“Apollo 16 Scientific Debriefing”

silence 00:00-00:02

00:02speaker 1And the areas in black are the total area covered, which we obtained uh from the mission. And the areas in red are the pieces which we missed due to the uh deletion of the plane change and the uh the early return. This little piece down here was a oblique pass which we had planned with the pan camera. Uh would have taken place on rev 72 in order to get photographs of Descartes, which is a a an area of particular interest to the geologist. Uh so, you can see that we did lose some data. On the other hand, we did pick up some data that we would not have gotten. Uh and I think overall the effectiveness of the pan of the coverage was about 90% of what we had hoped for uh pre-mission. I really want to express the uh thanks of the photo team uh to the flight planners here and also to Ken for his operation of the cameras uh during the mission. I know that uh it was very confusing to be continually changing the flight plan and uh Ken probably wondered what the hell we were doing with all these on-offs and so on. Uh but uh uh really, I think we did uh a very effective job of recovering almost all of the data that we had planned uh for the mission. Uh may I have the the next slide, please?

01:35speaker 1Uh this is a diagram showing what the Apollo 15 coverage was like. Uh this is the planned coverage for the uh 16 mission, and in the dotted line is the planned coverage for the 17 mission. The only reason I show this is to indicate that the areas where we did lose data uh unfortunately are in the areas uh that will uh were not covered by 15 and will not be covered uh by 17. So that the losses, although small, were real. May I have the next slide?

02:11speaker 1Uh Ken, during the film recovery EVA, you reported that the stellar camera glare shield was hung up on the handrail. Uh I'm not uh 100% clear as to exactly what that uh situation was. This is the stellar camera glare shield, and this is a little cover that comes down and covers that when the when the mapping camera is retracted. Uh maybe you've discussed this with the other people here at uh the center, but for my own information, I would like to know whether this is the cover that was hung up or this cover.

02:44speaker 2Both of them. The uh the shield at the forward end, that one.

02:48speaker 1This one?

02:49speaker 2No, the first one you looked at, yeah. That was sticking up.

02:51speaker 1That was sticking up, uh-huh.

02:53speaker 2Yeah, but the the tip out here was mashed against the handrail.

02:57speaker 1Mashed against the handrail out in along here?

02:59speaker 2Yeah, the the rail isn't in this picture. It's not installed, but it would have been along here.

03:03speaker 1That's right.

03:04speaker 2And this lip was up against it and and bent back out of the way.

03:07speaker 1I see.

03:08speaker 2It was not in the full extend position. It looked like it was a partial extension.

03:12speaker 1Uh-huh. Uh could you tell whether this was bent, whether this rail was bent, this extend rail?

03:19speaker 2No, but I think we have a photo that'll probably tell you that. I don't I don't remember. The the end of the shield was bent, now whether that rail, no.

03:26speaker 1Here?

03:27speaker 2Yeah, and the next the next section of the accordion, that one.

03:29speaker 1The next section of the rail.

03:31speaker 2Now, whether that rail itself was bent, I didn't notice.

03:34speaker 1Uh-huh. Uh the implication, of course, is that if this uh had happened early in the mission and this shield were bent down, uh we might get excessive light into the stellar camera and our our background density would be uh low uh or would be higher than we expected, and we might not see as many stars. Uh the other indication of uh malfunction that we had, of course, was in the exposure control on the pan camera, and uh that uh would indicate that uh the pictures away from the terminator may be overexposed. That situation is also being looked at, and again, we're going to talk about it this afternoon before we actually process the film. Uh may I have the next slide?

