|Geology Station 2 on Mt. Hadley Delta||ALSEP Off-load|
[Station 2 is near BC.5/68.8, very close to the planned location. A navigation fix at the east rim of Elbow Crater has allowed Houston to get a good estimate of the landing site coordinates.]MP3 Audio Clip ( 15 min 40 sec ) by David Shaffer
123:26:02 Scott: Okay; here we go; rolling again. Okay; we'll try getting home on the Nav system here. Oh, look at that big fresh one in the side of the rim! (Garbled) that stereo pan, so we're right up...
123:26:20 Irwin: Got to make a...Don't want to go (directly) downslope too much.
123:26:24 Scott: I'm not. I'm going slow. I'll cut back over here.
123:26:28 Irwin: Yeah.
123:26:31 Scott: Easy does it. (Pause) Looks like it (the navigation system) takes us right back the way we came, doesn't it?
123:26:45 Irwin: Yeah, that's the closest way. We're going to have to go to the right to go around Elbow.
[Elbow cuts into the rille rim and, unless they were willing to drive down into the crater or the rille, they will have to skirt the east rim.]123:26:50 Scott: Oh, yeah; I was suggesting that we could go to the left, but I guess we don't want to do that.
123:26:53 Irwin: I don't think we'd better try it, Dave.
123:26:55 Scott: (Laughing) That's a neat place down into the rille though, isn't it?
123:27:01 Irwin: See the way it comes back?
123:27:02 Allen: Roger, Dave and Jim.
123:27:03 Scott: ... down into the rille, Joe, (lost under Joe) would like...
123:27:04 Allen: ...we'd rather that you don't take that option.
123:27:07 Scott: (Laughing) Okay. And if anybody ever comes back, Joe, and wants to go down into the rille, have them come talk to us, because there's a good place to do it here.
123:27:16 Allen: Roger. We'll suggest that. (Pause)
[Good overhead photographs of the site indicate that there is a considerable amount of debris from St. George covering the southern rille wall west of the bend at Elbow. See AS15-87-11720.]123:27:23 Irwin: Okay; we're moving at about 5 clicks (km/hr). And the slope, I'd guess is about 6 or 7 degrees; and we're going cross-slope.
[Scott, from the 1971 Technical Debrief - "Right between Elbow and Station 2 was a neat slope. I'd say at least 5 degrees less than the rest of the rille, a very subtle, V-shaped depression or slope into the rille. That's why I get the impression that that's a portion of the fracture (means the rille) along there filled by a slide. I felt that, if we'd turned left there, we could have very easily driven down into the rille and back out."]
[Irwin, from the 1971 Technical Debrief - "Very easily; just a little more (probably means 'less') slope there."]
[Jones - "I gather that it's a smooth slope covered with talus off the mountain and ejecta from St. George; and that it was steep enough that you'd want to tack on it - swing back and forth so that you're not driving straight downhill."]
[Scott - "I don't know. The Rover was built for something like 24 degrees and the rille's something like 22 to 25."]
[Jones - "That's the rille slope, itself; and, with the extra talus, you're even less than that."]
[Figure 5-2 from the Preliminary Science Report indicates that, along section E-E', the rille wall drops 300 meters over a horizontal distance of 800 meters, giving a slope of 21 degrees.]
[Scott - "Before the flight, there was discussion about driving into the rille - probably not serious discussion. And the answer was: the rille's steeper than the Rover's built to drive. So, from a technical point of view, the answer was no. But, on the other hand, it could have been interesting. But unlikely to ever try it at that time."]
[Jones - "Certainly the 16 and 17 guys did a fair bit of sidehill driving. That was no trouble at all. You also did a fair bit on EVA-2. So you could probably handle steeper slopes by that expedient."]
[Scott - "Yeah. When we were going upslope, we didn't really realize we were going upslope."]
[Jones - "Are you going sidehill here, or relatively straight?"]
[Scott - (After some thought) - "We are going cross-slope, 6 to 7 degrees. At one point earlier, Jim aligned the Nav system and it had 8 degrees roll. So the slope's got to be around that. That's a pretty good slope when you think about it. What's a steep grade with an automobile? Six, or something like that? So we're parked on a relatively steep slope."]
[Jones - "The Rover had no trouble with this, and it had no trouble with steeper stuff on 16 and 17. Going up Hole-in-the Wall to the flank of the South Massif, Gene and Jack were probably doing 15 degrees. It's a really capable vehicle."]
[The following is taken from my 1989 conversations with Jim.]
[Jones - "Was there any difference in sensation riding on the uphill side versus the downhill side? Jack told me that he did not like riding on the downhill side."]
[Irwin - "No. Just in case it would roll, I suppose. That was Jack's concern?"]
[Jones - "Yeah, they were on some pretty steep slopes, such as climbing up the Scarp to their Station 2."]
[Irwin - "Yeah, the slope there was probably steeper than we ever encountered on the Front."]
[Jones - "You had what? About ten degrees, here, you said."]
[Irwin - "The steepest might have been, maybe, fifteen (near Station 6)."]
123:27:34 Scott: Whooee! I'm going to go down this way.
123:27:37 Irwin: Yeah, we better go down to...
123:27:38 Scott: Yeah.
123:27:39 Irwin: ...a slope that's not quite as steep. I didn't realize we'd gone up so high.
123:27:43 Scott: Oh, looking back, man, we really climbed it. (Pause)
123:27:50 Irwin: Okay; we're moving downslope now. (Pause)
123:27:57 Scott: Come back up here (that is, angle more to the east so that they are not headed directly down the slope). (Pause)
123:28:04 Irwin: Yeah, we know our tracks are to the right of us.
123:28:07 Scott: Yeah, we're in good shape.
123:28:11 Irwin: Heading right toward Mount Hadley.
123:28:13 Allen: (Making a mis-identification) Roger, Dave...
123:28:15 Scott: What a checkpoint.
123:28:16 Irwin: Yeah. (Lost under Joe)
123:28:17 Allen: ...any idea of whether you can see the LM or not?
123:28:21 Scott: Well, Joe. I took a look when we were up there (at Station 2), and I couldn't see it.
123:28:25 Allen: Roger. Sounds reasonable. (Pause) And if you cross over Rover tracks, Dave, we'd like a depth estimation of them, please (for use by the soil mechanics and Rover traction experts).
123:28:39 Scott: (Laughing) Okay.
123:28:40 Irwin: (Joking) I hope we do, Joe. (Pause)
[They are currently west of their outbound tracks and, because they are headed straight for the east rim of Elbow and, then north northeast to the LM, they will necessarily cross the outbound tracks before they go beyond Elbow.]123:28:42 Scott: Hang on. Whoa! Hang on!
123:28:47 Allen: (Responding to Jim's joke) Oh, mercy, yes (laughter).
123:28:49 LM Crew: (Laughing)
123:28:55 Scott: Got to go easy downhill, huh?
[They have just done a '180', a spin in which the back end swung around, leaving them suddenly pointed uphill.]123:28:57 Irwin: I'd say so (both laugh; almost giggle).
123:28:59 Allen: (Unaware of the reason for the laughter) It's uphill from here on in.
123:29:00 Scott: (Lost under Joe) though, is it?
123:29:06 Irwin: (Laughter) That's what you think, Joe. There's a hill we have to climb here.
[In order to resume the journey, they will move forward (uphill) so that they can get turned around.]123:29:11 Scott: You just...You can't go fast downhill in this thing, because if you try and turn with the front wheels locked up like that, they dig in and the rear end breaks away, and around you go. And we just did a 180. (Pause)
123:29:28 Allen: Dave...
123:29:29 Scott: Strictly up (lost under Joe) skiing.
123:29:30 Allen: Tell Jim it must be that powdered material on the slope there.
123:29:36 Scott: (Laughing) Yeah. (Pause)
123:29:40 Irwin: Yeah. We just did a christy. Okay; we're down (on to the mare). It's fairly level now and we're going to start upslope (out of a trough at the base of the mountain); and we're just about on the south rim of Elbow.
123:29:54 Allen: Roger.
123:30:00 Scott: (Laughing) What a ride. (Pause)
123:30:05 Allen: Jim, that's probably the first christy...
123:30:06 Scott: If we get back up here...
123:30:07 Allen: ...you've ever managed.
123:30:08 Scott: ...Rover'll be able to make it.
123:30:12 Irwin: (Laughs) Just sitting still, huh?
[Jones - "You remember the 180? Which way did the back end go?"]123:30:20 Scott: Okay; now we're going.
[Scott - "I think to the right. I don't really recall, but I remember it was real quick, before you could do anything about it. As I said here, the front wheels dig in. We were trying to maneuver around stuff, and it just broke. It was over before we even knew it. That's why we're laughing. Tsuuuu! and around it went. And then we went uphill, turned around, and came back downhill. And I know that the people in the back row at the Control Center were probably all crossing their legs tight."]
[Jones - "And it was basically a really stable little vehicle."]
[Scott - "Very stable. There was never any feeling of maybe turning over, at all. That's why it (incidents like the 180) was interesting: even though the rear end broke out - several times - and you spin all the way around, you don't have any feeling that it's going to turn over. It's sliding"]
[Jones - "Gene said that on their third EVA, when they were doing a fair bit of cross-slope driving on the North Massif, they had the feeling that if the upslope wheels started bouncing that they were getting toward the margins of stability. Did you ever have that feeling?"]
[Scott - "Nope. Gee, it's hard to imagine. I think you'd have to go look at the c.g. (center-of-gravity) and it would be easy to calculate. 'Cause if you know the c.g. and you know the angle the Rover is driving, you know the difference between the center of gravity and the center of pressure and you can figure our how much force it would take to push it over. And I think'd be really difficult to turn over."]
[Jones - "You'd have to be well tilted and you'd really have to bounce the uphill wheels."]
[Scott - "And you don't get a lot of angular momentum from the force, because of the low g. It's just kinematics, freshman physics."]
[Jones - "Assume you're going along at some tilt angle and at some speed and you hit a crater which gives you a force."]
[Scott - "And your force would be a reactive force from the Rover, which is limited by the Rover mass. There's nobody pushing you, so it has to be a wheel going into a crater to create a reactive force. Boy, I think it would be hard to get enough reactive force, with the suspension system which damps out the force. Boy, tough to do, but it could probably be done. It'd be interesting. If you were going very fast, then you've got a lot of energy in the system and, you might translate the energy into an overturning moment. It would be a great little exercise for somebody at school."]
[Jones - "Let me go back to Jim's statement at 123:29:40 that you're 'going to start upslope'. On the next traverse (at 143:44:53) you mention what appears to be a trough at the base of the Front. Is it a proper interpretation here that 'going to start upslope' refers to the trough?"]
[Scott - "Yeah, probably. Because, as Jim says, we're now going back uphill. So we go down and up. And, you know, there's that 'water mark' all the way around the base of Hadley, too. That shows up in the (500-mm) photos, that nobody expected. Appears to be some sort of subsidence." (See the discussion and references at 123:38:50 and 143:41:11).]
[Jones - "Any gut feeling for how deep that trough was?"]
