It is 5 August 1971 and the crew of Apollo 15 are settling down to the remainder of their day on board Endeavour. Al Worden has just completed an EVA to bring film canisters into the Command Module from the Service Module's SIM bay. The remainder of the day is devoted to photography, science and a navigation exercise.
242:52:38 Scott: Houston, 15. We're prepared to maneuver to the thermal attitude a little early if you'd like us to go over there.
This is an attitude to mitigate the effects of solar heating on one side of the spacecraft and the chill of space on the other. However, the version of the Flight Plan used in the compilation of this journal does not show a change in attitude until 245:30, when there is a further period of X-ray astronomy using the SIM bay's X-ray Spectrometer.
242:52:47 Henize: 15, this is Houston. That would be fine with us.
242:58:10 Henize: 15, Houston. We'd like to have Auto on the High Gain [Antenna] and go from Reacq to Auto quickly.
242:58:18 Scott: Rog. Going Auto.
Very long comm break.
If they were to place the HGA's Track switch from Reacq to Auto slowly, it would pass through the Manual position, whereupon it would begin to slew to the positions set on the HGA's position dials and go off lock. Since the HGA is already correctly pointed, they want to keep that position, perhaps to keep a solid telemetry record.
This is Apollo Control at 243 hours, 02 minutes. Apollo 15 now 169,526 nautical miles [313,962 km] from Earth. Velocity, 3,031 feet per second [924 m/s]. Weight, 26,509 pounds [12,024 kg].
243:26:10 Henize: After some discussion down here, we'd like to disable your jets A2 - Alpha 2 and Bravo 1, mainly because the Mapping Camera's still out and our concern is that the plume will be deflected down into the SIM bay and possibly damage some of our electrical wiring or some of the - the N2 plumbing, which may give us other problems.
243:26:36 Scott: Rog. Sounds like a good idea. If there's any other particular configuration you want, just let us know.
This is Apollo Control at 243 hours, 58 minutes. The crew of Apollo 15 busy stowing equipment, reconfiguring the cabin. Very quiet time as far as communications are concerned. Apollo 15 now 167,882 nautical miles [310,917 km] from Earth. Velocity: 3,070 feet per second [936 m/s]. And the clock showing 51 hours, 12 minutes to landing.
244:01:47 Scott: Rog. The OPS pressure is 2,000 [psi] and we'll be off comm for about 5 or 10 minutes here while we reconfigure the suits and everything.
Since the OPS was not bled to depletion, Dave reports the source pressure reading on the bottle instead. Before use, its pressure gauge read 5,800 psi (40,000 kPa) and is now reading 2,000 psi (14,000 kPa).
Other items to be completed are a dump of the excess water produced by the spacecraft's fuel cells and a purge of those cells with oxygen. There is an additional item which is to charge battery B, delayed from before the EVA but the crew will delay all these items a little longer. The spacecraft's batteries are regularly charged during quiet periods to replenish them after any discharge that might have occurred during heavy usage in the meantime.
244:34:13 Henize: 15, this is Houston. [No answer.]
244:34:31 Henize: 15, this is Houston. How do you read? [No answer.]
Comm break.
This is Apollo Control at 244 hours, 35 minutes. The Apollo 15 crew apparently still off the communications system as they are reconfiguring their cabin. We're showing cabin pressure holding at 5.7 pounds per square inch. Temperature, 68 degrees.
244:36:43 Henize: Apollo 15, this is Houston. How do you read? [No answer.]
Comm break.
244:38:25 Henize: Apollo 15, this is Houston. How do you read? [No answer.]
244:39:41 Scott: Houston, Apollo 15. We'll start to charge on battery B now, if you're ready.
244:39:46 Henize: Roger, 15. We're ready for the battery charge; and, while we're about it, the experimenters are getting a little fidgety about the waste water dump because that will impact their Mass Spectrograph work, so we would like to get the dump and the O2 fuel cell purge started also.
244:40:04 Scott: Rog. We'll get on it right away. [Long pause.]
244:40:56 Henize: And, 15, whenever Al has a couple of minutes, we have a few questions about the SIM bay that we'd like to debrief on. [Pause.]
244:41:09 Scott: Okay, give - give him another 15 to 20 minutes here.
This is Apollo Control at 245 hours. Apollo 15 picking up velocity, getting closer to home each second. Endeavour is now 166,043 nautical miles [307,511 km] from Earth. Velocity: 3,115 feet per second [949 m/s].
245:04:28 Henize: We need to make a small change in the Flight Plan, because there's a need now to turn the X-ray experiment on. If you'll go down to that group of steps at 245:30, we'd like to do four of them. We'd like to get the "Data Systems - On - switch to On." We'd like to "Disable the jets." We'd like to get "S-band Aux, TV to Science."
245:04:48 Worden: Hey, stand by one.
245:04:50 Henize: Rog. [Long pause.]
245:05:12 Worden: Okay. Go ahead.
245:05:14 Henize: Roger. Four of those steps down to 245:30 we want to do right away, if possible. We want to get the "S-band Aux, TV to Science." We want the "Data System On switch to On." We want to "Disable all jets except -" and we want "X-ray Experiment, On." [Pause.]
245:05:39 Worden: Okay. Understand at 45:30 - 245:30, you want "S-band Aux, TV to Science, Data Systems On to On, disable all jets, and X-ray Experiment, On" immediately.
245:05:54 Henize: That's correct.
Very long comm break.
245:13:15 Worden (onboard): We need the repress time on the cabin. [Garble].
245:13:18 Scott (onboard): Yes.
245:13:53 Scott (onboard): Ten days and 5 hours we've been gone, Jim.
245:13:59 Worden (onboard): Long time. We beat your old record.
245:14:00 Scott (onboard): By 3 minutes.
245:14:03 Worden (onboard): Sure does. Went farther from home, too.
245:14:10 Scott (onboard): That's great.
245:14:11 Worden (onboard): Didn't go as far.
245:14:13 Scott (onboard): Let's not count the miles.
245:14:15 Irwin (onboard): [Garble].
245:14:16 Scott (onboard): Huh?
245:14:17 Worden (onboard): Didn't go as far, but went farther.
245:14:19 Irwin (onboard): Yes, coming back.
245:14:22 Scott (onboard): And a lot more fun, too.
245:14:30 Worden (onboard): A lot more to it.
245:14:35 Scott (onboard): Big Dipper, do you know, on 9, we could have missed any one thing and pressed on.
245:14:41 Irwin (onboard): Yes.
245:14:42 Scott (onboard): Here, it's a lot different; you can't miss anything and press on.
245:14:46 Worden (onboard): Well, it looks like we can't miss anything.
245:14:49 Scott (onboard): Very different. Very different.
245:15:13 Scott (onboard): This is sort of an all-or-nothing kind of operation, you know it?
245:15:18 Worden (onboard): Yes, it really is, you know. It's really all your eggs in one basket, boy. I got to thinking about that after you guys left for your descent. Once you start that descent, man, that - that's it...
245:15:40 Irwin (onboard): We're all hanging out.
245:15:41 Worden (onboard): We're there. That's right. It's all hanging out from there on.
245:15:46 Irwin (onboard): [Garble].
245:15:54 Worden (onboard): It would be better for [garble] to put pills in all the food drawers.
245:15:59 Scott (onboard): [Laughter.] For sure.
245:16:02 Worden (onboard): Make him [garble].
245:16:03 Scott (onboard): Let's put them away somewhere.
245:16:07 Worden (onboard): Where will I put them? It's the last time I'm saying it, but you better not lose your pills.
245:16:13 Scott (onboard): You didn't see them in your TSB, did you, Jim?
245:16:16 Irwin (onboard): What?
245:16:17 Scott (onboard): You didn't see the pills in your TSB when you cleaned out, did you?
245:16:20 Irwin (onboard): No. [Garble].
245:16:31 Scott (onboard): Ohh, what did I do with it?
245:16:33 Irwin (onboard): [Garble].
245:16:34 Worden (onboard): It's almost back to normal times.
245:16:38 Scott (onboard): Where did you see them?
245:16:40 Irwin (onboard): Down in U-1.
245:16:45 Worden (onboard): Do you really know what [garble]?
245:16:49 Henize: Apollo 15, this is Houston. We're having some ground problems in communications networks, and we'd like to have a comm check. [Long pause.]
245:16:57 Scott (onboard): Oh! Did you notice anything loose?
245:17:03 Worden (onboard): Well, I thought I saw - Well, I saw a...
245:17:08 Scott (onboard): Hey, do you guys [garble] get some orange juice? [Garble]. Let's enjoy it - let's enjoy it while we can.
245:17:16 Worden (onboard): [Garble].
245:17:17 Scott (onboard): Except for bad stuff, we can always put up with it for 1 more day.
245:17:20 Worden (onboard): Yes, that's right. Well - Hey, let's - [garble] will be our last meal. We have three meals below and breakfast [garble] 1 day.
245:17:28 Scott (onboard): And a long way to go.
245:17:29 Worden (onboard): Oh, hush.
245:17:29 Henize: Apollo 15, this is Houston. How do you read? [Pause.]
245:17:39 Worden: Hello, Houston; this is 15. Loud and clear, and I got your first message, Karl. I'm sorry.
245:17:44 Henize: Hi, Al. Yeah, we've got some sort of problem on ground circuits here. Just wanted to make sure we were in contact with you.
245:17:54 Worden: No, we're here.
245:17:55 Henize: Roger; very good. [Long pause.]
245:18:46 SC (onboard): [Cough.]
245:18:53 Henize: Al, we have some questions for you on the SIM bay experiments, whenever you have some time to answer them.
245:18:58 Worden (onboard): Oh, yes. That's right. That's great.
245:19:04 Worden: Okay, Karl. Tell you what, I'll give you a call back in about 10 minutes when I'm ready.
245:19:10 Henize: Very good.
Very long comm break.
245:19:14 Worden (onboard): No, he's got some questions on the SIM bay.
245:19:37 Scott (onboard): SIM bay looks pretty good.
245:19:42 Irwin (onboard): What'd [garble].?
245:19:43 Worden (onboard): I'm coming. I'm coming, Jim. [Garble].
