“Apollo 16 Scientific Debriefing”

20:01speaker 1rascal down because of the 15 problems. But maybe it's uh before a guy leaves that uh ALSEP site, if he's got a problem like it. Maybe Is ALSEP on 117? Probably it's not, is it?

20:14speaker 2ALSEP is on the seismic.

20:16speaker 1Seismic, okay. Well, those rascally things uh assume some different kind of uh orientation than they did for before we left before we left, and maybe you ought to go back one more time and make sure those things are haven't changed. Don't ask me uh I think maybe they outgas a little and then take up a different sh- shape.

20:42speaker 2Well, it's not only it's not only your your near activities. I think when we saw that that uh TV picture degrade on LM ascent, it's obvious that a lot of debris is being thrown around and you just can't avoid a good dusting down from that source. So, our our carefully prepared thermal surfaces act more like black bodies than anybody figured on as a result of all of this.

21:05speaker 2And we saw your rover signals, which this time uh provided uh very, very interesting data, uh in that they showed rather abrupt changes in signal level as you moved around.

21:22speaker 2Uh we're not sure yet what to make of that. We're going to work with Bill Muehlberger and his crew carefully on the traverse to see whether or not we can identify specific provinces in which the signal level is quite a bit higher.

21:37speaker 2I guess I I would like to ask your impression uh as you were rolling along and given along the given EVAs that you you felt at at given times that the rover was bouncing uh noticeably more than at other times that might have generated higher signal levels.

22:01speaker 1Sometimes she was off the ground, there's no doubt about that.

22:04speaker 3To the south, uh on EVA 2, that area was a lot rougher than the uh traverse route to North Ray Crater. My impression of North Ray Crater traverse, once we passed Palmetto, was it was really boulder-free area, very subdued old craters, and the rover just sped along and much like a West Texas type terrain. Whereas to the south, it was uh really rough. You had to maneuver.

22:34speaker 1And par- particularly on Survey Ridge when we were traversing that area with all the secondaries and blocks, uh we managed to be up in the air quite a bit uh simply because there were so many secondaries and blocks that we had to hit some small ones to avoid the big ones.

22:52speaker 3The uh subjective opinion of mine also is that around, at least at Stop 13 where we actually got off the rover, uh the regolith did not seem as as loosely compacted as to the south. And in fact, at North Ray Crater, at Station 11 and 12, it was no more than a couple inches deep, because you we couldn't get the rake in without bending the tines of the rake.

23:19speaker 2Hm.

23:19speaker 3So, the regolith up there was very thin. Uh and I don't know whether that means there's a just some very cobbly, uh loosely compacted blocks under there from that were thrown out or or that are now that much covered or whether we just picked some bad sites. But we tried to rake twice and both times, the only luck we had was kicking stuff into the rake. We couldn't pull the rake through the regolith.

23:45speaker 1And you couldn't stick the tongs in, either.

23:46speaker 3Yeah, and the tongs wouldn't go in. And every other place, you could take the tongs and stick in the ground, they'd stand up for you.

23:53speaker 2Well, in general, this area, from from the general character of our signals, it it gives the appearance of being the thickest pile of of what we can might loosely call regolith of any of the sites. And I guess Bob Kovach will talk on his results on on that. And and, of course, we await his his uh mortar firing to give us a little more information on that. Well, we'll be looking at these rover signals and see if we can we can somehow pin them down to to roughness of terrain or or just what uh from the pictures that you took along the way.

24:29speaker 2Uh we now have the the quiet nighttime period and we're waiting for the first moonquake of the session, which which uh ought to be, well, I was hoping it would be in the last 24 hours, it wasn't, uh but should be before May 12th, so in the next few days. And and, of course, with this last station, we now have completed a very nice triangular array. The other three gave us a a very narrow-based thing. Now, we have a thing with a 1,000-kilometer baseline, which which, if it lasts for as long as uh they appear to be lasting, will give us the tools to really do the job over the next couple of years.

25:08speaker 2Uh and, of course, we'll be using that in the S-IVB impact from the next mission.

25:14speaker 2I'd like to turn to to one observation reported from orbit that that has interested us a great deal, and that was the flash that was reported. I I haven't seen, I understand the transcript is not now has not yet been typed.

25:29speaker 1I haven't seen it yet, so that's my only hope for pinning down the time. I can get it to about 5 minutes with that other thing.

25:36speaker 2If you can help us pin down the time and roughly the location, we'll certainly look at our records, and that would be a an important piece of data if we if we recorded that. Would like to ask, was this like a colored flash or a white flash?

25:49speaker 1Just white.

25:52speaker 2Uh what was your how does it differ from the kind of thing you get with a cosmic ray impact on your brain?

25:58speaker 1I didn't see any of those.

26:00speaker 3He didn't see any of those.

26:01laughter

26:08speaker 1Redhead.

26:09laughter

26:11speaker 1They were cosmic flashers.

26:15speaker 2Well, we're we're very much excited by that. As far as I know, it's the first report of a transient event of some nature that's been seen from orbit.