[Scott - "I'd have to go back and think about it. Remember, in this next part, we're going down and up in all these depressions so that we can see the LM and then we can't see the LM. Again, it's just a calculation. How far are we from the LM, what's our eye level, and you could draw the troughs."]
123:30:24 Irwin: Yeah, now we're up to 9 clicks; you have to swing to the right here, Dave, whenever you can.
123:30:31 Scott: Yeah. We want to get up on the ridge line here.
123:30:34 Irwin: Yeah.
123:30:35 Scott: And also stay away from up-Sun. That...
123:30:37 Irwin: Yeah. (Pause)
123:30:44 Scott: There, now we're cooking. Up-Sun isn't too bad though, you know? There's a lot more definition than straight down-Sun. I don't think we'll have any trouble driving up-Sun, because the craters seem to show up pretty well.
[In the up-Sun direction, there are plenty of rock and crater shadows to give definition to the scene and the only problem with visibility is the glare of the Sun. In the down-Sun direction there is little visible detail due to the glare produced by countless, highly reflective particles, the general gray color and the fact that most shadows are hidden by the objects casting them.]123:30:58 Scott: Have you noticed here on Elbow, it seems like there's a very subtle bench on the southern side?
123:31:03 Irwin: Yeah, I kind of got the idea there were several subtle benches in the downslope, particularly on the eastern wall.
123:31:13 Scott: Yeah.
123:31:14 Irwin: On the wall.
[Benches can represent strength differences between layers of material penetrated during the impact. Benches were often seen in craters surrounded by rocky ejecta, with the benches corresponding to the regolith/bedrock interface.]123:31:15 Scott: Oh, there's a big boulder! We just crossed over a buried, rounded boulder. Must've been a meter and a half across, with...Of course, it's all gray.
123:31:24 Irwin: Gets pretty rough up ahead, Dave.
123:31:25 Scott: Yeah, man. No kidding. (Pause) Lots of debris. There are some Rover tracks! How about that?
123:31:36 Irwin: Yeah, here they are! Somebody else has been here.
123:31:40 Scott: Somebody else has been here.
123:31:41 Irwin: You know, they really don't sink in very far.
123:31:43 Scott: No, they don't.
123:31:44 Irwin: I'd say less than a half an inch, if that.
123:31:46 Scott: But they're here.
123:31:47 Irwin: They're here.
123:31:49 Allen: Roger.
123:31:50 Irwin: Maybe you can find a smoother way home. (Laughs)
123:31:53 Scott: I'm going to do (means 'follow') the Nav system here, once we get squared away and get out of the hole. (To Houston) Incidentally, Joe, I don't think we saw any indication of flows or a slide or anything coming off of Hadley Delta there. I didn't see anything that looked like a change in granularity or any subtle scarps of any sort. Did you notice any, Jim?
123:32:19 Irwin: No. (Lost under Joe)
123:32:20 Allen: Roger. Dave, that's exactly the picture we built from your verbal description there and that's one of the reasons we're going to omit Station 3. We think that there probably is not at least a sharp debris flow down the side.
123:32:37 Scott: Yeah, okay. I think that's a good decision. I don't think we're going to find much more over there than we've already found.
123:32:42 Irwin: You know, looking out to the east now, Dave, I see some very subtle ridges. I think they're ridges rather than craters. And it's probably...Well, it's out toward the secondary crater cluster.
123:32:56 Scott: Yes.
123:32:57 Allen: South Cluster, Jim; sounds reasonable. (Pause)
[Irwin, from the 1971 Technical Debrief - "We could very easily look over the EVA-2 route and see that it was just as smooth - or maybe smoother - than the EVA-1 route."]123:33:04 Scott: Okay, bearing 11 for 3.3 kilometers. We'll see how (lost under Joe).
123:33:09 Allen: Right on.
[The bearing and range at the Station 1 stopping place was 11 degrees and 3.2 kilometers. See the discussion at 122:11:11. The range difference is inconsequential.]123:33:15 Scott: Hey, there's some footprints, Jim. Ha! How about that. Hey, see that white albedo I kicked up over there?
123:33:20 Irwin: Yeah.
123:33:21 Scott: Gosh, I sure wish we had more time to sample.
123:33:25 Irwin: I think I see the...I see something reflecting over there. I think that's the LM. Sure is!
123:33:29 Scott: See a reflection?
123:33:30 Irwin: See the reflection of it at 12 o'clock (that is, straight ahead)? (Pause)
123:33:35 Scott: Yeah. Yeah.
123:33:36 Irwin: Yeah, we see it, Joe.
123:33:39 Scott: Sure do. And we're heading right straight for it on a bearing of 11 degrees (laughs) - except for the wanders through the craters. (Pause) Boy, I'll tell you, Joe, this is a super way to travel; nice and cool; uphill without any strain. This is great.
123:34:00 Allen: Yes, sir. (Pause)
[Jones - "From my perspective, the three things the Rover gives you are carrying capacity, higher speed, and a chance to rest between geology stops. Is that a complete list?"]123:34:10 Scott: And it's easy to drive; no problem at all. Just have to be careful because of the locked front wheels, but other than that, very responsive. I can put the throttle right up to the stop or at some intermediate position; and take my hand off and rest my hand. If I want to go left or right, I just put a little pressure until I get the angle I want and then let it off and we re-center on the steering. It's really neat, even with the locked front wheels.
[Scott - "Right. You get there rested, and you could recoup, too. And you also don't burn up as much energy and, therefore, you don't burn up as much oxygen, etc. If you were on a continuous, stand-up, walk-around EVA, you wouldn't be able to stay out as long."]
[Figures 10-3a and 10-3b in the Mission Report show Dave's and Jim's heart rates during EVA-1. On inspection of the graphs, the low rates recorded during the two long drives are immediately obvious. Estimates made from the Apollo 17 data indicate that, while riding, Cernan and Schmitt had half the metabolic rate they had while doing geology.]
[Scott - "The Rover also gives you range; and it gives you a television."]
[Jones - "And it gives the guy who's not driving a chance to look around and describe things."]
[Scott - "And it could also be operated remotely. The Russians did that, right?"]
[See, also, the discussion at 121:06:03.]
[Jones - "Gene suggested how he'd love to drive up to the top of the mountain and have somebody else drive the Rover back down (remotely)."]
[Scott - "Well, it (tele-operation) was in the Rover plan, but they took it out for budgetary reasons. We were supposed to have left the Rover so that it could be tele-operated after we left. But, relatively early on in the program, they took that capability out, because of the money. Too bad. Because it would have been useful for a long time. There again, what were the objectives of the program at the time? And I guess the objectives were, 'We're out of money.'"]
[Jones - "And that's relatively early in the Rover program, which started in May '69. So relatively early means that summer."]
[Scott - "Yeah. Not too long before the flight. You ought to dig into that some time, because that's something we really missed, in retrospect. And we should have learned from the Russians, because they'd already done Lunokhod and they were very successful with it. (Lunokhod 1 landed on Mare Imbrium on 17 Nov. 1970 and was operated successfully for 11 months. An improved vehicle, Lunokhod 2, landed on 16 Jan. 1973 and returned data for nearly 4 months.) When I go back and look at some of the Lunokhod stuff, 'Wow!'. I mean, (with a tele-operated Rover) the guys in the Backroom could have explored for probably the completion of that lunar day (that started with the Apollo 15 landing). It would have been difficult to get through the night but, on the other hand, you would have had another week of driving around. You could have gone to Mt. Hadley, and you could have gone down into the Rille to see if it works down in the Rille. You could have gone to the North Complex. Think about what they could have done with that television."]
[Jones - "Well, let's see. I believe the batteries had a range of over 100 kilometers, of which you used 28 kilometers."]
[Scott - "It's too bad. Of course, it's hindsight, right? Who ever would have thought that television would have worked as well as it worked? When you're in the program making these decisions, nobody's ever shown you that you'd get anything out of it, because nobody's ever shown you that the television would work. And, if the television doesn't work, tele-operation isn't going to do you any good. In retrospect, it's hard to criticize the decision. Had the possibility been available after 15, it might have been different because they would have known how much data they got from the TV."]
123:34:44 Allen: Sounds mighty smooth, Dave. And we're still working on your front wheel problem. We may have them back before you know it.
123:34:53 Scott: Okay; I'd like to try it that way, too.
[Scott - "When I was driving at a fixed setting of speed, I put my hand down and just tilted it with my thumb and forefinger. I could just put pressure on it to the left, and it would turn left, and if I took the pressure off, the wheels would automatically center and we'd go off in that direction. I didn't have to grip it all the time."]123:34:56 Irwin: Looking over to the east, Dave, I see a very large crater, and it could very well be...Could it be Dune? No, it's probably too close to be Dune.
[Jones - "And the speed was controlled by the forward position and there was enough stiffness designed into it that it wouldn't spring back."]
[Scott - "Right. The handcontroller was designed like an aircraft handcontroller. On some airplanes in those days - and, in fact, we had one at Edwards, the 101 - had a sidearm controller instead of the stick in the middle. There were a few experimental airplanes that had sidearm controllers which were sticks that would move about a pivot point for the hand. And the guys who designed this in the Flight Crew Support Division, several of them were pilots and they adapted some of these sidearm controller concepts to the handcontroller. So that it was drivable like an airplane is drivable, except you're on the ground and if you want to go faster you push forward further and if you want to put the brakes on, you pull your hand back. And like in an airplane, if you want to turn left or right, you tilt left or right. So it was an adaptation of an airplane handcontroller."]
["It worked real well and, I think, during the tech debrief we said 'Why doesn't Detroit do this?', because it is so much easier. And they are doing that now. I don't know if you've read, but there are some experimental cars in which the steering wheel has been removed and they're talking about handcontrollers on the side. And the reason they can do that now is the digital, fly-by-wire kind of thing. You don't have to have cables and pulleys like the old airplanes had. Nevertheless, it becomes such an easy way to drive 'cause I literally don't have to pick my arm up to move this controller around. I can put my hand down in a neutral position of the suit and it just takes a little bit of pressure."]
[Jones - "And with your fingers in the rest position of the glove, so you're not having to flex your fingers against the internal pressure."]
[Scott - "Right. Great system."]
[Jones - "Now, the controllers in the LM and the Command Module were pistol grips and this is a T-handle."]
[Scott - "Same kind of idea. I probably should have referred to the LM and the Command Module, because they came from aircraft handcontrollers. So the genesis of this is probably better described as going from aircraft to LM and Command Module to the Rover."]
[Jones - "Now, at one of the early looks at the proposed Rover design, they originally had a pistol grip and John Young, I think, suggested a T-handle. Were you around at that point or did you and Jim come in a little later?"]
[Scott - "Everybody in the office got to look at some of the early designs. I don't recall specifically but I remember having seen all sorts of pistol grips and stuff like that probably came out of the LM and the Command Module. When we got assigned to the Rover, it had the T-handle in it."]