245:19:46 Irwin (onboard): Yes, I can see through on the handles.
245:19:55 Worden (onboard): I didn't even see any scorching or any burning or anything down there.
245:19:59 Irwin (onboard): [Garble].
245:20:02 Worden (onboard): The covering on the - on the Service Module, if it hadn't been covered, boy, that would have been burned and scarred and scorched and everything else.
245:20:10 Scott (onboard): Yes. That's right.
245:20:11 Irwin (onboard): Yes. Yes. Excuse me one second, will you?
245:22:11 Worden (onboard): Excuse me, Jim. Let me get out of your way here.
245:22:27 Scott (onboard): [Garble].
245:22:28 Worden (onboard): Really?
245:22:49 Worden (onboard): Well, I guess it doesn't make any difference on this food if we take it back home anyway.
245:22:58 Scott (onboard): Yes, that's probably true. They can decontaminate it back there.
245:23:02 Worden (onboard): Sure.
245:23:03 Scott (onboard): You can tell them we ran out, though. Do you think this salad's good, Al?
245:23:11 Worden (onboard): My what?
245:23:12 Scott (onboard): Sandwich spread [garble]. It's a whole half a can.
245:23:16 Irwin (onboard): [Garble].
245:23:17 Scott (onboard): Sure you can, Jim.
245:23:18 Worden (onboard): We have to finish after you.
245:23:21 Irwin (onboard): Okay, I'll eat it.
245:23:23 Worden (onboard): That's right.
245:23:24 Irwin (onboard): What?
245:23:30 Scott (onboard): If you wouldn't complain so much, we wouldn't leave you so much.
245:23:33 Irwin (onboard): You guys didn't leave me nothing.
245:23:36 Worden (onboard): Freak you!
245:23:38 Irwin (onboard): I'm thinking.
245:23:39 Worden (onboard): [Laughter.]
245:24:10 Scott (onboard): What kind of desserts we got there, Jim? A lemon pudding, huh?
245:24:16 Worden (onboard): Mmmm.
245:24:46 Irwin (onboard): [Garble].
245:24:50 Worden (onboard): Yes, you're right, mouth, and I'm going to catch it [garble].
245:24:58 Irwin (onboard): I'm ready, if you can catch it.
245:24:59 Worden (onboard): [Cleared throat.] That's the only way a power bowler makes it.
245:25:04 Irwin (onboard): [Garble].
245:25:14 Scott (onboard): Huh? Yes, I suppose we ought to think about doing that. We can get to all that stuff now.
245:25:20 Irwin (onboard): Bright idea. [Garble].
245:26:00 Scott (onboard): I would.
245:27:56 Scott (onboard): That's a pretty good sandwich.
245:27:59 Worden (onboard): Mm-hmm.
245:29:27 Scott (onboard): How much food we got left?
245:29:32 Worden (onboard): I don't know, at least a couple of days.
This is Apollo Control at 245 hours, 30 minutes. Apollo 15's distance now 165,125 nautical miles [305,811 km]. Velocity, 3,137 feet per second [956 m/s].
The SIM bay power and communications links were re-established early and the X-ray Spectrometer started. Now Endeavour is manoeuvred to aim the X-ray Spectrometer in the direction of the Scorpius X-1 x-ray source for 35 minutes. This was the first x-ray source to be discovered outside the solar system by a sounding rocket in 1962 at a time when many had believed there would be little to detect in x-rays above the atmosphere apart from the Sun. Later observations showed Scorpius X-1 to be a close binary star system in which material from a normal star accretes onto the surface of an extremely dense, collapsed star; probably a neutron star. The extreme temperatures reached in the process generate a prodigious x-ray flux.
The rest of the bay's instruments are also to be brought online. Associated with the X-ray instrument is the Alpha Particle Spectrometer. The Mass Spectrometer is deployed on the end of its boom and left to outgas for an hour or so. The boom for the Gamma-ray Spectrometer is to be deployed 4½ metres (15 feet). To do this, Al extends the boom fully, then, knowing how long a full retraction takes, retracts it for an appropriate fraction of that time.
245:31:04 Scott (onboard): Six-foot waves in the recovery area, huh?
245:31:05 Worden (onboard): Yes.
245:31:06 Scott (onboard): That'll be sporty.
245:31:08 Worden (onboard): Yes, if we can dodge and land, that's great.
245:31:11 Irwin (onboard): Yes.
245:31:15 Worden (onboard): That's better than dead calm.
245:31:21 Scott (onboard): It is?
245:31:23 Irwin (onboard): Yes. [Garble].
245:31:25 Worden (onboard): It's probably because the power's [garble].
245:31:27 Irwin (onboard): Hmm.
245:31:28 Scott (onboard): That's why we had so much trouble on 9. [Garble].
245:31:41 Worden (onboard): Why can't we just hop on over her pretty good in that fashion, too?
245:31:46 Scott (onboard): Yes.
245:31:49 Irwin (onboard): It's not that bad, boys.
245:33:31 Henize: Roger. Just sending up a reminder about the X-ray pointing attitude, which is due very soon now, and the activation of the SIM bay experiments.
245:33:43 Scott: Okay, Karl. Thank you.
Long comm break.
245:33:47 Worden (onboard): Okay, Houston. Boy, oh, boy, I used to think it was a good thing to get on a flight and then they could only talk at you one at a time. Whew, boy! Now, I think it's a good thing to get back so you - you don't have to listen to that goddam radio all the time.
245:35:00 Worden (onboard): The DAC, yes. But the Hasselblad's above your head.
245:35:05 Scott (onboard): No, mine's - I don't think so. No, that's Jim's.
245:35:13 Irwin (onboard): What else we got?
245:35:28 Worden (onboard): It's time for the UV stuff, huh? Let me get out of your way. You couldn't find any more pills, right?
245:35:36 Irwin (onboard): [Garble].
245:35:41 Worden (onboard): No, I thought I put them in your TSB. I just saw them hanging there just before we started all that stuff, and I don't know.
245:38:22 Henize: Apollo 15, we'd like to have Omni Alpha. [Pause.]
245:38:31 Worden: Rog; Omni Alpha. [Pause.]
Comm break.
As Endeavour is manoeuvred to the x-ray pointing attitude, the High Gain Antenna is liable to lose lock with Earth. By selecting one of the four omni-directional antennae mounted around the periphery of the Command Module, communication can be maintained, if at a lower quality than before.
245:39:43 Worden: Houston, 15.
245:39:47 Henize: Go ahead, 15.
245:39:50 Worden: Okay, Karl. I'm ready to talk SIM bay; but first, a couple of questions.
245:39:53 Henize: Fire away. [Pause.]
245:40:00 Worden: Okay. What attitude do you want us to do the UV photo - photography at. [Long pause.]
245:40:32 Henize: Roger, Al. The information on - on UV photos is to follow the procedures - Okay - you want the attitude - the procedures are on page 3-352, and the attitude to be used is 210, 242, 322.
Dave had requested that the UV photography session, planned to occur prior to the EVA, be postponed as all the required equipment was stowed in preparation for Al's excursion. Now Al has realised that in the six hours delay, the direction for pointing the spacecraft will have changed from that given in the procedures on page 3-352 of the Flight Plan.
245:40:57 Worden: Say the attitude again, please.
245:41:00 Henize: 210, 242, 322. Also, note use of magazine P, and also the time - the time that we start the maneu - the time that we finish the maneuver is 247 plus 45. [Long pause.]
After each session of UV photography of Earth, an additional image is taken using the same camera/lens combination, but using conventional colour film rather than UV-sensitive film. Henize is letting the crew know that this shot should be taken on magazine P instead of M as prescribed. He also reminds them of the time the new attitude numbers are relevant.
245:41:35 Henize: And let me clarify that magazine. That is the magazine for the UV color photographs. That is magazine P instead of magazine M. [Long pause.]
245:42:02 Worden: Okay. Understand. Use the procedures on page 3-352, except change the attitude to 210, 242, and 322, and this whole thing is to be done at 247:45.
245:42:19 Henize: Roger. That's the time for completing the maneuver. [Pause.]
245:42:29 Worden: Well, what time would you like us to maneuver to that attitude then? [Long pause.]
245:42:53 Henize: Roger. The time to start the maneuver is 24 - 247 plus 36.
245:43:03 Worden: I understand. 247 plus 36. Rog. Thank you, Karl. [Long pause.]
245:43:33 Henize: Okay, Al. Are you ready for the SIM bay questions? [Pause.]
245:43:43 Worden: Rog, Karl. Sure am.
245:43:47 Henize: Okay. First of all, the guys down here would like send up their warmest congratulations on such an ex - successful EVA. You sure made it look easy up there. And the questions. The questions we got are about the Mapping Camera, and they're directed at the general problem of is there - was there anything you could see which might indicate why it jammed? And there are three - three particular items that you might have looked at. First of all, it was the main camera cover at the bottom of the camera. Was it touching or scraping the camera in any way that you noticed?
245:44:29 Worden: The answer to that is negative. In fact. I checked it. I checked the Mapping Camera cover, Laser Altimeter cover quite carefully to make sure, because I do know that there have been some interference problems with that before, particularly with the Pan Camera, so I was looking at that in particular to see that it was maybe adjusted too close or - or interfering along the side of the Pan Camera, and it was not. There was about half an inch clearance between the upper edge of the cover and the body of the Mapping Camera, so that I - I don't see that that was responsible for the thing jamming.
245:45:07 Henize: Roger. I think you've very clearly put that suspicion to rest. There are also two covers to the solar camera in the upper left side of the Mapping Camera. And did you notice any - any distortion or any scraping in - in these covers? There's one possibility. The one that stuck out to the left - it - it might have jammed and the screwjack that controls it might have twisted it or distorted it. Was there anything you noticed like that?
245:45:37 Worden: Negative, Karl. I noticed nothing out of place with the Mapping Camera, nothing interfering. I checked all the way around it, down into the cavity, nothing interfering. I saw no evidence of anything interfering, and it looked clean underneath, so I don't think there was anything blocking it from underneath. I don't know. My distinct impression after surveying the Mapping Camera and looking around the cavity where the Mapping Camera fits was that there is a problem with the drive.
