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Apollo 15

Day 10: Orbital Science

Corrected Transcript and Commentary Copyright © 2000 by W. David Woods and Frank O'Brien. All rights reserved.
Last updated 2008-12-06

[This is the tenth day of the mission. Date: 4 August, 1971.]

[Although their primary mission is completed, the crew of Apollo 15 still has a long day of work ahead of them before they head home. Photography and running the SIM bay will occupy virtually all of their time for the next ten hours as they orbit the Moon in Endeavour. Following these tasks, all efforts will focus on preparations for Trans-Earth Injection (TEI) which will raise the spacecraft's velocity, slinging it out of lunar orbit and on a course towards the Earth.]

[Currently, the crew of Dave Scott, Jim Irwin and Al Worden have just begun their 8-hour rest period on time. As they orbit the Moon, Endeavour's SIM bay is kept facing the surface by having the spacecraft slowly rotate in synchronism with their orbital period, a so-called orb-rate rotation. They are flying backwards with the SPS engine bell facing the direction of travel. This orientation aims the rearward-facing inlet of the Mass Spectrometer into any oncoming molecules of the Moon's staggeringly tenuous atmosphere. Other experiments operating just now are the Alpha Particle Spectrometer, the X-ray Spectrometer and the Gamma-ray Spectrometer.]

Public Affairs Officer - "This is Apollo Control and we're now less than 30 seconds from regaining radio contact with Apollo 15, and we do not expect to hear from the crew for the remainder of their sleep period. It's a scheduled 8-hour rest period. And we said goodnight to them before we lost radio contact at the end of the last revolution. And we presume that they're either going to be asleep or close to it. We will have biomedical data on the Lunar Module Pilot, Jim Irwin and also on the Command Module Pilot, Al Worden. And INCO [Instrumentation and Communications Officer] says we have acquired the signal; we'll be waiting for the signal strength to come up so that we can see the data on all of the spacecraft systems and also the biomedical data. And we will expect from this point on through the remainder of the rest period that it will be rather quiet here in Mission Control."

Public Affairs Officer - "The Flight Surgeon has gotten his biomedical data and reports that, based on the heart rates he's seeing right now, it does not appear that the crew has gone to sleep yet. We'll continue to watch those through this frontside pass and the Surgeon will get a fairly good indication of when the crewmen are beginning to settle down and get to sleep."

Public Affairs Officer - "This is Apollo Control. We're getting quite a bit of noise on the air to ground circuit at this time. And since we do not anticipate any further conversations with the crew aboard the spacecraft during this sleep period, we'll take the air to ground line down and leave the recorders running to play any conversations that we should get should we hear from the crew. At 204 hours, 37 minutes, this is Apollo Control."

Public Affairs Officer - "This is Apollo Control at 205 hours, 44 minutes. Apollo 15 has gone around the corner of the Moon on it's 65th revolution: spacecraft in good shape. The Flight Surgeon reports the crew has been asleep, based on the biomedical data we're getting from Jim Irwin and Al Worden for about 30 minutes now. Prior to the beginning of the rest period the crew set up the Gamma-ray and X-ray/Alpha Particle experiments in the Scientific Instrument Module bay - also the Mass Spectrometer and while they're asleep these instruments will be gathering information in lunar orbit on the surface properties and atmospheric characteristics of the Moon. We'll be reacquiring Apollo 15 in about 43 minutes. Again, we do not expect any conversations with the astronauts during the sleep period - 8-hour rest period. We'll come up at Acquisition Of Signal [AOS] and again Loss Of Signal [LOS] for periodic status reports and in Mission Control the principal activity will be to monitor spacecraft systems and biomedical readings from the crewmen. At 205 hours, 46 minutes, this is Apollo Control."

Public Affairs Officer - "This is Apollo Control. We are about to reacquire the spacecraft now on its 66th revolution of the Moon. INCO says we have gotten radio contact now and we'll stand by to take a look at all of the spacecraft's systems, biomedical data on the crew and reassure ourselves that everything continues to be the same normal situation that it was when last we saw the spacecraft about 45 minutes earlier. The crew at this time is in the midst of a sleep period and we're not scheduled to awaken them for nearly 5 hours. Flight Director Glynn Lunney will be checking with his systems engineers to assure that everything is normal. Guidance and Control Officer reports everything looks good and EECOM [Electrical and Environmental Officer] says everything is Go from his point of view. The cabin pressure at this time is 5.2 pounds per square inch which is normal and the temperature about 73 degrees [Fahrenheit]. Surgeon says, based on heart rates he is seeing, it appears that the crew is still asleep at this time. We'll continue to monitor the systems on telemetry data and provide status report periodically at Acquisition Of Signal and again just before we lose radio contact. At 206 hours, 32 minutes, this is Apollo Control, Houston."

Public Affairs Officer - "This is Apollo Control at 207 hours, 12 minutes. The mission continuing to progress smoothly this evening. We have about 4 hours, 13 minutes remaining in the crew sleep period. And, in Mission Control, we are in the midst of a shift handover. Flight Director Milton Windler coming on to relieve Flight Director Glynn Lunney. ... We have about 30 minutes remaining in this pass before we once again lose radio contact with Endeavour. And we plan to provide status reports at Acquisition Of Signal and Loss Of Signal. In between times though, we will have the lines down with the tape recorders running to pick up any conversation, should we hear anything from the crew. The Spacecraft Communicator on the coming shift will be astronaut Karl Henize relieving astronaut Bob Parker in that role. At 207 hours, 14 minutes, this is Apollo Control, Houston."

Public Affairs Officer - "This is Apollo Control; 209 hours, 42 minutes Ground Elapsed Time. 1 hour, 43 minutes remaining in the Apollo 15 crew sleep period. A little over a minute ago, Apollo 15 spacecraft, Endeavour, went behind the Moon during the end of the 67th lunar revolution. All well aboard the spacecraft - all systems are percolating normally. Apollo 15 in an orbit measuring 52 nautical miles [96.3 kilometres] at pericynthion and 66.6 [123.3 km] apocynthion. Current height is, or at LOS was 52.2 [96.7 km]. The velocity; 5,387 feet per second [1,642 metres/second]. During this last front-side pass the cabin pressure was holding steady 5.2 pounds per square inch [35.9 kiloPascals] and a temperature of 72 degrees [Fahrenheit, 22°C]. At about 4:15 Houston time, the lunar surface television camera on the Rover vehicle, just east of what is left of the Lunar Module Falcon descent stage will be powered up for about 15 minutes look around in the landing site area; camera will be zoomed and panned only, but no tilt commands will be given. It will pan the local horizon and also zoom in on some local features such as craters and outcroppings for geology investigators. And at 209 hours, 45 minutes Ground Elapsed Time, this is Apollo Control."

[Flight Plan pages 3-316, 3-317, 3-318, 3-319, 3-320, 3-321, 3-322 and the current page, 3-323.]

[The Apollo 15 Index of 70-mm Photography lists a sequence of photographs as having been taken anytime between revolutions 64 and 72, the photo analysts having been unable to tie the exposures down more accurately. This seems as good a time as any to discuss the images taken.]

[As seen from Earth, the Moon is very near full and as a consequence, there are only about 5 minutes between Endeavour passing the terminator and AOS. Only limited photography can be achieved on the far side, so with magazine TT and the slightly wide-angle 60-mm lens, three images are taken during this short interval. AS15-88-11985 looks towards the north and the Sun is shining from the west. Bottom right is an unnamed crater which obliterates the north rim of Alden which will be shown better in the next frame. Beyond it is the larger ring of Hilbert and on the far right is Kondratyuk, identified by two large craters within its walls. Beyond, and nearly at the horizon, is Meitner. The camera is tipped down to show Alden, a highly degraded and obscured ring. At 168:06:09, Karl Henize asked Al to get an image of this crater. AS15-88-11986 would appear to be Karl's requested shot. Looking slightly north of west, AS15-88-11987 shows the 130-km Sklodowska. Just as the Moon appears nearly full from Earth, so the home planet reciprocates by displaying a striking crescent to the crew. AS15-88-11988 and 11989 show an Earthrise which is very different to those images which have been heavily publicised before in that few ever reveal Earth in this repose. Cut off in the foreground is Schorr, 53 km in diameter with Gibbs A directly adjoining it. Beyond Schorr is the 77-km Gibbs.]

[Under an overhead Sun, Plinius is the washed out circle in the centre of AS15-88-11990. Mare Tranquillitatis is in the foreground and the southwestern shore of Mare Serenitatis lies beyond. AS15-88-11991 is taken from approximately the same position but looks northeast instead of northwest. The 30-km Vitruvius is to the right and in the foreground is Jansen D (at the edge of frame) and Jansen C, a 8.4-km simple crater now named Beketov after a Russian chemist, 1827-1911. Notice the irregularly shaped, vaguely looping dark area near the centre of the picture. In the foreground just in front of it is Mons Argaeus, a 50-km range of hills. A dark spur to its right is the Taurus/Littrow valley, destined to become the Apollo 17 landing site. Excluding AS15-88-11994, which has no image, the next four frames (AS15-88-11992 to 11996) are all washed-out pictures of Aristarchus and Herodotus. AS15-88-11997 to 11999 are further images of Earthrise which are somewhat afflicted by sunlight scattering in the window and lens. AS15-88-11999 is the best of these. Curie's western rim is in the foreground, the Schorr/Gibbs-A pair are at the extreme right and Gibbs lies beyond.]

[AS15-88-12000 and AS15-88-12001 is of the Sulpicius Gallus region and the southwest rim of the Serenitatis basin though the high Sun elevation makes the boundary between the mare and the Montes Haemus mountain chain that forms the rim is difficult to see. The final five images of this sequence all return to the western mare. Aristarchus and Herodotus are well shown in AS15-88-12002 including the Cobra's Head, the source of Vallis Schröteri, but a finer reproduction from Kipp Teague's Project Apollo Archive is AS15-88-12005 which, although showing some of the reflections which are difficult to avoid when shooting down-Sun, is a spectacular image nonetheless. AS15-88-12003 shows the 24-km Schiaparelli and, right at the terminator, the 43-km Seleucus - both surrounded by the expanse of Oceanus Procellarum.]

Public Affairs Officer - "This is Apollo Control; 211 hours, 16 minutes Ground Elapsed Time. The communications officer Ed Fendell here in the Control Center has just - either has or is preparing to send a turn-on command to the color TV camera left at Hadley Base. And we're some 9 minutes away from the wake-up call to the crew of Apollo 15 still in lunar orbit around the Moon. Where else would you have lunar orbit? Still waiting for the first glimpse of the color picture. Starting to get a signal in now. And the camera is alive and well at Hadley Base, swinging around to get a view of the descent stage of Falcon. There's the ALSEP station looking somewhat like Boot Hill from a distance. And there sits the lower half of the great bird Falcon. Fendell is panning the horizon from one stop to the other which is something like 340 degrees around. The geologists are interested in seeing the terrain over an increased sun angle - with an increased sun angle since the last look. Also, the camera will be zoomed in on the individual features in the landing site. However, the camera will not be tilted at this time. Looking backwards from the front of the Rover to the Rover control console. It should be about the maximum amount the camera will pan in that direction before it hits the stop. The camera temperature has reached it's upper limits of design specifications toward the end of EVA-3, but it is hoped that the way the camera was stowed, the final position it was left in that the shadow of the camera itself and the fact that it was powered down would cool the drive mechanism and perhaps alleviate the slipping clutch problem encountered during EVA-3 in which the camera several times tilted straight up. Beginning wide angle panorama to the right, stopping briefly to allow color Polaroid photos to be made from a TV monitor which later will be taped together to form a photo mosaic continuous panorama, almost a full circle. Okay. Do it now."