04:17speaker 1Uh this is the information which I have with regard to the laser altimeter operation. Uh the first row across here is what the nominal mission would have been, and the second row is the uh actual results from the Apollo 16. Uh we had planned a total of 20 hours and a few minutes of operating time; we got 14 hours and a half, so that we are down about 25% in the total operating time. This is the total uh revolutions in longitude that we had planned, uh 10.3, and we got 7 and a half, so again, we're down about 25% in that regard. Uh a total number of firings, 3283, and 2106 is the actual number that uh was recorded, so we are down uh nearly 30% uh in the total number of firings. Also, the number of valid elevation uh readings that we got was appreciably uh less than the total number of firings, so that we the actual mission in terms of altimeter observations uh gave us a little bit less than half of what we had actually planned. Uh that's that's really not as serious a a uh shortfall as it sounds just from the numbers uh because the readings were quite well distributed throughout the mission. Uh the general operation that we saw on the altimeter, uh the first several revs were completely nominal, all of the elevation readings were valid. Then it began to fall off about 75%, 65%, down to about 60%, except on the last data pass on rev 62 where it was only about uh uh 10% effective. Uh the generally what we seem to observe is that there would be one good shot and then one bad shot, then one good, one bad, and then maybe several good ones in a row. Uh we can talk about the reason for that, but uh that's more appropriately uh covered in the systems review tomorrow. Uh the effect that it will have on the data is simply to give us a a uh larger spacing between data points. So far as the its effect on the reduction of the photography is concerned, that's absolutely inconsequential. So far as its effect on the uh correlation between the tracking and gravity data and the uh profiles, it's a little bit uh more of concern. Uh they do have a little bit more smoothing to do between the data points that they got, but essentially, I don't think that it really hurts us so far as the scientific return uh from the mission is concerned. Uh I would like to say uh just a word or so about the utilization of the photography. The it has been proceeding much more slowly than I had anticipated in reducing the pictures from Apollo 15. However, the work which is being done by the ACIC in St. Louis is indicating that the photography photographic reduction will provide uh positional coordinates of features on the lunar surface with the the accuracy of 10 to 12 meters in position and in elevation. And that seems to coincide very well with what we had predicted pre-mission. So, uh we are quite confident that uh that we're getting very good information from the pictures in that regard. Uh the tracking data uh generally uh is consistent within an orbital pass, but we do find uh discrepancies of uh up to a kilometer between adjacent photographic passes. So that the uh reduction of the photographs is giving us a much better tie between orbital uh passes than we get from the from the tracking data uh itself. Uh consequently, we do expect eventually to come up with a an internally consistent coordinate system, reference system, figure of the moon, with an accuracy on the order of 12 to 15 meters. Uh that's uh highly gratifying to me. Uh so far as the pan camera utilization is concerned, there have been some uh map compilations done. Uh the indicated precision of those is on the order of 3 meters, which again is about what we had expected, but that is a precision and not an accuracy number because uh of the geometric problems with the pan camera photography. However, so far as the resolution of the pan camera is concerned, that has held up to just about what we had expected uh from 1 and a half to 3 meters at the uh sub-vehicle point and decreasing off to about 5 to 6 meters at the limits of the of the film. Uh so, so far as uh our indications at the moment are that the results from 16 are quite satisfactory. We do have these problems that we have to resolve in the processing of the film, and uh once that is done, we will be able to say exactly what we did obtain. But again, I want to express the photo team's thanks to you, particularly Ken, for the uh uh time and attention uh that you gave to the camera operation and the results that we have obtained so far.

09:59speaker 3Thanks, Fred. Any questions uh for?

10:01speaker 2Could you do you have a plot of the uh altimetry? You know, last time someone had drawn up a rough hand sketch of of the altimetry and what Did anyone do that this time?

10:11speaker 1The profiles? Yes, sir. Uh no, I don't, Ken. I think maybe uh Sheldon (?) has one of those uh and uh I don't Is he here, Bill?

10:18speaker 3Yeah, Bill.

10:19speaker 1Yeah, Bill. Do you have a plot? Yeah, I thought you had one. He'll show that.

10:23speaker 2Okay. And these uh particles that you found in the mapping camera, the Is that handfuls or or a couple of shavings or?

10:33speaker 1I don't know how extensive they they were. Uh they were enough to concern the uh uh the people in the processing lab. Uh all I know, that's about all that I know about it. We're supposed to have a review of that this afternoon. Uh it could have uh very serious implications, obviously. Uh one one thing that I seem to recall from the uh during the mission is that we had apparently more film left for post-TEI photography than we had anticipated. And what that could mean, of course, is that the camera was not passing film when we thought it was, and things were being chewed up pretty badly inside. So, uh we're going to have to to look that over very carefully before we go ahead with the processing of the film. We expect the uh camera contractor to uh look at the shavings and tell us where he thinks they came from, and that may give us a better clue as to what they are actually are.