245:46:08 Henize: Roger. You didn't see anything inhibiting its motion, not even the electrical cables up on the top, huh?
245:46:14 Worden: Negative, and I guess I can ask a question along that line. Has anyone noticed any high current when we've gone to Retract on the Mapping Camera to indicate that it was hanging up?
245:46:28 Henize: We didn't see any, Al, although there had been a long controversy down here about the long amount of time required to extend and retract. It was, even though it was about the 4 minutes predicted several months ago, it was somewhat longer than what we'd observed at the Cape. People had been worrying about that for some time.
245:46:48 Worden: Yeah, I realize that. And I also, as I re - as I go back to what we saw at the Cape, there was some problems with that thing hanging up in drive itself at the Cape.
245:46:59 Henize: Roger. Okay, a couple of questions on the Mass Spectrometer. You gave us some good information there, but when you said the Mass Spectrometer cover wasn't completely closed, could you give us some idea at - as - to - to what degree it had closed, to what angle, and was there any poss - any cocking, any - any twisting in - in that cover.
245:47:28 Worden: Well, I couldn't tell whether there was any warpage in the cover or not, particularly because that kind of a cover is a little - looks like its warped anyway. It looked to me, I could - I pulled the cover out of the way enough to look at the Mass Spec. inside, and I could see the guide pin and along the sides of the carriage coming through the holes all the way up, so that they were plainly visible from the outside which - which meant to me that the - the Mass Spec. was either very close to being seated on the carriage or it was seated. I - I guess I don't really know how far those guide pins extend out beyond the - the carriage. The other thing was that the - that the cover - the Inconel cover was - it - was rotated about 30 degrees on its - on its hinge point from the full close position. And I thought at first, as I indicated when I was there, that there - there looked like there was some interference in one of the outer covers or one the outer edges, but after playing with that and pulling it a little bit when I was out there, it was quite obvious to me that that wasn't the problem either. And - and beyond that, I couldn't see down around beside the cover enough to tell whether there was something internal between the cover and the Mass Spec. that was - that was binding the cover. [Pause.]
245:48:52 Henize: Roger, Al. We copy that. And would you open the X-ray and Alpha Covers right now, please?
245:49:05 Henize: Okay. I guess you've answered most of our questions on the Mass Spec., and you've approached one that we might get a little more out of, and that is those guide rails sticking through the guides. There is a tapered portion, and when it's completely seated, you actually see the - the - the cylindrical portion beyond the tapered portion. Did you actually see the cylindrical portion, or was it all tapered area that you looked at on the guide rail?
245:49:32 Worden: Okay, that's good scoop. All I saw was the tapered area.
245:49:37 Henize: Roger. You probably - If it was fully seated, you would have seen about a half inch of - of the cylinder there, and this is a good indication that it was not all the way seated even though it was close. [Long pause.]
245:49:57 Henize: Here's a couple of other questions. Give me a second to look at them.
245:50:03 Scott (onboard): Why don't you get the [garble]?
245:50:04 Worden: Okay. [Long pause.]
245:50:40 Henize: Okay, Al. Mostly questions here about the contamination status and things in the SIM bay. First of all, how about the - the - the door eder - the door edges? Did they blow off smoothly and cleanly?
245:50:58 Worden: Yes, very cleanly. I saw no rough edges at all. [Long pause.]
245:51:22 Henize: Stand by a moment, Al.
245:51:26 Worden: Okay. [Long pause.]
245:51:27 Irwin (onboard): Don't forget to [garble].
245:51:29 Worden (onboard): Ion - Ion Source to Standby.
245:51:41 Henize: Al, we're anxious to bring up the High Gain Antenna. I've got a couple of angles here if they'll help.
By using the HGA, Mission Control can acquire a greater amount of telemetry from the spacecraft's systems.
245:51:48 Worden: Okay.
245:51:49 Henize: Minus 76 and 117. [Long pause.]
245:52:03 Worden: Okay. Minus 76 and 117. [Pause.]
245:52:12 Henize: Okay. We copied your comment on the SIM bay door jettison, and further questions go as follows. The white coatings in the SIM bay were - Did you notice that any of them why - were obviously discolored or - or coated from contamination or overheating? [Pause.]
245:52:37 Worden: I saw no evidence of heating in the SIM bay. I saw no evidence of discoloration of the white surfaces. There were - [cough] - as - as best I could tell, no particulate matter that had come to rest on any of the surfaces in the SIM bay. It looked very, very clean. And - even across the top of the Mapping Camera where there was a - such a heating problem expected, I saw no indications of heating whatsoever, particularly on things like the cover over the Mapping Camera cassette, which was supposedly a very hot spot, and it was just as clean as a whistle. There wasn't - there wasn't any evidence of scorching or contamination anywhere that I could see.
245:53:23 Henize: Roger. And, on the insulation and foils, I guess there's a question here - Were any of them burned or discolored? You probably already told us that. Were any of them torn or were there any attachment failures? [Long pause.]
245:53:46 Worden: No, I couldn't see any evidence of - of any burning or tearing or anything else back there, Karl. [Pause.]
245:53:59 Henize: Okay, we got one more general question there. And our Flight Dynamics Officer, who is vitally concerned about our reentry weight, would like to know whether or not we jettisoned more or less than a nominal 32 pounds; and, if so, by how much?
245:54:18 Worden: Okay. Stand by one.
Comm break.
245:55:29 Scott: Say, Houston, we've talked it over, and I guess we'd say it was pretty close to a nominal - as far as weight. We have no idea of - of determining exactly what the weight was, but we're going to try and work our reentry stowage over this afternoon and tomorrow morning, and we hope to give you a - a plan by - somewhere around noon tomorrow, of where all the rocks are stowed and where everything is stowed and what we have on board. So you can start - so Mr. FIDO can work up his entry plan.
245:56:03 Henize: Roger. And, if somebody has the time to copy it, I've got a small Flight Plan update available now.
245:56:14 Irwin: Okay, Karl. I'll take that.
One of Jim Irwin's roles is to copy down Flight Plan changes as they are read up by the CapCom.
245:56:17 Henize: Hi, Jim. How're you doing?
245:56:22 Irwin: Just fine.
245:56:23 Henize: Okay. 246 hours and 20 minutes; we have High Gain [Antenna] angles of pitch, 00; yaw, 240. [Pause.] At...
245:56:41 Irwin: ...00 and 240.
These angles for the HGA are associated with a second x-ray pointing attitude at 246:20.
245:56:44 Henize: Roger. And at 246 plus 46, we want to add "Change discriminator to low." [Pause.]
245:57:03 Irwin: Understand. Scratch "Discriminator, High," and make it "Discriminator, Low."
245:57:08 Henize: That's correct. And, on 247 plus 28, delete that DAP load. [Pause.]
245:57:20 Irwin: Okay. We already have that change.
245:57:23 Henize: Sorry about that. On 247 plus 30, we'd like to have the "Alpha/X-ray Covers, Closed; then Off", and delete the note on the Cover Open/Close. [Long pause.]
At the time given in this update, the spacecraft is to be placed into an attitude suitable for the PTC rotation. This is perpendicular to the Sun as required to spread its heat evenly across the outer skin as the spacecraft spins. The original plan had been to operate the X-ray/Alpha Particle Spectrometer during PTC, but to protect the instrument from damage, the covers were to be closed within certain angular limits once every 20 minutes. This onerous task would have been aided by setting a kitchen timer to warn of when to open and shut the covers.
245:57:49 Irwin: Okay, understand. At 247:30, you'd like "Alpha/X-ray Doors, Closed," and just delete the note here. [Pause.]
245:58:00 Henize: Roger. And stand by one second. [Pause.]
245:58:10 Henize: 247 plus 30. Also, we would like to add "Mass Spectrometer Multiplier, High; Discriminator, Low." [Long pause.]
245:58:34 Worden: Understand. At 247:30, you want to add "Mass Spec. Multiplier, High, and Discriminator, Low."
245:58:40 Henize: Rog. And, at 247 plus 32, we'd like to have "Mass Spec. Multiplier, High; Discriminator, High." [Long pause.]
245:59:15 Henize: Roger. And I guess you need to save room, if there's any left there, because at 34 and at 36, we want to change these two switches again. At 34, we want "Mass Spec. Multiplier, Low; Discriminator, High." [Long pause.]
245:59:40 Irwin: Understand. At 34 you want "Multiplier, Low; and Discriminator, High."
245:59:45 Henize: Affirmative and at 36, we want "Multiplier, Low; Discriminator, Low." [Long pause.]
246:00:01 Irwin: Okay. At 247:36, it's "Multiplier, Low; and Discriminator, Low."
246:00:05 Henize: Affirmative. Also at 247:36 is "Add the UV photos," and we've already sent up the changes required for that; the changes over and above what's on page 3-352. And there's one reminder there, and that is to verify that when you use filter 2, that you take one frame for 20 seconds and one frame for 2 seconds.
246:00:31 Irwin: Roger. We remember that.
246:00:33 Henize: Okay. The next step is 247 plus 45, "X-ray to Standby." [Long pause.]
246:00:52 Irwin: Okay. At 247:45, "X-ray to Standby."
246:00:57 Henize: And, at 247 plus 50, we want to move the PTC initiation steps from 247:30 to 247:50. [Long pause.]
246:01:24 Irwin: Okay. Understand. The initiation of PTC to be delayed from 247:30 to 247:50.
246:01:32 Henize: That's affirmative. At 248 hours and 0 minutes, we'd like the following: we'd like the Mass Spectrometer boom retraction sequence. Each retraction step will last 20 minutes, instead of 12. [Pause.] And terminate this test at 249 plus 30. [Pause.]
246:02:13 Irwin: Go back to 248, Karl, on that Mass Spectrometer boom retraction sequence.
246:02:18 Henize: Roger. I...
246:02:20 Irwin: I have that in there.
246:02:22 Henize: I - I guess all - all we're doing there is changing - The - the retraction step will be 20 minutes instead of 12 minutes. Down at the end of the writing there, it says "Each sample period will last 12 minutes." We'd like to have that at 20 minutes. [Pause.]
246:02:42 Irwin: Okay. I'll change the note there then. It occurs about 248:20; this 12 will be 20.