[As can be seen in the Apollo 15 Training Log ( 343k ), Dave and Jim trained with the MET (Modular Equipment Transporter aka rickshaw) as late as 19 May 1970 and had their first training session with a Rover mockup on 17 August. Re-designation of Apollo 15 as a Rover mission was publically announced on 2 September.]
[Because John Young and Charlie Duke were originally scheduled to be the first crew to use the Lunar Rover on the Moon, they participated in an LRV Preliminary Design Review meeting at Marshall on 18-19 January 1970 along with astronaut Gerry Carr. As Charlie discusses following after 123:00:29, they recommended replacement of the pistol-grip controller. Deke Slayton formally approved what was undoubtedly the T-handle handcontroller in a 15 May 1970 memo ( 48k ). Thanks to Marshall Space Flight Center Historian Mike Wright for providing a digital copy of the memo.]
123:35:05 Scott: Yeah.
123:35:06 Irwin: Maybe it's Fifty Four (at BG.0/73.9).
123:35:08 Scott: Yeah, it could be.
123:35:09 Irwin: I think it's Fifty Four.
123:35:10 Scott: You see it?!
123:35:11 Irwin: Yeah.
123:35:12 Scott: Good for you! Fifty Four's on the Moon!
[Scott - "I came out of the class of '54 of the Military Academy (at West Point). So we named a crater for the class. The idea is to be able to say that '54's on the Moon'."]123:35:16 Allen: All right! (Pause)
123:35:23 Scott: Hey, look at this rock right on the sur(face)...Hey, you know...See that one on the surface there?
123:35:27 Irwin: Yeah.
123:35:28 Scott: I'll bet you...I wouldn't be surprised if it didn't come from that crater. Too bad we can't stop. (To Houston) There's a rock that was sort of rounded, but had a rough surface texture to it, about a half a meter in size; and it was about 10 meters downstream from a nice fresh crater that had a lot of angular debris in the bottom and the walls. (Pause) There are a lot of little craters around here - 'little' being less than a meter - which are very rough; have a lot of debris right up to the rim and over the top side of the rim; and no ejecta blanket to speak of, but the whole inside of the wall...Take a half a meter crater and it's filled with angular, gray, fragmental debris on the order of inch size or less; very uniformly distributed and fairly well sorted. Like, maybe, the debris is from one of our Aristillus or Autolycus friends.
[Dave is suggesting that these craters are secondaries dug by pieces of ejecta from Aristillus and/or Autolycus. The ejecta from those craters would impact at Hadley at relatively low velocity and one would expect to see pieces of the ejecta in the craters. Alternatively, some of the fragmental debris in these craters may be pieces of regolith breccia, rock-like masses of soil compressed during an impact. Jim describes the process during the 'seatbelt' sampling stop at 123:44:14. See, also, the Apollo 17 discussion related to the stop at Van Serg Crater, Station 9.]123:36:42 Scott: And there's a lot of it, so I think we'll have a chance to get it later on. (Pause) They're rather shallow craters, too. Let's say that they're only about, oh, 1 to 6 (that is, the depth is only one-sixth the diameter, suggestive of a low-velocity impact). (Pause)
[Scott, from the 1971 Technical Debrief - "There was a wide variety of (crater) sizes, all very subdued, with the occasional fresh one which had almost 100 percent coverage of fragmental debris within the inner walls, and maybe a quarter of a crater diameter out over the rim. It didn't go very far."]
[Irwin, from the 1971 Technical Debrief - "With the glass portion in the center?"]
[Scott, from the 1971 Technical Debrief - "Yes. That was the one we were going to sample sometime along the way, but we never sampled it."]
[Irwin, from the 1971 Technical Debrief - "We sampled one along the Front - the first one we stopped at (Station 6)."]
[Jones - "That is a long, excellent geology description. Probably the longest I've ever heard from anybody driving. Was it a particularly flat stretch, maybe, where you didn't have to watch the road as carefully?"]123:37:04 Scott: Hang on, Jim. (Brief Pause)
[Scott - "It was sort of automatic geology description a la Lee Silver. This is the kind of stuff Lee Silver pumped into us and pumped into us. It's sort of like you turn a switch on and it comes out. There's not a lot of analysis here. This is observation, based on what we had done many times with Silver. Not on these kinds of craters, but the process of describing what you see is what Silver, Swann et al - but primarily Silver - taught us: to go through this process, regardless of what you're seeing. It might be a rocky crater with an ejecta blanket or whatever. With this descriptive process, you're mentally tuned to categorize what you see in terms of the size, the depth, the sorting, the ejecta blanket, etc. That's automatic, so you don't have to do a lot of thinking about that."]
[Jones - "So you could be watching the road and doing this."]
[Scott - "Yeah. 'Cause this is sort of like the behavioral response. I'd been taught this behavior by Silver et al. So, when I saw a crater, it turned a switch in my mental bank and these things he'd taught me over and over and over again would come out, in various forms, depending on what my eyes were seeing. And this sounds almost exactly like the one I took the picture of later on."]
[Photo AS15-82- 11065, which Dave will take at 164:53:35, shows a small crater at the upper-right with a great deal of what is probably regolith breccia on the rim. The crater may have been dug by the boulder near the center of the image.]
[Jones - "The other factor for me to consider here is that the other two Commanders had chatty LMPs, so there was plenty of geology talk going on. But this is a lot, even for you. So I think the automatic behavior - plus the fact that you've just come from a geology stop - got you tuned."]
[Scott - "Although it is relatively easy driving, here. We've got to miss the craters, but now I'm more comfortable with the driving since we've been driving for several hours. It has become more comfortable, more automatic, more behavioral. So we're becoming more comfortable with the environment and with the Rover."]
123:37:07 Irwin: Yeah, look; there's a large flat rock over at 1 o'clock.
123:37:11 Scott: Yeah.
123:37:12 Irwin: Several large rocks there.
123:37:13 Scott: Yeah.
123:37:14 Irwin: Must be 5 feet in diameter.
123:37:16 Scott: Right.
123:37:18 Irwin: Concentration in this one area; and then there's a large one down in the pit of that subdued crater.
123:37:26 Scott: How we doing on time there, Houston? (Pause)
123:37:32 Allen: Stand by.
123:37:36 Scott: Ooh, look at that...Ooh, oh! Look at that one. It had...It almost looked like pahoehoe, didn't it?
123:37:43 Irwin: Yeah.
['Pahoehoe' is the Hawaiian term for the smooth types of volcanic rock that form as thin, low-viscosity lava cools. 'Aa' is the jagged, blocky type that forms from thick, high viscosity lava.]123:37:44 Scott: Did you see that one!? Oh, my! (Pause) How we doing on time, Joe?
123:37:46 Allen: Dave, you'll be about 20 minutes down from the original plan when you get back to the LM.
123:37:57 Scott: Okay.
123:37:58 Allen: We're not in bad shape at all. It's looking real fine.
123:38:04 Scott: Okay.
123:38:06 Allen: And we may be in better shape when you arrive there.
123:38:11 Scott: Okay; we'll see how we do. (Pause) Oops! Hang on, buddy.
123:38:18 Irwin: Yeah.
123:38:19 Scott: Every once in a while, when one of the steering (that is, rear) wheels comes off the ground due to bumping in a crater, and we get a side force, why, the rear end will break out, because we've lost our directional control.
123:38:33 Irwin: Dave, did you comment on the horizontal bedding in Hadley. I'm looking at the foot of Hadley - that spur that comes out...
123:38:40 Scott: Oh, no.
123:38:41 Irwin: ...out northwest.
123:38:42 Scott: The lineations across there?
123:38:44 Irwin: Yeah. The horizontal.
123:38:46 Scott: Yeah. There are two or three of them right at the base.
123:38:47 Irwin: Yeah.
123:38:48 Scott: I didn't see those yesterday. It was all in the shadow.
123:38:50 Irwin: Yeah. Joe, there's definitely a horizontal pattern in the spur of Hadley.
[The best picture of these layers is AS15-84- 11315, which Dave takes from Station 6 on the flank of Hadley Delta at about 144:46:38. These bands may represent the "high water" marks of the mare lavas. The reason the bands are now above the valley floor could be either mare subsidence or mountain uplift. See the discussion at 142:35:59 in the Apollo 17 Lunar Surface Journal.]123:39:00 Scott: Ooh! Hang on. (Pause)
123:39:06 Irwin: Just at the base.
123:39:07 Allen: Roger.
123:39:08 Scott: Oh shoot, it really gets bumpy.
123:39:09 Irwin: And then as you go up above that - and, again, that's maybe only 10, 15 percent of that particular exposure of the spur - then there's a definitely linear pattern that looks like it dips 30 degrees to the west. How come we stopped?
123:39:32 Scott: I got to put my seatbelt on. (Pause)
123:39:42 Allen: Dave, stand(ing) by for mark when you start. Help us on our speed calculations.
123:39:49 Scott: Yes, I'm sorry about that, Joe, but I'm pretty unstable without that seatbelt and there's a lot of feedback into the controller.
123:39:55 Allen: Yes, sir; buckle up there.
123:39:56 Scott: Okay; Mark (as they start rolling again).
123:40:05 Irwin: Anytime we stop, Joe, I'll let you know (Laughs).
123:40:08 Scott: (Laughing) I was going to tell you, but your descriptions were so neat. (Pause)
[Jones - "It was a 30-second seatbelt stop."]123:40:14 Irwin: Well, it's nice to be able to see the LM.
[Scott - "Yeah. This is a quickie."]
[Jones - "This is a real seatbelt stop?"]
[Scott - "Yeah. And I was just going to comment and I see, finally, it gets into the dialog. On these bumps, when I had my hand on the handcontroller I would feed back into the controller. When I moved in the seat, my hand moved on the controller, and the controller moved, which commanded something in the Rover. So, if we hit a bump and my hand moved right - because of the response to the bump - the Rover would turn right. So you get this oscillation, which is sometimes unstable because of the feedback into the system. Which was another reason to keep your hand off the handcontroller, because you wouldn't feed back into it so much."]
[Jones - "When you left Station 2 you certainly went through a fair bit of effort with the seatbelt, but it must have come unhooked at some point during this drive."]
123:40:17 Scott: Yeah. Our bearing is right on.
123:40:18 Irwin: There's home.
123:40:23 Allen: Okay, Jim, and keep talking; the description's beautiful.
123:40:26 Scott: (Lost under Joe) (Pause)
[Scott - "I think Jim's comment here is interesting in that, it was nice to see the LM. Because nobody had ever been away from the LM before to where they couldn't see it. Not that we had any real discomfort. But, once you got to see it again, it was like 'Boy, there's home'. Even though we were still pretty far from home. It was nice to be able to see the LM. Prior to the flight, we didn't know if (A) the Nav system would work, (B) whether we could ever see the LM because the horizon broke so quickly - on the Earth it's like 12 miles and on the Moon it's like a half a mile. We knew we'd be over the horizon, and there was a lot of talk before the mission on finding your way back. Hansel and Gretel stuff and following your tracks. On the other hand, that would have been very constraining relative to the traverses that we could have planned."]123:40:41 Irwin: We can see several craters on Hadley. Hard to estimate what the size of them is, but the ones that I can resolve seem to be a fairly uniform size, that I can resolve from this distance.