26:24speaker 1I I just have to wait for the I should have written it down, and it just didn't occur to me to write it down.

26:30speaker 4Did we get a time on it and all, Ken?

26:32speaker 1It's on the DSE.

26:33speaker 4It's on the DSE.

26:34speaker 1If I ever get that, I'll

26:35speaker 4Well, then we'll correlate any information we get from the seismic uh if they've

26:42speaker 2Yeah, how about its persistence? Did it just

26:44speaker 1No, it was just it was just a flash. And and the way I happened to notice it, I was looking at a at a horizon that was showing up from solar corona or zodiacal light, whatever you want to call it in that region. It was very shortly after we lost uh signal from Earth. And I was watching stars pop up over the horizon. And uh got this flash, which was in size was about I hadn't I wasn't looking directly at it at the time it happened. It happened down in the side of my vision. But it was brighter than the than the brightest star that I had in the field of view at the time. And I had the feeling that it was uh in physical or angular size, it was equivalent to the size of the larger stars in in my perceived vision. But it was just a it was just an instantaneous flash. And it took a a couple of seconds for it to soak into me that it wasn't just a star popping up over the horizon, but rather it had been distinctly below the horizon.

27:58speaker 2Mhm.

27:59speaker 2Is there a way for me to get that transcript? Uh I I don't know if I would normally get it.

28:05speaker 5I'm glad I'm glad you asked.

28:06speaker 2Oh, that's it?

28:07speaker 5I forgot to mention this in the opening remarks, but we have about 50 copies of this technical air-to-ground voice trans- uh from right back there. And uh for the PIs and the co-Is and uh there's a copy for you, Gary, back there.

28:21speaker 1Gary, that's not what you're after. You need the tape recorder.

28:23speaker 2No, I need the tape recorder. Yeah.

28:24speaker 1Oh, the DSE.

28:25speaker 2Oh, the DSE. Yeah.

28:26speaker 1And that hasn't been completed as far as I know.

28:28speaker 2Okay.

28:29speaker 1Now, one other thing that I'd like to mention, it from orbit, it appeared to me that there was a distinctly different unit up around North Ray and and the area that a prop- I'd say a third to a half of the traverse to North Ray went across. And uh that may or may not fit in with your seismic deltas.

28:53speaker 2That at some point between North Ray and the LM, they they would cross a contact of some kind.

28:58speaker 1Yes.

29:03speaker 2Well, except to add my thanks for a very fine uh deployment. That's all I have. Thank you.

29:08speaker 4Thank you. Any questions from the floor?

29:11speaker 6What time does uh this flash on the S-IVB impact?

29:16speaker 1Well, I don't know whether the S-IVB hit, but this is on the on the back side of the LM, so I would assume that the S-IVB didn't hit there. And it was well after that. Like couple of days. Lunar days.

29:34speaker 7Where did the S-IVB impact?

29:37speaker 8Oh, it hit about

40:00speaker 1...of the previous missions is that some pieces of platinum foil have been attached to the previous design which was composed of a pure aluminum foil. These platinum foil pieces can be cleaned by fluoridic acid which allows to remove all the possible lunar dust contamination. This technique has been tested in the lab on bombarded foils and showed that you can remove essentially all the lunar dust contamination without losing any measurable amount of trapped rare gas ions or atoms of of solar wind origin. This technique should allow us to determine the isotopic composition of the rare gas elements of solar wind origin up to the mass of possibly krypton. A first visual inspection of the foil here at MSC showed that the foil is crimpled but essentially free of lunar dust. That's of course only a visual observation. We don't know how the foil looks like under microscope. I would like to thank the crew for the proper deployment and retrieval of the foil. We are very pleased with what the foil looks like. Thank you very much.

41:37speaker 2Can mission tell us where the sun is?

41:39speaker 3Yeah, point this at sun. [laughter] Yeah, I would uh the the thing didn't roll up like I thought it was going to, and I'm sorry I had to crinkle it, but it was so big and that I had to squeeze it down and get it into the bag, and it and it ripped once, too. I guess you saw that.

41:55speaker 1That's That's only a problem of aesthetics. It doesn't hurt the scientific value.

41:59speaker 3Okay, good. I didn't think it did. Thank you.

42:02speaker 2Don?

42:04speaker 4Uh, if the local magnetic field is standing off the solar wind here, how will that affect your...

42:11speaker 1We don't know yet. There might be that we have a uh discrimination between the the lighter and heavier elements in in the solar wind. We have to check that. Maybe that there's a dependence on on on the height over the lunar surface of of the composition between the heavier and lighter elements. But we have to check that first and see.

42:37speaker 4Will it stand off the lighter particles?

42:39speaker 1The lighter particles would be deflected much more than the heavier ones.

42:47speaker 3Can you see those uh I don't know, this is probably a stupid question, but these cosmic ray these particles that cause the light flashes, I was seeing them on the lunar surface at uh during the sleep periods. Do those things register on your experiment?

43:01speaker 1No, they have higher energies and and they go through the foil.

