Mattingly: In general because of our altered time line, due to the delay in circularization, the entire time line seemed to get rejuggled. The primary activities and comments, I think we had to address out of all this, are going to be the way you handle that kind of an operation in real time, and what is a reasonable way to do that.
The Operation of the Spacecraft - I think the command module is a real fine one-man spacecraft in orbit. ItÂ’s a pain in the neck to fly a simulator in one g. YouÂ’re climbing over and under things, but when you get in orbit itÂ’s much more efficient for one man to operate it in space than it is for three men. And one of the mistakes I think weÂ’ve made in our planning is that weÂ’ve assumed that with three men in there you could really pursue parallel efforts and it didnÂ’t turn out to be that way at all. I had the feeling that throughout the entire solo operation that I was getting more Flight Plan operation done with less fuss and bother than we did in any time when we had the extra people in there.
Navigation, we scrubbed several of the P52s to save time, because the platform drifts were so small that it just didnÂ’t justify taking the time with it. And it was during this period that we looked at the scanning telescope and I kept looking for stars on the back side. I had in mind the Apollo 15 problem of not being able to recognize patterns. And this is where we picked up the fact that when the telescope is out of focus you just donÂ’t get enough light to image. Once you get it back into focus, they become quite obvious and it looks just like it did in Earth orbit. ItÂ’s an excellent device. And I think we've already covered the fact that these things change their focus due to vibration or whatever it is that allows the jam nuts to back off. The systems operation actually is no problem. The ground did it all. The thing that we did differently and I think bears comment is that for all the Flight Plan objects, that were done on the front side of the Moon, are within communications with the ground. We gave the time line responsibilities to the Capcom, and that gave me a chance to sit back and do whatever it was I wanted to do. If I wanted to get a drink of water, I could do that. If I wanted to look out the window, I could do that. I didnÂ’t have to just sit there and stare at the clock. I could tell there was a big difference; I could relax when I got AOS and I could stop staring at the clock, which is your primary activity any time youÂ’re running the responsibility for the Flight Plan and the time line. And those guys on the ground just did a super job of keeping us on step. They would call and say itÂ’s time to turn the pan camera on and I would just float over there and flip it on. That way I could take the Flight Plan and take about ten minutes out of each rev and look ahead at what was going to happen on the next rev and get an outline in my head of the things that were coming and the sequence of things. I had the proper phase of the experiment checklist out and I had the right film magazines adjacent to the cameras. It was really no problem to stay with the time line. The places it got to be a little bit sticky were when I didnÂ’t have that luxury because we had altered the Flight Plan. There were a couple of revs where we finally resorted to taking a blank piece of paper and Henry read up to me the sequence of events for the next 4 hours. I jotted them down and we worked from there and that was actually a lot easier than the times we tried to go through and alter the Flight Plan and delete the item in 99-10 and add some other item. And all the deletions turned out to be taking up an awful lot of your time.
We had the same problem in operating solo that we had before. It really didnÂ’t allow adequate time for taking time to go to the bathroom and a few things like that. Inadvertently during the development of the Flight Plan we allowed things to creep into the eat period. They look innocuous when you write eat period down and it shows Gamma Ray Gainstep 1 or something, and as long as there is some guy on the front side to give you a call you can afford that. But when youÂ’re on the back side and trying to eat, trying to mix your food, trying to keep your eye on the clock and run this, it becomes a messy thing. And we discussed this preflight and agreed that since it had slipped in there we recognized that we werenÂ’t going to make a big issue out of it - WeÂ’d go ahead and do it this way. I would strongly recommend that eat periods be exactly that - they have got to be sacred. This includes no updates from the ground. We were continually getting Flight Plan updates during the eat periods, which requires you to read them back to the ground and you just canÂ’t talk back to the ground and choke off the food bag and do all these other things at once.
I found that the Vox circuit, which I never thought much of in the Command Module before, really worked great. That freed two hands so you can hold a pencil and a Flight Plan and write and read them back at the same time. I donÂ’t know how well it came through on the ground, or how much clipping there might have been but it sounded to me as though the Vox circuit was performing superbly. I just turned it to maximum sensitivity and left it there. I think I ran in Vox almost the entire period. It was not clear to me then why we altered the time for the plane change. The flight planners did an outstanding job real time of giving me an outline of the items that were coming up so that I could have some plan for it. We protected against the yaw gimbal motor by going to the plane change attitude then rolling 90 degrees for redundancy. This attitude is a good redundancy mode for the middle gimbal direction, so if you did lose it you wouldnÂ’t go into the gimbal lock region.