246:02:50 Henize: That's correct. At 249:05, we'd like to move the Mass Spec. boom deploy from 05 to 30 - from 249:05 to 249:30. [Pause.]
246:03:16 Irwin: Understand. Move the Mass Spec. boom deploy from 249:05 to 249:30. [Pause.]
246:03:30 Henize: Roger. And one final one at 251:48, which you may already have, is delete the DAP load there.
246:03:40 Irwin: I do; we have that one, Karl.
246:03:42 Henize: Okay. That completes the update. Thank you.
246:03:47 Irwin: Thank you. [Long pause.]
246:04:25 Henize: 15, Houston. We'd like to have Gamma-ray Gain Step up 4 clicks. [Pause.]
246:04:34 Irwin: Okay. That's Gamma-ray Gain Step up 4 clicks.
Very long comm break.
In an attempt to keep them fit for a return to the strain of Earth's gravity acting on their limbs, the crew have a half-hour period of exercise.
This is Apollo Control at 246 hours, 15 minutes. Apollo 15 now 163,766 nautical miles [303,295 km] from Earth. Velocity: 3,171 feet per second [967 m/s].
This is Apollo Control at 246 hours, 20 minutes. Apollo 15 is maneuvering now to the X-ray pointing attitude.
This is the second successive period of x-ray astronomy. This time the X-ray Spectrometer is to be pointed towards the constellation of Cygnus, primarily to observe the source, Cygnus X-1. Discovered just prior to the flight of Apollo 15 by the Uhuru satellite, this x-ray source is now believed to be a binary stay system in which one component star has collapsed to form a black hole which is consuming material from the other star. The intense heating of this matter as it spirals towards the event horizon of the black hole generates the huge x-ray flux.
Woods, from 2004 mission review: "The astronomy that was done, the black hole, Cygnus X-1 and such like, were you much across what the scientists were hoping to do with the spectrometer? Was it just something afterwards you found out?"
Scott, from 2004 mission review: "We were probably briefed before we went but we were briefed on a lot of things. Bitty, bitty, bitty experiments, if you will. I don't recall exactly. I'm sure somebody briefed us on the details but didn't really absorb them at the time. Jim and I are focussed on the surface. Al's focussed on trying to keep everything running. We had, I don't remember how many hours of microbiology scheduled when we first got assigned to the mission. Twelve to fourteen hours, something like that. Because you can't absorb it, you just can't take it all. There's too much to do."
O'Brien, from 2004 mission review: "What kind of training in microbiology would they have you do and what would you do with that information once you got there."
Scott, from 2004 mission review: "Bugs! They had a lot of stuff that, I don't remember how many hours. A lot of hours. They also wanted us to carry the waste management system, the new waste management system. We said no, because we don't want to take some new device on an already loaded spacecraft. And there was always this outside plethora of people who want things to be done on this flight. Things, things, things. At some point you have to cut it off and say no because in order to accomplish our major objective, we're saturated anyway. So at the beginning, we cut a lot of things out. And we added a lot of things too. We added a lot of geology. So there's a trade-off in what you really do."
O'Brien, from 2004 mission review: "Was there anything that you felt short changed about in the end."
Scott, from 2004 mission review: "No. Can't think of anything. At the end of the day, that's why, when we got ready to go, we were ready. Probably wouldn't want to take another month of training. Be over-trained."
O'Brien, from 2004 mission review: "Would have been more of a waste of time."
Scott, from 2004 mission review: "Yeah, I think so. We probably peaked about when we should have peaked. Because we were sitting in the simulator, you know, last couple of days, we figured out how to simulate driving the rover on the model of the lunar surface. So Jim and I would sit in the simulator and pretend like we're driving the Rover. [Laughter.] It's because we'd done everything we could do. You could run another landing, another this, another that. But, you know, you're just saturated."
Woods, from 2004 mission review: "Is that part of the thinking that says we've simmed all the horrendous things, we've done the training for the abort procedures. Let's do something that is nominal and then something that is fun to relax you a little bit the last couple of days before the flight."
Scott, from 2004 mission review: "Sure. Yeah."
O'Brien, from 2004 mission review: "Stories of people putting little toys on the models. You pitch over and there's Godzilla or something."
Scott, from 2004 mission review: "Yeah. We did that. It was fun."
Once the exercise period is completed, the crew begin their meal break. During this, at 246:45, the Mass Spectrometer will have had enough time to outgas and will be switched on.
This is Apollo Control at 246 hours, 36 minutes. The high voltage has been turned on, on the subsatellite, everything is normal and the vehicle is considered fully operational.
246:37:35 Henize: 15, this is Houston. We trust you'll be pleased to hear the news that the high voltage has been turned on to the subsatellite, and that they find that all systems are operational.
246:37:50 Scott: Oh, that's very good. Glad to hear it.
Very long comm break.
The subsatellite requires a high voltage power supply, derived from the solar cell supply to power its particle detector.
This is Apollo Control at 246 hours, 59 minutes. Apollo 15, is 162,429 nautical miles [300,819 km] from Earth. Velocity, 3,204 feet per second [977 m/s], and the clock counting down shows 48 hours, 11 minutes to landing. Here in the control center, Flight Director Glynn Lunney and his team preparing to relieve Flight Director Gerry Griffin and his team of flight controllers. The CapCom on the next shift will be astronaut Bob Parker. We estimate the change of shift news conference for 4:15 pm Central Daylight Time in the News Center Briefing Room.
247:04:46 Henize: 15, Houston. We have a couple of more comments on the UV photo procedures, if somebody can copy.
247:04:56 Irwin: Go ahead, Karl.
247:04:59 Henize: Roger. We overlooked the fact that you are taking these photos in the midst of SIM bay operation, so a couple of little things change. Going back to page 3-352, you can first of all delete, below the damp rates notation, in - you can delete "Inhibit all jets, except" the jets that are there, and just keep the jet configuration you got right now. [Long pause.]
247:05:43 Irwin: Okay. I copy that. Do you have any other comments?
247:05:46 Henize: Roger. Under "Remove the CM5 window," put in there "CMC, Free," and likewise, about four lines up from the bottom, just above "note", put in "CMC, Auto". And the final comment, "Enable all jets"; you can delete that. [Pause.] And that's all.
247:06:18 Irwin: Okay; understand. Just below "Remove CM5 window cover" put "CMC, Free," and then down at the - the bottom there, just above the note, put "CMC, Auto," and scratch "enable all jets."
247:35:39 Worden: Dr. Parker, I presume. Listen, Bob, we got to pull the Gamma-ray [boom] to 15 feet at 50, and wonder if you've got an updated retraction time for us.
247:35:49 Parker: That's affirm, Al. We have a retract time of 247 plus 50, for 72 seconds. Over.
247:36:00 Worden: Understand, 72 seconds.
Both the Gamma-ray Spectrometer and the Mass Spectrometer are to be operated at various fractions of their booms' full 7-metre extension. The Gamma-ray boom was set to 4.5 metres when it was initialised at 245:30. In 15 minutes time it will be retracted to 2.4 metres and this will be achieved by operating its motor for 72 seconds, a value based on the boom's previous performance. This boom will be held in this position for 1 hour, 40 minutes.
In the meantime, Endeavour begins manoeuvring to the attitude for the ultraviolet photography. This is carried out according to the procedures listed on page 3-352 of the Flight Plan.
247:36:03 Parker: That's affirm. And, 15, if you got your Flight Plan out, we can update a couple more times in that same general vicinity for you. [Pause.]
247:36:19 Worden: Okay, the Flight Plan is out and the door is open.
247:36:23 Parker: Okay. At 248:02, the Mass Spec. boom retract time - that should be 33 seconds. And that time will apply to the first retraction. The second, third, fourth, and fifth retractions will be 32 seconds. Over. [Pause.]
The progressive retraction of the Mass Spectrometer boom will be carried out in a slightly different manner. There will be five steps lasting 20 minutes each, between which the boom will be retracted for 33 or 32 seconds.
247:36:51 Irwin: Okay, Bob. Understand that the first retraction is 33 seconds and the succeeding retractions will be 32 seconds. Is that 4 or 5?
247:37:04 Parker: Stand by. [Long pause.]
247:37:33 Parker: Apollo 15, Houston. That will be 32 seconds for all succeeding ones, and we are going to do that up to 249:30. And so all succeeding ones you get will be at 32 seconds. And we will finish that test at 249:30, no matter where we are. And I believe I see that Karl has sent up comment that the sample period would be 20 minutes instead of 12. Is that right?
247:38:02 Irwin: That's Roger; we have that.
247:38:04 Parker: Okay. And another change: at 249:36, the Gamma-ray deploy. That time will be 63 seconds. Over. [Pause.]
247:38:19 Irwin: Copy, 63 seconds.
247:38:21 Parker: Okay. That's all we have for right now.
This is Apollo Control. Flight Director Glynn Lunney is completing his mission status review with his Flight Controllers at the present time. We're about to begin the change of shift press briefing, and that briefing will be held in the Briefing Room at the MSC News Center. At present time, Apollo 15 is 161,117 nautical miles [298,389 km] from the Earth and the spacecraft velocity is 3,237 feet per second [987 m/s].
247:43:13 Parker: Apollo 15, Houston. Request Omni Delta, please.
247:43:20 Worden: Roger. Omni Delta.
Very long comm break.
Having moved to the UV photo attitude, omni antenna D is best placed for communication with Earth.
Ultraviolet photographs are taken out of window 5 because it is constructed from quartz which transmits UV. A Hasselblad camera is fitted with a specialised 105-mm lens whose elements are likewise transparent to UV. Magazine N is used for this photography. The spacecraft is allowed to stabilise for 5 minutes with the FDAI set to its maximum sensitivity. Once stable, and in a change to the original procedure, the CMC mode switch is set to "Free" to inhibit further firing of the RCS thrusters, giving the crew a steady platform from which they can conduct the photography.
Knowing the size of the Hasselblad's film gate (55.5 mm), the focal length of the lens (105 mm) and the radius of Earth (6,371 km), the approximate distance at which these images were taken can be determined. The values clump around 156,000 nautical miles or 289,000 km. This matches well with the PAO announcement three quarters of an hour ago which gave a figure of 162,429 nautical miles [300,819 km].