Public Affairs Officer - "The spacecraft communicator is preparing at this time to make a call to the crew. Punching up his air/ground button on the console."

Real Video file (2,635K)

211:24:15 Henize: Apollo 15. [No answer.]

211:25:05 Henize: Apollo 15, this is Houston. Good morning. Apollo 15, this is Houston with a message from Richard Strauss, Arthur C. Clarke and Stanley Kubrick.

211:25:17 Music - ("Also Sprach Zarathustra", Theme from "2001: A Space Odyssey")

211:26:58 Henize: Good morning, fellows. We have only about 10 minutes of comm left and we'd like to start out the morning with an Accept so we can send you up a state vector. Are you up there? [No answer.]

211:27:23 Henize: And after giving us Accept we'd like to have you manually roll clockwise 40 degrees. And then we'd like to get the sharp end forward. I'll give you the P20 when you're ready to copy. [Long pause.]

[Karl Henize is reminding the crew, who have just awaken, of two items in the Flight Plan that occur soon after wakeup. First, they need to obtain the latest state vector that has been determined by the ground controllers. This can only be uplinked while the spacecraft is in contact with the Earth, and there only a few minutes left before the Endeavour sails around the back side of the Moon. The request for rolling 40° is part of the maneuver to position the spacecraft for SIM bay observations with the CSM pointing forward instead of backwards. It makes the spacecraft avoid those attitudes that might cause gimbal lock while it maneuvers.]
Public Affairs Officer - "[Lunar Rover] camera now aimed at Mount Hadley. Close up of some of the..."

Real Video file (561K)

211:28:15 Worden: Hello, Houston, 15.

211:28:18 Henize: Good morning, Al. How are you doing?

211:28:24 Worden: Good morning, Karl. I'm doing just fine.

211:28:27 Henize: Righto. If you didn't hear what I said before, I'd like to repeat that we'd like to have Accept, and we'll send you up a state vector. And then we need to manually roll clockwise...

211:28:38 Worden: Roger. You've got Accept.

211:28:40 Henize: ...Righto. Then we need to manually roll clockwise 40 degrees, and I have here P20 data for you to get the sharp end forward.

211:28:57 Worden: Okay; we're rolling, and stand by one until I get a pen.

211:29:09 Worden: Okay, go ahead with the P20.

211:29:11 Henize: Roger; P20, option 5; plus-X forward, SIM attitude. The time is 211 plus 40. Verb 23, Noun 78, plus 180.00. The attitude is 141, 000/177, 000.

[The computer uses P20 and the values entered into it to keep a particular side of the spacecraft pointing, in this case, at the centre of the Moon. Option 5 also includes an entry which defines the spacecraft's orientation about the theoretical line between the two bodies. When used for pointing the SIM bay, this latter value can define whether the spacecraft flies blunt-end-forward or, as in this case, sharp-end-forward (CM apex first).]
211:29:51 Worden: Roger, Karl. Understand. You want that P20 turnaround done at 211 plus 40, instead of 212:00.

211:30:15 Henize: Al, we'd like to have you start the maneuver as soon as we finish the uplink, and that time is the time we should be completing the maneuver.

[This implies that science teams have been watching the results from the Mass Spectrometer and would like to gain more time in the sharp-end-forward attitude. Then the inlet to the instrument will aim away from the direction of travel and it is believed that any data in this mode will be due to outgassing from the spacecraft, not from the indigenous lunar atmosphere.]
211:30:26 Worden: Okay. Fine, Karl. I'll just move that whole thing up. We're doing the roll maneuver now.

211:30:32 Henize: Roger. And while you've got the Flight Plan there, the only update that concerns us for the next hour and a half - is to - Over there at 21:54 [means 211:54], delete Manual - "Manually roll clockwise". You got that one?

211:30:56 Worden: Yes. Roger.

211:30:57 Henize: And everything after that, all the way down to 212 plus 20. And then we'll be in contact with you again for further updates.

211:31:14 Worden: Okay. Understand. That block between 21:54 - or 211 plus 54 and 212 plus 20, that - that all goes as - as scheduled.

211:31:30 Henize: Entire thing deleted. Roger.

[The steps that are being deleted are the procedures for starting a Mapping Camera pass. Flight Plan updates are necessary to manage spacecraft systems, or where from real-time analysis, new targets of opportunity are revealed. In this case, the update relates to problems with the Laser Altimeter. This instrument was to be used primarily in conjunction with the Mapping Camera where it would provide accurate altitude data for each frame by having the value optically encoded on the edge of the image. During night-side passes, the Mapping Camera would continue to operate so that even though no optical image was being produced by the Metric section of the instrument, the altitude information and the associated imagery from the Stellar Camera would still be gathered.]

[After a useful period of operation, the Laser Altimeter began to fail and is now considered a lost cause. While daylight use of the Mapping Camera still provides useful imagery from the Metric Camera, the defunct Laser Altimeter makes night-time operation a pointless exercise.]

211:31:40 Worden: Roger. Then we'll be in P20 attitude and standing by for your word when we get contact again then.

211:31:57 Henize: Okay, Al. The computer's yours.

211:32:05 Worden: Roger. Understand. [Pause.]

211:32:16 Henize: Al, would you do a Verb 66 for us?

[Verb 66 copies the CSM's state vector from its location in the computer to a second location normally used to store the LM's state vector. Normally, this is done when the CSM and LM are docked, to give the CSM's computer an initial idea of the LM's location. The reason why it is being done here isn't immediately obvious, but it seems to be a way to save the newly refreshed copy of the uplinked state vector.]
211:32:25 Worden: Roger. You got it.
[Comm break.]
211:34:49 Henize: Al, we need the - the TLM [Telemetry] switch in Block, please.
[In the rush of attending to chores before losing contact with Houston, Al has inadvertently left the computer uplink switch in Accept. This effectively prevents any other use of the computer.]
211:34:58 Worden: Roger, Karl. [Long pause.]

211:35:34 Henize: 15, if you'd like a quick consumables update, I can give it to you now or I can wait until the next rev.

211:35:48 Worden: Go ahead, Karl. If there's time, I'll copy it now.

211:35:52 Henize: Roger. The time is 211 plus 00; RCS [Reaction Control System] total 46; Quads: Alpha, 48; Baker, 45; Charlie, 44; Delta, 46; hydrogen tanks: 49, 47, 39; oxygen tanks: 61, 64, 48.

211:36:33 Henize: 15, this is Houston. Are you still reading?

[Very long comm break.]
Public Affairs Officer - "And the good ship Endeavour has gone behind the Moon for the 68th time. Wake-up call by spacecraft communicator Karl Henize, was followed by a brief passage from the music used in the motion picture - science fiction motion picture '2001', which in turn had been borrowed from the tone poem by Richard Strauss, 'Also Sprach Zarathustra.' It'll be another 47 minutes approximately before Acquisition Of Signal, with Apollo 15 coming around on the 69th revolution. And at 211 hours, 41 minutes Ground Elapsed Time, this is Apollo Control."
[During this far-side pass, the Mass Spectrometer experiment was to be turned off and its boom retracted. This task was deleted during the update immediately before LOS to give more data collection time in their current attitude. Indeed, this period of LOS is much quieter than originally planned because of the many deletions. The platform is to be realigned at 211:45 using Falcon's lift-off orientation as its primary reference. Aligning the platform is not only essential for navigation, but the accurate attitude information that results is critical for locating surface features photographed by the Panoramic Camera. The two-part Mapping Camera has its own independent attitude reference whereby the Stellar Camera images a starfield at 96° to the axis of the Metric Camera's optics.]

[Flight Plan page 3-324.]

[Just before the spacecraft comes around the corner and reestablishes contact with Houston, and an hour after waking up, the crew begins making breakfast.]

211:49:57 Irwin (onboard): Trade you for your cocoa.

211:50:17 Scott (onboard): 35, 45.

211:51:23 Scott (onboard): Okay. Okay?

211:51:33 Scott (onboard): ... Right? ... 3.

211:51:51 Irwin (onboard): Here you go, Al. There. Okay. Good.

211:52:23 Irwin (onboard): Here's your bag, Al. Give me your juice, then, Al. I'll take the juice.

211:52:58 Scott (onboard): I think I'll ... Okay. ... eggs ...

211:53:20 Irwin (onboard): We have sausage and eggs. How about sausage this morning.

211:53:24 Scott (onboard): ...

211:53:25 Irwin (onboard): Sausage this morning.

211:53:27 Scott (onboard): Scrambled eggs and sausage? That'd be good.

211:53:29 Irwin (onboard): That'd be good. Yes.

211:53:48 Scott (onboard): ...

211:54:14 Irwin (onboard): Our favorite compartment.

211:54:43 Scott (onboard): ... sleep, Jim?

211:54:45 Irwin (onboard): Pretty good. I just woke up once.

211:55:54 SC (onboard) (Humming)

211:56:18 Scott (onboard): ... down there ....

211:57:03 Irwin (onboard): Want me to try to put that separator on the - dispenser down here, Dave?

211:57:09 Scott (onboard): Well, we haven't got any ...

211:57:21 Irwin (onboard): That's probably why we're farting so much.

211:57:23 Scott (onboard): What'd you say?

211:57:24 Irwin (onboard): Probably why we're farting so much up here.

211:57:27 Scott (onboard): Yes, I didn't put...

211:57:28 Irwin (onboard): All smells like hydrogen, really.

211:57:30 Scott (onboard): ...

211:57:31 Irwin (onboard): Check it here.

211:57:32 Scott (onboard): ... What's that number.

211:58:58 Irwin (onboard): Okay, Dave. Here's that other cocoa.

211:59:10 Scott (onboard): ...

211:59:12 Irwin (onboard): Too late now. Don't be an Indian giver.

212:01:08 Irwin (onboard): If you have something there to go in the hot water, Dave, I'll stick them on for you.

212:01:15 Scott (onboard): Yes, I got ...

212:01:26 Irwin (onboard): What do you want, Dave?

212:01:28 Scott (onboard): Oh, that's all right. What do you have?

212:01:32 Irwin (onboard): Okay, I'll see what I can dig up out here.

212:01:34 Scott (onboard): ...

212:01:35 Irwin (onboard): No...

212:01:36 Scott (onboard): ...

212:01:38 Irwin (onboard): Be easier since I'm here.

212:02:32 Irwin (onboard): Can you bring this back a little, Al? Will that go back?

212:02:50 Irwin (onboard): Yes.

212:03:40 Irwin (onboard): Anybody want any fruit? Lot of apricots and peaches.

212:04:02 Scott (onboard): ..., Jim?

212:04:03 Irwin (onboard): Yes.

212:04:38 Irwin (onboard): How about some bacon squares?

212:05:02 Scott (onboard): ...?

212:05:05 Irwin (onboard): Coffee.

212:05:21 Irwin (onboard): Yes. Stick it on there. Did you tighten down on it?

212:05:31 Scott (onboard): ...

212:05:36 Irwin (onboard): Is it tightened down?

212:05:37 Scott (onboard): Turn around,

212:06:20 Scott (onboard): ...

212:07:59 Scott (onboard): ... Jim ...

212:08:10 Scott (onboard): Very simple.

212:09:11 Irwin (onboard): Ready? You really have to push it on there.

212:09:14 Scott (onboard): ...

212:09:15 Irwin (onboard): Is it up all the way? Yes - you - you have to push pretty hard to get it on there.