[The distance to the horizon depends on the size of the planet you are on, the distance your eyes are above the ground, and the nature of the local terrain. If the local terrain is smooth - say on a calm part of the terrestrial ocean - the distance to the horizon is sqrt (2 R h) where R is the radius of the planet and h is the observer's height. An astronaut seated on the Lunar Rover has his eyes about 1.6 meters above the ground, the Moon's radius is 1738 km and, in the absence of terrain effects, the distance to the horizon would be 2.4 km. On Earth, the horizon distance would be 4.5 km. Dave has overstated the difference but not the fact that he and Jim would be 'over the horizon'.]
[Jones - "I think some people would be interested if you could verbalize what it was about the LM that was nice to see."]
[Scott - "Yeah. It's our home base."]
[Jones - "It's the place where the food is? Or the way home (to Earth)?"]
[Scott - "Take it way back. It's nice to get back to the cave when you've been out in a storm, in the wilds."]
[Jones - "A familiar place."]
[Scott - "It's your protection. It's your survival. That's natural instincts. Humans, for years, have always wanted that cave and the open road. They got to get back to that cave. So it's six thousand years of programming that says, 'There's my cave. It's good to be back.' Although we always like to be out on the open road, it's human nature to like to get back to our cave. So, without even consciously thinking of it, in the stem of the brain, there's a thing that says, 'Gee, there's my cave. Got to get back to my cave, now' 'Cause you'd feel bad if you didn't have your cave, right?"]
123:41:03 Allen: Roger; understand. (Pause)
[As I did with the other members of the Apollo 15 and 17 crews, I asked Jim if there were any mountains on Earth that gave the same impression of size and height as the 4.5-km-tall (15,000 ft) Mt. Hadley and the 2.3-km South Massif at Taurus-Littrow.]123:41:10 Scott: Oh, there's a rough area ahead. (Long Pause)
[Jones - "Is there place that you can think of, down here, where the vertical rise is comparable to what you were seeing? How big are the peaks here (at Colorado Springs)?"]
[Irwin - "Pikes Peak is 14 (thousand feet). A little over 14."]
[Jones - "And, here in town, we're what - about 6? So that's about an 8000-foot rise and the rise up Hadley is..."]
[Irwin - "I say it was 15. It appeared very high; and it even appeared higher than we see it in any of the photographs and why it should appear that much higher when we were there, I don't know."]
[Jones - "Even Kilimanjaro rises from a pretty high plain. I'll have to look at that."]
[Irwin - "Kilimanjaro is what, about 19?"]
[Jones - "And the plain around there is about 4 or 5? So that might be comparable?"]
[Scott, from a 1996 letter - "Mt. Hadley is a BIG mountain. I have been to Pikes Peak, Fuji, and the Matterhorn - none compare. The mountains of the Moon are just awesome!"]
123:41:34 Irwin: I'd like to see Rhysling on the way in.
123:41:36 Scott: Yeah.
[During my 1989 conversations with Jim, he told me about the large site model that they used during simulations of the landing. He then added the following.]123:41:37 Allen: Dave, are you moving again?
[Irwin - " And it was interesting that we were able to modify that same system to actually simulate driving the Rover on the Moon. Using the same presentation. So we could stay in the Lunar Module and essentially drive it on an EVA! Actually driving the 'bug' on the simulated surface and actually go through a simulated EVA. And I think we went through almost all of our EVAs that way, and it gave us practice, you know, of direction, distance, time, and looking at the major craters - at least on the simulated surface."]
[Apollo 16 photo 72-H-430shows John Young and Charlie Duke doing a traverse simulation using a TV image from the Landing and Ascent (L&A) facility that included a site model suspended over a TV camera that responded to inputs from either the LM simulator or of the Rover mockup shown in the photo.]
[Jones - "And that was a useful exercise?"]
[Irwin - "Yeah."]
[Jones - "I'd never heard about that."]
[Irwin - "We figured if we can fly over the surface then, perhaps, on the surface we could drive it also. So they made some modifications to the simulator so we could have that capability."]
[Jones - "And would that have had the mountains in the background when you were doing that?"]
[Irwin - "I think it just had a portion. It didn't go all the way up to the ridge line and summit."]
123:41:41 Irwin: Yeah. We're moving.
123:41:42 Allen: Okay.
123:41:43 Scott: We gave you a mark when we started, Joe. That stop was maybe 15 seconds.
123:41:47 Allen: Roger; okay. Thank you.
123:41:53 Irwin: And we're moving about 10 clicks. Now this large one ahead could be...No, we're not close enough yet to be Rhysling.
123:42:06 Scott: Look at this boulder here, Jim. (Pause) (Garbled).
123:42:11 Irwin: Okay; we're coming out across either an elongate crater or two that are kind of joined up - running east-west. Kind of a doublet, and we're going across the bridge between them.
123:42:25 Scott: And it must be, maybe 30 meters across on each one of them with no debris and they're smooth on the bottom.
123:42:31 Allen: Roger, Dave and Jim. And we've got them on the map.
123:42:38 Irwin: Hey, great!
[At 123:49:31 they will report that they are 1.7 kilometers from the LM with a bearing to the LM of 13 degrees and, therefore, near BL.8/71.8 or, if the Nav system is still biased west, a little farther east. Making allowances for the upcoming 4 1/2 minute sampling/seatbelt stop and assuming an average speed of 10 km/hr on a heading of 13 degrees in the interim, they are currently 400 meters SSE of that later location or at about BK.2/71.4. On the map, there is a pair of craters near that location and they may, in fact, be quite close to BK.1/71.7. There is another pair of craters at BK.6/72.0 but, because the Nav system does not seem to have had range errors thus far during the traverse, the first of these locations seems most likely. In hindsight, it seems a bit strange that Joe didn't pass along the coordinates.]123:42:41 Scott: Oh, there's some vesicular basalt right there, boy. Oh, man! Hey, how about...? Let's just hold on one second, we've got to have...
123:42:50 Irwin: Okay; we're stopping.
123:42:52 Scott: Let me get my seatbelt.
123:42:56 Allen: Roger; mark that you stopped.
123:42:57 Scott: It keeps coming off.
123:42:59 Irwin: Why don't you hand me your seatbelt?
123:43:01 Scott: Just a minute.
123:43:02 Irwin: Then get off. (Pause)
123:43:08 Scott: If I can find it. (Pause) There it is. (Pause) If you'll hang on to it here for a second.
123:43:19 Irwin: Okay, I've got it. (Long Pause)
[Unbeknownst to Houston, Dave has stopped to pick up a piece of the basalt.]MP3 Audio Clip ( 20 min 55 sec ) by David Shaffer
123:43:41 Allen: And are you moving again?
123:43:45 Irwin: No, we're stopped here, Joe. I'll let you know when we move.
123:43:48 Allen: Roger. (Long Pause)
123:44:14 Irwin: You know, Joe, these small fresh craters that we've commented on, whatever caused them must create... (being more precise) or indurate the soil into the rocks - (that is) creates its own rocks (regolith breccia), because there's just a concentration of rocks around the very fresh ones (craters). And by 'small' I'm talking about may be a foot to 3 feet diameter.
123:44:49 Allen: Rog, Jim. Sounds very plausible.
123:44:50 Irwin: ...And create the (lost under Joe) breccia.
[Jones - "Jim is talking here impacts turning soil into rocks. The name for that, later on, became 'instant rock'. That's Jack's name for it. The geologists don't like that; they want it called regolith breccia. But instant rock is much better."]123:44:55 Scott: Okay, ready to hand me my (seatbelt)...
[Scott - "Much more descriptive."]
[Jones - "And Jim's given a lovely, clear description of it here. If you've got enough regolith and an impactor of the right size and velocity..."]
[Scott - "You create instant rock."]
123:44:58 Irwin: Yeah. (Pause) Get it (probably the piece of basalt)?
123:45:01 Scott: Yep. (Long Pause)
[Dave has finished getting the sample and is getting seated. The sampling has probably taken about a minute and 40 seconds, from about 123:43:19 to 123:45:01. In the process, he has taken nine photographs, using Jim's tongs - with the broken clip still attached - as a gnomon.]123:45:15 Scott: Okay. (Pause)
[Frames AS15-86-11579 to 11581 are the "before" photos.]
[The sample is the rock just to the left of the tongs in 11580. According to Bailey and Ulrich, this sample is 15016, a 0.9 kg basalt.]
[In 11581, note the three small, equally-spaced pebbles and a fourth one below the line and closer to the center. These can be seen in the "after" photo 11582.]
[Frame 11583 is a locator to St. George. Note the Rover tracks and the fact that they are not darkened like Rover tracks often are near the LM.]
[Dave apparently decided to do a mini-pan (assembled by Dave Byrne), taking two frame to the right, 11584 and 585; and then two to the left, 11586 and 587.]
[Journal Contributor Erwin D'Hoore has created a red-blue anaglyph from 11583-4, which gives an impression of the vertical variations in the local terrain. It is far from 'flat'.]
[D'Hoore has also used a pair of post-flight images (S71-46962-3 taken by NASA for stereo purposes) of the 'N' face to create a red-blue anaglyph. See, also, an anaglyph showing the 'B' face.]
[Jones - "This really is a fascinating piece of dialog, if you know what you're listening to. We can hear you tell Jim that you're going to stop and pick up a rock. Then you cover it with the seatbelt business."]
[Scott - "Yeah, Jim got it, real fast. That comes from years of training. That's the Magic Johnson no-look pass."]
[Magic Johnson was a star of the Los Angeles Lakers basketball team at the time that Dave and I did the Apollo 15 mission review.]
123:45:21 Irwin: Shoot, Dave. I think I dropped the map. I did.
123:45:23 Scott: Did you? Where's...
123:45:24 Irwin: The 1 to 25(,000) for EVA-l .
123:45:26 Scott: Right there by you?
123:45:27 Irwin: Yeah.
123:45:29 Scott: Here, hold my seatbelt. Got it? (Long Pause; sound of Dave's struggle to get the map)
[Jim probably dropped the map on the ground next to the Rover and Dave is struggling to get his hand down low enough to grab it.]123:46:01 Scott: There you go. (Pause) Dirty, dirty.
[Jones - "In getting Jim's map, would you have gotten the tongs off the back or just gone over and leaned on the Rover?"]
[Scott - "Probably just leaned on the Rover. It's easy enough to do."]
123:46:07 Irwin: Yeah, the map's so dirty you can hardly see it.
123:46:15 Scott: Better tighten this thing up a little bit better.
123:46:16 Irwin: You going tighten it up?
123:46:17 Scott: Yeah. It keeps coming off. Make a lot better time (garbled). (Pause) Okay, hold it.
123:46:26 Irwin: Maybe we should trade seatbelts.
123:46:27 Scott: Here; hold it for me. (Long Pause) There. Okay. (Pause) Okay, Houston. Mark. We're moving.