Speaker:You did the plane change then a 90-degree roll?
Mattingly: Yes, that seemed like a very reasonable thing to do. No problem, a matter of retrimming the gimbals to make sure that after you calculated one angle that you retrimmed it again before you let it off. Both the circ burn and the plane change had a larger attitude excursion than I would have anticipated. They may be nominal. I would like to get the system guys to explain.
Speaker: Is there a short burn logic?
Mattingly: Yes, what it tells me is that the gimbal angles we put in for trims really werenÂ’t as smooth as they could have been. Perhaps thatÂ’s the normal response.
The deployment of all the experiments seemed to go nominally. The mass specs, as weÂ’d already stated started not indicating on board that it was retracting fully, but the ground TM showed that it was retracted to a safe distance for the SPS maneuver. The mapping camera on its first retraction had shown an excessive retraction time. We deleted several of the extension retraction cycles trying to minimize the problem. There was one time when we got off and operating in this open loop fashion where the Flight Plan was being read up somewhere between 5 and 30 minutes ahead of the time that the maneuver operation was to be executed. We ended up going to full calibration and the ground read me in great detail all of the SIM bay switches, and did not remind me of configuring the jets for the SIM bay operation. I had the feeling that there are two ways you can handle real-time Flight Plan changes. One of them is to tell the flight crew weÂ’d like for you to operate a particular experiment at a certain time. And let the flight crew be responsible for configuring it and doing it all. The other way is to have the ground figure out each switch and each activity that has to be done just like you would the normal Flight Plan and read those up to you one at a time. And then, let them bear the responsibility. I had the feeling that we were always operating in a mixed mode. The ground never had sufficient time to work ahead so they were reading me detailed steps they hadnÂ’t had a chance to verify that something wasnÂ’t left out. They left you alone in the sense that you had all the data that you needed to do the job when, in fact you really had to go back and scrutinize the procedures that were read up because no one else had had a chance to verify them either. They were sort of waiting for me to cross check it and as you get a little tireder you start thinking, well, theyÂ’ve done it. And this one time I know we caught ourselves off guard.
Young: Well, if you are going to call the data up to a single crewman a short time before he has to execute it; he doesnÂ’t have time to think it through and make sure youÂ’ve done the right thing.
Mattingly: Now, my whole theme on real-time Flight Plans are that we certainly did a lot of it. I guess IÂ’m against revamping and reordering your priorities, burns, and trying to optimize things. It seemed to me that we spend months and months building a Flight Plan to go fly. We try to screen it and make sure that maneuvers donÂ’t go into gimbal lock, and that you have sufficient time to get to the new attitude and really thought of all the things that go wrong. Then you go and do all this thinking on the spur of the moment. It seems to me the chance of doing it wrong is so much greater that instead of getting slightly optimum data you probably are going to mess something up. I would feel much more comfortable when we discussed this preflight, that if you ever get behind the time line, we should drop what it was that we missed and press on with the rest of the time line. So that everybody knows where weÂ’re going and in which direction and why we do the things you have practiced and know how to do them. And we did not do that and I hope all the data works out. WeÂ’ll just have to wait and see when it gets back.
Young: I agree with you, Ken. I really feel strong that once a Flight Plan is written down it shouldnÂ’t be changed. I just donÂ’t think the science people should be allowed to redo the whole thing. I donÂ’t know what they were doing it for, but I just donÂ’t think we ought to do that. ThatÂ’s asking for trouble.
Mattingly: To me thatÂ’s the time when youÂ’re likely to extend the mapping camera, while the door is still open and things like that. You get in a hurry and you need to get the camera on and you hit the switch and you forgot all about that door thatÂ’s covered or something. I felt uncomfortable from that aspect before. I didnÂ’t often get far enough ahead that I felt like we crammed the bistatic radar around and I think many of our problems were caused by regrouping. The ground knew that we were going to cut the mission a day short and tried to get all their major objectives in one day less.
Slayton: It was all supposed to stay the same and they were knocking a day off the end period.