11:36speaker 2Do you have a processing schedule yet? I I guess it's all in abeyance till you figure out what to do with the shavings.

11:40speaker 1Yeah, everything is on hold until this afternoon, yeah, after our meeting this afternoon we'll decide what to do.

11:44speaker 2Assuming you determine to go ahead and develop it, what will it take you, three or four days to process?

11:48speaker 1Yeah, yeah. Uh I think the the anticipated schedule was to have uh the original film processed within this week and all of the duplicate copies within four weeks uh distributed.

12:02speaker 4Fred, you stated that what is the accuracy of the altimeter?

12:05speaker 1The uh least count of the altimeter is uh 1 meter. Uh the accuracy is uh dependent uh pretty much upon the slope in the area which is illuminated and uh a little bit uh on the albedo in the area which is illuminated. Uh in general, I think it's fair to say that uh the reading that we get from the altimeter will be correct uh to within 3 to 5 meters.

12:37speaker 2Ha- have you figured out what to do with the pan camera for processing? Have you got a correction for the for the overexposure?

12:44speaker 1Uh I don't know what has been figured out. We had a group working on it last week, and they're going to give us a report right after this meeting and we'll decide what to do.

12:53speaker 5I can I can comment. Uh photo lab has made their recommendation of full path processing, and uh they think that there will be some slight loss in the terminator if they do do that. Um in other words, that they can handle the overexposure, but at some penalty where we have minimum light. And Fred is going to query the other users if the penalty of having it on the other end, which is not much.

13:22speaker 1The situation is really that uh near the terminator, the pictures are underexposed anyhow because we can't open the slit wide enough and so on. Uh so, the camera was wide open at the terminator, uh but it was open wider than it should have been when we were away from the terminator, so that the terminator pictures are a little bit underexposed, then they become properly exposed, and after that uh uh they will be overexposed. So, what we would really like, of course, is a variable uh processing uh through each photo pass, but that's probably not a feasible thing to even contemplate.

14:02speaker 3Thanks, Fred.

14:05speaker 3Next subject will be the particles and fields of the sub-satellite, and uh I think Jim McCoy is going to cover that. Is he here?

14:12speaker 1Yeah.

14:14speaker 3Oh, there he is.

silence 14:16-14:26

14:26speaker 3We got a mic on the wall.

14:28speaker 6Yeah, we have even a little.

14:30speaker 3Yeah, they'll they'll they'll project it up there in the back booth if you want to.

14:34speaker 6Okay, uh.

14:35speaker 3Uh Dick, is Where's where's Paul? Paul, would would you get this projected up there?

silence 14:40-15:06

15:06speaker 6Okay, can you hear me okay on? Okay, uh guess uh quickly, the sub-satellite was deployed successfully. Our spin rate was nominal, about 5.9 second uh spin period. We want 5 plus or minus a couple. Uh the attitude was good, according to preliminary indications of the sun sensor. We have a couple of degrees uh tip-off from the ecliptic, which is well within the limits we needed. The operation of all of the uh electrostatic analyzers and both solid-state telescopes is good. Uh we don't seem to have the noise problem that we had on Apollo 15 in a couple of the analyzers. And we've, of course, gotten rid of our accumulator counting error that was characteristic of 15, giving us some problems in our data analysis now on that satellite. Uh the quick-look uh results on our first magnetotail pass indicated again the uh presence of these rather uh unexpected, rather high uh fluxes of low-energy protons, which have also been seen now with uh new IMP uh series I satellite experiment 2. And on this magnetotail pass, we appear to have the remnants of a uh small solar event in uh the form of some high-energy solar cosmic ray electrons and protons around, which uh should prove uh interesting for shadowing interpretation, particularly on electric fields in the magnetotail. Beyond that, if they have those slides there, I'd like to briefly describe uh some of the results we got from Apollo 15, which would hope to be similar for this one. Uh our primary uh experiment was to examine particle shadow configurations in the magnetotail, at the moon while we're passing through this region back here where we are in the Earth's magnetic field. And uh use that to examine the uh question of openness and access through the magnetotail to the magnetic field lines and ultimately to the Van Allen belts, where uh theory generally holds that uh the Van Allen radiation must somehow come in and then be trapped and accelerated. The degree of connection back here with the interplanetary field has been in quite a bit of question. And briefly stated, the Apollo 15 results indicate pretty clearly that at least most of the time at the uh latitudes where we passed through the tail, of course, we only have a couple of passes, that uh these uh field lines are, in fact, open out here, connect directly into the interplanetary field, and have direct access uh of uh solar cosmic ray particles. We have also observed uh the existence of a uh plasma sheet, which is known to form in closer to the Earth, to extend out to the moon's distance. And uh on at least a couple of occasions, we have observed uh cross-tail electric fields, which are important to theoretical models uh accounting for uh aurora and for accelerating particles into the radiation belts. An unexpected observation, which uh we've found interesting, was 30 keV or thereabouts protons in very large numbers, which we observed quite frequently back in the magnetotail and also observed outside the magnetotail in very similar fluxes. Our uh first feeling was that these must also be some uh component of the uh solar cosmic ray proton spectrum. They're, of course, very low energy, uh would be stopped by even the thinnest uh piece of material.