123:47:09 Allen: Roger. Mark. (Long Pause)
[I asked Dave if this incident might have led to the development of the tool called the LRV Sampler, which Jack Schmitt used on Apollo 17 to grab samples from his Rover seat.]123:47:47 Scott: There's a pretty fresh one right up ahead, Jim. Looks like about 10 meters across, and it's got up to 6-inch frags around the rim. Maybe 15, 20 percent of the rim has frags in it but no significant ejecta blanket - which I think is typical of all these around here. That one looks like it's maybe a meter and a half deep. Nah, we can't get in it, and I bet it has glass in it, too.
[Scott - "Yes, I think so. In fact, I think we talked about it when we got back in our post-flight debriefing. 'Gee, wouldn't it be great to be able to just reach down and pick one up, instead of all this stopping and getting off and stuff.' It was just eating us up, in terms of the time, just to collect a little old sample. I'm almost certain we had relatively lengthy discussions about this after the flight. And it would have been useful if we had figured it out before we went. It's surprising we really didn't but, when we were in the field, we didn't have the suits on. So we weren't hi-fi, were we? We drove the one-g trainer around with suits on, but we didn't do any geology 'cause it was too much to move about. But, if you sit and think it through, in retrospect, twenty-twenty hindsight, you say 'Of course! A sampler so that you can drive along and pick up from the Rover.' That's pretty easy to figure out, uh huh? After the fact."]
[It took us a while to decided that this was, indeed, the place where Dave stopped to get his secret sample. Once we were sure, he filled in the story.]
[Scott - "This was the seatbelt basalt. It was sitting out there, all by itself. No other fragments around. Very vesicular. Dark black. Rounded. Almost like somebody had seeded it. And so, when I saw that, I decided we had to have it. So I stopped, and that's when I went through this seatbelt exercise when, in fact, I was out picking up the rock. 'Cause they wouldn't let us stop to get a rock, they wanted us to get back to the LM. So, I concluded that, had we said 'There's a good rock to stop for,' they would have said 'get on back, because you've already done all of that'. But that one, I could not pass up. It was just too different. I mean, it was really one of the most unusual ones we had seen. So I went out, put it in my pocket (undoubtedly one of his two strap-on thigh pockets) and we headed on back to the LM. And they never knew it until we got home. And that's 15016."]
[Jones - "Was the seatbelt actually giving you trouble here? Or, was that a ruse?"]
[Scott - "That was a ruse."]
[Jones - "Good boy!"]
[Scott - "It was a scoriaceous basalt and, if you've ever seen one, it's got lots and lots of vesicles, lots of bubbles. And it's round. A gorgeous thing. And, in fact, after the flight was all over, when the guys in the lab made Styrofoam models of the rocks, they gave me one of 15016. And this is where we did it. And Jim was sitting very calmly there...I'm sure he dropped his map. I guess he dropped his map. But he was talking about the craters. It took us four minutes. That's a long time just to adjust the seatbelt and pick up a map."]
[Jones - "You handed Jim your seatbelt at 43:19 and then, by 44:55, you've got your seatbelt back. So it was a minute and a half to grab the piece of basalt and take the pictures. Would you have gotten the tongs off the back of the Rover?"]
[Scott - "I probably did get the tongs. Because I think the only rock I picked up with my hands was a big one at the end of the mission. So I think I picked up the tongs and hopped over to it. It was not in a position were we could have picked it up from the Rover. Which is the other trade-off in talking about the Rover sampler. You've got to be able drive up to the sample you want, which may take longer than getting off the Rover."]
[Jones - "A hundred years down the line when somebody's back at Hadley doing a Ph.D. thesis on this traverse, they can see that stop, look at the footprints, and use this as a guide to what you were doing."]
[Scott - "One of the interesting parts of the mission is the trades; and you've got to make some trade-offs. Jim was real cool. They can hear everything we say, so this is another part of the teamwork thing, because Jim knew exactly what I was doing. Maybe he didn't drop his map. I don't know."]
[Jones - "All this 'dirty' stuff makes me believe he probably did."]
[Scott - "Yeah, he probably did."]
[Jones - "Back before you spotted this basalt, at 39:49, were you really having trouble with the seatbelt?"]
[Scott - "Yeah, but if you go read this, I give the belt to Jim, and then Allen says, 'Are you moving again?' and Jim says 'I'll let you know when we move.' So Jim knows what I'm doing. And then, Cool Irwin starts talking about all these craters and has them completely distracted from what's really going on. Good show, Jim. Of course, I don't remember him talking, 'cause I was focused on this dude out there. And I mean, it was a gorgeous thing. You know, so dark black in such a light grey setting. And I remember it, all by itself. It was one you couldn't miss. You could not avoid picking it up. That was one that anybody would have gotten suckered into, one way or the other."]
[Scott, from the 1971 Technical Debrief - "One time, I had to stop and fix my seatbelt. We picked up that rounded, vesicular basalt fragment that was setting there. Through the (LM) windows, prior to leaving the LM, we had seen a large black fragment on my side. And you had seen a black frag on your side, as you looked out the front window. These were unique to the local surroundings. I don't think we'd seen other fragments that black and prominent." (See the discussion about the black rock near the LM at 126:02:08.)]
[In a 2006 exchange of e-mail, Dave said the Seatbelt Basalt "was meant to be a nice surprise for our teachers." and, while I believe that may have been true in some sense, I am convinced that this isn't the reason Dave didn't tell Houston what he was doing. As he said above in 1992, he didn't want to be told to keep driving.]
123:48:18 Irwin: You know, you can almost tell the ones that are going to have glass...
123:48:19 Scott: Yeah.
123:48:20 Irwin: ...by looking at them before you get there.
123:48:21 Scott: That's right, you sure can.
[Scott - "Let me make another comment about the glass in the craters. Because we had studied the previous flights, we were sensitive to glass. You remember that, on 11 and 12, glass was a real phenomenon, because nobody had really expected to see glass! And I remember when we looked at some of the 11 and 12 rocks to see what this glass looked like. It was fascinating. Prior to 11, I don't remember anybody talking about glass in craters or on rocks. And then, all of a sudden, it became a very normal thing. So, when we saw glass, we were familiar with glass. At this stage of the business, glass is no big deal. But I'm sure, when you did 11 and 12, glass was a big deal. 'Wow. Look. What is that stuff? Glass!'"]123:48:25 Irwin: Hey, we were up to about 11 or 12 clicks on that last burst.
["In fact, I took a picture of one of those craters later on; and I did a little paper called 'Glass in the bottom of small craters' that the guys in Flagstaff wanted me to write. It's in some geology journal. I had made this observation - and we'll see it as we get along...You'd asked before if we took any pictures from the Rover and, as I was seated, I did take a picture of this little crater. And it was typical of small craters with glass in the bottom. In fact, I think that one was a little different in that you could see the projectile that made the crater, off in the distance. In many of these, you couldn't; which meant, maybe, the projectile came in at a higher angle and turned into glass itself, rather than skipping off."]
[Jones - "It depends on impact velocity and the angle of approach and all that good stuff."]
[In a 1999 note, Gerald Schaber writes: "As a member of the Apollo Lunar Surface Geology Experiment Team from the USGS in Flagstaff, I had been very interested in the controversy about the origin of the glass melt in the floors of many small lunar craters, as first noted by Armstrong and Aldrin during AP 11. When Dave and Jim stopped briefly alongside a small (couple of meters diameter), shallow, crater during EVA-1, Dave mentioned seeing a small crater with glass in it. He also noted the presence of a fist-sized, darkish, glass-covered rock lying along side of this small crater. The Backroom encouraged the crew to take a picture of it - as I recall - but not to get off the Rover to get the picture, as their remaining time to return to the LM for closeout was getting short."]
["Upon examining that picture after the mission, I became interested in trying to figure out - once and for all - what the origin of these small, glass-coated craters might be. It was clear to me that the fist-sized rock lying nearby the crater rim more than likely created the crater - as a secondary, not a primary crater - and then bounced out. Using that as a working assumption, I calculated the velocity that such a rock - assuming a basalt density - would have to have to make such a small, shallow crater. It turned out that the energy required to make such a shallow crater in the upper few tens of centimeters of the regolith was far from sufficient to shock-melt the regolith and, thus, create the glassy lining of the crater floor or the shiny glass coating observed by the crew on the rock itself."]
["The answer hit me right between the eyes: the rock was a secondary projectile from a much larger and higher energy impact in the vicinity and the molten glass was on the rock when it struck the surface and made the 'secondary' crater that Dave and Jim photographed. The molten glass was forced off the rock upon impact and was deposited in the bottom of the crater. The rock then bounced out of the crater still maintaining at least some of its original glassy coating. How wonderfully simple! Puzzle solved."]
["The previous solutions to the glass-in-the-small-lunar-craters controversy had raged ever since Apollo 11. Solutions proposed even included the possibility that the small lunar craters acted as a focusing dish for the Sun's rays--like a solar mirror--that melted the fine-grained regolith. I have always found that Occum's Razor is indeed the best way to explain anything. The simple answer is usually the correct answer. It was in this case at least. I wrote and senior-authored the scientific journal paper that Dave mentions. He and Jim, as my co-authors, were sent the paper to edit--which they did. The paper was published in 1972 in the Geological Society of America Bulletin, volume 83, pp. 1573-1578. It is authored by Schaber, Scott and Irwin and is entitled: 'Glass in the Bottom of Small Lunar Craters: An Observation From Apollo 15.' Following the publication of that brief paper, I am personally unaware of any further commentary or debate in the literature regarding the origin of melted glass in the bottom of small lunar craters. Everyone must have bought our theory."]
["Dave and Jim did a remarkably good job of being 'geologists' during all three EVAs. In the case of observing and photographing the small, glassy crater with the associated rock/projectile--they helped to solve a scientific curiosity that had been hotly debated since Apollo 11."]
123:48:29 Allen: Roger, Jim; I'm standing by for amps readings.
123:48:32 Irwin: Roger. At any particular speed, Joe?
123:48:40 Allen: Give us anything.
123:48:44 Irwin: Okay, right now we're going at 10 clicks, and I'm reading about 10 amps.
123:48:50 Allen: Roger; sounds consistent. (Pause)
123:48:58 Irwin: Still no reading on the motor temps.
123:49:05 Allen: Must be that smooth driver! (Pause)
123:49:13 Irwin: Okay, we're 1.7 (from the LM) so Rhysling is...We should be near Rhysling.
123:49:21 Scott: Yeah.
[At 123:49:31, Jim mentions that the bearing to the LM is 13 degrees, so they are 1.5 grid units west and 6.6 grid units south of the LM or at about BL.8/71.8. As has been the case during the earlier stages of the traverse, they may be a few tenths of a grid unit farther east than the Nav system would suggest. In any event, they are already north of Rhysling. Jim is not yet aware that they landed north of the target point.]123:49:22 Irwin: In fact, we ought to be...Rhysling ought to be off to our right.
123:49:26 Scott: Yeah, there's a pretty sharp one right there. It's not big enough though.
123:49:31 Irwin: No. (Pause) Do you agree, Houston? We're reading 013 to the LM, and we're at 1.6. We ought to be able to see Rhysling.