Mattingly: But we didnÂ’t. We rewrote the whole thing. Apparently some science priority team got together and redid the whole business. Because thatÂ’s the way it was coming up to us. ThatÂ’s the only thing I could think of that was going on down there and that is hazardous. As a matter of fact, on landing day when we were six hours behind they didnÂ’t do that. They just picked up six hours later and took the Flight Plan from that point on. I knew where we were and what we were doing. I went back and I started at the nominal landing time. I went back to see what things we had missed and by the time I went to bed I had picked up and done everything that was to be done on the three revs that we didnÂ’t do, except track the LM with the sextant, and that meant maneuvering. But all the rest of the photography and experiments, I went back and picked up. No, there was one exception and that was the photographs of the Moon and earthshine. And I was in the process of that when ground called and said knock it off and go to bed. We closed up shop on that one. But we had picked up everything else. And I think I was able to do that because I understood where I was and. I knew what was going on and I had the feeling that the ground was in conanand of the situation. Okay, I think thatÂ’s really enough of that. But that problem persisted throughout the rest of the orbital mission.
Young: The bistatic radar was a source of continual confusion to us because we never knew what was coming next. ItÂ’s kind of difficult to be right in the middle of doing something else and all of a sudden have to change your mind to something else. The crew has a Flight Plan which you can go by, and the ground changes it just for two percent more data of one kind or another, is asking for trouble. And I think we proved that on the LM jett day. I donÂ’t know where the mistake was in the LM jett day but there are three places it could have been. It could have been before it ever got off the ground if nobody ran through the procedures. I assume they did. It could have been in running through the procedures and not having the configuration right when we shut the thing down. It could have been that running through the procedures, the communications loop could have gotten messed up, in that somebody has to transcribe the procedures, somebody has to check them over and pass them to the Capcom and then he has to read them up to us. Then, Charlie is there standing, in the LM, in his skivvies, copying those things down and IÂ’m copying them down and we may have misread some of the things that they gave us. And then, of course, in our execution of them we could have made a mistake. I really had serious misgivings about doing something that we hadnÂ’t practiced. We practice all the things that constitute abort-type situations like Apollo 13. We practice a contingency checklist. But we never practiced the phase of jump around, and grab here and there for LM jett. I was real nervous about being able to do that right.
Duke: It ended up we didnÂ’t get to bed any earlier than if we had jettisoned it right at that day. It caused about two or three times more work the next day. Of course that ought to work, but itÂ’s only going to work if somebody on the ground has time enough to go over and run through the complete thing end to end in the simulator and make sure his base is right when he starts and his base is right when he ends. Then, he gets the procedures written right and thereÂ’s a lot of changes that you have to make to do that sort of thing right. We practiced LM jett a lot of times. And it always worked.
Slayton: In that respect, we should have let you get tired that day and kept going instead of shutting down.
Duke: I think so.
Young: I would have sure felt better.
Mattingly: It turned out that we got to bed later than if weÂ’d gone ahead and jettisoned it. We had more work to do the next day and I never felt like I was on top of what was happening.
Duke: Nobody talked about that much after we pulled all the breakers and while we were waiting on that we were doing the same thing we would have been doing anyway.
Mattingly: Now you had a plan to store all that stuff in this order. But you canÂ’t do it because you have to review each item you have to stow and see how many of these things you need to use tomorrow. And can we get them in places that are easy to get to. As far as the SIM bay operation was concerned, the ground did it all and I just responded to their commands and what little I know about the experiment operation is what the ground told me, so IÂ’m not going to comment on any of that.
Dim Light Photography, IÂ’m going to comment on that right now only to the extent that says how we performed it. The dim light photography that we did do was accomplished just exactly like the PI wanted it. Much to my dismay, we did two solar corona sunrise sequences. I used the tape recorder countdown for both of those and for the zodiacal light. They really worked out super. The countdown tape would come up the sunrise and say turn the camera off at sunrise. There would be the old Sun, and I think we got a1l that done. ThereÂ’s one section in the zodiacal light sequence where it was changing every 10 seconds. We were taking two exposures, changing the filter, and changing the exposure setting. I dropped my hand off the filter or something and lost track of where it was. I ended up having to skip two exposures.
Mattingly: ThatÂ’s noted in my experiment checklist. I think we cover that later. The conclusion [inclusion?] of a star chart that shows the pointing targets for each of the dim light sequences I think is a good thing. One time we caught ourselves pointing in a different direction. It turned out that what had happened was that they had changed their mind on what they had wanted to take a picture of. But as a rule, I always felt very comfortable and I knew I was pointing in the right direction because I could verify against the star patterns.