40:00speaker 1No, I'm not a, not a geologist type. Uh...

40:04speaker 2Well, I already know about 17.

40:06speaker 1Yeah, that's...

40:08speaker 2That would change it.

40:12speaker 1It would seem to me that the, the younger a crater was, the more chance it would have to produce a, a good, clean-cut signature on the magnetic field data.

40:24speaker 1For example, Van de Graaff itself looked like a fairly young crater because there's no, there's very few secondary craters in the bottom of it, so it looks fairly young, whereas uh, things like Hertzsprung seem to be very old, they're well blasted with secondary craters.

40:41speaker 2What's the distance from, say, the center of Van de Graaff to the center of the anomaly?

40:46speaker 1Uh, it's 80 kilometers from the northern rim. So, from the center of Van de Graaff, it's about 130, 140 kilometers.

40:57speaker 2Any other questions? Okay, thank you, Larry. And...

41:03speaker 2Got a question?

41:04speaker 3No.

41:05speaker 2Last subject will be the transponder. Bill Sjogren.

silence 41:10-41:36

41:36speaker 4Uh, this is a uh gravity experiment, and uh we monitor the gravity by just monitoring the velocity of the spacecraft, or the LM, or the uh sub-satellite. Of course, on uh this particular mission, we lost our LM data on impact because it started tumbling, and so that data was lost. We do, however, have the uh CSM in the low-altitude orbit, which is uh very interesting data.

silence 42:09-42:27

42:27speaker 4Here is the orbital track, and hopefully I can get this aligned. Uh, about like that. This profile just below it uh is the uh gravity anomaly that was detected. This line right here represents zero uh gravity, essentially isostatic equilibrium, and uh anything below it, of course, that'd be negative gravity uh deviations. Uh, here we are at Ptolemaeus going uh essentially over the center of it with the track, and we can see the large uh negative anomaly, again, almost a hundred milligals. Uh, and here we see uh some highland material where we have a a positive, then we drop down into a relative low in between these two old craters, Hipparchus and Albategnius, and then a a high in here. Uh, at this point is the Descartes uh landing site, and we're actually at about a 50-milligal negative anomaly in that region. Uh, there's some nice correlations here with the uh laser altimetry measurements. I'll show them next uh profile. But this is continuous. I've just taken one small section here. We have this thing from uh limb to limb, so about 110 longitude plus to 110 minus. And uh essentially three revs, from rev 3 through rev uh 11, that's uh eight revs. Eight revs of data that uh are pretty good, and then they started their station keeping, and uh the data kind of got garbage-ed up a lot with all of the maneuvering that was going on.