212:09:27 Scott (onboard): Think it ...

212:09:30 Worden (onboard): I don't know ...

212:10:42 Scott (onboard): I don't know. Something coming out of there?

212:10:47 Irwin (onboard): Yes, it's coming out there, but - looks like there's a lot of water collecting at the end of the separator. No, I just - it's got a pool there at the end.

212:10:58 Scott (onboard): ...

212:11:12 Irwin (onboard): In fact, it looks like it's leaking. It is leaking. It's leaking, Dave.

212:11:23 Scott (onboard): I guess it's just ... water ...

212:12:43 Scott (onboard): ...

212:12:50 Irwin (onboard): Went to bed at 9, Got up at 2.

212:12:55 Scott (onboard): Got up at 4!

212:13:03 Irwin (onboard): Seven hours.

212:14:14 Scott (onboard): ...

212:14:54 Scott (onboard): What?

212:16:54 Scott (onboard): ...

212:17:02 Irwin (onboard): When are we going to listen to music? Were you listening to - your recor - the recorder last night, Dave?

212:17:12 Scott (onboard): Say what?

212:17:13 Irwin (onboard): Were you listening to your recorder last night?

212:17:15 Scott (onboard): ...

212:17:17 Irwin (onboard): Did - didn't you have some music on last night? I'd swear I heard music just before I went to sleep.

212:17:24 Scott (onboard): ...

212:17:26 Irwin (onboard): Put me to sleep anyway.

212:17:32 Scott (onboard): ...

212:17:34 Irwin (onboard): (Laughter)

212:17:45 Scott (onboard): ...

212:19:25 Scott (onboard): ...

212:20:48 Irwin (onboard): Want me to put some hot water in those eggs, Dave?

212:21:13 Scott (onboard): ...

212:21:15 Irwin (onboard): About ready to go again.

212:21:31 Scott (onboard): ...

212:21:32 Irwin (onboard): Yes.

212:22:21 Scott (onboard): ...

212:22:23 Irwin (onboard): Yes.

212:22:24 Scott (onboard): ...

212:22:26 Irwin (onboard): Yes.

212:22:27 Scott (onboard): ...

212:22:40 Irwin (onboard): Okay.

Public Affairs Officer - "This is Apollo Control at 212 hours, 21 minutes Ground Elapsed Time. The color television camera left at Hadley Base by Apollo 15 crewmen Dave Scott and Jim Irwin was found to be alive and well this morning when it was commanded to wake up. The camera made a slow panorama for the benefit of lunar geologists who wanted to view the features around Hadley Base at a higher sun angle. Only zoom and pan commands were sent to the camera for it was feared that the tilt clutch might again slip and cause the camera to topple belly up on its mount as it did several times during Scott and Irwin's third Moon walk. There would be no one out there to right the camera if it tilted straight up again. Signals from the camera stopped suddenly when the downlink was hopefully lost temporarily. We're less than 2 minutes away from Acquisition Of Signal with Apollo 15 on the 69th revolution. We'll leave the air/ground up and catch the first words as the crew of Apollo 15 begin their day's work."

212:22:57 Irwin (onboard): Want some more?

212:22:58 Scott (onboard): Yes. Sure. ...

212:28:05 Henize: Apollo 15, this is Houston. How do you read?

212:28:14 Scott: Hi, Houston; 15. Loud and clear. How us?

212:28:17 Henize: Hi, Dave. You're coming through loud and clear. How did our consumables update get to you. Okay?

212:28:25 Scott (onboard): Yes, we got normal ...

212:28:30 Scott: Okay. We got everything but the oxygen.

212:28:35 Henize: Okay. Want me to read those three up?

212:28:46 Scott: Okay. Go ahead.

212:28:51 Henize: Roger. Oxygen tanks at that same time that I gave you originally were 61, 64, 48.

212:29:12 Scott: Okay. 61, 64 and 48. And I have a P52 for you and a crew status report.

212:29:20 Henize: Fire away with them.

212:29:26 Scott: Okay. The P52: Noun 05 was .01, Noun 93 was plus .029, minus .025, plus .018. [The platform] was torqued out at 211:52:00.

212:29:48 Henize: Roger.

[This alignment of the platform was done quite accurately. The true angular difference between the stars, whose positions are well defined, and as measured by the sextant sightings performed by the crew, give two values. Only 000.01° (as displayed by Noun 05) separated these two values. A low value is a source of pride, as it indicates that the sightings were done particularly well.]
212:29:55 Scott: And if you still have your pencil handy, why, the sleep came out to 7, 7¾, and 7. And the PRD's: 25026, 23182 and 08033. And go ahead with your updates.
[Flight Plan updates are a important part of the housekeeping for each revolution.]

[From the 1971 Mission Report - "After rendezvous and with all three crewmen aboard the Command and Service Modules, the Flight Plan was updated to utilize the full capability of the Scientific Instrument Module bay. The Flight Plan changes were considerable, but with one crewman free to copy the updates, the other two crewmen were available to monitor and perform the Scientific Instrument Module activities. This meant that all three crewmen were utilized a good percentage of the time. The operation was performed satisfactorily and the real-time changing of the Flight Plan was accomplished without difficulty. The philosophy, that there would be no changes in the Flight Plan during solo operations, and that the Flight Plan would be subject to real-time change when all three crewmen were aboard, was satisfactory."]

212:30:18 Henize: Roger. Okay. [I have] Flight Plan updates for the coming rev and - There's several of them here. And just to keep you feeling a little bit more optimistic, on the following revs, there are very few updates. Okay. At 212:40, we want to delete "Map Camera Image Motion, Increase." At 2...

212:30:57 Scott: Roger. Got the deletion at 212:40. Go.

212:30:59 Henize: Roger. At 213 plus 24, we want to delete the "Gamma-ray Boom Deploy", and at that - there are 3...

212:31:11 Scott: 213:24 [I] have the deletion. [Onboard transcript has "Marking Deploy."]

212:31:15 Henize: Roger. And just below that, the "MSFN verify lens tuck in" and also the "Pan Camera, Power, Off", delete both of those.

212:31:27 Scott: Roger. Copy the next two deletions also. Go.

212:31:30 Henize: At 214 plus 02, we want to change that camera configuration to 250-millimeter lens, 250. The f-stop should be 5.6; the exposure time should be 1 over 125.

212:32:00 Scott: Roger. 214:02. Camera configuration: 250-millimeter lens, f/5.6 at 1/125. Go.

[Originally, they were to use a 80-mm lens on Hasselblad, but the crew is to substitute a 250-mm telephoto instead. This change affects terminator photography at 124:02, where the science team wishes to get a closer look at the terrain. The change in lens type also affects the f-stop as the telephoto cannot achieve as wide an aperture as the standard lens. To compensate, the exposure time must be increased.]
212:32:08 Henize: Correct. At 214 plus 06, add "Mass Spectrometer, Ion Source, Off. Experiment, Standby". And at the same time, add "Logic Power to Deploy/Retract".

212:32:42 Scott: Roger. At 214:06, "Mass Spec. Ion, Off. Experiment, Standby. Logic Power to Deploy/Retract". Go.

212:32:49 Henize: Roger. At 214 plus 11, "If Ion source, Off, 5 minutes, Mass Spectrometer Boom, Retract." [Pause.]

212:33:13 Henize: 15, we'd like High Gain [Antenna], Auto.

212:33:17 Scott: Okay. At 214:11, "If Ion, Off for 5 minutes, Mass Spec. Boom, Retract." Go.

212:33:26 Henize: At 214 plus 12, we add "Mapping Camera/Laser Experiment Covers, Open; Mapping Camera Track, Extend; Mapping Camera Image Motion, On."

212:34:00 Scott: Okay. 214:12. "Map/Laser Experiment, Open; Map Track, Extend," and "Image Motion, On."

212:34:09 Henize: Roger. At 214 plus 16, we change the "EL on to T-stop minus 1:40" to "T-start 1:40." Simply change stop to start.

212:34:29 Scott: Roger. Stop to start. Go.

212:34:31 Henize: And at 214 plus 17, again change stop to start. And at that time also, add "Laser Altimeter, On."

212:34:53 Scott: Okay. 214:17, stop to start and "Laser Altimeter, On." Go.

212:34:58 Henize: And at 214 plus 18, change "Mapping Camera On, Off" to "Mapping Camera On, On". In another words, change Off to On. Add parenthesis T-start. Delete the next line, "Mapping Camera," - delete "Mapping Camera On, to Standby". And the third line, change "Mapping Camera, Image Motion, Off", to "Mapping Camera, Image Motion, Increase; barber pole plus four steps/On."

212:35:42 Scott: Okay. 214:18. "Map Camera, Image Motion, Increase; barber pole plus four steps/On."

212:35:57 Henize: Roger. And did you get the "Mapping Camera" - "Mapping Camera, On" on T-start?

212:36:09 Scott: Oh, Roger. "Map Camera, On", on T-start, and scratch the "Map Camera, On, to Standby".

212:36:14 Henize: Roger. That takes care of all the - all the updates required for the next rev.

212:36:24 Scott: Roger. Understand. Thank you.

[Comm break.]

[The changes to the Flight Plan are, in part, a continuing adjustment to the changes in Mapping Camera operation in light of the failing Laser Altimeter. Instead of being turned off, the camera is now to be turned on at 214:18:00, this being the start of a daylight pass. Terminator photos scheduled be taken starting at 214:13 were to coincide with the last few pictures in the original Mapping Camera pass. As the Mapping Camera is now scheduled to be started immediately after the terminator passed below, the back room wants detailed pictures of the terminator areas with a telephoto lens.]

212:39:26 Henize: 15, this is Houston. A couple of comments, and then a - one change in your G&C checklist. The comments are as follows. As you will note from the consumables update, we now have single-tank capability at the 40-amp level.
[The call of "single tank capability" refers to an electrical power contingency mode. If troubles should occur that leave the spacecraft with only a single hydrogen tank and oxygen tank, the spacecraft can make it home if they power down to a 40-amp level. At a nominal 28 volts, this translates to a mere 1.1 kilowatts; about the same amount of power used for a stylist's hair dryer. Although this is a small fraction of the 4.3 kilowatts the fuel cells can generate, it provides for far more systems (and options) than the Apollo 13 crew had.]
Henize (continued): And, concerning the Mass Spectrometer boom problem, it appears to us that this is temperature-associated problem. And the next time you retract the Mass Spectrometer boom, we suggest that you retract it only once for 4 minutes. And if it [the talkback] hasn't gone gray, just leave it there. There is no need to go in and out until it turns gray. That won't be a critical problem until we come closer to a burn.

212:40:15 Scott: Okay. I understand. Just retract it for 4 minutes and leave it there. Okay?

212:40:20 Henize: That's right. And has somebody got a G&C checklist there on page 9-4?

212:40:32 Scott: Okay. Stand by. We'll pull it out. [Long pause.]

[Endeavour's time in lunar orbit is drawing to a close and there is no point in bring unexposed film back to Earth so an intensive period of unplanned Hasselblad photography across the near side of the Moon begins with a sequence taken over Mare Fecunditatis in support of Luna 16, a Soviet probe which soft-landed and returned a core sample to Earth just ten months before Apollo 15. These are taken using magazine O and a medium telephoto lens and AS15-97-13213 to 13216 have been combined into a single image, as have AS15-97-13218, 219, 221, 223 and 225. The probe itself sits somewhere within this latter image. The sequence continues until AS15-97-13229. This photography was held over from yesterday at 200:50 during rev 63.]
212:41:07 Scott: All right. I've got page 9-4. Go ahead.