I didnÂ’t trust the light shield around the 35-millimeter camera and consequently I darkened the spacecraft completely for all dim light and photo sequences in lunar orbit. Now, we did some on the way home with the dump sequences where we left a couple of lights on in the LEB flashlights that Charlie could use to read the checklist. All the ones I did in lunar orbit I did entirely in a darkened spacecraft. The operation of those things in the dark is really no problem at all. The magazines used were recorded and read down in real time as far as, which magazine, which frames went with each experiment. I have those things noted here in the experiments checklist. I think that really covers all the comments that are necessary to be said about this zodiacal light, solar corona, galactic light, Gum Nebula.
Attitude excursions during the CMC free periods were recorded. There was one set of pictures that required a free control mode and I missed that and left it in auto, but I knew that as soon as it started. I finished the sequence and I did not see any engine flashes, so I believe the data is correct. That experiment is noted in this checklist also.
Earthshine - I donÂ’t think we did that one justice. Much to my surprise, when we first got to the Moon, looking at the Moon with a nearly full Earth, earthshine, you could really see an awful lot of detail. I had always wondered if earthshine photography was worth the effort. Had we done it on Day 1, IÂ’d have no question that weÂ’d have learned an awful lot about features that are on the western limb of the Moon, which weÂ’ll never get a chance to photograph in sunlight during Apollo. Each day the features became less and less sharp. That was the reason that after PDI day I wanted to run that strip off, because I could already detect the difference in the earthshine sensitivity from the previous night. It was scrubbed and I tried to get it in the first thing after I woke up the next day. It kept getting pushed back in priorities. When we did get around to it IÂ’m not sure that we really picked up very much at all. ThatÂ’s a shame because there really were some interesting things to be seen back there. You could see the outer rings of Orientale. You could see the Mare Rille between two of the rings. You could see the radial fractures, you could see some of the radial ejecta patterns. It was really a beautiful thing. I would suggest that if Apollo 17 has a chance to look at the Moon with really full Earth that they really should expend a magazine and take a full strip back there.
UV Photography was accomplished primarily trans-lunar and trans-earth. We did some in lunar orbit. We took some pictures of the Descartes formation in UV. I speeded up the times and centered around the Descartes light material. When I say Descartes, in this case, IÂ’m talking about the crater Descartes and the light material that is just to the north of it.
Skylab Contamination Photography was scrubbed in lunar orbit.
Orbital Science Photography, I took as many of the strips as I could. Just having reviewed them, it appears that the prints I was looking at are accurate. Our exposure settings were rather poor. We did not expose all of our film. We only had one roll of film that was available for crew option photography. That was magazine Victor. I kept trying to pace myself on that, and save it. I figured that we had 160 exposures to last us 6 days at the Moon. And I kept trying to ration myself instead of taking a whole bunch of pictures the first time I saw something. As it turned out, we ended up at the end shooting it up just to finish it off. Not only did we spend as much time in lunar orbit, but a lot of the time when we could have been taking photographs out the window we were copying and executing the Flight Plan updates, which is really dead time. ThatÂ’s wasted time in lunar orbit.
I did a lot of work with the binoculars. I compared the binoculars and the monocular by using one against the other - by trying to observe, binoculars by just putting my hand over one of the barrels. Ten-power binoculars are, in my opinion, about the maximum magnification that a man can hand hold. I found that to really see resolution I had to lay one end of it up against the window in order to stabilize the optics, to keep them from bouncing around. I really felt like the binocular size was proper. It would be nice to have a wider view on them, because target acquisition was a little difficult at times until you learn how to do it. YouÂ’d look out and see a feature in your unaided field of view, then youÂ’d want to look at it with the binoculars. The field of view with the binoculars was so small that it was hard to find the sequence of patterns that would lead you into the small area you wanted to look at. Or worse yet, youÂ’d want to see something in there, then youÂ’d look outside and try to put it into the perspective, and again it was kind of difficult because of the small field of view. The binocular small size meant that you could stick your head up in the corner of the window and look at it. I really donÂ’t think you could handle much larger. I found that the Hasselblad with a 250 lens on it was really too big to get between my eyeball and the window and see most of the things I was looking at.
The SIM bay attitude that you fly, Window 5 generally, includes the nadir, but not in the middle of the window, itÂ’s over in the corner. And for all the things youÂ’d like to do you really feel like youÂ’re cramped looking out of Window 5. You get a crick in you neck. Window 3 is a good one for looking away from the nadir and up towards the horizon. Got a good look at the northern part of the horizon because when I was awake we were generally in plus-X forward in SIM bay attitude. I could see up to the north very nicely. I had very few chances to look to the south of the ground track, because that was always when we were minus-X, and that generally meant that we were in a sleep period. So we didnÂ’t see nearly as much to the south of the ground track as we had anticipated.