Eight frames are to be taken in all, two through each of four filters, though only seven appear in the Apollo 15 Index of 70-mm Photography. These are AS15-99-13476 to AS15-99-13482. The proximity of the Sun to the camera's field of view is apparent in these frames. Earth is only dimly visible as a faint crescent within one of the iris reflections. The linear marks to the right are cause by reflections from wipe marks on the window after someone has tried to clean the pane.
In the following presentations, the contrast of these images has been stretched to make the image content clearer. Links have been provided to unstretched versions.
AS15-99-13476 - Ultraviolet photograph of Earth taken through filter 1. Image is contrast stretched. Image without contrast stretching - Image by NASA/JSC/Arizona State University.
AS15-99-13477 - Ultraviolet photograph of Earth taken through filter 1. Image is contrast stretched. Image without contrast stretching - Image by NASA/JSC/Arizona State University.
AS15-99-13478 - Ultraviolet photograph of Earth taken through filter 2. Image is contrast stretched. Image without contrast stretching - Image by NASA/JSC/Arizona State University.
AS15-99-13479 - Ultraviolet photograph of Earth taken through filter 3. Image is contrast stretched. Image without contrast stretching - Image by NASA/JSC/Arizona State University.
AS15-99-13480 - Ultraviolet photograph of Earth taken through filter 3. Image is contrast stretched. Image without contrast stretching - Image by NASA/JSC/Arizona State University.
AS15-99-13481 - Ultraviolet photograph of Earth taken through filter 4. Image is contrast stretched. Image without contrast stretching - Image by NASA/JSC/Arizona State University.
AS15-99-13482 - Ultraviolet photograph of Earth taken through filter 4. Image is contrast stretched. Image without contrast stretching - Image by NASA/JSC/Arizona State University.
Though an additional photo is to be taken through the same combination using colour magazine P, this magazine was exhausted in lunar orbit. However, there are two colour photographs on magazine Q which match the two UV sequences that will be taken later in the mission. Prior to the first of these is a grossly overexposed frame, AS15-98-13103, and it seems likely that, except for a photograpic error, this ought to have been the colour reference image for this sequence.
AS15-96-13103 - Overexposed image, likely meant to be a reference image of Earth on colour film - Image by NASA/Johnson Space Center.
Afterwards, a protective cover is placed over window 5 and spacecraft attitude control is returned to the computer by placing the CMC switch to "Auto".
This is Apollo Control at 247 hours, 59 minutes. During our change of shift briefing, we had no conversations with the crew. It's been quiet in Mission Control. And we're standing by live at this time.
248:00:27 Parker: Apollo 15, Houston. Over.
248:00:35 Worden: Go ahead. [Pause.]
248:00:42 Worden: Houston, 15. Go ahead.
248:00:43 Parker: Roger, 15. If you guys will give us a hack when you start the first Mass Spec. retraction, we'll keep an eye on those 20-minute periods for you.
248:00:54 Worden: Okay; good deal. [Pause.]
248:00:57 Irwin (onboard): Just completed one.
248:00:59 Scott (onboard): Did you do one?
248:01:00 Worden (onboard): Yes. I'll talk to him.
248:01:01 Irwin: Bob, we just completed one retraction for 33 seconds.
248:01:06 Parker: Okay, we're starting our time.
Long comm break.
248:01:11 Worden (onboard): [Garble].
248:01:15 Irwin (onboard): And away we go.
248:01:17 Worden (onboard): [Garble].
248:01:44 Irwin (onboard): Hey, you woke up just in time to eat again, Dave.
248:01:51 Scott (onboard): [Garble] fresh.
248:01:54 Worden (onboard): To sleep in [garble] work [garble].
248:02:08 Worden (onboard): Okay, valve pressure is getting good and [garble] is [garble].
248:02:14 Worden (onboard): Surge tank pressure greater than 400?
248:02:15 Irwin (onboard): Yes, 487. [garble].
248:02:36 Worden (onboard): [Garble].
248:02:48 Scott (onboard): Any surge?
248:02:50 Irwin (onboard): Yes, it's 600.
248:02:52 Worden (onboard): [Garble].
248:02:54 Irwin (onboard): Yes.
248:03:00 Scott (onboard): [Garble].
248:03:03 Worden (onboard): Yes. [Garble].
248:03:13 Scott (onboard): [Garble].
248:03:16 Worden (onboard): You got that solar stuff?
248:03:17 Scott (onboard): [Garble].
248:03:26 Irwin (onboard): Sure a relaxed schedule here today.
248:03:28 Worden (onboard): We're going along all right until we get to [garble].
248:03:39 Irwin (onboard): You never do any more UV work, Al?
248:03:42 Worden (onboard): Yes, we get another one tomorrow.
248:04:11 Irwin (onboard): Hand me the log there, will you? Oh, we don't have the log out, do we?
248:04:16 Worden (onboard): [Garble] find it.
248:04:21 Irwin (onboard): It might be in my TSB. My [garble] TSB.
248:04:33 Worden (onboard): [Garble].
248:05:06 Irwin (onboard): Let's see. I have a G&C Checklist over here. But I don't have the - I don't have the other good information. I take it back; I have it. I have it.
248:06:20 Irwin (onboard): Did you take any UV photos in - in orbit?
248:06:37 Parker: Roger, 15. We'd like to get a pitch of minus 4.0 and yaw of 90 for the High Gain Antenna. And then, if you'd change your antenna switch to High Gain without hitting the Command Reset switch, we'll maintain comm that way, please.
Comm break.
By the Flight Plan, the spacecraft would be in the PTC mode now. Instead, it is still in the UV photography attitude. The flight controllers are missing having full telemetry from its systems so have requested that the HGA be brought into operation. Al does manoeuvre Endeavour to the initial PTC attitude in less than 10 minutes anyway.
248:08:28 Parker: Apollo 15, Houston. Over. [Pause.]
248:08:38 Worden: Go ahead, Houston.
248:08:39 Parker: Negative. You did the right thing without us calling you. Thank you. [Pause.]
248:08:47 Worden: Whatever that was, okay.
Long comm break.
248:08:49 Irwin (onboard): Are we going to press on with the High Gain?
248:09:21 Scott (onboard): Yes, yes. If you just get your [garble] down here, [garble].
248:09:30 Worden (onboard): Ah, mark it.
248:09:32 Scott (onboard): [Garble]. We want to take four breathing samples and do our [garble]. What do we have - we have about 50 left to make, don't we?
248:09:40 Irwin (onboard): We have 50 in this one.
This is Apollo Control. The crew, at the present time, is setting up their Digital Auto Pilot and this will damp out the rates of the spacecraft, set it up in a stable position just prior to starting it rotating at the rate of about 3 revolutions per hour. And this is the condition that the spacecraft will be in during the sleep period to maintain the proper temperature and the proper - proper thermal equilibrium. Prior to beginning the sleep period, which will be a 9-hour rest period, the crew will also run a Program 52 which is a platform alignment, aligning the stable platform used by their guidance and control system in the spacecraft as an attitude reference, and will also take a series of sightings on 3 different stars as part of a midcourse navigation exercise using Program 23. During this period of time also, they have been alternately extending and retracting the boom which holds the Mass Spectrometer. As the spectrometer moves alternately closer and farther from the Service - Service Module bay, it allows the Principal Investigator to gather data on the cloud of contaminants that are presumed to follow along with the spacecraft, and to construct from this a stratification model of this contamination cloud. Once the model is constructed, then this data can be used to interpret the scientific results that are gathered with that instrument. At 248 hours, 12 minutes; Apollo 15 is 160,000 nautical miles [296,320 km] from the Earth and the spacecraft velocity is down now to 3,262 feet per second [994 m/s]; actually now, we're watching the velocity increase but very slowly and will continue to do so reaching its maximum shortly after Entry Interface where it'll be at about 36,000 feet per second [10,900 m/s] or a little more.
The spacecraft has been manoeuvred to the initial attitude for the PTC roll. This attitude is at right angles to the PTC REFSMMAT (the current alignment of the guidance platform) and essentially places the spacecraft's longitudinal axis broadside to the Sun, ensuring that, once it begins rotating, the heat received it evenly spread across its skin.
248:13:23 Worden (onboard): [Garble] change that one.
248:13:24 Scott (onboard): Bring it in [garble].
248:13:28 Irwin (onboard): You should bring that. I used the scissors to cut mine on the LM, but - Is there a file on the end of those scissors?
248:13:43 Worden (onboard): I don't think so. That one's [garble].
248:13:54 Scott (onboard): Not much of a file, huh?
248:14:00 Irwin (onboard): I got a razor blade [laughter].
248:14:17 Parker: And 15, Houston, your rates look good to us for spinup.
248:14:23 Worden: Okay, Bobby.
Long comm break.
During the PTC rotation, S-band communication is maintained by the HGA which is in its reacquisition mode. In this mode the antenna tracks Earth on its articulated mount until the rotation of the spacecraft takes it to the edge of its range of movement. When this happens, the "Reacq" mode causes it to move to a setting that has been dialled in on the Main Display Console and which has been precalculated to bring it back onto Earth after the spacecraft has brought it around to the other side.
248:15:38 Irwin (onboard): Maybe we better turn the heat up a little in here.
248:15:42 Scott (onboard): Getting cold?
248:15:45 Irwin (onboard): My feet are a little cold. I wonder where my - my little slippers went.
248:15:51 Scott (onboard): [Garble].
248:15:53 Worden (onboard): Open up my - open up my sack. Here's my little slipper.
248:15:58 Scott (onboard): [Garble].
248:15:59 Irwin (onboard): Get me into my slippers in here.
248:16:00 Worden (onboard): Are they yours?
248:16:01 Scott (onboard): Two-hundredths.
248:16:16 Irwin (onboard): I'll take them.
248:16:21 Worden (onboard): [Garble].
248:16:25 Scott (onboard): [Garble].
248:16:26 Irwin (onboard): Yes.
248:16:27 Scott (onboard): [Garble].
248:16:31 Irwin (onboard): Yes, I think I did.
248:16:32 Scott (onboard): [Garble].