212:41:10 Henize: All right. We'd like to correct one of the short burn constants, and it's in column D, row 5. The number should be changed from 1 - 01605 - it should be changed to 01614.

[Short burn constants are used, not surprisingly, for very short burns of the spacecraft's main engine, the Service Propulsion System or SPS. All engines have reasonably well defined startup and tailoff thrust characteristics that may last from milliseconds to several tenths of a second, as engines take a few moments to come up to full thrust, and thrust does not fall to zero at the moment the engine valves close at shutdown. In very short burns lasting less than a few seconds, the transitions from zero to full thrust, and from full thrust to zero, become a non-trivial part of the total impulse of the engine. The computer uses these constants when calculating the total time for the burn.]

[Accurately monitoring the progress of the burn is also a problem when its duration is very short. Although the computer updates the change in velocity every 1/10 of a second, and updates the entire state vector every two seconds, this is not sufficient to accurately determine the precise start and stop times of the engine. When a short burn constant is used in these calculations, an accurate burn is achieved, and very little manual trim is required from the crew.]

[Because of the problems with the intermittent short in the circuitry controlling the SPS's Bank A valves, all the short burns in lunar orbit will be performed using a single bank of valves. While this does not significantly affect the performance of the engine when it fires for several seconds, the startup and shutdown characteristics change quite a bit. Engineers from Aerojet General, the manufacturer of the engine, have calculated the new engine characteristics based on its operation seen so far in the flight, both in dual-bank and single-bank operation. This information has allowed them to recalculate the short burn constants, which will be used for the rest of the mission.]

212:41:36 Scott: Say again the location.

212:41:39 Henize: It's column Delta, row 5.

212:41:52 Scott: Okay. I've got it now. I'm sorry. I thought you said B, Bravo. How about reading that number again, please.

212:41:59 Henize: Roger. The correct number is 01614.

212:42:13 Scott: Okay. 01614 by 01605.

212:42:18 Henize: That's correct. [Long pause.]

212:42:33 Henize: And whenever somebody tells me he's ready to stop breakfast and copy a PAD, I have TEI-71 and also a Mapping Camera photo PAD.

212:42:48 Scott: All right. Stand by one, please. Probably be a couple of minutes.

212:42:52 Henize: Righto.

[Comm break.]

[Photography continues on magazine QQ with black and white film and the 500-mm telephoto lens. The first in this sequence is AS15-81-10987, an unremarkable patch of Mare Fecunditatis dominated by an unnamed elongate crater. The following six images take alternate shots of two of the most extraordinary elongate craters on the Moon, the Messier twins. Good images from this set include AS15-81-10991 of Messier A, actually a double crater. In this image, the full extent of the crater's shape is not obvious as the depression of the second bowl is very indistinct towards the top of the image and is of a similar dark tone to the surrounding mare. Messier itself is superbly captured in an excellent reproduction donated to the Journal by Michael Light from his collection published in the 1999 book, Full Moon. This frame, number 33 in his collection shows the beautiful elliptical form of Messier, believed to have been carved out by a very oblique impact. These two close-up photos do not show the striking comet-like jets splayed westwards across Mare Fecunditatis from the crater pair.]

[At around the same time, a photo is taken with the medium wide-angle (60-mm) lens looking northwest towards Mare Tranquillitatis. In the foreground of AS15-90-12293 is a small mountain range, Montes Secchi, and the crater after which the range is named. Pietro Angelo Secchi, 1818-1878, was an Italian astronomer who pioneered the use of spectroscopy to analyse the chemical makeup of stars. In this picture, the very high Sun elevation makes the crater virtually invisible. The dark bay at the top of the photo is Sinus Concordiae which leads off the northeast edge of Mare Tranquillitatis.]

212:44:04 Irwin: Okay, Karl. I'm ready to copy the TEI PAD.

212:44:11 Henize: Roger, Jim. Good morning. TEI-71, SPS/G&N. The weight is not applicable. P trim: Noun 48 is plus 0.64, plus 0.98; 217:49:18.04; plus 2838.6, minus 0581.0, minus 0027.7; 178, 129, 351; the rest is N/A. Four jet ullage for 12 seconds. And that's all.

212:45:16 Irwin: Okay. TEI-71 readback. SPS/G&N. Weight is N/A; plus 0.64, plus 0.98; 217:49:18.04; plus 2838.6, minus 0581.0, minus 0027.7; 178, 129, 351; four jets for 12 seconds. Over.

[An interpretation of the PAD follows:

Purpose: This is the next-to-the last in the series of abort PAD that are sent to the crew in the event of communications breakdown or problems with the spacecraft.

System: The maneuver would use the Service Propulsion System, the main engine with 22,500 pounds of thrust, under the control of the primary Guidance and Navigation system.

CSM Weight (Noun 47): is not applicable as the current weight is assumed.

Pitch and yaw trim (Noun 48): +0.64° and +0.98°. These are the angles to which the SPS engine must be aimed to align its thrust axis with the spacecraft's centre of gravity.

Time of ignition, Tig (Noun 33): 217 hours, 49 minutes, 18.04 seconds.

Change in velocity (Noun 81), fps (m/s): x, +2,838.6 (+865.2); y, -581.0 (-177.1); z, -27.7 (-8.4). Velocity components are expressed with respect to the local vertical/local horizontal frame of reference.

Spacecraft attitude: Roll, 178°; Pitch, 129°; Yaw, 351°. These attitudes are expressed with respect to the lift-off REFSMMAT.

SPS propellants are settled in their tanks by firing the plus-X thrusters on all four of the Service Module RCS quads for 12 seconds.]

212:45:44 Henize: Roger, J - Roger, Jim. And would you repeat the - the yaw trim.

212:45:54 Irwin: Yaw trim was plus 0.98.

212:45:56 Henize: That's all correct. Thank you; and the last bit of information I have down here is a Mapping Camera photo PAD. At 214 plus...

212:46:14 Irwin: Okay. Go ahead.

212:46:15 Henize: Roger. It's at 214 plus 20 in your Flight Plan and there is no slot for it. You'll just have to stick it in. Mapping Camera, Start, 214:20:03; Stop, 215:19:49.

212:46:43 Irwin: Copy 214:20:03 and 215:19:49.

212:46:48 Henize: That's correct.

[Comm break.]

[This Mapping Camera PAD puts some numbers into the earlier change at 212:34:09 whereby a planned T-stop time was converted into a T-Start time.]

[The next photography takes place over the southern shore of Mare Tranquillitatis. There are four shots of Censorinus and one of the 24-km crater, Maskelyne. Of the four Censorinus shots, AS15-81-10996 is probably the best, looking south. Unusually, it is the smaller of the two craters in this shot, only 3.8 km in diameter, that carries the name Censorinus by virtue of its brightness and visibility from Earth at high illumination angles. The brightness reflects its relative youth. The 7-km Censorinus A beside it probably once looked much like its companion, but over a large fraction of an aeon (an aeon being one billion years) or more, the lunar environment has darkened its ray system to invisibility.]

[Censorinus was often considered as a possible site for the more limited Apollo H-class missions once Apollo 12 had proved that pinpoint landings were possible. Had Apollo 13 not aborted and budget cuts not converted Apollo 15 to a J-class mission, Censorinus might today have a spent LM descent stage sitting nearby, very likely the same one that now hangs in the Apollo/Saturn building at Kennedy Space Center, Florida. Instead, Apollo 14 visited Fra Mauro to the east and subsequent missions moved on to the multi-objective J-class missions, of which Apollo 15 is now the first.]

[Censorinus was interesting to Apollo planners because it is a fresh crater from a meteorite which had driven into an ancient terra landscape. It is a happy fact of crater formation that the distance of ejecta from a crater is related to the depth from which it was hauled by the impact, with the deepest material being deposited on the rim. If you radially sample an ejecta blanket going towards a crater, you are lifting rocks brought from successively deeper layers below. By looking at a large scale lunar map you can see that south of Censorinus is Mare Nectaris (Sea of Nectar). An arc-shaped scarp to its west, Rupes Altai, betrays the truth that the Nectaris basin is a much larger structure than Mare Nectaris and Censorinus just happens to lie at the northern extreme of this basin. So Censorinus provides a convenient drill-hole into the Nectaris basin and if a crew had been able to sample its ejecta, a rich record of one of the earliest major impacts might have been recovered.]

[The other image taken at this time is AS15-81-10998, which looks straight down into the 24-km, frame-filling crater, Maskelyne. The right of the picture shows some slumping of the crater walls. A central peak rises from the floor but is indistinguishable in this image. Nevil Maskelyne, 1732-1811, was the fifth Astronomer Royal of Britain at a time when one of the main goals of astronomy was in aiding navigation around the globe. He was involved in assessing the accuracy of various designs of chronometer which would help ships determine longitude while at sea and he is also noted for determining the density of the Earth.]

212:48:29 Henize: 15, this is Houston with just a passing comment to Dave. We have Lee Silvers and Jim Head in the backroom - available for any questions or comments concerning the lunar surface activities that you'd like to make. Is there anything on your mind you'd like to discuss with them?
[Lee Silver led the training of the crew for their geological exploration of the Moon. Jim Head was primarily involved in the analysis carried out by Bellcomm on NASA's behalf to select a site and study the logistics for its exploration. Both men were part of the science backroom team interacting with Dave and Jim while on the surface and with Al during his solo mission. As they did for many of the geology team, the crew named features at the Hadley landing site in their honour. Silver Spur is an apparent peak 20 km SSE of the landing site which fascinated geologists for its layering, and everyone else for its beauty. Head Valley, seen in this annotated view of the landing site, is actually that part of Rima Hadley where it runs along the base of Mount Hadley Delta before turning North at Elbow Crater.]
212:48:54 Scott: Well, it shouldn't take more than about a couple of weeks, I guess, if we started now. I guess we got a lot to discuss with them. We've talked it over a little bit, and we've come to some conclusions about rilles and mountains and those sort of things. And I - I guess, rather than get into the details now, we probably ought to wait until the debriefing. If they have any questions for us, we'd be happy to answer.

212:49:21 Henize: Okay. It's my understanding that they didn't - you - you gave them so much data they didn't really have any questions left but stand by. I'll see if they - if they come up with some after you've invited them to. - Joe says, hey, they just might have...

212:49:37 Scott: Okay.

212:49:38 Henize: ...something. So stand by.

212:49:42 Scott: Yeah, that's right. I've never seen the day yet when those two didn't have some questions.

212:49:47 Henize: You opened yourself up there Dave.

212:49:53 Scott: Yeah, that's good. We're ready.

[Long comm break.]

[The spacecraft has just coasted across Mare Tranquillitatis and looking far to the SSW, the crater Dionysius is photographed in AS15-81-10999 using the 500-mm lens and magazine QQ. From Earth during the full Moon, the 17.6-km Dionysius appears quite bright as a spot at the southwest shore of Mare Tranquillitatis. The appearance of the crater and its striking, classic ejecta blanket in this photograph shows why. Notice the transition from the continuous to the discontinuous ejecta blanket at about one crater-diameter from the rim.]

[Other notable photographs taken at this time include AS15-81-11002 of Al-Bakri, formerly Tacquet A, on the northwestern rim of the Tranquillitatis Basin. Al-Bakri, 1010-1094, was an Arabian geographer. AS15-81-11006, 11007 and 11008 are all views into the 27-km crater Menelaus. Living about 100 AD, Menelaus was a Greek astronomer and geometer. The crater named after him is situated at the southeastern end of Montes Haemus on the rim of the Serenitatis basin. These shots were taken using the 500-mm lens whereas AS15-90-12294, taken with a 60-mm lens, shows the crater in context with the southwestern shore of Mare Serenitatis and the Sulpicius Gallus region.]