123:49:45 Allen: We agree, Jim. (Pause) It should be about a 125-meter crater.
123:49:52 Irwin: Okay. We're cutting at 12 (km/hr) now.
123:49:57 Scott: Gee, I don't see it, do you?
123:49:59 Irwin: No, there's one over here at 2 o'clock that's fairly deep and might...
123:50:06 Scott: It's deep, but it's not near that big. It's only...
123:50:07 Irwin: It's not that large, no.
123:50:09 Scott: ...like 10, 15 meters across.
123:50:12 Irwin: Haven't really seen any large enough that we'd call Rhysling, Joe.
123:50:22 Allen: Okay, Jim, it may just be...
123:50:23 Scott: We see the old LM.
123:50:24 Allen: ...hidden by the undulations.
123:50:29 Irwin: Yeah, it could be.
123:50:32 Scott: And there are those. (Pause)
123:50:41 Irwin: Yes. Occasionally as we drop down in these...You know, I kind of get the impression, Dave, it's almost like...Well, there's depressions and then there's the rises, and they're generally perpendicular to our direction of travel.
123:50:57 Scott: Yeah? Now that you mention it, you're right. Sure does seem that way, doesn't it? We're just going up and down the...(Chuckles) Now what's the frequency (that is, how often do they encounter depressions and rises)?
[If the depressions were due to old, subdued, overlapping craters, the distribution would be random and they should encounter occasional features parallel to their direction of travel.]123:51:08 Scott: Whoop; watch out; hang on. On that one. Hang on the next one. Oh, ho.
123:51:16 Irwin: Like just small valleys that are trending upslope, Joe. And we go down low enough so that we can't see the LM anymore. Won't see it until we get on top of the next rise. They're very gentle valleys.
123:51:37 Scott: And they're about - would you say - 60, 70 meters across?
123:51:41 Irwin: Yeah. (Long Pause)
[Jones - "What Jim's saying is that you're getting a lot of up and down but you're not, very often, getting sideways."]123:51:53 Irwin: And, you know, the terrain, looking from the east (means 'to the east'), is just a general rise to the east. It looks like, oh, 2 or 3 percent. Notice that, Dave?
[Scott - "Yeah. His impression is that we're going across waves. And my comment, obviously, is that it appears it might be that way. It's hard to tell what the frequency is and whether it's uniform. And it may just be in this area. These were very long-period oscillations and we would not have had any physical sensation of riding up and down waves because the slope didn't change quickly."]
[Jones - "Hmm. You're not going to have as many overlapping, eroded craters as the 14 crew had at their site, because the surface is pretty young."]
[Scott - "I think we had a lot of craters, and that's what caused the undulations. Why else would you have an irregular surface? The wind doesn't blow. It's not like the desert, it's not like the sand, where you get a very clear, uniform waves in the sand. It's not like that. So the only things that can cause an irregular surface are impacts."]
[Jones - "And a lot of them are old enough that their rims have been worn away and it gives you an undulating surface with the all the overlaps."]
[Scott - "Impacts on impacts on impacts. Gardening. It's the gardening process. And, from what Jim says - and I did agree with him - that this appears somewhat more uniform, in that there was a trending, perpendicularly to our direction. What would cause that? I don't know what process."]
[Jones - "The only thing I can think of is that you have a particular set of overlaps of older crater, that you're cutting through a sample that happens to give you a fairly regular spacing of rims perpendicular. But what's the odds of going through a stretch like that?"]
[Scott - "It could be the debris from the excavation of a larger crater which, because of the excavation of layers, could have laid it out radially in mounds. We're hypothesizing, but, based on the comment...maybe Pluton excavated the mare in layers and dumped this array out there, which was subsequently gardened and covered with regolith, still leaving some sort of inverse layering as you would have excavated Pluton."]
[Jones - "Or some sort of a secondary phenomenon where you have a directionality: a line of secondaries that you happen to be driving down from something off to the north or south. Lots of intriguing possibilities, but we will leave this as an exercise for the next bunch going to Hadley."]
[Scott - "Jim's observation is very good, because he's sitting there, watching the LM - I'm watching the road, I don't see the LM...road? He's focused in the distance and he's seeing the LM show up and disappear. Show up and disappear."]
[Jones - "And he's also got a chance to look side to side to see if there's any bounding craters on the outside and, if he'd seen them, he would have mentioned them."]
[Journal Contributor David Woods comments: "This discussion is very interesting. I wonder whether their perception of gentle rising and falling as if riding across linear features is due to the human brain trying to impose some sort of order on an inherently chaotic landscape."]
["It would have been interesting to know whether they would have experienced the same undulating effect had they been traveling in a different direction. I suspect they might. If one were to carry out a spatial frequency analysis of the area, would one find that along one direction there was a greater component of 60-70 meter undulations compared to other directions? I imagine that the spread of spatial frequencies will be found to be the same in all directions and that the brain will tend to 'tune in' to those frequencies which are on a scale with which the mind tends to cope with best. The effect would be similar to putting white noise through a narrow pass resonance filter and discerning a note through the chaos."]
123:52:06 Scott: Yeah, up to...
123:52:07 Irwin: Right to the base of the Apennines.
123:52:10 Scott: Yeah.
123:52:1 Irwin: And it's a gradual...
123:52:11 Scott: Right up to the Swann Range there.
123:52:14 Irwin: Yeah. Now when we go out on EVA-2, why, it'll be uphill going out, and probably downhill all the way back.
[On EVA-2, they plan to drive due south to the base of Hadley Delta, climb up a short way, then drive east to look at craters that may have penetrated into the mountain bedrock. See the EVA-1,2/Part C map.]123:52:25 Scott: That's nice. Whoop! There's a shocker. Boy, what a great suspension system this thing has. (Chuckles)
123:52:33 Irwin: It'll be a tremendous view back to the LM when we get out to the last station on EVA-2 (planned for the west rim of Front Crater at AU.7/87.0). (Long Pause) And rather than this being the 'plains', as such, I get the idea it's a base of a very gentle talus slope.
123:53:08 Scott: Yeah, that's right. We're not on a flat plain; it looks like it slopes down from the Swann Range over there into the rille; and then when you get to the rille rim, there's another slight break down to a sharp break. The slight break goes, maybe, 50, 60 meters; and then you drop off steep into the rille. It doesn't look like we're in a basin so much...Although if I look to the left, Jim, I can see a rise up to the rille.
123:53:36 Irwin: Well, there might be a rise, you know, there at the rille.
123:53:39 Scott: Yeah. Rise at the rille. But you're definitely right, we're traveling on a slope (which is down) to the left right now.
[On Earth, gravity and the downhill movement of water create talus slopes at the base of mountains that can slope gently outward for miles. Such slopes are easy to see in the western US - for example, near Albuquerque and Las Vegas - because of the sparse vegetation cover. On the Moon, impacts on the mountains create debris and preferentially moves it downhill because of both gravity and the fact that the downhill ejecta will travel farther than the uphill ejecta. Similarly, impacts at the base of the mountain will spread the talus outward. Jim's observation suggests that, in the 3.3 billion years since the lava flows stopped at Hadley, the Mt. Hadley/Swann Range talus slope has reached at least to the LM location but, apparently, not the rille. See the conjectured north-south cross-section of Mt. Hadley Delta, which is Figure 10.22 in the Lunar Sourcebook.]123:53:48 Irwin: And, boy, you really get that impression if you, you know, look east, look up-Sun.
123:53:52 Scott: Yeah, you sure do.
123:53:59 Irwin: (Laughing) I can't believe we came over those mountains.
123:54:05 Scott: We did.
123:54:07 Irwin: It's just a beautiful little valley.
123:54:11 Scott: (Laughing) Yeah, those are pretty big mountains to fly over, aren't they? (Pause)
[Jones - "Is there any thing that you can think of that would give us feel for the scale of the mountains? I mean, you're on this flat plain and suddenly these mountains go Whoosh! Up 4500 meters to the summit of Hadley (and 3500 meters to the summit of Hadley Delta)."]123:54:17 Scott: Here's a nice, subtle crater about 70 meters across, with a sharp, 15-meter one on the rim which scattered debris out. But no big ejecta blanket, no rays. (Pause) We can't see the LM now. (Pause) And we're traveling at about 12 clicks. (Long Pause) Let's see, 018 degrees (bearing to the LM) for 0.7 (km range), so right over the next rise, we should see home plate. (Pause)
[Scott - "15,000 feet above the plain. Higher than from the base of Everest, as I recall somebody said once. We have a preconceived notion of how high they are, because we've studied them. We know, in general, that they are going to be big mountains. Jim and I both spent some time in the mountains, skiing; and, therefore, we can fairly well create a mental image of the height...But they are so big, when you look out there, you say 'Wow'. From where we're sitting, you can look straight out and way up. I mean, you look way up. Those are very, very big mountains."]
["But they're all rounded. The striking thing to me was that there are no sharp peaks. Some of the old science fiction illustrations that you've seen and old science fiction movies show sharp peaks on the Moon. There are no sharp peaks; but the shadows are sharp, so I think the people who looked through the telescopes in the old days saw a sharpness of definition on the lunar surface, because of the shadows, and perhaps interpret that as sharp mountains. But the mountains are all very rounded. Very rounded. And that was a very striking feature compared to Earth mountains. The Rockies are not rounded, but sharp. And the Alps are very, very sharp. Lunar mountains are very rounded, but very big. Again, I don't know how you describe it, in terms of size, because..."]
[Jones - "Now, Grant (Heiken) and Dave (Vaniman), in one of their illustrations (Figure 2.2 in the Lunar Lunar Sourcebook), have Mt. Fuji set down at one of the sites (actually, at the rim of Mare Crisium). Have you been up close to Fuji?"]
[Scott - "Yeah. I've had lunch at the base of Fuji."]
[Jones - "Now, that rises from a fairly level surrounding countryside (to a summit of 12,389 ft or 3776 m). Of course, it's conical rather than being one of these big, smooth, elephant-sized things..."]
[Scott - "It would also be interesting to see what the slopes of Fuji (about 25 degrees) are compared to the slopes at Hadley (about 30 degrees), 'cause I would guess that Hadley is steeper. I don't know. Of course, you also have a different visual situation on the Moon in that you're not looking through the atmosphere; and that creates a different impression, too - which I've never heard anybody explain, and I don't know how to explain it. But, when you look at a mountain on the Earth, it's quite different from looking at a mountain on the Moon, 'cause there's no air to look through."]
[Jones - "Sometime in the last couple of weeks, driving down here to Santa Fe from home, there's a pile of rock north of Pojoaque which, when you come down off the hill out of Santa Fe, looks a little like a dinosaur's backbone. It's really very striking, especially when the light's right and you get nice shadows on it. Well, Di and I were driving by it the other day when it was snowing, so the optical depth of the atmosphere was a lot greater and the obscuration was more than it usually is. And they looked a lot bigger than they do on a normal day when it's clear and you don't have as much lost detail. Now, does that jibe with - let's see - mostly underestimated distances on the Moon because you're used to having things far away be a little indistinct."]