43:06speaker 3I see. Yeah.

43:08speaker 2Huh?

43:09speaker 3They won't show up on his foil.

43:14speaker 2Uh, while while you were closer to the thing, could you tell any difference in the material between the time of deploying and the time you brought it back? Was there any realness or anything you might have observed?

43:24speaker 3No, uh, no difference there. Uh, looking at it one time out the window, I thought I saw some white streaks on it, but uh that might have been just the way the sun was uh or might have been those platinum strips that I never noticed when I deployed it. I really don't know. It just looked like it had a couple of uh randomly oriented streaks on it to me from the win- LM window, but uh when we rolled it back up again, instead of rolling straight up, it rolled out in a big long thing, and I had to redo it again, and when that happened, I I ripped it and then had to crunch it down.

44:02speaker 1We we don't see any difference between the foil we sent up and the foil that came down, except of some lunar dust on it. Nothing else. Can I ask the crew a question? Do you have a an idea how the foil was oriented? Was it essentially vertical to the...

44:21speaker 3The photographs.

44:22speaker 1...line, mean along the the gravitational force lines, or or was it in reclined or inclined? It's hard to tell it from from pictures.

44:32speaker 2Yeah, you can't tell from pictures.

44:34speaker 3I I think I put it in almost uh uh parallel to the gravity vector there. It's it's on a slope, a little slope, but it if I recall, it was it's aligned almost vertically.

44:45speaker 1Okay. Thank you very much.

44:48speaker 2Thank you. The uh next subject will be the cosmic ray detector, uh Dr. Bob Fleischer. See here?

45:01unknown speakerOh, okay.

45:03speaker 2He's not here.

45:09speaker 5The PIs couldn't be here this morning. They're busily at home uh uh studying the data that they got back. I have uh some words from them that I'll pass along as to what they they think they'll be able to see. Uh, they are very excited about the possibilities they have. Uh, early in the mission, there was a solar particle event that occurred, which uh will enhance their data uh very significantly, they think. Uh, they think they'll have the opportunity to see particles from the sun that uh on an ordinary mission, they would have never had the opportunity to to see. Uh, when they got the experiment back, panel one did have considerable dust on it, and uh this, from the best we can tell, without uh any analysis, came from the uh landing itself, from the uh uh blast up from the uh DPS. Uh, panel one was hot. Uh, in the uh uh taking the panels apart, panels two and three were cooler, and uh uh panel four uh was of the same order of temperatures as uh panel two and three. The uh uh cosmic ray data itself in the plastics appears to be degraded somewhat because of the temperature, but uh they're very hopeful that uh a great part of the data will be uh retrievable. At the first look on panel two, Dr. Fleischer says that uh the number of particles they see on the plastics uh indeed are uh a great deal higher than they would have normally anticipated, indicating the effects of the solar particle event. And uh they really haven't uh in detail etched the plastics or analyzed them. They're just beginning to do that.

47:00speaker 2But they think they are usable?

47:01speaker 5Yes, the plastics.

47:02speaker 3I was really surprised because uh we had some lengthy discussions about this pre-flight, and I could never understand how we're going to fly this rascal to the moon and get it there with us with these long periods of attitude hold that we're going into where it might see plus 250 all the time, and uh of course, I'm sure those three revs in lunar orbit prior to landing didn't do any good uh either because we're oriented uh many times so that we're facing with uh to maintain communications, we had the sun shining on that rascal uh all the way around. And uh I really think that those 140 temperatures that we saw on the panels, if you go back and look at it thermally, you're going to find out they were they had to be there long before we ever got the thing on the ground. And, you know, and I was really concerned about that as to why we didn't put some kind of shielding over it, but it was too late, I guess, to do this.

47:56speaker 5Well, the thermal design was such that it could sit, I believe, in direct sunlight almost indefinitely without any degradation. It's the IR heating off the lunar surface that really cooks it. So, that's what the thermal people say. Uh, I think, and it's hard to say, and uh we did see the the early picture did show that the temp-a-labels had already changed uh early at the beginning of the EVA.

48:18speaker 3They were black first time we looked at them.

48:19speaker 5Right. And uh uh I guess is the 15 hours, the the thermal analysis says if there's like 15% dust on the panel after uh 20 uh degrees of sun angle or so, you will sort of exceed the 140 degrees on the frame. Uh, it appeared that there was probably 50 or 60% dust on the lower part of the panel, or maybe even higher than that, and it's been about 15 hours on the surface, uh so it it may have just turned out to be a a number of problems that uh probably uh ones that could not be avoided under the circumstances that caused that lower panel to overheat. It was the hottest, and the next panel was uh about 20 degrees cooler, the best we can tell, and the panel third panel up was 10 degrees cooler than the second panel. So, it seemed to be a dust problem, but uh it doesn't seem to to have hurt the data too much. Panel four was the one uh which uh was we were afraid wasn't going to be activated because of the anomaly on the red lanyard, but after they have taken the panel apart, apparently every portion of the experiment was activated to some degree or another. The neutron portion uh was partially uh deployed, and they think they will get some data from it, not not as much data statistically as they wish they had. But uh uh every portion of panel four does look like it will provide some some useful data, and they have a lot uh higher hopes now than they did when they first saw the gear. Apparently, the problem, and we haven't, again, haven't sent the hardware back to the manufacturer for analysis, but apparently was uh a malfunction in the assembly of it that caused that uh thing to jam.