212:53:35 Henize: 15, this is Houston.

212:53:43 Scott: Go ahead, Karl.

212:53:46 Henize: Lee and Jim are sitting right beside me here; and their comment is they - they don't really want to ask very many questions and perturb the debriefing a week from now. But they do just have a couple. And the first one - the first one concerns a unique crater close to Scarp that you described as having about a 40-meter diameter, with a very soft rim. And the texture of the material in it was - instead of being fine angular fragments, was more in the form of clods. They'd like to know a little bit more, if - if possible, about it's location relative to Scarp, and any other comments you can make about the unique - the particular uniqueness of this crater.

212:54:34 Scott: Okay. Stand by one.

[Comm break.]

[The crater Henize is referring to is actually a 15-metre crater southeast of Scarp. It became Station 9 during the third EVA and attracted Dave and Jim's attention because of its blockiness and freshness. A pan of the crater and its environs has been constructed from AS15-82-11066 to 11092 by David Byrne and shows the crater on the right and the large amount of debris scattered in and around it. A bench structure, visible left of the crater's floor, is what interests the geologists most. Normally a bench indicated that the crater has uncovered a subsurface layer. However, the soft, fragile clods of breccia around the crater's rim indicate that it never got past the regolith, the thick layer of debris that covers everywhere on the Moon. While studying it, Jim had noticed the amount of glass covering the rocks at or below the bench and surmised that this crater was a larger version of the many small craters they had seen which have a pool of solidified melt glass at the bottom. His observation turned out to be correct. The crater had not hit bedrock and instead the shock of impact had produced a ring of glass which welded the clods of rock together to form the bench.]

212:56:25 Scott: Okay, Houston. I guess our answer to that is that we had interpreted that particular crater as being Scarp. Perhaps it wasn't. Perhaps we were near Scarp and that was a somewhat smaller crater. But, I guess, as we remember it, that was the one we had called Scarp, and it was, I believe, the only crater we really sampled as we approached Rim Crater in the terrace there. And that particular crater had very soft rims - extremely soft, and all the fragments - the apparent fragments were very frangible. They just fell apart like dirt clods. And we did sample some, and we had a discussion, I think, at the time, and - and I guess we still don't exactly agree relative to the amount of glass that was present in the fragments. Jim seems to think there was a fair amount, and I - I don't remember any particular. But it was a fairly uniform crater. And all the debris around the crater - as I remember, there was something like 20 percent or so of angular frags - all of it apparently would break apart very easy. And there were no solid fragments that we could see or distinguish. Of course, everything is covered by dust. And we did sample some. And I guess that's about the size - the size of it. Is there anything more specific you'd be interested in?

212:58:20 Henize: Dave, this particular crater sounds more interesting to the people down here. And I guess the next question is what - Was there anything about the crater, it's shape or anything else, that would lead you to think it had a different origin than most of the other impact craters?

212:58:44 Scott: No. It - it's depth-to-diameter ratio was about par for the - for the course up there. And it had a slightly raised rim, and the rim may have been somewhat higher than - than others. But I wouldn't be able to distinguish that specifically. It - it was a rather standard-appearing crater, until we walked up onto the rim, and it was extremely soft. And, of course, we only sampled one edge of the rim there. We didn't get any circumferential sampling on it, so it might have been a - a unique part. But it looked pretty uniform all the way around.

212:59:21 Henize: Roger.

212:59:25 Scott: And, we did get the appropriate photographs plus a pan at that site, which, I think, when we go over during the debriefing - perhaps we can extract some more of what we saw. As you remember, at that particular time, we were pretty well hustling, and we didn't have a chance to do much looking at the maps as we got there.

212:59:47 Henize: They say that's great. Thanks a lot.

212:59:52 Scott: Okay. Anything else?

[Flight Plan page 3-325.]

[A small but rather touching moment ensues when Lee Silver becomes the only geologist to speak to a crew during a flight.]

213:00:00 Silver: Hey, Dave. You've done a lovely job. You just don't know how we're jumping up and down, down here.

213:00:10 Scott: Well, that's because I happened to have had a very good professor.

213:00:16 Silver: A whole bunch of them, Dave.

213:00:22 Scott: That's right. As a matter of fact, so many of them, it's just hard to - hard to remember it all. But we sure appreciate all you all did for us in getting us ready for this thing. And I'll tell you, I think Jim and I both felt quite comfortable when we got there, about looking around and - and seeing things. I just wish we had had more time, because, believe me, there is an awful lot to be seen and done up there.

213:00:48 Silver: Yes. We think you defined the first site to be revisited on the Moon.

213:00:57 Scott: Well, as we go around in lunar orbit here, I can look down - and I could just spend weeks and weeks looking. And I can pick out any number of superb sites down there which would take you several weeks to analyze on the surface. There is just so much here. To coin a phrase, it's mindboggling.

213:01:18 Silver: Beautiful, Dave. Thank you so much.

213:01:24 Scott: Yes, sir. I hope someday we can get you all up here too. I - I think we really need to have some good professional geologists up here. As a matter of fact, good professional scientists of all disciplines, not only in lunar orbit, but right on the surface, because you all would just really have a field day, where - with your backgrounds and what you know. There's just so much to be gained up here.

213:01:55 Henize: Great, Dave. Thanks a lot.

213:02:03 Scott: Roger.

[Very long comm break.] [Woods - "In this conversation, you are very vocal about human exploration of the Moon. The Moon nowadays is sidelined by many in the planetary sciences world. You suggest here that having humans wander about the surface, being geologists, is a great thing. In the present environment [in light of the 2004 Bush Moon/Mars plan] do you think it's still a great way to go?"]

[Scott - "Yeah, especially for a geologist. If you're a geologist, it's a great place to go. If you are trying to collect science and you don't have any money, you send a robot. The variables in that equation are about ten. So if you want to solve that equation, you have to put all the variables in there. It's not that simple. It'd be great, go back and everybody have an opportunity to go, do geology on the surface of the Moon, given unlimited budgets, unlimited technology. Just like if you want to go out in someplace on the Earth and do geology and you can get your four-wheeler somewhere and drive out into the mountains or the fields or - geology started in England, yeah? Drive out there and spend a couple or three weeks, terrific. Got your petrol, got your tent, got some fire? Got your boots, your hammer? Head on out there. Same thing on the Moon. Gee, if you're gonna go out there and do it, do it! That's what I'm saying here. I'm not looking at all the other elements of the equation."]

[Harland - "It's also seeing it from the perspective of the time."]

[Scott - "Sure. But I'd still say the same thing."]

[Woods - "It was a time when it was thought it was possible. It was a time when we felt it ought not to be long to a return."]

[Scott - "It's part of a general discussion. It not a programmatic debate or a project pitch to try and sell anything. It's sort of like what's there, what would you like to do? I'd like to do a lot of things."]

[Harland - "Yours was the first science mission and you're talking to your mentor and you're just being very enthusiastic saying it was a good thing to do and we should keep doing it and there are plenty places to see."]

[Scott - "Plenty. And the point is that there's lots of variety on the Moon. All the landing sites we didn't go to as an example. And all the landing sites we could have gone to. Tycho and Tsiolkovsky and, I mean there's fabulous places that nobody had been to that have great variety. But, you couldn't do them all in Apollo, obviously. You were limited to a band around the middle - couldn't get down to Tycho - and the surface areas were questionable. That's why we had all these debates on landing sites. Had to factor all the issues in there to decide where to go. But I'd say, yeah, that's great, go. Bring everybody up here!"]

[Woods - "How do you reply to people that describe the Moon as a useless ball of dirt? Would you argue with that outlook?"]

[Scott - "Of course. I mean, it's not a useless ball. It influences a lot of things on the Earth. Without the Moon, we wouldn't have the Earth as it is. Right? So the Earth-Moon system really creates the environment in which we live."]

[Woods - "But as a place to go and visit, either by humans or remotely."]

[Scott - "Well, you know, the more you learn about the Solar System, the more you learn about the Earth, the more you learn about yourself, and humans and where they live and how they live in the environment. We did, in the whole discussion - in fact we've just been going through quotes for the book [Two Sides of the Moon, David Scott and Alexei Leonov with Christine Toomey, 2004, Simon & Schuster] and found a good one by Socrates. 'The only way you're going to understand the world in which you live is to get above the atmosphere and look back at it.' Kinda paraphrased. So I think those who say it's a waste to go to the Moon don't really understand, or else they'll choose to think about the environment and the way the Earth was created, if you will, and the influence of the Moon and what we learn by going into the Solar System, about ourselves, about the Earth, and it sort of goes on and on and on. But that's why, if somebody says the Moon is a worthless ball of dust, I say 'OK, fine. If that's all you're interested in, if that's all you know about it, fine. Choose your path.' And I don't really have a lot of time for them. You're not going to convince them and if you get into a big debate and they argue about it, I don't have any time for that."]

[Woods - "But it's useful to know what you think of it, what your point of view is. It's interesting, as someone who has been there and who has invested an important part of their life in that exploration, it's interesting to know how you view exploration."]

[Scott - "Oh yeah. But, you know, I'm only the sort of point of the pyramid because all 400,000 people who worked on it probably think the same. And you guys do too, for it's worth doing because it's worth learning about who we are and how we are and how we live and people who take the opposite view; that's OK, they get their choice, you know, and they can view it that way if they want to but I would suggest they spend a little bit of time trying to understand more about the scientific aspects, the geology, etc., and just the spirit of exploration. Why people do this. Why people go out and, you know, fly in the sky and plunge to the depths of the ocean and go to the Moon and all that. It's adventure and that's why humans are humans."]

[Woods - "Adventure and knowledge."]

[Scott - "Yeah."]

[Woods - "Thank you for that."]

Public Affairs Officer - "This is Apollo Control in the discussion with the crew on the observations in geology at the Hadley Base landing site with spacecraft communicator, Karl Henize. Henize was joined by a doctor Leon T. Silver of California Institute of Technology, who is one of the mission geologists for Apollo 15."

[This exchange was portrayed in Mr Galileo Was Right, the Apollo 15 episode of Tom Hanks' excellent From the Earth to the Moon TV series, made in 1998, on which Dave served as a technical adviser.]

[While Dave and Lee Silver were conversing, the photography has been continuing and will do for the next 20 minutes, most likely taken by Al. AS15-81-11009 is a black and white image taken with the 500-mm lens of an area beyond the rim of the Serenitatis basin and shows a bright craterlet within an area of mare material known as Lacus Gaudii (Lake of Joy). AS15-81-11012 shows another bright craterlet, this time 50 kilometres west of Sulpicius Gallus.]

[On colour magazine O using a 250-mm lens, AS15-97-13231 looks directly north across the western shore of Mare Serenitatis towards Montes Caucasus. The spacecraft is approaching the Apennines and the landing site and a frame, AS15-97-13232 is taken looking forward and north to Rima Hadley. Mount Hadley Delta is on the right with the landing site beyond it. The source of the rille, the arcuate cleft, Bela, is at the extreme bottom left.]

[On magazine PP, two frames, AS15-90-12295 and 12296 are taken of the same view of the Apennine range but with a 60-mm lens. The bright crater is Aratus and the darker crater to its lower right is Galen, a 10-km bowl named after a Greek physician, Galenos, c. 129-200 AD and formerly known as Aratus A. Extend a line from Galen to Aratus and the same distance beyond and you come to Mount Hadley Delta and the landing site. AS15-90-12297 and 12298 show the 22-km crater Conon slipping by the Command Module window with the light-coloured Apennine Bench Formation beyond.]