The overlays that are in the flight data file, used for preparations of the visual targets and overlays that you put on the maps to see what your field of view is from each window, turned out to be surprisingly close. We questioned that they were perhaps too small, that they had assused an eye positioned too far back from the window. But in reality I actually had the feeling you had to decrease the overlay for Window 5. Window 3 was probably about correct. Window 1 is much larger than is useful.
We took the gegenschein. Took a sequence of photos at the antisolar point, the midway point and the mobile point. I did that twice. If the star charts are right about where to point, we were, in fact, pointing in the right direction. The long exposures should show anything that happens to be out there.
?We did a water dump on the Trans-Earth Coast. John pointed out if you look down-Sun at it you had a lighter spot in the sky. I looked out and saw the same thing. I think if we had taken densitometry photography of that area weÂ’d have found that there was a little bright spot looking directly down the water dump. That may, or may not have any bearing on the gegenschein, but I think itÂ’s similar phenomenon and ought to be considered.
One more thing about the binoculars, several times I kept trying to compare binocular and monocular vision and I could never find a discrete test wherein I could say the binocular saw things that you couldnÂ’t see with monocular vision. But I always had the feeling that I saw a fuller picture, and that there was more information, and that I saw more things when I looked through binocular vision. Several times through the mission I found that I got my fingers on the lens, or something, and IÂ’d pick it up later and one of them would be in focus and one of the lenses would be out. I felt like the picture was missing. IÂ’d start squinting with one eye, or the other, and find that I had a bad lens. I'd clean it off and all of a sudden everything was better again. Once I finally got the lenses cleaned off, and realized you had to work on it, and once I had adjusted the binocular I really didnÂ’t have to mess with the focus again.
Plane Change 1 was essentially a nominal burn. There was no problem with it. Comm was good. In fact the communications throughout the whole period were excellent. Supporting lift-off maneuvers were a piece of cake. We tracked the landing site landmark. We never did try to track the LM itself. I saw a glint of sunlight off of something bright. Sort of like the kind of a reflection youÂ’d see from a wave out over the ocean. One time when I was looking with the binoculars, at the landing area, I believe I saw the glint off of the LM or maybe the ALSEP. And, another time I saw a glint over on the flanks of Stone Mountain. Right after that, Hank said that was in fact where the Rover was. It was nothing I could identify or pinpoint, but it was a flash of sunlight reflected off of something that looked entirely unlike any other features that you see around the Moon. As far as looking for the LM or the Rover or anything like that in 10-power optics I think itÂ’s really a waste of time and should never be pursued.
Rest and Eat Periods - rest periods are really okay, but the eat periods were continually being violated with Flight Plan updates of one form or another. It turned out that my favorite experiment in orbital science was the bistatic radar. That meant the ground couldnÂ’t talk to me for an hour and a half. I had a chance then to go to the bathroom, eat dinner, and get an exercise period or look at the Flight Plan. I think you really need those kind of periods every now and then throughout the day.
TPI Backup; we talked about in the rendezvous portion. Midcourse backups were completely nominal and right down sequence.
There are a couple of items I noticed in the Flight Plan leading up to the rendezvous point. First of all, we chose several photo targets and visual targets that were too far off the ground track to be appropriate. The photo targets may well turn out to have value taken near the horizon. They’re hard to reach from the SIM bay attitude. The visual target, to be useful, really ought to be confined to those things that can be done within probably a 30° cone of the spacecraft nadir. The targets again will be biased toward the side that SIM bay will support. Because of the SIM bay attitude, you generally don’t have a chance to look straight down and you can’t use the full two minutes from plus or minus 45 degrees elevation, even when you fly directly over the target. Generally, you end up getting about a minute or a minute and a quarter, because of the SIM bay acquisition problem. You either see it early and you get to look at it a long time before it gets close enough to see, or, you fly over it and then you lose some time due to target acquisition, and the target is at best viewing position when you first see it and you may not recognize it unless you’re really on top of the patterns that come in with it. I found that one of the things that saved me a great deal of time in doing the visual strips, and in just general operation with the photo targets and so forth around the lunar surface, was the rather large amount of time we spent preflight, learning the ground track and learning the significant features every 10° across it. This really paid off, in that you could just walk over to the window, look outside, and you knew where you were. That would give you a good handle on where to pick up the cameras, how to set them, and what you ought to do with it. I think you can waste a lot of time trying to cross check between a map if you don’t have that kind of familiarity with it.