248:16:42 Irwin (onboard): No. I think I - There is one.
248:16:43 Scott (onboard): Are you sure, Jim?
248:16:55 Irwin (onboard): The last time I saw it, we - it was in B-1. You know, wrapped in there with the - the jett bag. But it's not in there any longer.
248:17:04 Scott (onboard): [Garble].
248:17:06 Irwin (onboard): No, it's not in there now. Just - just the...
248:17:10 Scott (onboard): [Garble].
248:17:11 Irwin (onboard): It's not in there now.
248:17:12 Scott (onboard): [Garble].
248:17:14 Irwin (onboard): I don't know, Dave. I'll have to look. I don't know - I don't know who took that stuff out of B-1.
248:17:20 Worden (onboard): [Garble]...
248:17:21 Irwin (onboard): What'd you - Al, the one - the cam - we had the 500 - millimeter camera, Al?
248:17:27 Scott (onboard): [Garble].
248:17:30 Irwin (onboard): Yes.
248:17:31 Scott (onboard): Remember, we pulled the cameras out [garble] and put them in the Jett bag.
248:17:35 Irwin (onboard): Yes.
248:17:36 Scott (onboard): I gave you yours, and you [garble].
248:17:39 Irwin (onboard): You gave me my camera at that time?
248:17:41 Scott (onboard): Yes, [garble].
248:17:45 Irwin (onboard): Tell me where it is and I'll look.
248:24:20 Parker: Roger. If you guys are - have a moment free, we'll pass up three comments to you preparatory to some stuff you want to do later on. [Pause.]
248:24:35 Worden: Yeah, go ahead.
248:24:37 Parker: Okay, first is a reminder that we're counting on using the OPS to pump up the cabin for sleep tonight - another way of bleeding off the OPS. Guess we'll remind you now so you don't stow it away down underneath something where it's inconvenient. And we'd like a read-out on the OPS after you finish pumping up the cabin tonight. Second comment is a reminder that we'd like a cue on the vacuum cleaner, if you intend to use it for this contamination control period coming up in a half hour or so. And third one is that as far as the medics are concerned, it's dealer's choice on who wears the biomed tonight. Over.
248:25:23 Worden: Okay, We copied, Bob.
Long comm break.
Parker's last comment overrides the Flight Plan which, at 249:30, calls for Jim to wear his biomedical harness tonight. However, the crew will elect to stick with the Flight Plan.
248:29:39 Parker: Roger. We'd like to confirm Auto, Auto, Off on the O2 heaters. It looks like we've gone beyond the point where they should have come on. [Pause.]
By this, Parker means that oxygen tanks 1 and 2 should have their heater controls set to Auto with tank 3's heaters being switched off. The heaters in each tank are used to increase their internal pressure up to operating levels. Otherwise during use, the pressure falls as gas is extracted. The heaters can be set to switch automatically, controlled by a pressure-driven switch. Mission Control can monitor the pressure within the tank and are aware of the conditions that should trigger the heaters to come on.
248:29:53 Worden: They're all Off right now, Bob.
248:29:56 Parker: Roger. That explains what we are seeing. Roger: we'd like Auto, Auto, Off, please.
248:30:07 Worden: Understand; Auto, Auto, Off.
248:30:09 Parker: Thank you. [Long pause.]
248:30:44 Worden: Houston, 15.
248:30:46 Parker: Go ahead, 15.
248:30:48 Worden: Okay, just wanted to clear up the O2 heaters with you. Are you aware that the last instruction that we had in the Flight Plan was at 243:30 that said "O2 Heaters, three, Off"?
Al is mistaken here. The instruction, though, is badly formed and easy to misinterpret. This author (Woods) also made the same mistake (at first) when deciphering the line. The printed form is "O2 HEATERS 3 (1) - OFF" where the "(1)" indicates that only a single switch is being dealt with.
248:30:59 Parker: Stand by. That wasn't on my shift. [Pause.]
248:31:05 Worden: You're not the regular crew chief, huh? [Pause.]
248:31:05 Parker: 15 - Apollo 15, Houston. That callout at 243:30 is the O2 heaters for tank 3, only. [Long pause.]
248:31:36 Worden: Okay, Robert, I stand corrected. [Long pause.]
248:31:55 Worden: That's one I owe you.
248:31:58 Parker: 15, you called? [Pause.]
248:32:04 Worden: Negative, negative.
Long comm break.
248:32:09 Irwin (onboard): I think this package of mags goes into A-8.
248:32:12 Scott (onboard): [Garble].
248:32:17 Irwin (onboard): Ah, you think so, huh?
248:32:41 Worden (onboard): Should be pictures [garble] we used all that film. [garble]. It picked up a little here [garble].
248:32:55 Scott (onboard): Who's going to [garble]?
248:32:58 Worden (onboard): Where's your bag? [Garble].
248:33:06 Scott (onboard): It's down here right now. I got to get these straightened out.
248:33:18 Worden (onboard): [Garble].
248:33:28 Worden (onboard): Yes.
248:33:29 Scott (onboard): [Garble].
248:33:39 Worden (onboard): I'd like - I'd like to get a mag of that, too. Start eating it. [Garble].
248:33:58 Scott (onboard): [Garble].
248:34:06 Irwin (onboard): The mag, you mean?
248:34:08 Scott (onboard): [Garble].
248:34:12 Worden (onboard): Well, no matter what you do, it's got to come back tightly, before you start it.
248:34:17 Scott (onboard): I knew you could, but you could - you could do it [garble] perfect here, or you could [garble] Now can you get it started?
248:34:30 Worden (onboard): Yes.
248:35:41 Irwin (onboard): Al, one pack of this film goes in A-8, the 70s in the LM.
248:35:48 Worden (onboard): Yes.
248:36:07 Worden (onboard): [Garble] 40. Want three of them?
248:36:10 Irwin (onboard): Yes.
248:36:12 Worden (onboard): Did you get three?
248:36:13 Irwin (onboard): Yes.
248:36:14 Worden (onboard): Okay.
248:36:19 Irwin (onboard): We're going to get the other three in today. We'll have 13. We'll have to split the package up.
248:37:07 Worden (onboard): [Garble]. We can put some mags in here.
248:37:09 Irwin (onboard): Yes.
248:37:11 Scott (onboard): We only got this one mag.
248:37:16 Worden (onboard): [Garble] that?
248:37:18 Scott (onboard): Right on. Why don't we just [garble]?
248:37:23 Worden (onboard): Probably, because nobody can [garble].
248:37:25 Irwin (onboard): Probably.
248:38:32 Irwin (onboard): [Garble] in there? Al. That bag is much too big to fit in there.
248:38:43 Worden (onboard): [Garble] but we can certainly get [garble].
248:38:47 Scott (onboard): We need one bigger than this, though.
248:38:49 Irwin (onboard): Well, this bag probably should not have come over from the LM. I used this bag, though, to wrap up these - these mags. You know, neither one have been used.
248:39:29 Worden (onboard): I think they might be [garble].
248:39:51 Scott (onboard): What are you going to get out of here?
248:40:01 Scott (onboard): Carry it for me. Can't help but be better.
248:40:12 Irwin (onboard): You got to work - work it out.
248:40:15 Worden (onboard): [Garble] that one [garble].
248:40:18 Scott (onboard): [Garble].
248:40:19 Worden (onboard): I wouldn't [garble].
248:40:22 Scott (onboard): Yes, I wouldn't [garble].
248:40:25 Worden (onboard): Yes. Tool - tool B on the - wait - wait a second.
249:01:03 Parker: And, Apollo 15; Houston. It's time to retract again.
249:01:07 Irwin: Okay, thank you.
249:01:09 Parker: And, 15, be advised that this is the last retract we'll do. We will not do the fifth retract in order to ensure that we don't damage the filament by getting it in too close. We'll sit in this retracted position for 30 minutes, and then deploy the Mass Spec. boom as per the Flight Plan at 249:30. Over.
249:01:33 Irwin: Okay, understand.
Very long comm break.
249:19:15 Irwin (onboard): Oh, and then CDR doffing biomed harness. LMP donning. Alpha X-ray. Let's get a little SIM bay and then eat. Eat and then we do a canister change, You do a little P23 stuff. Then we'll get ready to go to bed.
249:19:46 Worden (onboard): Three hours to bedtime.
249:19:50 Scott (onboard): [Garble] sleep. [Garble].
249:20:05 Worden (onboard): [Garble] 3 to 4 hours [garble].
249:20:22 Scott (onboard): [Garble] here?
249:20:25 Worden (onboard): [Garble]...
249:20:26 Irwin (onboard): Otherwise, it would have been pretty boring.
249:20:28 Scott (onboard): [Garble].
249:21:32 Worden (onboard): [Garble].
249:21:39 Scott (onboard): [Garble].
249:21:40 Worden (onboard): [Garble].
249:21:50 Irwin (onboard): [Laughter.]
249:21:51 Worden (onboard): [Garble].
249:21:55 Irwin (onboard): Yes.
249:21:56 Worden (onboard): [Garble].
249:22:06 Scott (onboard): [Garble].
249:22:09 Irwin (onboard): You work mighty hard, I'll tell you.
249:22:11 Scott (onboard): What [garble]?
249:22:12 Irwin (onboard): You work mighty hard.
249:22:20 Scott (onboard): [Garble].
249:22:23 Irwin (onboard): No, a little [garble].
249:22:35 Irwin (onboard): I wish I would have tried running alongside the Rover at a - the same pace, you know, to see how...
249:22:42 Scott (onboard): You'd have never stayed with it, Jim. You know [garble]...
249:22:47 Irwin (onboard): Yes, true.
249:22:48 Scott (onboard): ...[garble]
249:22:56 Irwin (onboard): I would have liked to have, you know, to run alongside of it. It'd been neat to do a few things like that, you know.
249:23:01 Scott (onboard): What?
249:23:02 Irwin (onboard): It'd been neat to try a few things like that.
249:23:04 Scott (onboard): Yes. I know. Yes. [Garble].
249:23:43 Irwin (onboard): You can take off your biomed harness, Dave.
249:23:44 Worden (onboard): Whoo!
249:24:05 Irwin (onboard): He'll lose sleep for 9 hours tonight.