[Going from the wide-angle to the 500-mm telephoto lens, AS15-81-11014 is an oblique view of Bela and the first few kilometres of Rima Hadley. This scan was prepared for the journal by Kipp Teague. Compare it to frame 10899 taken yesterday when the full length of this arcuate cleft could not fit the 500-mm field-of-view. Frame AS15-81-11015 and 11017 are of a small ray crater within the Apennine mountain range and AS15-81-11018 and 11019 show another small impact blast on the Apennine Bench Formation. AS15-81-11020 and 11021 are general views of the Apennine Bench Formation just south of the small crater, Archimedes N.]

[AS15-81-11022 is a spectacular view across Mare Imbrium. In the foreground is Montes Spitzbergen, and rising out of the horizon is the Beta Prominence, an isolated minor hill about 60 km south of Mons Pico. These hills, along with two other ranges to the northwest, are believed to be remnants of an inner ring of the Imbrium Basin. Bringing the camera away from the horizon, the next photograph is frame AS15-81-11023 showing MacMillan, formerly known as Archimedes F. This 7.5-km crater is named after William Duncan MacMillan, 1871-1948, an American astronomer and mathematician and is also shown in 11026.]

[Using a 250-mm lens and colour film on magazine O, AS15-97-13233 and 13234 look northeast over the 83-km ring of Archimedes towards Montes Spitzbergen. These two frames have been combined into a single image. Rima Bradley and Rimae Archimedes are covered by four images from AS15-97-13235 to 13238. Both rilles are seen in AS15-97-13236 with Rima Bradley running from right-centre to bottom-centre. A major component of the Rimae Archimedes system runs right to left from the dark area on the right through the cleft on the left. The same area is seen closer in AS15-97-13238.]

[Moving towards the centre of Mare Imbrium, two photographs are taken of Timocharis which have been combined to show three quarters of this prominent crater's rim. The terracing or scalloping around the rim is a classic example of what happens to the walls of large craters which are unable to retain the original bowl shape that smaller craters exhibit. These are essentially large scale landslides. The crater also has a small crater-like depression at its centre where a central peak would normally be expected. Two further images of interest on this magazine as Endeavour continues across Mare Imbrium are AS15-97-13242, which shows the ejecta blanket and part of the north rim of Lambert, and AS15-97-13243 of Mons La Hire.]

[These last targets for the crew's cameras, plus a few others, are captured in more detail by simultaneous photography using magazine QQ and the 500-mm lens. AS15-81-11027 and 11029 are of a little triangular hill that lies between Timocharis and Lambert. These isolated hills, including Mons La Hire, are a feature of Mare Imbrium and are thought to be traces of the original multiring structure formed directly by the impact that created the Imbrium basin. AS15-81-11028 is another little hill between Timocharis and Lambert with a distinctive triple peak. Lambert exhibits an unusual asymmetry in its ejecta blanket which is shown in detail in 11030 and 11031. Compare this shot to AS15-97-13242 which shows it in context with the crater rim. This ejecta "spur" may be traces of a wrinkle ridge that Lambert just happens to lie upon.]

[There are two further sequences in magazine QQ before it is fully exposed and the best frames of each have been composited together. Al took particular interest in the area when he observed it under low-angle illumination on the third day of his solo mission after noticing traces of lobate margins to lava flows. AS15-81-11032 to 11036 show the two small craters, La Hire A and La Hire B, and the part of Dorsum Zirkel that runs between them. These craters are about 50 km from Mons La Hire and crater A is distinguishable by the little "rim-shot" crater on its northern rim. Mons La Hire is shown in the image compiled from AS15-81-11041 to 11043. In the oblique sunlight Al first saw them by, he was struck by the crater-like depressions along its northern flank which gave him a sense that he was looking at the remains of a volcano.]

[Now that magazine QQ is finished, subsequent photography on this rev is carried out using PP and O. Dealing with magazine PP first and its wide-angle shots, AS15-90-12299 begins a sequence of four images which allow the spacecraft's motion to track the camera across the western Mare Imbrium. Frame AS15-90-12299 shows the 25-km crater, Delisle, Mons Delisle to its southwest, the thin, Y-shaped rille, Rima Delisle and just disappearing behind the Command Module window is Delisle A. The camera is tipped up to the horizon in AS15-90-12300 so that the 16-km crater, Gruithuisen comes into view. Beyond and near the top of the picture is Mons Gruithuisen Gamma. This image does not show it well but it is an interesting dome-like structure with a 900-metre craterlet at the top. AS15-90-12301 continues the sequence. These photographs illustrate one of the features of lunar illumination which is rarely seen on Earth, the "zero-phase" which is the bright spot to the lower left next to the crater Angström. This author (Woods) has noticed the same effect while flying on a sunny day over a dew-covered grassy field, and it is also used to make road signs strongly reflective to drivers who illuminate them with their own headlights. It is always seen on the Moon at a point exactly opposite the observer and, like the dew on the grass and the road signs, it is due to the presence in the lunar regolith of countless tiny beads of glass produced over the aeons by the incessant pounding and melting of rock when rocks fall from space. A fraction is also due to glass sprayed out during early volcanic processes. This zero-phase light proved very uncomfortable to surface crews when they had to walk or drive away from the Sun. Notice how, by AS15-90-12302, it has "moved" with the spacecraft. In this latter frame, the 9.8-km Angström is in the foreground and the complex of craters centred around Krieger is plainly visible beyond. The single crater this side of zero-phase is Wollaston. Next to Angström is the dim outline of a ghost crater about 7 kilometres across. This would have been formed just before the final deluge of runny lunar lava passed this way filling the bowl and leaving the crater rim sitting proud of the mare surface.]

[After a couple of poor frames, the photographer, probably Al, takes an unusual image framed in the window of the main hatch. This is one of the images from Apollo 15 included in the astonishing book, Full Moon by Michael Light, who has kindly donated this version to the Journal, this being number 28 in his collection. North is to the top and the large crater is Krieger at 22 kilometers in diameter. Interrupting its southern rim is Van Biesbroeck, a simple 10-km crater. The two craters to the east are Rocco (the larger crater) and Ruth. Note the rille that runs from a breach in the western wall into Oceanus Procellarum. As was thoroughly documented during yesterday's photography, this area, the Aristarchus Plateau is very rich in rilles. AS15-90-12306 takes the viewpoint away from Krieger somewhat to the craters north of Aristarchus which are the source of some of these rilles, the Rimae Aristarchus. The crater to the right of the rille-producing pair is Toscanelli. The remaining ten frames on magazine PP for this pass follow slightly to the west of Toscanelli across the northern edge of the Aristarchus Plateau to Montes Agricola, finally settling on its northern end. A representative selection from this series includes AS15-90-12309 which shows Toscanelli bottom-right and part of Montes Agricola to the top-left. The northern meanders of Vallis Schröteri or Schröter's Valley are visible bottom-left. Montes Agricola is the subject of 12314, showing the northern tip of the range and 12316 showing much of the southern end, with Dorsa Burnet quite prominent in the low sunshine. Both of these pictures suffer from the same reflection of a cabin lamp seen in earlier pictures in this sequence.]

[Simultaneously with these wide-angle images in and around the Aristarchus Plateau, another crop are being taken of this rich area using colour film and the medium telephoto (250-mm) lens. Many of these shots can be pasted together to give a greater view and this is what we have done.]

[First frame in this sequence is AS15-97-13245. This shows the area just north of Krieger, whose ejecta blanket is visible at the very bottom-left corner of the image. Two wrinkle ridges run north across the image. These features are signs of the stresses within the basalt beds of the mare. As the bulk of the dense basalt sinks unequally, some areas sustain compressional forces which causes upthrust along points of weakness. As they protrude above the surrounding surface, they are collectively called "dorsa". Linear features that are sunken are called "rima" and two images, AS15-97-13246 and 13248 show examples of this type, particularly Rima Archimedes VIII running from bottom-left in this composite. This author (Woods) believes the large cleft to the left is the inundated remains of a much older and wider rille which may have been somewhat similar to Vallis Schröteri which the crew will photograph soon. Part of Montes Agricola is seen running across another composite using AS15-97-13249 and 13250. The edge of the Aristarchus Plateau is along the bottom of the picture.]

[Of much interest to lunar geologists before Apollo were the "special features", odd landforms that were outside the ordinary when looking at the Moon. Only later would the collective mind of science realise that much of the important story of the Moon can be deduced by looking at the big picture - the maria, basins and terra - and the impacts that modelled them. Mons Rümker, seen in this composite image made from frames AS15-97-13251 to 13253, is an example of a special feature. It is a collection of low volcanic domes in the northern regions of Oceanus Procellarum named after a German astronomer Karl Ludwig Christian Rümker, 1788-1862. A high resolution version of AS15-97-13252 has been kindly donated by Kipp Teague. Frames AS15-97-13254, also scanned by Kipp, and 13255 look further to the west at the terminator. A composite of these two frames shows the 9.6-km Naumann to the right and the complex of wrinkle ridges that cross the mare.]

[As Endeavour passes over the Aristarchus Plateau, a crewmember, probably Al, takes one of the most spectacular sequences of Hasselblad photographs from the mission. The seven frames in this sequence look approximately south and have been composited to show the full 160-km length of Vallis Schröteri from its source in the so-called "Cobra Head" on the left to where it fades out in Oceanus Procellarum. Note that this is a rather large image. The valley is visible from Earth with even a small telescope but it took spacecraft to reveal the smaller meandering rille within. When compared to the bulk of the rille, the Cobra Head is very heavily pitted with craters. These are secondary impacts from the ejecta thrown out by Aristarchus a few dozen kilometres to the left and much younger than the rille. While Schröter's Valley is about 3 aeons old, Aristarchus' age is "only" about ½ an aeon. The composite was produced from frames AS15-97-13256 to 13263. Paul Spudis is a geologist at the Lunar and Planetary Institute in Houston and we discussed the sinuous rilles.]

[Paul Spudis, from 2000 correspondence - "Basically, these are lava channels, formed during eruption of the mare basalts. There is currently a debate about whether the rilles are constructional features (i.e., that they are built up by lava overplating, as here on Earth) or if they are erosional features (hot, runny, turbulent lava actually erodes the Moon's surface.) It may be that different processes are of differing importance in different rilles."]

[The final images in this series are of a wrinkle ridge which runs across Oceanus Procellarum south of the small crater Humason (formerly Lichtenberg G). AS15-97-13264 and 13265 have been composited to show its length.]

213:30:33 Henize: 15, this is Houston. Just a point of curiosity. Are you guys seeing Aristarchus and Schröter's valley in daylight yet? [No answer.]
[Long comm break.]
213:34:31 Henize: 15, this is Houston; 3 minutes to LOS, and all your systems are Go. [Long pause.]

213:35:19 Henize: 15, this is Houston. How do you read?

[Comm break.]
213:36:29 Henize: 15, this is Houston. Could you give us a comm check, please.
[Very long comm break.]
Public Affairs Officer - "This is Apollo Control. We've had Loss Of Signal as Apollo 15 sailed around behind the Moon again. Nearing the end of the 69th lunar revolution. Back around the eastern side of the Moon, back in view of the big dishes in the Manned Space Flight tracking Network in about 47 minutes. And 213 hours, 38 minutes Ground Elapsed Time, this is Apollo Control."