50:00speaker 3Well, we could have pulled, if I'd have known about it at the time, uh we could have got that pair of pliers out of there and pulled harder.

50:07speaker 5The investigator's opinion was it would have done no good. It was very severely jammed, and uh he doesn't think uh any additional effort would have would have uh would have freed it. It was jammed pretty bad.

50:17speaker 3Okay.

50:18speaker 5But I think, in all, they're they're very uh excited about the data, and I think they're very optimistic now that they'll get uh a considerable amount of data from it.

50:27speaker 2Jim, it's probably worth mentioning on the plastic panels overheat that they did have calibration plastics in there, and they'll be able to, the effect of the overheat is just to anneal the tracks and reduce the track density, but with the calibration in there, they'll be able to take out most of that effect. The other thing is that on panel four, is those experiments which are activated by pulling the cord are only a small fraction of of the total part of of panel four. So, there's a lot of panel four that hasn't been affected at all by the jam.

50:52speaker 5That's true. They'll still get a lot of good data, just as good data as if the jam had never occurred.

50:57speaker 2That's uh for all practical...

51:00speaker 3Okay, I don't think we uh in fact, I'm sure we you may find a fingerprint on there, but if there is, it we uh

51:09speaker 2That thing was clean.

51:10speaker 3We really were careful uh to get it out of there, and we didn't uh once we got it loose, we gave it the usual tender loving care and folding it up, so I don't think there's any crew fingerprints on the panel surfaces.

51:23speaker 5Uh, that's correct. We looked at it very carefully, and it was, except for the po- bottom part of panel one, that you could see was a spray uh pattern, uh it was very clean, and the PIs were very pleased about that.

51:36speaker 2This uh solar particle event, when did it occur?

51:40speaker 5Yes, it started on about uh I believe Monday, which was the day after launch, and went through about Wednesday. So, about a two or three-day type event. I think the peak was uh must have been about Tuesday. There are some satellite data available. I don't have that uh on hand.

52:03speaker 5It was a small event, but for this solar cycle, it was very surprising that it happened at all during the mission, and to have it during the portion when the cosmic ray was deployed, or available to accept data, was the probability of that is very small, so it's a very gratifying thing to occur.

52:22speaker 2Jim, I'm curious about the uh dust being kicked up by the DPS. Uh, did you guys observe any dust on the thing or any other part of the LM at that level? It's always been our impression that the dust is sent out in a pretty thin layer, that you don't get a billowing effect.

52:41speaker 3Yeah, I'm sure it's sent out in a thin layer, but with all those vernier blocks around there, it's a possibility some of it could come back at you, that's for sure.

52:48speaker 2Yeah.

52:49speaker 5It's extremely hard to see, and when we photographed it, the lights are not similar to the sun, probably must much less in intensity, but yet, the photographic lights did wash out. It's a very pale uh kind of dust, but it's very predominant, and it came up from the corner, even in a pattern that you would expect it to be blown, and there were some black streaks in there that appeared to be melted something or other on it, and I think they are going to attempt to chemically analyze the material on it, try to find out what it is.

53:17speaker 2How high is it above the surface on the on the LM, roughly?

53:24speaker 5That first panel must be about chest high, is it not?

53:29speaker 3Yeah.

53:31speaker 2Any other questions?

53:33speaker 3One I just want to comment, that was uh the the frame of that thing was hot really it was hot. That was the only thing I felt through my gloves the whole stay. While it was jammed and John tried to pull it out and I was holding the frame, and I I started feeling it through my gloves.

53:49speaker 2Did you get any feel for why it was jamming or where it was jamming? Do you have any clue of what caused the jam?

53:53speaker 3It was jamming at the base.

53:55speaker 2Yeah, down at the bottom.

53:56speaker 3Right right at the bottom part.

53:58speaker 2At the bottom.

54:00speaker 3Yeah, it's something that broke free right at the base, and then it just came out like like it had grease on it.

54:08speaker 2Maybe we spilled some orange juice on it or something.

54:11speaker 3No way.

54:16speaker 3That's the only thing we didn't spill orange juice on.

54:21speaker 2It's not that you didn't try, huh?

54:25speaker 3That's a good cement you guys. You ought to start thinking about that when it [laughter] suppose that stuff's a vacuum, boy.

54:33speaker 2Okay, our next uh experiment was the uh far UV camera, Dr. Page.