249:24:08 Scott (onboard): Good! [Garble].
249:24:35 Scott (onboard): Can you see the Moon?
249:24:36 Irwin (onboard): Oh, yes.
249:25:45 Worden (onboard): Can you get that? Thank you.
249:25:58 Irwin (onboard): On a lunar eclipse - Let's see, we take a total there of...
249:26:06 Scott (onboard): [Garble].
249:26:07 Irwin (onboard): No, we take some with the EL.
249:26:10 Scott (onboard): Yes.
249:26:11 Irwin (onboard): Yes. We take eight with the EL.
249:26:13 Scott (onboard): What kind?
249:26:14 Irwin (onboard): Color.
249:26:17 Worden (onboard): [Garble].
249:26:27 Scott (onboard): Yes, eight with color.
249:26:40 Irwin (onboard): Here's some more Lunar Orbiter.
249:26:44 Scott (onboard): Is that the same?
249:26:47 Irwin (onboard): No, you have it on two different pages.
249:26:51 Scott (onboard): Oh, yes.
249:26:54 Irwin (onboard): Hey, what was this one for?
This is Apollo Control at 249 hours, 27 minutes. Apollo 15 is now 157,700 nautical miles [292,060 km] from the Earth, traveling at a speed of 3,322 feet per second [1,013 m/s]. The crew, at this time, should be about to get something to eat. Following the eat period they'll be aligning their platform, the guidance system stable platform used in attitude reference. And [they] will also be taking some star sightings using program 23 for midcourse navigation. During the rest period, which is scheduled to begin at 252 hours, 30 minutes, or about 3 hours from now, the Gamma-ray, Alpha Particle and Mass Spectrometers will be operating, gathering background data to be compared with the information collected in orbit around the Moon.
249:27:08 Scott (onboard): Don't you have any more?
249:27:09 Worden (onboard): [Garble] think we need any [garble].
249:27:12 Scott (onboard): Yes. [Garble].
249:27:15 Irwin (onboard): It's in the lockers.
249:27:20 Scott (onboard): [Garble] more?
249:27:22 Worden (onboard): [Garble] time to figure it out - figured out [garble].
249:27:26 Scott (onboard): Going to give them [garble]?
249:27:31 Worden (onboard): [Garble].
249:27:34 Scott (onboard): [Garble].
249:27:38 Worden (onboard): Yes, you got to reckon with him yet.
249:27:40 Scott (onboard): Huh?
249:27:41 Worden (onboard): You're going to have to reckon with him yet on those ...
249:27:42 Scott (onboard): Yes. [Garble] make sure to recommend that he [garble].
249:27:49 Worden (onboard): Yes.
249:27:52 Scott (onboard): [Garble].
249:28:00 Worden (onboard): Yes.
249:28:24 Parker: Apollo 15, Houston. About 2 minutes to Mass Spec. boom deploy. And we'd like a Delta-T on the length of time it takes to deploy it, please.
249:28:37 Worden: Roger, Bob.
Long comm break.
249:29:51 Scott (onboard): [Laughter.] They can't tell that, I don't think.
With this being essentially an engineering test flight for the SIM bay, Al carefully timed the deployment and retraction of the booms and the Mapping Camera throughout his solo mission. Mission Control are asking him to continue this practice so that they can check that the deployment time is consistent with how far they believe the Mass Spectrometer boom was retracted. This is especially important in light of the difficulty Al had at times in retracting this boom, a problem which turned out to be caused by excessive cold.
Note that the Gamma-ray boom is retracted also to operate for the next 2¾ hours close to the spacecraft.
249:33:43 Irwin: Bob, the deploy time on the Mass Spec. was 3 and 25.
249:33:50 Parker: Roger. Copied 3 plus 25, Jim.
249:33:53 Irwin: Roger.
Very long comm break.
Dave, Al and Jim begin their final meal period of the day. After that they have two hours of activities before settling down to rest. The major activities will include a P52 platform realignment, some P23 cislunar navigation exercises and a reestablishment of the PTC rotation.
249:43:03 Scott (onboard): There must be a mag around somewhere. There must be two of them.
249:43:07 Worden (onboard): In the bag.
249:43:09 Scott (onboard): Okay.
249:43:11 Worden (onboard): Now, all we're missing is S, per his [garble].
249:45:32 Worden (onboard): Is that mag hooked up?
249:45:35 Scott (onboard): I don't know.
249:45:58 Worden (onboard): I've got - I've got two whole reels of color stereo.
249:48:50 Worden (onboard): Yes, that goes back up for [garble].
249:48:55 Scott (onboard): Why?
249:48:56 Worden (onboard): Why?
249:48:57 Scott (onboard): Why?
249:49:08 Scott (onboard): Let's see. Next is the [garble].
249:56:47 Parker: Apollo 15, Houston. While you're eating your supper there, I thought you might be interested in knowing how the vectors are going. Your vector and the ground's vector are extremely close, and - at least at the moment - we'll see what happens when we take the next P23. Right now we're looking at no midcourse 6 and about 1.8 foot per second for midcourse 7. [Long pause.]
249:57:22 Worden: Houston, 15. That sounds pretty good, and it looks like we'll see what happens on the P23s. One - You say 1.7 on midcourse 7 is what it looks like right now.
249:57:32 Parker: Roger; 1.8. The vectors, I guess right now, about 4,000 feet apart and about a couple of feet per second in velocity and no more.
Endeavour's computer has two spaces set aside in its memory to store two state vectors. On the way out from Earth, a copy of the LM's state vector was kept in one of these. Now on the return leg with the LM left behind on the Moon, this slot is used by Al to keep the state vector that he calculates using his own sightings and P23 in the computer. These state vectors are collections of seven values, six of which define the position and velocity of the spacecraft as expressed in three axes. The seventh value is the time at which the other values are current. A comparison of Al's vector with that calculated by the computers in Mission Control shows that the difference between them is indeed slight. Only 1.2 km separates them across the 400,000 km gulf between Earth and Moon, and less than 1 metre per second in the velocity of a craft moving at over 1,000 metres per second.
This is Apollo Control. We've still got about 5 or 10 minutes left in the crew eat period. They'll be finishing up their evening meal before completing the last activities, prior to their sleep period. That'll be a platform alignment, and some midcourse navigation. A little while ago, spacecraft communicator, Bob Parker, told the crew that it did not appear, at this time, that we would have to do a midcourse correction at the midcourse correction 6 opportunity, which is in about 22 hours; at 272 hours, 58 minutes. Possibly a small midcourse correction will be required just prior to entry at 291 hours, 58 minutes. However this would, at the present time, appear to be only about 1.8 feet per second [0.55 m/s] velocity change, which would be well within the capacity of the Reaction Control System thrusters. Probably would be a two-jet burn, using just two of the attitude control thrusters. One of the clocks in Mission Control at this time is counting toward splashdown; 44 hours, 35 minutes from now; and the Flight Dynamics Officer reports that the spacecraft appears, at this time, to be comfortably within the entry corridor, with an entry angle at Entry Interface of about, negative 6.69 or 6.7 degrees. The normal, or preferred is about 6.5, but 6.7 is considered within the entry corridor. Tomorrow at 11 am, there will be a briefing in the MSC News Center Briefing Room on the subsatellite and the X-ray experiment. That'll be at 11 am Houston time tomorrow. Apollo 15, at the present time is 155,500 nautical miles [287,986 km] from the Earth, and the spacecraft velocity is 3,382 feet per second [1,031 m/s].
250:37:40 Scott (onboard): What seems to be [grble]?
250:38:20 Worden (onboard): Hey, what do you [garble]?
250:38:25 Scott (onboard): Yes. Yes, [garble].
250:38:44 Scott (onboard): [Garble].
250:38:45 Worden (onboard): [Garble].
250:38:48 Scott (onboard): [Garble].
250:39:30 Worden (onboard): Yes, I guess the worst thing in the world would be to try to do something like that and not be able to do it.
250:39:35 Irwin (onboard): Oh, boy, [garble].
250:39:50 Worden (onboard): Tired?
250:39:52 Scott (onboard): Yes.
250:40:01 Worden (onboard): Well, I'll tell you, I'm sure glad we got rid of that clothesline operation [garble].
250:40:06 Irwin (onboard): [Garble].
250:40:16 Worden (onboard): In fact, it's really a ball, when you get all suited up, get cooled off, and get the hatch open.
250:40:24 Irwin (onboard): Sounds good. Sounds real good.
250:40:29 Scott (onboard): Oh, it's great.
250:40:32 Worden (onboard): The Sun would have been some better - It would have been better if it could have been a little bit higher. Because when I went down around the side of the mapping camera, it was pretty dark.
250:40:47 Scott (onboard): Yes.
250:41:06 Scott (onboard): Yes.
250:41:19 Worden (onboard): Boy, I hope the - I hope the TV came out all right.
250:41:23 Scott (onboard): Yes. [Garble].
250:41:25 Worden (onboard): Did you? Okay. [Garble].
250:43:17 Scott (onboard): Got them. Got them.
250:43:18 Worden (onboard): Okay.
250:43:19 Scott (onboard): Somehow they got way down in there...
250:43:20 Worden (onboard): Well, we didn't lose anything of value out the hatch. [Garble].
250:43:23 Scott (onboard): Everything's okay.
250:43:25 Worden (onboard): We lost a spring clip. We lost a paper clip...
250:45:04 Parker: Apollo 15, Houston. We can terminate battery Bravo charge now. [Pause.]
Battery B has been charging for the last 6 hours.
250:45:16 Worden: Houston, 15. Roger; will do. [Long pause.]
250:45:32 Parker: And 15, Houston. A reminder that when we exit PTC in about 15 minutes, we'd like to do it using the SIM bay RCS configuration. [Long pause.]
Al has to stop the PTC rotation to carry out his cislunar navigation sightings. When he does so, he will avoid using the thrusters that impinge on the SIM bay.
250:45:46 Irwin: Roger, Houston; understand.
Very long comm break.
Al now realigns the spacecraft's guidance platform to the PTC REFSMMAT. As usual, Mission Control can copy the gyro torquing angles from their telemetry mirror of the DSKY's displays.