[As the PAO announcer soon intimates, the crew will finish their breakfast during this far-side pass, then get on with the science objectives for the day. First among these is to prepare a Hasselblad with a 250-mm lens and very high speed black and white film for photography of the terminator just before AOS. The Mass Spectrometer is turned off and, after five minutes, retracted into the side of the Service Module, along with the Gamma-ray Spectrometer. With these two instruments out of the way, the Mapping Camera is extended and readied for operation once the spacecraft crosses the terminator. As a last hope, the Laser Altimeter will be switched on in support of the camera but it is believed to be useless now having been seen to progressively fail during its operation in lunar orbit.]

[Flight Plan page 3-326.]

[Revolution 70 begins at about 214:00. When the terminator does arrive, nine images are taken of the extremely low-angle lighting. These are AS15-98-13365 to 13373 but all are rather fogged and of little aesthetic quality. AS15-98-13366 is an example from this sequence and is of the landscape at the northeast rim of crater Scaliger.]

Public Affairs Officer - "This is Apollo Control; 214 hours, 22 minutes Ground Elapsed Time. Less than a minute to acquisition. As Apollo 15 comes around to the front side of the Moon on the 70th lunar revolution, the crew by this time should have tidied up from their morning meal and be settling down for a fairly busy day's work; orbital science task, and later on in the day, the shaping burn for jettisoning the little mini-satellite. Ten seconds away, we're standing by from - for notice from the network controller that we have Acquisition Of Signal. Spacecraft communicator Karl Henize sitting back down at the CapCom's console and should be calling the crew with some additional Flight Plan updates. We're up and live on air/ground 1, this is Apollo Control."

214:26:03 Henize: 15, this is Houston. How do you read?

214:26:10 Scott: Houston, 15. Loud and clear.

214:26:14 Henize: Roger, 15. We're reading you loud and clear. We have Flight Plan updates available any time you're interested in copying it.

214:26:27 Scott: Okay. Stand by one.

[Comm break.]
214:28:01 Scott: Okay, Houston. Go ahead with your updates.

214:28:08 Henize: Roger, Dave. We'd like to have you start the battery A charge first.

214:28:15 Scott: Roger. We just started right now.

[The crew regularly charge one of the three general purpose batteries aboard the CM to keep them topped up. These batteries provide extra load capacity during periods of heavy power use and will be the CM's primary source of power during re-entry. Two further batteries are used to fire pyrotechnic devices like parachute deployment and are left untouched during the mission except to monitor their voltages.]
214:28:19 Henize: Okay. Flight plan updates; 214 plus 41. The - we delete the Pan...

214:28:33 Scott: Go ahead.

214:28:34 Henize: ...we delete several lines there. "Pan Camera Mode, Standby; Power, On; Stereo; Exposure, Normal;" and "Pan Camera Mode to Operate", all deleted.

214:28:50 Scott: Roger; understand. Three lines deleted. Deleted at 214:41. Go.

214:28:55 Henize: Roger. At 214 plus 50 we delete "Pan Camera Mode Standby" and "MSFN veri; verify lens tuck in".

214:29:11 Scott: Roger; 214:50; delete 2 lines. Go ahead.

214:29:15 Henize: At 214:53, delete "Pan Camera Power, Off", and at 55 delete "Gamma-ray Boom, Deploy".

214:29:27 Scott: Roger. At 53 and 55, delete one line each. Go.

[This Flight Plan update cancels the Panoramic Camera photography scheduled between 214:42 and 214:50.]
214:29:33 Henize: At 215:17, we add "Map Camera, On, switch Off, parenthesis T-stop; Laser Altimeter, Off; Map Camera, On, Standby, T-stop plus 30 seconds. Map Camera, Image Motion, Off".

214:30:00 Scott: Stop - break - break, Karl. Try it again - a little slower so I can write it.

214:30:05 Henize: Roger; 215 plus 17. First line, "Map Camera, On, Off, parenthesis T-stop". Second line, "Laser Altimeter, Off". Third line, "Mapping Camera, On to Standby, T-stop plus 30 - 30 seconds". Fourth line, "Mapping Camera, Image Motion, Off".

214:31:05 Scott: Okay. Copy. At 215:17, "Map Camera, On to Off, T-stop; Laser Altimeter, Off; Map Camera, On to Standby at T-stop plus 30 seconds" and "Map Camera, Image Motion to Off".

[This latest set of updates affecting the Mapping Camera formalises an earlier update at 212:46:15 when a T-Stop time was given for the camera without detailed instructions for the switching-off procedure.]

[Dave Scott's request to Karl Henize is hardly surprising. Even for trained pilots, attempting to copy a lengthy update or clearance while it is being rapidly read can be quite a challenge.]

[As Dave began this series of updates, Al was busy with a Hasselblad. Using the 250-mm lens on colour magazine O, he captures a sequence showing Earthrise that in the opinion of this author (Woods) gives us one of the most profound images of the Apollo program. Not only did it become the cover of Al's book of poetry, Hello Earth, Greetings From Endeavour, it also found its way into Michael Light's beautiful and lyrical collection of Apollo imagery, Full Moon. This version of the image, number 107 in his collection, showing a delicate crescent Earth rising over the crater Curie, was kindly donated by Michael to the Journal. Just below the rising Earth in the frame are the walls of the huge "walled plain", Humboldt. Frame AS15-97-13268 is the best of the Earthrise frames. Other frames up to 13274 continue viewing the Earthrise and do not add anything to the earlier image. Frames AS15-97-13275 and 13276 look within the 200-km Humboldt which was named for Wilhelm von Humboldt, 1767-1835, a German statesman. Humboldt displays a number of interesting features. The floor is filled in with what are probably light coloured lava flows, though around the margins there are dark areas. The floor itself is heavily fractured with radial and arcuate rilles and in the centre, the beginnings of a ring replace the familiar central peak.]

214:31:20 Henize: Roger. At 215 plus 19, add "Gamma-ray Boom, Deploy".

214:31:39 Scott: Okay. 215:19; "Gamma-ray Boom, Deploy". Go.

214:31:45 Henize: 215 plus 25, delete "Laser Altimeter, Off".

214:31:55 Scott: Roger. 215:15 [sic], delete "Laser Altimeter, Off". Go.

214:31:59 Henize: Over at 216:01, "Laser Altimeter, On", is moved down to 216 plus 15.

214:32:24 Scott: Okay. 216:01 "Laser Altimeter, On", deleted; at 216:15 "Laser Altimeter, On" added. Go ahead.

214:32:32 Henize: Correct. 217 plus 14, add "Laser Altimeter to Off".

214:32:49 Scott: Okay. 217:14, "Laser Altimeter, Off". Go.

214:32:54 Henize: At 217 plus 20, we delete - three lines. "Mapping Camera, Image Motion", "Mapping Camera, On", and "Mapping Camera, Image Motion" - steps, all three.

214:33:12 Scott: Okay; 217:21 delete three lines. Got 'em. Go ahead.

[These are further updates in light of the failed Laser Altimeter, with the final one being to prevent the Mapping Camera from photographing an unlit lunar surface in view of the lack of altitude data.]
214:33:18 Henize: Right. And, in that place at 217:20, put the line down below at 217:25 "Gamma-ray Boom, Deploy".

214:33:38 Scott: Okay. At 217:20, we should have "Gamma-ray Boom, Deploy" vice 217:25.

214:33:46 Henize: Roger. At 218:02, we change the camera configuration there. We're going to use window 5, CM-5. We need the 80-mm lens - 80-mm lens, and the setting should be stop 2.8, exposure time 1 over 250.

214:34:19 Scott: Okay. 218:02, use CM-5/EL/80- 2.8, 1/250th. Go.

[Photographs of the terminator are scheduled for 218:12, and were originally planned to use a 250-mm telephoto lens. This now has been changed to a "normal" 80-mm lens. The photographs are to taken from the LMP's window rather than the Command Module hatch window. This window is made of quartz to allow it to transmit ultraviolet light and so a UV-opaque shield made of polycarbonate (proprietary name "Lexan") must be used to prevent unwanted exposure of the film to UV.]

[Continuing the photography on magazine O, AS15-97-13277 is of a small crater, Hecataeus B, associated with another of the large walled plains near the Moon's eastern limb. Looking further north are two irregular craters, Kapteyn E and Maclaurin A, seen in frame 13278.]

214:34:25 Henize: And the note there is - use the - use the Lexan shield on CM-5; in other words, leave it on the window.

214:34:37 Scott: Okay. Lexan shield. Got it.

214:34:40 Henize: At 218:10, delete "Mapping Camera, Image Motion, Increase".

214:34:52 Scott: Okay. One line deleted at 218:10. Go.

214:34:56 Henize: At 218 plus 14, we add "Laser Altimeter, On". We have four lines here. "Mapping Camera, Image Motion, On; Mapping Camera, On to On at T-start; Mapping Camera, Image Motion, Increase; talkback barberpole plus 4/On".

214:35:42 Scott: Okay. 218:14 "Laser Altimeter, On; Mapping Camera, Image Motion to On; Mapping Camera, On to On at T-start; and Mapping Camera, Image Motion, Increase; and talkback barber pole plus 4 seconds/On".

[Continuing the corrections to the Mapping Camera schedule. The crew is requested to turn on the camera when reaching daylight on the 72nd orbit.]
214:35:56 Henize: Roger. At 220 plus 07, we add "Pan Camera Mode, Standby; Power On", and that will be "Mono and Exposure, Normal".

214:36:32 Scott: Okay. 220:07 "Pan Camera to Standby; Power, On; Mono; Exposure, Normal". Go.

214:36:40 Henize: At 220 plus 13 we add "Pan Camera Mode, Operate at T-start".

214:37:00 Scott: 220:13, "Pan Camera to Operate at T-start".

214:37:05 Henize: Roger. And about 220:18, expect the talkback showing you film depletion - the film finished. At that time, go Mode, Standby; and wait for a MSFN cue to go Power, Off.

214:37:43 Henize: And 15, we'd like to have High Gain [Antenna], Auto.

214:37:46 Scott: Okay. 220:18, Pan Camera - 220:18, we should have film depletion; Pan Camera to barber pole, then go Standby and wait for MSFN cue for Power, Off. Go.

214:38:03 Henize: And that's the end of the update.

214:38:09 Scott: Okay. I guess when you run out of film, you run out of updates.

214:38:13 Henize: That's about the size of the situation.

[Long comm break.]

[Endeavour is coming up over Mare Fecunditatis and two cameras are in use. Taken on black and white magazine PP and the 60-mm lens are AS15-90-12317 and 12318. These look northeast over the Mare with the Messier crater pair in the distance. The most prominent crater in the foreground is Lindbergh, a 13-kilometre bowl formerly known as Messier G but now named after one of the heroes of American aviation, Charles A. Lindbergh, 1902-1974, who was the first person to fly solo across the Atlantic Ocean, taking 33½ hours on May 20-21 1927. AS15-90-12319 and 12320 look northwest to give a wide-angle view of the Messier Twins, Messier and Messier A. The twin rays emanating westwards from this pair are well shown as is a fainter ray that crosses the craters perpendicular to their axis from an unknown source.]