54:43speaker 6I want to run through some of the geologist's here, all of our company goals, purposes of this experiment, which uh were to uh obtain photographs in the far ultraviolet of the geocorona and the upper atmosphere of the Earth. Uh, these photographs, of course, include spectra as well. And uh solar wind clouds, possibly, uh interstellar hydrogen, um colors of stars in the far ultraviolet, and possibly intergalactic hydrogen. We had a lot of uh troubles, I guess John well knows, um before launch. The difficulty was to keep the camera dry because its uh optically sensitive surface would immediately uh run away if it got damp. And this was um accomplished with a bag that caused uh Captain Young a little bit of trouble in practices in advance, but apparently worked all right on the lunar surface.

55:48speaker 3Great.

55:49speaker 6The uh second difficulty was getting through the Van Allen belts without fogging our film, and I'll show you in a moment that we did that all right with a rather small amount of shielding around the film cassette. Um, then um uh we had some difficulty with the LM being in the way. This uh came about because of the delay in touchdown, high sun angle, and the necessity to keep the camera close to the LM so that it would be in the shadow. Uh, with its gold surface, uh it would have heated up very rapidly had it been out in the full sunlight. The uh accomplishments that uh I will show you in a moment on the screen include uh 92 photographs in Lyman-alpha imagery and 53 spectra, uh some of them extending from 500 angstroms to 1550 angstroms. That's, I think, the farthest into the ultraviolet anybody's ever uh taken astronomical pictures. Uh, we may get evidence of gases in the lunar atmosphere from several of our uh pointings which were low across the lunar horizon. And uh if anything were uh coming out, like uh geysers of water or whatever it is, uh we'll certainly pick it up. The data on these photographs are extremely numerous, and it'll take us an estimated six months to a year uh to get them all out, which will be done with a big computer here at the MSC. So, Dr. George Carruthers, who is the PI and who designed the camera, uh happened to be free today from work on an Aerobee flight and is here, and will undoubtedly make comments whenever he sees something to comment on the photographs. Do we have the first slide? I might say that I got into trouble with the American Photographers Union in making the prints of these, um because I'm not a member of that union, and they tried to throw me out of the darkroom over here. [laughter] Uh, this is probably one of the most uh dramatic pictures of the Earth that uh shows uh auroral belts on the dark side. You're looking at the Earth with the sun off to your right. Uh, the South Pole of the Earth is down, and that uh funny lip-like thing sticking off to the left at the bottom is aurora, we think, around the South Magnetic Pole. Uh, the most striking thing is the next lip up, which uh on the original, you can see better than on this slide, goes around the full back side of the Earth. Uh, it's called the equatorial auroral belt, and disappears back of the dark side in the upper uh left corner. Uh, the third lip is another belt that looks at first as if that was just all one, but there are two separate belts there, and was quite unexpected. This photo...

58:56unknown speakerWhat's the dimension of the Earth's actual size on the...

58:59speaker 6Well, you know, it's 8,000 miles across. [laughter] You're...

59:08unknown speakerIs there some halo...

59:09speaker 6Uh, it is there's some halation here, uh and I guess I'm not too sure, and perhaps George knows, this is a special Eastman NTB3 emulsion, very, very thin. And, of course, the exposure was made with electrons, not with light. It's electronographic camera. Uh, but um the dimension works out right. You can't see it too well on this print. The um there's a ring or a uh a limit to the field, which on the originals is 30 degrees 30 millimeters across. It's 20 degrees in the sky, and the Earth is 2 degrees, and it's it checks out, so um the dimension you see there is 2 degrees across the full diameter of the Earth.

59:52unknown speakerNow, you say this is this is the uh equatorial auroral belt. The thing I want to try to say is, what is that the third line from the bottom? Is that the back side of...

60:00speaker 1No, you can't see through the Earth. Uh-uh.

60:02lunar module pilotThat's why I asked you, is the Earth covered, not the...

60:05speaker 1No, that, uh, the geometry is such that that is probably inclined 30 degrees to the magnetic equator and is an unexpected auroral belt. Uh, it'll take a little more, um, figuring to figure this out. But...

60:19lunar module pilotWhat is the latitude of that third belt?

60:21speaker 1Um, as I just said, my guess looking at the picture, it hasn't been measured accurately, is 30 degrees north.

60:28lunar module pilotThat's due to the southern, uh, hemisphere.

60:31speaker 1[laughter] [chuckle] Okay.

60:35speaker 1You'll, uh, notice on these pictures that, um, they're overprinted. Uh, that's because I'm not a member of the photographers' union. And, uh, the originals have a good deal more on them. Uh, this picture was taken, uh, excluding hydrogen light, Lyman-alpha. Uh, we have two filters on the camera, and, uh, this one is taken in light between the wavelengths of 1230 and 1550 Angstroms. Now, the next slide...

61:02lunar module pilotYeah.

61:03speaker 1Yeah.

61:04lunar module pilotIs that whole diameter you're seeing there, is that all the Earth or is that twice what the Earth is?

61:08speaker 1No, it's it's the Earth, just the Earth.

61:10lunar module pilotThat whole thing you're seeing is the Earth.

61:11speaker 1The Earth, right.

61:12lunar module pilotI thought it was double, not twice the image.