250:57:43 Worden (onboard): Want me to write?
250:57:46 Scott (onboard): Where do you want this? In your [garble]?
250:59:24 Scott (onboard): Okay. Plus four balls 8, minus three balls 67, plus three balls 54.
250:59:34 Worden (onboard): Wait a minute; maybe that's 34.
251:01:22 Parker: And, 15, this is Houston. We have your torquing angles. That's some platform, isn't it?
251:01:31 Worden: Yes, sir, Bob. You bet you; it sure is beautiful.
Very long comm break.
Al continues his program of sightings designed to navigate him and crewmates home safely in case of a loss of communication with Earth. Once he has stopped the PTC, calibrated the optics and manoeuvred to the appropriate attitude, he begins with marks on Pollux, one of the twins of Gemini, followed by Earth's horizon nearest the star. The process is repeated twice using Aldebaran, in Taurus, and Capella, in Aurigae; each time measuring angles to Earth's horizon furthest from the star.
251:01:35 Scott (onboard): You say that sure has been planned for me?
251:01:41 Worden (onboard): Yes, [garble].
251:02:08 Scott (onboard): [Garble].
251:02:09 Worden (onboard): The platform gets us home without a midcourse, by golly.
251:02:16 Scott (onboard): No range error, but pressure's a little low.
251:02:18 Worden (onboard): Hey, Jim. While you're down there, we need a canister change. Twenty-one into B. Stow 19 in A-4.
251:03:51 Scott (onboard): Twenty-one. Yes. Twenty should be in A. Get it out of A-4.
251:04:21 Scott (onboard): No!
251:04:22 Worden (onboard): [Garble] catch it.
251:05:03 Scott (onboard): That a boy.
251:05:04 Worden (onboard): Lock her, Dave. You can [Garble].
251:05:07 Scott (onboard): [Garble].
251:05:09 Irwin (onboard): Yes, it is. I think we can [garble] I hate to use those pulleys.
251:05:16 Scott (onboard): [Garble].
251:05:20 Worden (onboard): Yes. If you use your own tool.
251:05:30 Irwin (onboard): [Garble].
251:05:34 Scott (onboard): Who stole my [garble]? [Cough.] Boy, [garble], didn't I?
251:17:37 Parker: Apollo 15, Houston. Over. [Pause.]
251:17:45 Worden: Houston, 15. Go.
251:17:46 Parker: Roger. Mister Lightning Fingers, we'd appreciate it if you'd keep your Noun 49 on for about 5 seconds on this P23, so we get a nice chance to look at it here on the ground. [Laughter.]
This is Apollo Control. Al Worden is presently using program 23 to update the spacecraft guidance system's knowledge of the trajectory. Taking sightings on stars and marking. This information is integrated into the computer memory and is used to update the state vector or the trajectory information contained. This is the last task that the crew has to perform prior to beginning their rest period, and just before deploying the Gamma-ray boom. During the sleep period they will be in the Passive Thermal Control mode with the Gamma-ray, Alpha Particle and Mass Spectrometers collecting data.
251:43:01 Parker: Super marks, Al. You can do my P23s any day. [Pause.]
251:43:09 Worden: They looking okay down there, Bob?
251:43:10 Parker: Rog. We caught all of them. Hey, when you go back into PTC now, we'd like to change Noun 79, the rate one anyway, to a minus .42. Over.
251:43:25 Worden: Going to try a little higher one, now? Okay, minus .42.
When Al first set up a PTC roll during the translunar coast, he had a couple of attempts at getting what was a new procedure to work smoothly. During the troubleshooting then, Mission Control asked him to enter a higher rate of rotation into the computer, up from 0.35°/sec to 0.38°/sec. Now, for reasons unknown at the time of writing, this is being raised once more to 0.42°/sec making the spacecraft rotate once every 14¼ minutes.
251:43:29 Parker: Roger. [Long pause.]
251:43:46 Parker: And, 15; Houston. If you've got a minute, we've got a couple more comments for you.
251:43:52 Worden: Okay. Anything I need to write down?
251:43:55 Parker: Negative. Number...
251:43:59 Worden: Okay. Go ahead.
251:44:00 Parker: ...number one, we'd like to know the film status of magazine Victor. And number two, if you're planning on being the loop tonight, Al, for the biomed, your harness needs some attention. The heart rate that we're getting down is getting a little noisy. Over. [Pause.]
251:44:23 Worden: Well, in the first place, my heart rate is always noisy; and, in the second place, I guess Jim's going to be on tonight.
251:44:29 Parker: Understand.
Comm break.
251:45:41 Worden: Houston, 15.
251:45:45 Parker: 15, Houston. Go.
251:45:48 Worden: Okay, Bob. Mag Victor is 12 frames expended.
251:57:26 Parker: 15, Houston. We suggest that you go ahead with your Gamma-ray deployment while you're doing your rate damping. [Pause.]
Having spent the last 2¾ hours operating while retracted, the Gamma-ray Spectrometer will be deployed at the full extent of its boom. In terms of Parker's comment, it may also be that having the boom extended makes it easier to stabilise the spacecraft's motions prior to PTC.
252:19:50 Scott: Hi, Bob; got a presleep checklist for you.
252:19:55 Parker: Shoot; we're ready. Dave, hold on. We got a...
252:19:59 Scott: Okay. [Long pause.]
252:20:16 Parker: Okay, 15, we're back with you. We just had a site changeover.
252:20:23 Scott: Okay. Crew status is all good, no medication. And I've got the onboard read-outs if you've got a pencil.
252:20:31 Parker: I've got a pencil.
252:20:34 Scott: All righty. Starting with Bat C, 37.0, 37.0, 37.0; RCS A is 56, B is 50, 48, and 52. And I guess everything else has been done, and I guess you got your E-memory dump. We pressurized the cabin with the OPS, and, when we got to about 5.7 or 5.8, the OPS was down to 800. And I reckon that's the size of it.
252:21:10 Parker: Roger, Dave. That sounds like the size of it to us. We copy all that, and there will be no vector update. Ground says your vector is just as good as theirs right now.
252:21:22 Scott: How about that? Oh, that's pretty good. We got a good navigator.
252:21:27 Parker: And, 15, let's hold a couple of minutes while we check some data on SIM bay and while we go around the MOCR one more time. And we'll be back with you in final status, I hope.
252:21:42 Scott: [Laughter.] Okay, we got - we got time. We're not quite ready to go to bed yet.
Long comm break.
252:22:04 Scott (onboard): [Laughter.] Bob says, if he - says, okay, let me go around to the MOCR and check it and come back with your final status, I hope.
252:22:24 Scott (onboard): But, you know, they got to old Joe, I can tell. Joe's changed. He's a changed man. They had him, boy.
252:22:32 Irwin (onboard): They did?
252:22:33 Scott (onboard): They were all over his ass during that EVA. He was just really humping. That poor fellow - I bet he's exhausted.
252:22:49 Scott (onboard): He probably had so damn many inputs, he didn't know which way to go.
252:23:04 Worden (onboard): [Garble].
252:23:08 Scott (onboard): Huh?
252:23:09 Worden (onboard): [Garble] apart.
252:23:14 Scott (onboard): Oh, he's pretty close to them. That - that group's all tied together pretty well. Yes. It was in pretty good shape. We got all those guys out on the field trips and sat down and talked to all of them, and that - that group's pretty well squared away.
252:23:28 Worden (onboard): [Garble].
252:23:32 Scott (onboard): No, they're in the back room. And the guy who really comes up to him is Jerry Griffith.
252:23:40 Worden (onboard): Oh, yes?
252:23:41 Scott (onboard): He's really the experiments officer. But...
252:23:45 Irwin (onboard): Who's Gerry Griffith?
252:23:46 Worden (onboard): Yes. [Laughter.]
252:23:47 Irwin (onboard): [Garble].
252:23:48 Worden (onboard): Yes.
252:23:50 Scott (onboard): And - But it really goes from Gordon Swann through Griffith to the Flight Director to Joe. And it's - it's a straight loop because Griffith and Griffin both understand the problem, so it - it isn't any big deal. Except that all the other people who aren't in the loop and don't understand were there - all the guys up in the back row with their input - with them.
252:24:12 Irwin (onboard): [Garble].
252:24:15 Scott (onboard): Gerry Griffin said he - one of his main problems was going to be holding the people off behind him - you know, to let Joe do his job, and I'm sure it was [garble] - especially when they can see it all on the TV. And they're clanked...
252:24:29 Irwin (onboard): They're all there?
252:24:30 Scott (onboard): Yes. They're all clanked up anyway. Then we go up on top of some big frigging mountain or stand right next to some big frigging valley, and, you know, they can't do anything about it; they're all bunched up like a nickel cigar.
252:24:40 Irwin (onboard): [Garble]. They [garble] and. [Garble].
252:25:15 Parker: Apollo 15, Houston, the only thing we show lacking at the moment is Gamma-ray Gain Step, Shield, On. Other than that, you're Go for sleep.
252:25:27 Scott: Okay, understand. Gain Step, Shield, On.
This is Apollo Control at 252 hours, 35 minutes. The crew is scheduled to be in their sleep period at this time. However, Dave Scott mentioned a few minutes ago that they still had a few things to complete before they tried to get some sleep. We'll keep the air to ground lines up live until it appears from the biomedical data that the crew is in fact beginning to drop off to sleep at which time we'll take the lines down, keep the recorders running to record for playback any conversations that should develop unexpectedly. Apollo 15, at the present time, is 151,632 nautical miles [280,822 km] from the Earth and the spacecraft velocity up now to 3,485 feet per second [1,062 m/s]. During the sleep period, as is normally the case, the spacecraft will be rotating at a slow rate to maintain proper temperatures. Tonight, that rate just a tad higher than it's been, rotating at the rate of about 4 revolutions per hour instead of the normal 3 to 3¾. And we understand this is being done because the booms supporting the Mass Spectrometer and Gamma-ray Spectrometer are deployed. The Lunar Module Pilot, Jim Irwin, will be wearing the biomedical harness during the sleep period tonight; we'll have heart and respiration rates on him which will be our indicator that the - that he is beginning to sleep and by inference that the crew is dropping off to sleep.
