15:11 Allen: Roger.

107:15:14 LM Crew: (Garbled)

107:15:17 Scott: Cabin's at .5, 1.0. (Intermittent sound of repressurization; Long Pause)

107:15:52 Irwin: Okay, Dave. We can go Cabin on the Regs.

107:15:58 Scott: Okay. "Press Reg A and B to Cabin."

107:16:01 Irwin: Okay. I'm going Cabin on both Regs.

107:16:07 Scott: Okay. (Pause)

107:16:15 Irwin: Okay. You going to read to me?

107:16:17 Scott: Yep. "Cabin warning light off. Verify cabin pressure stable at 4.6 to 5." We're at 4.6.

107:16:23 LM Crew: Stable.

107:16:26 Irwin: Time to take off gloves.

107:16:27 Scott: Rog. "Doff gloves. Stow on comm panel." (Long Pause)

107:16:52 Irwin: Okay. "Doff helmets with visors and stow in the helmet bag."

107:16:54 Scott: Okay. (Long Pause)

107:17:15 Irwin: Okay. "Verify safety on dump valve."

107:17:19 Scott: Okay.

107:17:18 Irwin: (Garbled) there.

107:17:20 Scott: (Garbled) head is on.

107:17:22 Irwin: Okay. "Hoses, red to blue and blue to red. Go to ICS/PTT."

107:17:30 Scott: Hi, Joe. (Pause) Okay, Houston. Hadley Base here. We'll get the cabin cleaned up a little bit, and you might want to jot down some questions. And as we eat, we can maybe discuss some with you.

107:17:52 Allen: Roger, Dave. We'll do that and be standing by.

[Static; Comm Break]

[Dave and Jim had planned to end the SEVA at about 106:40 and, consequently, they are now about 37 minutes behind the nominal timeline.]

[The following discussion concerns Dave's experiences during the SEVA.]

[Irwin, from the 1971 Technical Debrief - "How about comfort while you were there, were you particularly warm without the LCG (Liquid Cooled Garment) on?"]

[Scott, from the 1971 Technical Debrief - "No, I was very comfortable. As a matter of fact, I thought the cooling was fine, and there was no problem at all wearing the CWG (Constant Wear Garment, the long-johns). As a matter of fact, I thought it was more comfortable wearing the CWG. How did you feel?"]

[Irwin, from the 1971 Technical Debrief - "Yes, I was plenty comfortable. I just thought maybe you would be a little bit warmer, being up in the Sun."]

107:20:31 Scott: Houston, Hadley Base here. What do you think the problem with our H2O Sep(arator) is? (Pause)

107:20:41 Allen: Stand by, Dave.

107:20:45 Scott: Okay.

[Comm Break]

107:22:14 Allen: Hadley Base, Houston. (Pause)

107:22:21 Scott: Go ahead, Houston. Hadley here.

107:22:23 Allen: Roger, troops. While you're getting squared away there, regarding your question, Dave; on the Sep 1 unit, we think that you had some residual condensation in your hoses. And when you stood up, it ran down into the separator and waterlogged it, causing it to go off the line. It'll be draining, and we think the next time we try it out, it'll be okay. Over.

[A discussion of the Water Separator anomaly, taken from theApollo 15 Mission Report, can be found at 106:49:19.]

107:22:51 Scott: Okay. I understand. But, we haven't seen any water around lately, but there has been quite a bit of moisture on the windows. There was when we powered up (in orbit, prior to separation from the Command Module); we had to bring the heaters on for a while to get the windows cleared.

107:23:06 Allen: Roger, Dave. Understand. We think the water was condensed in the suit hoses.

107:23:14 Scott: Okay. Understand.