61:16speaker 1No, no, it's it's, uh, as I said, the little halation which makes it a little bigger than it ought to be, but...

61:22lunar module pilotJust only a few percent.

61:23speaker 1Yeah, a few percent. Now, in this one, it's exactly the same view was taken, uh, after John so accurately pointed the camera at the Earth. Uh, the Earth is in the middle there, and if you look real hard, you can see the dark side of it off to your left. Uh, this is the geocorona. The streaks are an instrumental, uh, matter. Uh, actually, we have a, um, barrier membrane that George, uh, put very close in front of the film, uh, to to keep, uh, visible light from, uh, getting in there, and the barrier membrane wasn't quite uniform, and that's where the streaks come from. The circular thing on the right is an overlap, another defect. Um, the little motor that, uh, advanced the film between exposures didn't pull it quite far enough for this one. And, uh, those dust specks, I guess, are, um, my pipe tobacco on the, uh, slide. [laughter] [chuckle]

62:15commanderYou know, uh, Thornton, that, uh, that rascally thing was moving, uh, at first it wasn't moving. The wheels weren't going as far as they did toward the end.

62:26speaker 1No, we have a complete transcript of everything you said about it, and, uh, in looking at the film, which I've done in great detail, uh, you can see, um, the most serious, uh, defect in that, uh, film advance was during your short exposures on the Earth, John. Everywhere else, it it worked fine. And, uh, I have an idea that the, uh, pushing the buttons so frequently, um, sort of, uh, confused the motor, and it didn't, uh, turn as far as it should have. Well, in any case, uh, you'll notice that the shape of the geocorona is as predicted by, uh, Dr. Meier at the Naval Research Lab. It's got a dip- dimple in the back, down sun. Sun is still to the right here. And, uh, our other photographs, uh, show that it, uh, extends at least twice as far as you see here off to the right. The print, of course, can be printed dark or light, and if I'd printed this one lighter, I'd have got the, uh, the background all over the whole, uh, slide, and you wouldn't have been able to see as pretty a picture as this. Now, the next slide shows, uh, uh, the one further to the right. The sun is still to your right. The Earth now is off the edge of the picture to the left. Uh, this, uh, was one of the, uh, sequence taken through the night between EVAs 2 and 3. Uh, you see a star background here, and again, the geocorona, uh, those streaks, which are not real, extending, uh, actually right across this frame if you, uh, print the thing lighter. Um, now, the next slide shows the two of these combined, and that printed a lot darker, and, uh, I guess is not as artistic an effort as I had hoped. [laughter] [chuckle] The, uh, geocorona, uh, produces is, uh, hydrogen, uh, in 1216 Angstroms, Lyman-alpha. And the next slide shows the spectrum, uh, actually taken on that first slide. The spectrum is dispersion is vertical, and that white band across, horizontal, roughly horizontally, is Lyman-alpha. You see how strong it is. The Earth is in the middle of this picture, and the spectrum of the upper atmosphere is, uh, spread out, uh, on that vertical line from, uh, far ultraviolet down at the bottom to nearer ultraviolet up at the top. A bright line just above Lyman-alpha is 1304, which is, see, an oxygen line. And, George, do you want to describe this in more detail?

65:02speaker 4We've, uh, so far only made a very crude analysis of the spectrum, uh, by comparison with laboratory spectra, uh, made in the pre-flight calibrations. However, we have, uh, tentatively identified, uh, the 584 line of helium, the, uh, 834 line of atomic of ionized oxygen, the, uh, 1026 line, uh, Lyman-beta of hydrogen. These three lines are, uh, the first, uh, spectral measurements in the Earth's upper atmosphere. Uh, all previous measurements have been limited to wavelengths longer of 1100 Angstroms, uh, which we also cover and which includes the Lyman-alpha line at 1216, the 1304 and 1356 lines of atomic oxygen, and the Lyman-Birge-Hopfield bands of molecular nitrogen between 1200 and 1600 Angstroms. Uh, the Lyman-alpha line, of course, is by far the strongest emission that we have seen in any of our spectra and is the only one that we have conclusively identified in any of the spectra that do not include the Earth. However, by comparison of spectra taken with and without our lithium fluoride corrector plate, which cuts off at 1050 Angstroms, we will be able to determine, uh, whether we see a general background in the 584 line of helium and the 1026 line of, uh, atomic hydrogen, as we, uh, expect, though it will be much weaker than the Lyman-alpha line.