[Scott - "And, if there are trees, trees are all the same size, roughly (and provide a 'feel' for distance and, hence, elevation). I've been on top of some mountains since the mission and sort of thought 'How do I scale where I am?' How do I know how big these mountains are? (That is, what is it that tells me how big the mountains are - at least in relative terms - without having to think about it?) And I know because I can see the trees. It's tougher above the treeline. But, still, you've got a better sense of it, I guess because we've spent six thousand years on the Earth and not much time on the Moon."]
["It would be interesting to try to quantify, somehow, the difference in the perception. And, boy, there is a difference. It's clear, it's more distinct, more definitive in it's own way. You've got a black horizon, not a blue horizon. And there's no diffusion at all at the top of the mountain. It's sharp. Even though it's rounded, (snapping his fingers) the cut-off is that fast. It's an instantaneous cut-off into the black. So it's a completely different view. On the Earth, the mountain sort of blends into the blue sky, in a sense. Even a snow-covered mountain, it goes from white to light blue. On the Moon, it goes from grey to instant black. Totally different. Big mountains. And I guess that's the comment, as we looked at them and hadn't really thought about them until Jim pointed it out. You look over there and say, 'Yeah, those are very big mountains.' Whatever big is, it was big."]
[Jones - "And you tucked that trajectory..."]
[Scott - "Yeah, flying over mountains...As we commented coming down, we looked out the window and briefly saw these things but, from orbit, yeah, they looked big...I don't think we ever worried about hitting the mountains because the trajectory was very clear. We would have to have had a major problem...anyway."]
[Jones - "And you were watching the track and where you were and where you were supposed to be."]
[Scott - "In general, yeah. But you could have been short and run into the mountain. Put Apollo 11 four kilometers short. I don't know where we would have been on the mountain."]
[Jones - "At Hadley, four kilometers is a significant distance. At Tranquility, it isn't. That's easy enough to figure out."]
[Journal Contributor David Woods offers the following addition to the discussion.]
[Woods - "Here in Scotland (and Ireland, where I and my relatives come from) the terrain is quite hilly and it is difficult not to be able to see hills in the middle and far distance, wherever you live."]
["Once, while visiting my uncle at his farm in Lanarkshire, he muttered that it was going to rain because the hills looked near! I thought about this piece of homespun wisdom and came up with the following explanation."]
["When the air pressure over the British Isles is high, air movement tends to be slow, with a high water and dust content. It comes from the east - with the dirt from Europe - and there is much haze obscuring the view of the hills. Thus they look further away and larger."]
["Our rain comes in from the Atlantic on frontal systems carried by trains of anticlockwise spinning depressions. This fast moving air is very clean after its journey across the ocean and hills tend to look clearer, nearer and thus smaller. So when the hills look nearer, there is sure to be a rain bearing front on the way."]
["At the time (about 18 years ago) I immediately linked this phenomenon with Neil Armstrong's post-flight comments about distance perception on the moon. It seems to me our familiarity with the Earth's environment has programmed us into relating clarity of image with distance. In watercolour painting, it is the oldest trick in the book to suggest distance by lightening or thinning your pigment as you paint more distant features."]
[They are about 0.9 grid units west and 2.7 grid units south of the LM, which would put them near BP.7/72.4. the crater in question may be the one centered at BQ.0/72.4.]123:55:37 Scott: And I think I see, on the surface here, lineaments that are trending about northwest/southeast, Jim. Do you get that feeling? Gordon (Swann)'s little lineaments. (Pause) Look as we go across here and if you think about them, if you look down there...(Pause)
123:56:04 Irwin: Not convinced, Dave.
123:56:05 Scott: Not convinced, huh?
[This is a reference to the grooves or lineaments seen on the surface by other crews, often with a northwest/southeast orientation.]123:56:07 Irwin: Look right ahead of us here where we're driving, I see lineaments that are parallel with our direction of...
[Jones - "Do you have any recollection of what Gordon's little lineaments were?"]
[Scott - "I faintly recall we discussed lineaments because other people saw them. I think Gordon (Swann) discussed lineaments at length on one of our field trips before the flight and said 'look for lineaments'. Each of the people we worked with, naturally, had one focus or another. That's why we got all the pieces."]
123:56:11 Scott: Yeah?
123:56:12 Irwin: ...motion.
123:56:13 Scott: That's right. I see those, too. Whoooa!
123:56:14 Irwin: Ooohhh!
123:56:15 Scott: Hang on!
123:56:16 Irwin: Ohhh, brother! (They both giggle.) There's the LM.
123:56:19 Scott: Yeah. (To Houston) Came up over the rise, Joe, and right when we got over the rise, there was a (laughing) great big crater in our path. But we missed it.
123:56:30 Allen: (You) got some bad news and some good news.
123:56:35 Scott: (Laughing) Yeah, man. (Pause) But it's the only game in town!
123:56:44 Allen: Don't you know. (Pause)
[The interval from Dave's "Whoooa!" to Jim's "Ohhh, brother" is roughly 2.8 seconds.]123:56:52 Scott: Oh, Joe, I wish we could stop and pick up hundreds of rocks; there's so many. There's a little one sitting on the rim of a crater that's on a pedestal. It looks like a smooth, gray rock, subangular, and it was sitting up on a pedestal it looked like. Right on the very rim of the crater, and it was the only frag near the crater. (Pause)
[Jones - "Now, at 10 to 12 clicks, without braking you would have traveled 8 to 9 meters. That's reasonably quick."]
[Scott - "Especially when you don't see it."]
[Jones - "So you've got to put the brakes on and turn. The Rover stopped reasonably quickly, I gather.?"]
[Scott - "Not really. 'Cause you don't have all that much traction. You have enough traction to be able to move without spinning the wheels, but I don't recall being able to brake it...It was relatively easy to turn, but I'm not sure that I spent all that much time trying to slam on the brakes, because it didn't stop very well. It had too much momentum. Two guys and that weight. That's a lot of momentum"]
[In the Apollo 15 Mission Report, Dave and Jim mention that, "lateral skidding occurred during any hardover and maximum-rate turn above 5 kilometers per hour. Associated with the lateral skidding was a loss of braking effectiveness...At speeds on the order of 10 km/hr, response to turning was very poor until speed was reduced. The optimum technique for obstacle avoidance was to slow below 5 km/hr and then apply turning correction." Here, it seems very likely that they went into a skid. When, sometime in the 21st Century, someone returns to Hadley, the tire tracks will tell the tale.]
[At Spur Crater, they will find a pristine anorthosite sample, usually known as the Genesis Rock, sitting up on a similar pedestal.]123:57:18 Scott: (Laughs) Hey, there's the old Falcon!
[Jones - "Before I could get the tape back on, what you said was, 'It looked too easy'."]
[Scott - "It is going very smoothly..."]
[Jones - "You two are just cruising along and Joe's..."]
[Scott - "Cruising along and gathering up samples and doing this work, and Joe Allen is Mr. Smooth. It's totally coordinated, no hiccups, no blips, nobody hollering or shouting at anybody, and relatively little confusion. And the point is, it took years and years, and thousands and thousands of people to get it to this point. Wherein, today, I doubt that there are very many people in the system who experienced it or, if they did, remember it. That's why this review is good. (For example) we just made one little comment about lineaments; but somebody spent a long time working it. When people go back, they have to understand, that all this was not done overnight."]
[Jones - "Little groups of people taking care of their piece of it, and their results are incorporated; you get the procedures lined out, and you and Jim - with Joe over the hill with some of the Backroom people and a Flight Director...I gather that your Flight Director, Gerry Griffin, came out on one or two of those exercises."]
[Scott - "One of the (important) things we did was to finally convince the Flight Directors to come out into the field with us and see what we did, so they could understand better, during the mission, what we were doing and why we were doing it and so they would be more inclined to understand the science part and some of the challenges in doing that, rather than seeing the mission as just an operational/engineering exercise. Gerry Griffin was the first to come out, 'cause he was our Flight Director and I knew Gerry pretty well. And then other people started coming out and then, at the end of the session, when we went to the Coso Hills, Rocco Petrone came out and, when he came, the whole world came out. And, when they did and they saw this exercise in the field, they said 'Wow! Boy, this is really neat! These guys have done a lot of work!'"]
["We had all the geologists there - Lee Silver and Gordon Swann and Jim Head. And all the bosses - management - were able to see how we learned to do what we did because, in the field exercises, we'd go through a traverse (from start to finish). First we'd do the photo maps and do the traverse planning. Then we'd go do the traverse; and, at the end of that, we'd get debriefed and our professors would get up and critique us. That's how we learned. And I think, seeing that helped management understand some of the challenges and helped them understand why things were done the way they were done, and the value of doing it that way, and the trade-offs between the science and the engineering/operations."]
["And you don't have that today. You now have another separation of cultures. You have the scientists, and you have the engineers. And, I think, naturally so, because they really haven't been able to work together, at this level. (Chuckles) Like the basketball players say, 'We're at another level'. Well, we're at another level (doing the J missions). Nobody's been at that level for a long time. So I think it's going to be difficult to get back to that cooperative level. In our situation, I think cooperation between the operations, engineering, and science people was really excellent. I mean the trade-offs were excellent, and people were making good judgments, and they were really smooth. But it looks too easy, I think. When you look at the TV, it looks easy. It wasn't easy. It was a lot of work for a lot of people to get it to this point."]
[Jones - "A lot of time thinking it through so that, when you were down 25 minutes when you left for Elbow, during the drive out a group of them talked about priorities and asked themselves, 'How are we going to modify this EVA to handle that 25 minutes and still hit the main items we want to hit.' And they decided to have you do a little bit at Elbow and concentrate at St. George, do five of the seven priority items at St. George, then hop on the Rover and go home to get the ALSEP set up."]
[Scott - "And, as part of those discussions, you have the operational people who are concerned about the PLSS oxygen supply, as an example. They participate in deciding the trade-offs so that, if somebody asks 'Do we stop at Station 3?', consumables are part of the decision. And consumables may have driven it. I don't recall. But you had to have everybody together; and that's why we ran the field training exercises and, also, the integrated simulations, before the flight. In those, we sometimes had these science exercises with problems. And that brought the whole system together - all the people. And that's how we did it. That's how did we made it look so easy."]
[Jones - "I keep coming back to Amundsen and how thoroughly prepared he was. He spent the winter before making the dash for the Pole making sure all his equipment was right, making it and remaking it. And making practice jaunts. And, of course, he had spent years in the Arctic with Inuits and Eskimos learning the technologies that are appropriate for those kind of places. And the result was that it looked easy! The other Scott (Robert Falcon Scott) became the dramatic hero because he got into all kinds of trouble! There's an excellent play, called Terra Nova, about the Scott party, in which Amundsen appears every once in a while as kind of a ghost of Christmas Past. And it's a very well crafted play. Unfortunately, it's not done very often; so, if you ever get a chance to see it, I highly recommend it. Terra Nova, which was the name of Scott's ship. The script picks the five-member Scott party up a few days before they get to the Pole, takes them to the Pole and all the way back to the tent where they died just a few miles short of a supply depot."]