44:14speaker 4Uh, oh, let me point out one kind of interesting thing here. Uh, notice that Ptolemaeus here has an anomaly much, much lower than Nubium, although Nubium, which is this region right in here, this Mare Nubium right in here, uh is still at about minus 50 milligals.

silence 44:32-44:42

44:42speaker 4Here's a altimeter profile, and uh going right to the Nubium-Ptolemaeus region again, we see that Nubium uh elevation here is uh, by the way, the scale here is uh 2 kilometers per heavy line, so we've dropped down here almost 2 kilometers from the floor of Ptolemaeus to the floor of Nubium. Yet, the uh gravity anomaly is just the opposite, that Ptolemaeus is some 50 milligals lower than uh the Nubium region. And another interesting point is, Fred, on these ACIC maps, Nubium is shown a kilometer higher than Ptolemaeus. And here we are 2 kilometers lower, so we're talking about a 3-kilometer discrepancy in just that little area right there. So, I think some of these guys who were talking about, they're right there when they said we really didn't know the altitudes too well. [laughter]

45:38commanderI think that shows up quite dramatically when you look at the, at the low sun angle view as you approach the terminator, that things that were in Nubium didn't show up until significantly after we anticipated. We missed our times on those things a great deal, and that could only be caused by having a discrepancy in our relative heights.

46:00speaker 4Yeah, this is not just uh, this is rev 28. We've looked at, there are five real good uh tracking, laser tracking passes over this region, and we've looked at three of them, and all three show the same uh consistency of the drop there. Other interesting thing here, Proclus, Tranquillitatis, Fecunditatis are all seem to be about on the same level. Smythii, again, being the low, about 4 and 1/2 kilometers. That was the same thing on Apollo 15 when we passed over it. It was some 4 and 1/2 kilometers below, as mean radius here. And we're still referencing this to uh a 1738.1 uh radius uh off the CG. Uh, if you take this uh stuff and start fitting it to uh an optical uh center with a a CG offset, that uh you do indeed get uh the 2-kilometer shift again of the CG being closer to the Earth by some 2 kilometers.

46:57commanderWould you say that uh Tranquillitatis is about 2 and a half kilometers lower than Descartes?

47:03speaker 4That's right. Yeah, here's the landing site right in here, and uh this is where we had a negative gravity anomaly in here. Well, kind of according to this, maybe that's uh the situation because it looks like a a topographic low. Yeah.

47:28speaker 4This is the backside. We had some, these are the limbs where the data was missing. These are taken from those, this data is taken from that strip printout that we get in real time, and there are some gaps in the data. These will be filled in uh once they get the station tapes delivered. But we can see the crater Hertzsprung here very evidently with the central peak or something in it.

47:49commanderYou don't have any data in that 100 uh 120-degree region, huh?

47:55speaker 4Not now. We we should have it next week or so, when we get the tapes here and reduce.

48:03speaker 4Uh, one of the things that, well, on Apollo 15, there was a definite, well, centered about 180, there was a definite uh big uh trough in here, which went down about some 4 and a half kilometers. It was very jagged, but it was centered just about here, and on Apollo 16 now, we do not really see that. We see this highland material here, which we had uh on six, on 15, that's, that started about in here, and showed a, a marked uh high region in there, and uh this is holding on on uh 16 also. So, this is kind of consistent with uh 15.

48:44speaker 4Uh, here's uh another, this is orbit 38 on the backside. I'll just kind of lay it there to show you some of the consistency. This is 10 orbits later, and uh the profile is almost there, Smythii and uh... Oh, here we have some data in that, so there's there's your data, Ken. Uh, were you looking for some particular...

49:08commanderYeah, I was looking for something around 105.

49:11speaker 4105.

49:18commanderNothing in particular.

49:20speaker 4Nothing in particular. Okay.

49:25speaker 4Uh, I do have some data on uh the sub-satellite from Apollo 15, but I don't know if that's the time to really show it here. I think I've shown enough stuff on 16, huh?

49:33speaker 2Yeah, we'd like to stick to 16, any of the, any of the problems we have or any of the uh data that we got for the crew.

49:40speaker 4Well, I'm very happy with uh all the data we've gotten on 16, and uh the sub-satellite on 16, like uh Larry mentioned just before me, looks pretty grim. Although, there was an OD solution just run out about, oh, an hour ago, where the last state vector was uh used as the uh position for uh running out the lifetime program. And the lifetime program, if we believe that 15-8 model (?) that we had used initially back there when we ejected that thing, says that this thing should come back up. Still says it's not going to crash. But uh... [laughter]

50:20speaker 2This will be a very interesting thing to watch the next couple of days, I guess.