66:36speaker 1George, we've got that other spectrum coming. Okay, in other words, can you hold on a minute, and I think the order he's got them in has the Magellanic Clouds next, and we're probably taking too much time. We have the next slide. Uh, oh, that's it. Go ahead. [laughter] [chuckle] So, this this is without the corrector plate. You'll notice that the, uh, line, Lyman-alpha here, is broader, uh, the definition is poorer, but as George was just saying, uh, we get, uh, lines further down in the ultraviolet, uh, on spectra taken without the corrector plate than with it. And you see here, too, these other lines are not, uh, uniform. This this is a spectrum that was obtained, uh, with the Earth off the edge here. So, it shows that the geocorona goes right across this slide, as I said last time. By the way, that's 100,000 miles. And the, uh, other lines here show the either other materials in the geocorona or beyond the geocorona. I guess it's going to take a little while to figure out which are which. Go ahead. I didn't mean to interrupt. Is that all you had more to say about? The the next two slides quickly show the Oh, that's right, it's one. The Magellanic Clouds, which are, um Well, John was worried about what LMC meant, and this is the Large Magellanic Cloud, and that's the initials what the initials referred to. Uh, the picture on the left is with hydrogen, with Lyman-alpha, and the picture on the right is without. Um, in this far ultraviolet region, uh, all that you are seeing here are the very hot blue stars. And, uh, over here, you see the clouds of hydrogen gas. So, the difference between these two photographs is hydrogen, and we get the record of Magellanic Clouds are nearby galaxies, so we have a galaxy with all of its stars and nebulas and what not spread out in front of us to study. Um, now, Carl Henize has made special studies of these, uh, Magellanic Clouds, and is very much interested, already has copies of this these photographs for study. Uh, you notice that the hydrogen, uh, is not just from the Magellanic Clouds. This stuff up here is, uh, out in the open sky, and just what caused that background, I don't know. Is there any other slide? That's the last one. Okay. We had a couple of questions for John. One was that sticking, which had us worried. You talked about the, uh, the instrument may fly on Apollo 17. Rob, of course, is very interested in it. [laughter] [chuckle] And, so, what was what was the sticking, uh Did it continue right through? You didn't mention it in EVA 3.

69:24commanderWell, it got it got worse all along. I I just got the feeling there was some kind of hang-up between in in, uh, possibly, uh, long-term vacuum exposure or s- something to the to the operation of the of the way it was working in azimuth, and I never was able to or never able to really, uh, know it never got better. In fact, as the longer it sat there, uh, maybe the cold, uh, it just seemed to get stickier and stickier. Toward the end there, every time I had to every time I got to a new setting in azimuth, it completely, uh, destroyed the level, and, uh, we're unfortunate we were on that slope, uh, right there, it's under the footpad of the LM, and, uh, so, had to go back and re-level it every time, and that was, uh, we really had working at the limits of the level level ability of the of the of the machinery, I think, there, and, uh...

70:34speaker 1You you see that it didn't make much difference. For instance, that Magellanic Cloud should have been out in the middle.

70:38commanderI I know. I know, and, uh...

70:39speaker 1You were off by that much because...

70:41commanderBut, uh, well, that's I if we were if we were on a level slope, it would have been no problem in getting the bubble right in the middle every time, and if the azimuth had worked easily, it would have would have, uh, uh, remained level. I but I sure don't know what it was.

70:59speaker 1It couldn't have been dust that got in, uh... No, we thought that was impossible.

71:03commanderNo, I don't think we had any In fact, I'm sure we didn't have any dust on the legs, uh, up that far.

71:13speaker 1The film that you brought back had very little dust on it. In fact, it looked brand new.

71:19commanderWell, s- if it got if it got dust on it, it got it inside the LM. There was plenty in there once we got into zero gravity, although I don't know how it'd crawl through two bags.

71:29speaker 1I That's why I was quite surprised there was no dust. But we're disappointed because we're going to collect a little bit of dust off of it. [laughter] [chuckle] Any any questions from the floor? Um...

71:38commanderAnd what and I'm sure it got some dust on it when I, uh, removed it, though.

71:43speaker 1Well, I got a little, a very small amount, uh, which I'm illegally keeping in my desk. [laughter] [chuckle]

71:49commanderDon't don't tell anybody. The FBI will be around to see you.

71:54lunar module pilotDid did you see evidence of the magnetosheath or bow shock?

71:58speaker 4Uh, so far, we have not seen the, uh, any discontinuity in the up-sun geocorona, which would be indicative of that. It just sort of dribbles off the way it behaves sunward from the Earth, and there's no sharp drop.

72:12speaker 1But we're really not out as far as the bow shock, are we?

72:15speaker 4Uh, 10 Earth radii should have been in the middle of that, uh, up-sun geocorona.

72:20speaker 1Is it only it's only 10?

72:22speaker 412, something like that.

72:26speaker 1Okay. Any more questions?

72:30speaker 1Okay. Next, uh, subject is the lunar geology investigation, Dr. Muehlberger.

72:51speaker 5Okay.