A couple of times during the mission we recalled that we had a high O2 flow. Invariably it turned out that we had the suit circuit return screen clogged up again. I cleaned that thing off every night, and I was forever pulling off just piles of junk. It would take me four or five passes with the tape to pick off the screen on the main ones. When we went out and looked at the screens on each of the individual hoses there was always a lot of material in it. This was true even before the LM came back and brought all of its dust and dirt with it. This was true of just plain old spacecraft particles, little nuts and just little pieces of debris.
The use of visual targets at the subsolar point is probably a mistake in use of time, in that you just canÂ’t see very much. One of the things that bothered me a great deal the first two days in lunar orbit was the intense brilliance of the sunlight. I generally ended up with rather sore eyes or just tired eyes at the end of both the first and second dars. I tried to wear the sunglasses but the problem you run into for looking inside you need to take them off. You want to pick up a set of binoculars and look at a detail, now you have to take the sunglasses off. The nuisance of handling one more thing between your eye and what youÂ’re trying to see convinced me to do it with my naked eyeball and grin and bear it. I never had anything happen to my visual acuity as a result of this, but it was a real annoyance having your eyes get so tired. After a couple days it seemed to me that my eyes had acclimated to the situation and it didnÂ’t bother them anymore. Someone really needs to think about the fact that this is going to happen to you. If there was some way of covering the windows so that you can look outside and not be fighting the sunlight, and at the same time use your naked eye inside, I think that would be a big help. And I would delete all visual subjects except of a very specialized nature in the vicinity of 30 degrees either side of the subsolar point. Because the features are so badly washed out and itÂ’s just a toll on your eyeballs to look at it.
When I changed the lithium hydroxide canister at 144:50, it was the first time I noticed that we had a swollen canister. It was just slightly sticky. Later in the flight we had one that was extremely difficult to get out and weÂ’ll discuss that when we get to that point. But the first one was 144:50 where it was slightly swollen, but that was one I jettisoned. in the LM.
The VHF communications with the LM, I think we commented on earlier as being pretty outstanding. I could hear the LM comm right up through landing and through T1. Part of their comments were going on with the checklist and so forth following T1.
The tape recorder we had talked about using it for these time sequences. One of the problems that had been raised on previous flights was the idea that the tape recorder seemed to run at nonuniform speeds and things that were recorded on the ground didnÂ’t sound right when they got in the air. So, I made the decision to do our tape recording for the time sequences in flight instead of on the ground, then, whatever biases we had due to being inflight would be the same that the recording and the playback would be the same. It turned out that there werenÂ’t any differences they could find. The tape recorder seemed to be very stable as long as you Velcroed it down and left it sitting somewhere. But if you picked it up in your hand and shook it, or did anything with it, why you could hear the speed change. This was particularly noticeable when playing music. If you were touching it, just trying to hold it in your hand, it would cause the speed to oscillate. I ran several checks against the clock. In one 15-minute check, it was off just about 1 second, which I thought was pretty repeatable, so I continued to use it. Some time during the mission we found that we could not depress the little red button on the Sony recorder to make a recording. I was going to record some RCS sounds while I was in lunar orbit. I went to do this and was unable to get the button to depress. It had worked during the Trans-Lunar coast because thatÂ’s when I made my solar corona and Zodiacal light tapes. During Trans-Earth coast I noticed that once again it was working. There must have been or must be some foreign particles floating around inside the tape recorder.
The batteries on the tape recorder lasted much longer than I would have anticipated. We have one that seemed to last for only two tapes. And it really sounded terrible, like it needed to be changed. I subsequently played six tapes on one battery. I changed the battery not because it wasnÂ’t working, but because it was coming up on one of the low light level passes and I wanted to have a fresh battery in there to make sure I hadnÂ’t jeopardized the timing of it someway. I found that the number of batteries we carried was far more than sufficient. I wouldnÂ’t cut any off, but it was certainly enough. I had suspected preflight that there wouldnÂ’t be enough. I played all of the tapes in flight at least twice and probably half of them another time around. We used probably half the batteries.
The next item was on the landmark, F2, I think, that I tracked on rendezvous day. I was given a crater in Mare Smythii. The crater was so large that it seemed to me it was an inappropriate target to be tracking for landmark correlation, so, I selected a small feature on the northern rim, which shows up marginally in the sextant photography. I was marking on one small feature on the northern rim of the crater rather than on the center of the crater itself.