50:23speaker 4Right.

50:24commanderThat's all right, Bill's always has monitors that are up and ready. [laughter]

50:30speaker 4Uh, I asked uh Kovach about that, and I don't know uh whether we can speak for late (?) or not, but uh I told him it was 50 uh pounds, and whether they can actually see an impact of 50 pounds uh, I think that's all it weighs.

50:43commanderYeah.

50:44speaker 2The central station?

50:45speaker 4Uh, let's see, it should hit about maybe some 20 or 30 degrees west longitude and 5 or 6 degrees north. Is that right, Dick? Something like that. About 5 or 6 north latitude and about 30 west. That's what it looks like in that linear extrapolation we've got. That's...

51:10speaker 2Well, thank you, Bill. Thank you, gentlemen, for attending. This concludes our scientific debrief, and I'd like to thank the crew for giving their time up to come on over to give us some information and also learn some things that would happen.

51:24commanderOkay, uh let me say something for the crew. I want to commend Ken for the way that he operated the uh SIM bay. I don't think you'll ever find a guy who's either more interested in it or more aware of of what the operational problems were and uh who could do a better job. Uh, he really did an outstanding job, and I think he's uh well done. The other thing I'd like to say is, since I've been on this program, I've been continually impressed with the importance of what we're doing in in uh in our support of you guys. These experiments, they look way out right now, and they're difficult for the man in the street to relate to. But my feeling is, from the some of the things I've seen here and from the uh thrust of uh science and technology in this country, that in our lifetime, and uh I won't, won't want to say when, but I imagine it's going to be a damn sight sooner than anybody even here in this room can imagine, there are going to be practical applications of some of these discoveries that have been made that'll affect every one of us. And I think you're to be congratulated. The other thing is that I get out of all this is that I think the United States ought to be spending two to three times the amount of money that we are spending on basic research and development and applied research and development. And I think that if you really look at the big picture of our energy requirements for clean energy in the future, in order to improve the life of human beings on this planet, we ought to do that and get on with it. Thank you.

applause

52:59speaker 2During the next...

53:00speaker 2During the next couple of months, we'll probably have an opportunity to talk to a lot of people that helped uh have some influence or shape the pattern of our program and related programs. And I would appreciate it very much, I'm sure we all could use the data, as you find out things, we realize that you have preliminary data today and a lot of the things are are only hints and suggestions of things to come. I would personally appreciate it very much if you'd give us a call periodically and tell us what you found. Uh, it's too easy for us to go through here and at the end of a week or so walk off and never really know what happened, and never know what kind of data came out. And uh I think that makes us very poor salesmen. I think that you could help us do a job to kind of feedback the quality of the data that you've been getting, if you could keep us informed. And please don't ever feel like you're interfering with our operation or uh don't be inhibited to call us. If we can't come to the phone and take the data or talk to you about it, uh, you know, the secretary will take the number, we'll be glad to call you back. And if there's any time when you have some question about the data, doesn't matter how how trivial it may seem to you, if you want to look at some data and you're curious to know whether we'd ever seen a particular observation, or whether the spacecraft was moving at the time your data was taken, or I don't care how far out it might seem to you, uh questions are pretty cheap, and not asking questions can be very expensive. And so, please feel like our job isn't finished until you guys have all all the information you can use. And I would like for you to feel like you can call any time. Thank you very much.

54:45lunar module pilotI'd like to say uh give you my thanks also. Uh, was very pleased with the way all the gear worked, uh especially my part on the lunar surface and uh the part I saw of Ken in orbit. Uh, it was just a real pleasure to uh have emplaced all this stuff for all you people, and uh glad it's working so well. And uh thanks for the opportunity of going. If you can chin up another one, I'll be glad to uh go along again. Thank you.

applause

silence 55:13-55:41

Not transcribed: 04:17–09:59 and 15:06–40:00.

The audio quality is good with some room echo and background noise.

The audio quality is good, with clear speech from the speakers, though there are some periods of silence and rustling.