72:52speaker 5For the benefit of the astrologer in the crowd, [laughter] [chuckle] there's been very little evidence for water and, uh, none so far for geysers. Our experiment may not be as far-reaching as theirs, but, on the other hand, I think we've made a large step toward understanding the history of the moon, and therefore the Earth, and therefore the solar system. And if you guys can find any more, we're out there with you. So far, we've completed the, uh, mission itself, and all major objectives for the pre-planned traverses were reached, and were sampled, and were described, and photographed. And as far as we can tell with our quick look at the photographs, uh, all of these were done well. We've produced a, so-called, greenback at the end of the mission operations itself, which was a summary as of our knowledge at that time, as based on crew observations, TV, and the pre-mission data. Included in that thing are station sample maps, which were derived from the TV, uh, in real time, and that, uh, was a very useful tool to us, a sample inventory, a film usage inventory, and a station locations, again, resected from the TV pans. Uh, by the end of last week, we'd received black and white, two-time enlargements of all film. These are the typical drugstore quality prints, and sooner or later, we'll get, uh, good quality, so our analysis is very brief. We've assembled all the panoramas, uh, sample location, uh, studies are nearing completion, the film location inventory is also nearing completion, the geological analysis is still in its infancy, and I suspect should progress rapidly now that we've got all this inventorying over with. You guys took so damn many pictures, it takes time to get them organized. We've had one session with the crew in the LRL with samples, and most of our questions need samples in hand, and those will, I'm sure, we'll be able to discuss later. And so, the questions I've got relate more to, uh, surface observations that maybe we can amplify, and some of these are questions that we've asked you before, but I have a few Polaroid prints of these photos that maybe can jostle our minds and, uh, assist in refining some of the answers that we've got on the debriefs after the EVAs or on trans-Earth. Our photogeologic mapping group primarily talked about rays by their whiteness. There were a few spots where they thought they were seeing dark rays. Uh, you recognized both light and dark-colored rays, and I'm, particularly, the South Ray picture, if I can have, uh, slide one, please, which is the South Ray panorama, and the print I've just given to the crew, a single frame from that. Uh, there, I think we can see light and dark, and the real question I'm after is of, what led you to say that you were on or off a ray? And secondly, uh, were there any, uh, visible differences in the rock types as you drove by or had a chance of sampling ray material?

76:25commanderThat picture upside down, isn't it?

76:26speaker 5Yeah, it is.

76:27commanderIt's upside down.

76:28speaker 5Surely is that way.

76:29commanderThe hills are at the bottom.

76:34speaker 5Yeah, I think the thumbprint goes in the upper right. Could the projectionist give that a 180, please, around a horizontal axis? That one's, uh, got the same problem. There we go. Now it's a hill instead of a hole. This is your pan from station 4.

76:58commanderYeah, you see that you see that black line coming over the This this photo really doesn't do that much justice.

77:07speaker 5No.

77:08commanderUh, Polaroid prints never do.

77:09commanderWell, I mean, uh, you really have to see it to believe it. That white is so much whiter than than, uh, the contrast we're able to get out of the photographs. The... I think, uh, when I looked at it, my assessment of this, uh, which is kind of bad place, was that it was a black ray coming out.

77:34speaker 5The ray's rim there on the photograph.

77:35commanderGoing over there, yeah, and it probably went right down that, uh, as you know, that the the photograph that showed a black area coming out of South Ray.

77:44speaker 5Right.

77:45commanderRight, and there's a series of black black blocks, uh, there's a bunch right there.

77:50speaker 5Left edge.

77:51commanderYeah, and and there's also, and Charlie described this in real time, there's some some more black, uh, blocks in there, and they seem to come out in ray patterns, too. Don't you think, Charlie, that that rascally, uh, that's one spectacular crater. That, that ray coming down the south south, uh, right edge might have been the ray that made, uh, or at least part of it that made, uh, Survey Ridge, because it just ran right across, uh, those red trap craters, and and we could see it going all the way down.

78:27lunar module pilotIs that the bright ray you're talking about in the lower right?

78:29commanderThis ray right here, Bill, came right through Stubby, right up over and right out Survey Ridge, this this one right here.

78:35speaker 5So, that was the source of your terrific block field there.

78:38commanderMan, and, uh, just amazing how much rock that rascally laid down. I just couldn't believe it. Trafficability in close to that thing would probably have been very interesting. [laughter] [chuckle] Wish we'd had another EVA to find out. I'd make the heat flow one.

78:58lunar module pilotThe the the reason we call we were on a ray was really a, uh, uh, an abundance of secondary craters and an abundance of blocks, and they they thinned and thickened as we, I think, traversed rays, rays, but we never did get com- totally out of blocks to the south to the traverse to the south. There were always 5% at least 3 to 5% of the surface had cobbles, uh, when I say cobbles, uh, 20-centimeter blocks, uh, and larger.

79:32speaker 5And the blocks were generally asymmetrical in this to the crater or the crater shape was elongated, the or just a great spattering of craters is why you're calling them secondaries?

79:44lunar module pilotI think, subjectively, we felt they were oriented from South Ray all the time.

79:49commanderThere was really just a subjective feel as we're driving by them.

79:53lunar module pilotThere were a lot of the blocks that were not associated with any craters. There were there would be a pile of a, uh, a...

Not transcribed: 00:00–20:00, 29:37–40:00 and 79:53 to the end.

The audio quality is good, with clear speech from multiple speakers in a conference room setting.

The audio quality is good, with clear speech from multiple speakers in a room.