[Scott - "That's interesting. I read a lot of that, when I went down to the Antarctic in '70. I read a lot of stuff before I went down, 'cause it's fascinating. I had never paid much attention but, when I got a chance to go down there, I dug out the books and everything. Those are really fascinating stories. I mean, those are really hardy folks. In relative terms, Amundsen probably did as much (preparation) as we did. Because, in those days, nobody really did all that much preparation."]
123:57:20 Allen: Dave, that sounds like a...
123:57:21 Scott: Sitting down there in that hole.
123:57:23 Allen: ...a cairn to me!
123:57:25 Irwin: The Falcon...(Hears Joe)
123:57:27 Scott: [Responding to Joe's 'cairn' remark] Yeah. (Laughs) Hey, look at the...Would you think that the albedo (percentage reflectivity)'s - oop! - changed there where we landed?
123:57:38 Irwin: Sure is; it's lighter colored.
123:57:40 Scott: Sure is.
[Jack Schmitt has speculated that the LM engines preferentially sweeps away the smallest particles, leaving a higher than normal abundance of larger particles which reflect more sunlight. Whatever the case, orbital photos show a distinct brightening of the surface near the LM. In addition, soil disturbed near the LM by the Rover or the astronauts' feet tends to be relatively dark, presumably because the disturbance restores the surface to more or less the normal reflectivity. Photos of Rover tracks away from the LM - such as AS15-86- 11583 - show no darkening, while photos of Rover tracks near the LM - such as AS15-86- 11602, show considerable darkening. Dave was aiming the camera in about the same direction for both of these photographs and, consequently, there are no Sun-orientation differences between them. In 11602, the soil darkening shows up best in the isolated tracks beyond Jim to the left.]123:57:40 Irwin: Is this probably Index over here to the right, Dave?
123:57:43 Scott: Yeah; uh-huh.
123:57:44 Irwin: Yeah.
[They are actually looking at Last Crater.]123:57:47 Scott: Not very distinct, is it?
123:57:50 Irwin: [If] that's Index, our position is...I guess we're just a little east then...
123:58:04 Scott: Yeah.
123:58:05 Irwin: ...of our planned...
123:58:06 Scott: I think they've got our...
123:58:07 Irwin: ...landing site.
123:58:08 Scott: ...I think that the position they have picked out is pretty good.
123:58:11 Irwin: It's close, but it looks like it might be a little south.
123:58:14 Scott: Yeah. Hey, Joe, our Nav system's starting to wander now (that is, the bearing is beginning to change as they get very close to the LM and the relative errors become large). We got a range of 0.2 (km) and a bearing of 34 and we're heading about 015 into the LM, and it's just almost in front of us. I think it (the Nav system)'s done very well though. (Pause) Hey, do you know I think I almost landed in a crater, Jim. Look at the one on the right (east) there.
123:58:42 Irwin: Yeah.
123:58:47 Scott: If I'd have just gone down another...
123:58:49 Irwin: Yeah. I have that on the map.
123:58:51 Scott: Do you really?
123:58:52 Irwin: It looks like it's just west, northwest of Index.
123:58:57 Scott: Yeah. (Pause) Okay; come back here, and we want to park it (perhaps looking at CDR-15) cross-Sun, heading towards the ALSEP side (of the LM).
[Checklist page CDR-15 indicates that Dave is supposed to park heading southeast and facing the Scientific Equipment (SEQ) Bay, which is on the southeast face of the descent stage. See Figure 3.1-5 in the Apollo 15 Final Lunar Surface Procedures document. These two requirements seem contradictory, because a southeast heading would leave the Rover pointed away from the SEQ Bay. What Dave actually does is park the Rover southeast of the SEQ Bay heading northwest. We know this because, at 124:01:10 Jim reads a heading of 315 (NW). In addition, at 124:05:10 Dave discovers that, because of the northwest heading, he has the Sun in his eyes as he tries to orient the high-gain antenna. A northerly or northeasterly heading would have let Houston watch the ALSEP off-load while giving Dave better lighting for the high-gain orientation. Checklist page CDR-17 calls for a northerly parking heading at the ALSEP deployment site.]123:59:14 Scott: Okay, swing around. Yeah, I landed right in a little bench there, huh? No wonder.
123:59:18 Irwin: Just on the northwest rim of that crater.
123:59:21 Scott: Yeah. (Pause) Yeah. I was hoping...I think I saw that big crater; I was hoping by keeping like a foot per second forward all the way in, it'd keep us out of something like that. (Pause) Joe, we're back at the LM, by the way.
123:59:39 Allen: Okay, Dave; good news. Thank you. (Pause)
[Dave and Jim had planned to arrive at the LM at 3:50 into the EVA. They are currently at about 4:20. They are about 30 minutes behind schedule.]123:59:50 Scott: I'll park out here a little ways, Jim.
123:59:55 Irwin: There's a lot of glass fragments around here.
123:59:57 Scott: Yeah.
123:59:58 Irwin: More than I've seen any other...Yeah. If that's Index over there and this is the one that's northwest of Index, gee, that puts us at...
124:00:07 Scott: Yep. You know what?
124:00:09 Irwin: That puts us really at position D. Let's see that'd be 75.5 and Baker Queen.
[They are actually near BS.4/73.3, which is 800 meters NNW of the location Jim just estimated.]124:00:21 Scott: Yeah, and, you know, I can see why, now. I thought that was Salyut. Because Index is so subtle, and there's another one that is just to the north of Salyut, which I was going to call the landing site. Okay, we're parked.
124:00:46 Allen: Okay, Dave and Jim...
124:00:48 Scott: Let me get off.
124:00:49 Allen: You're certainly very close there, and we can sort out the details of that later. Dave, when you turn on the TV, could you police the TV cables for us again? We think that we may be hung up again. And we need a status check from both of your EMUs, please.
124:01:08 Scott: Okay, Jim. Would you do all that?
124:01:10 Irwin: Okay; here are the Rover readings: 315 (heading), 059 (bearing to the LM), 10.3 (distance traveled, in kilometers), 00.1 (range from the LM), 100, 107 (amp hours remaining in the batteries), 95, and 95 (battery temperatures), and motor temps are both lower limit.
124:01:36 Allen: Roger. And that lower limit's okay.
[This close to the LM, the bearing is meaningless. The very small residual range indicates that there was no significant wheel slippage which would have thrown that number off. Jim is on LMP-15.]124:01:38 Scott: And, Joe, my EMU flag...(With a slight scolding tone in his voice) Careful, Jim, come on. Go easy, babe. (Long Pause) (Concerned) Okay, everything nice and easy now, huh? Let me look at your camera. (Pause) Get the dustbrush out first. Hop off of that thing with the grace of a ballerina. (Pause) Get the brush on your RCU.
[As indicated on CDR-15, Dave planned to park the rover on a southeasterly heading (135) facing the SEQ bay. He has actually parked on a northwest heading.]
[Journal Contributor Jeroen Wackers notes that, since Dave gave the Rover readouts prior to the start of the traverse at 121:30:18, they have used 18 amp-hours, giving an average useage of 1.74 A-h/km. This is much lower than the pre-flight estimate of 3.67 A-h/km, which seems unlikely. Wackers notes, however, that the figures for EVA-2 and EVA-3 are 1.60 and 1.76 A-h/km, respectively. See, also, the discussion following 167:35:58.]
[Jones - "It sounds to me like Jim fell, getting off the Rover."]124:02:37 Allen: Okay, and while you're brushing it, Dave, we need a PLSS check.
[Scott - "I'm not sure he fell. He might have jostled the Rover somehow, 'cause it's pretty light."]
[Jones - "The reason I think he fell is the talk about the brush and you taking a look at his camera."]
[Scott - "Could be."]
124:02:42 Scott: Yeah; Rog. (RCU) flags are clear. I've got 40 percent and 3.85.
124:02:48 Allen: Sounds good.
124:02:49 Scott: Turn around here, Jim, let me get your...
124:02:50 Irwin: Okay, I'm...I'm 3.85 on pressure; flags are clear, and I'm reading 45 percent.
124:03:01 Allen: Okay. (Pause)
124:03:16 Scott: Let's see your camera so when you take those pictures it's not...(Brief Pause) It's alright. (Long Pause)
[Irwin, from the 1971 Technical Debrief - "I might make one comment, Dave. You know, coming back to the LM in preparation for the ALSEP (deployment), I felt that I was thirsty and kind of hungry; and I tried to get some water out of the water bag as we were approaching the LM. Couldn't any water out of it, but the food stick was there and I gobbled that down. I think that was the thing that pulled me through and gave me the energy to get through the ALSEP deployment. That really perked me up. I felt great after that."]
[Scott, from the 1971 Technical Debrief - "That's a good point. I, too, when we got back to the LM, tried the water and the food stick; and my water worked fine. I got several gulps of water. It was very refreshing and I ate about half of the food stick at that time. That helped quite a bit. I think, in looking at it, the problems I had (later) with the water bag were related to tie-down to the neck ring with only Velcro. On the second EVA, that came loose and I could never get to the water bag because it was under my chin. I think, maybe, if we had snaps in there, or some firmer method of tying it down, it would have helped me. Can you sort out why you couldn't get to the thing?"]
[Irwin, from the 1971 Technical Debrief - "I could get to it. I just couldn't suck the water out. I just couldn't make the valve operate."]
[Scott, from the 1971 Technical Debrief - "I'll tell you, the water bag is really a valuable asset because one quick swish of water and it really refreshes you. I think, if you really got thirsty, you could stand there and drink the whole thing, if it worked right. There was no problem putting it in the suit, no problem donning the suit with the water bag full, or with the food stick."]
[The following discussion is taken from the Apollo 15 Mission Report. "After each extravehicular activity, the in-suit drinking device was removed from the suit and all of the water consumed, thus verifying proper operation of the in-suit drinking-device drink valve. The problem was associated with the positioning of the in-suit drinking device within the suit."]
["Ground tests using suited subjects and other equipment configurations indicated that the existing equipment provides the optimum configuration. The tests also showed that personal experience is essential to obtaining optimum individual positioning. Crew training (will be modified) to include more crew experience in making the position adjustments required for the individual's needs."]
["This anomaly is closed."]
[Whatever changes were made in training and/or equipment, all of the Apollo 16 and 17 crew members were generally able to get drinks when they wanted them - and, in Charlie Duke's case, sometimes when they didn't. The only exception was that John's Young was unable to reach his drink valve during Apollo 16 EVA-1.]
[A detail from training photo 71-HC-724 shows Jim's drink valve.]
[In a 1996 letter, Dave questioned the relevance of the fact that the valve worked when Jim's drink bag was removed from the suit. "If the bag is removed, then the valve would not be positioned the same as when attempting to drink while in the suit. Jim may have had some form of 'interface' problem due to the insulation in the suit. Did we ever try these in the (vacuum) chamber? If not, we should have. But there was probably not enough time before the mission to try every gadget hi-fi (that is, in a high-fidelity simulation)."]
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