[On the colour magazine O and medium telephoto lens, frame AS15-97-13279 and 13280 are an oblique view across to the northwestern horizon over Mare Fecunditatis. The wrinkle ridge which curves in the foreground towards four craters is Dorsum Geikie named after Sir Archibald Geikie, 1835-1924, a geologist from Scotland. The furthest and largest of the four craters is Anville, formerly Taruntius G, an 11-km crater named after Jean Baptiste d'Anville, 1697-1782, a French cartographer, and the other three are, from left to right, Taruntius H, P and K. The next three frames return to Messier. AS15-97-13281 view the pair from afar with the Secchi range of hills in the background. By compositing AS15-97-13282 and 13283, we get a fine shot of the Messier twins. Note that the westernmost crater, Messier A (at the top of this composite) is classed as a double crater. Perhaps the darker component predates the lighter one and had its entire eastern wall obliterated by the newer impact. One could also theorise that the unique comet-like pair of rays (which run off the top of this image) might be due to the ejecta from the later impact being funnelled westwards by the walls of the pre-existing bowl.]

214:47:09 Henize: 15, Houston. If you're willing to listen, I have about a 3-minute update on the morning news.

214:47:22 Worden: Stand by one, Karl.

[Long comm break.]

[All the while, onboard photography continues during these last few orbits around the Moon. The copy of AS15-90-12321 available here is rather poor but it looks northwest across the centre of Mare Tranquillitatis. Near the right-centre fiducial mark are a pair of craters, Sinas and, further away, Jansen E. Simon Sinas, 1810-1876, was a Greek merchant who is remembered on the Moon for his patronage to astronomers in Greece. Sinas crater is 12.4 kilometres in diameter. The bright crater in the distance is the 16-km Carrel, formerly known as Jansen B, now named after Nobel laureate Alexis Carrel, 1873-1944. Frame 12322 is similar to 12321. Carrel becomes more prominent in frame 12323 and beyond is the large, at 43 km, crater Plinius. This image is looking at the northern stretches of Mare Tranquillitatis, and on the horizon, the Montes Haemus range mark the shore of Mare Serenitatis beyond. By the time 12325 is taken, Endeavour has progressed across Carrel. The large crater in the foreground is Ross. This somewhat elongated crater is about 26 km in diameter and has its name derived from two possible sources. Sir James C. Ross, 1800-1862, was a polar explorer after whom the Ross Sea in Antarctica was named; Frank E. Ross, 1874-1966, was an American astronomer who specialised in ultraviolet studies. To the right of the photograph, and beyond Montes Haemus, lies Mare Serenitatis with its distinctive dark margin. The small, bright crater just offshore here is Tacquet while the very bright feature on the mountain range itself is the 27-km Menelaus. The view is advanced in AS15-90-12326 seen here in a scan made for the journal by Kipp Teague which, on the right, shows Tacquet to the north of the light-coloured Montes Haemus and the ring-like crater Al-Bakri to the South. The left of this image is better displayed in 12327. In the foreground is Sinus Honoris (Bay of Honour), a bay on the northwest boundary of Mare Tranquillitatis. The bright crater at the top-right is Menelaus and the other large one at the top left is Manilius, a prominent 43-km crater. The dark area just in front of Manilius is Lacus Lenitatis (Lake of Tenderness). Much of the light-coloured terra in this region displays a northwest-southeast trend which betrays its nature as being part of the Imbrian sculpture, carved out and laid as the ejecta spoil from the impact event that created the Imbrium basin to the northwest. 12328 looks along the straight section of Montes Haemus from Menelaus with Mare Serenitatis to the right. The dark margin along this shore of Serenitatis is very plain, punctured halfway along by the crater Sulpicius Gallus.]

[While the preceding shots were taken looking northeast, the colour magazine O is being used on a Hasselblad looking south. A composite of four images, AS15-97-13284 to 13287, shows the southern shore of Mare Tranquillitatis and has been annotated to show the position of the Apollo 11 landing site and three small craters nearby which are exceptions to the rule that all lunar features are named after deceased scientists as they were named after Apollo 11's crew. Under the high Sun elevation, these craters are difficult to see and are to be found at the bottom left of each name. The rays seen to be emanating from the far left of the picture may be from Torricelli, 180 km distant. Statio Tranquillitatis or Tranquillity Base is photo target 22 in the Flight Plan. These four images, AS15-97-13284, 13285, 13286 and 13287 are available from the Project Apollo archive.]

[The main subject of the south-looking AS15-97-13288 is the 18-km crater Sosigenes and its associated rilles, Rimae Sosigenes. These rilles are a classic example of the graben type which are seen at the margins of many of the Moon's maria. They are caused by expansion around these margins as the weight of dense basalt in the mare sinks with respect to the surrounding land. Sosigenes lived in the first century B.C.E. A Greek astronomer, he was an adviser to Julius Caesar and was involved in the introduction of the Julian calendar. This is an appropriate name as this crater is near another named after the ubiquitous Roman emperor. The crater Julius Caesar is at the left end of a composite image constructed from AS15-97-13292 to 13296. It is about 90 kilometres in diameter and is highly degraded and flooded. The dark patch to the right of the composite is an unnamed lunar "lake" that lies between Lacus Lenitatis and Julius Caesar. Before taking this sequence, three shots were taken of Menelaus, two of which, AS15-97-13289 and 13290 have been composited. Looking at Menelaus, one is reminded somewhat of Proclus in that both craters display a notch in one wall.]

[The final full frame in magazine O is AS15-97-13297 which shows another of the irregular dark patches which lie within the terra between Julius Caesar and Manilius. This one, Boscovich, is photo target 24 in the Flight Plan and is classed as a 46-km crater, though its walls are considerably distorted and modified by the subsequent overlaying of Imbrium ejecta and flooding. Crossing the flat floor of the crater are a network of rilles, Rimae Boscovich. Ruggiero Boscovich, 1711-1787, was a Croatian astronomer and mathematician.]

214:53:17 Worden: Okay, Houston; 15. We're ready for the news.

214:53:22 Henize: Roger, 15. The flight of Apollo 15 is still front page news around the world. Even yesterday's relatively quiet activities were noted by most news media. The rail strike with the United Transportation Union has ended, and ten railroads that were out of operation for 18 days are back on the tracks. Growers in California were hardest hit by the strike, losing an estimated 45 million dollars in sales and related industries. President Nixon has asked Congress not to allow the use of federal funds to pay for bussing school children. The administration also announced that it is appealing a bench mark court ruling against massive bussing in the public - in the public schools of Austin, Texas. Treasury Secretary John B. Connally is attempting to stop a rumored increase in bank interest rates. Connally said he is distressed to hear reports that bank prime lending rates are to be raised again. Rates were increased only last month. New York stock exchange prices fell yesterday in the second largest decline of the year, with the Dow Jones industrial average dropping almost 15 points. Analysts say that the decline may have been caused by the rumored increase in interest rates. You got up too early to hear much news of last night's baseball games but we can report that the Astros lost to the Cubs, 5 to nothing. They did better Monday night when they beat the Cubs 2 to 1. The weather report from the Houston is one word: soggy. Rain has fallen off and on for more than 24 hours, and there was a long steady rain most of yesterday afternoon. Going to be a lot of grass cutting to do when you get back down here, guys.

214:55:19 Worden: Oh, yeah; but we sure got nice sunny weather up here.

214:55:23 Henize: No clouds up there, huh? That's amazing.

214:55:28 Worden: No. It's just as clear as crystal.

214:55:35 Henize: Thinking about all that sunshine up there reminds me that we're in a bind down here about your exposure to UV, and we recommend that, on the several times on the next couple of orbits when you're requested to take the - the Lexan cover off of window 5, that you alternate handling that photography to keep under the legal doses.

214:56:03 Worden: All right; we'll do that. [Long pause.]

[The crew's and Henize's deadpan exchange about enjoying the "sunny weather" belies the fact that the UV radiation in space can be quite intense, if not dangerous.]
214:56:36 Henize: 15, Houston. The doctors down here with their - with their electrocardiograms see that the CMP - or at least they think the CMP - is on the - the biomed apparatus; and, according to Flight Plan, they'd like to have the LMP on.

214:56:55 Worden: Okay. We thought we'd give you both since you were sort of interested in that yesterday.

214:56:59 Henize: Okay; that would be great.

[Comm break.]

[During the time on the surface, a combination of workload and diet resulted in Scott and Irwin experiencing episodes of cardiac arrhythmia that caused concern to the doctors on the ground. The request to monitor Jim Irwin reflects their need to monitor the recovery of his heartbeat.]

214:58:58 Henize: 15, Houston. We have a couple of camera PADs when you have time to copy.

214:59:08 Worden: Okay; stand by a couple of minutes, will you please, Karl?

214:59:13 Henize: Roger. [Long pause.]

214:59:48 Irwin: Okay, Karl. I'll copy those PADs for you.

214:59:52 Henize: Roger. They're in the Flight Plan at 216. The first one is the Solar Corona photo PAD. T-start is 216:03:55. Down below, the Mapping Camera photo PAD: Start 216:18:30, Stop 217:18:15.

215:00:31 Irwin: Copied. 216:03:55, 216:18:30, and 217:18:5 - 15.

215:00:39 Henize: That's correct.

[Very long comm break.]

[Flight Plan page 3-327.]

[Before their next communication with Earth, the crew continue with intensive handheld photography. Endeavour is reaching the point of closest approach to the landing site but the rotation of the Moon means that the spacecraft now passes well to the south of Hadley. In the five days since the now discarded Falcon landed, the Sun has risen to 60° in the sky above the Apennine Mountains around the southeast shore of Mare Imbrium. Under this shadowless light the lunar surface is bland and its topography difficult to discern. Photographs taken on magazine P at this time bear this out. For example, AS15-93-12577 and 12578. In this latter frame Rima Conon is the most prominent landform, running along the north margin of Sinus Fidei (Bay of Faith) between the Apennine Front and Mare Vaporum but otherwise, details are difficult to see. On the opposite side of the Apennine front, frames AS15-93-12579, 12580 and 12581 show Rima Bradley which, though it runs near to Rima Hadley, has an entirely different genesis. Whereas Hadley Rille was eroded by fast-running, very liquid lava, Bradley Rille came about by the stretching of the crust from the weight of the Imbrian basalts and would be said to be a tectonic feature. Looking to the south of Endeavour's groundtrack, three frames take in the Apennine Front from Mons Ampère to Wallace C. In a south-looking composite of AS15-93-12582 to 12584, this 100-kilometre stretch of the Front is seen in its entirety.]

[As they move south of Archimedes, AS15-93-12585 to 12588 form a sequence looking northeast including the pair of small craters, Feuillée and Beer, each about 10 kilometres in diameter and sited midway between Archimedes and Timocharis within the expanse of Mare Imbrium. The spacecraft passes north of Copernicus, a 93-km crater that is almost as important to our understanding of the Moon as the Polish astronomer whose name it carries is to the subject of astronomy. Nicolas Copernicus, 1473-1543, propounded a theory of the Solar System that placed the Sun at the centre, not Earth. While not a new idea - Greek astronomers had come up with it 1,500 years earlier - he introduced it into mainstream western thought at a time when the Renaissance made it acceptable. The crater is seen just on the horizon in frame AS15-93-12589 and in the foreground can be seen a scattering of little craters. These are mostly secondary craters from the impact of projectiles which were themselves sent aloft by the massive impact that produced Copernicus.]

[On a world as extraordinarily ancient as the Moon, Copernicus is relatively fresh, yet it is tentatively dated as having been formed about 800 million years ago, long before complex life took hold on the nearby Earth. The surface on which it left its mark is not only more than three aeons old, it also happened to be a smooth mare surface which preserved the fingerprint of the damage imparted by the impact. Around 1959, Eugene Shoemaker, a renowned geologist with United States Geological Survey, made a study of the distribution of secondary craters around Copernicus and showed that they were the result of the violent expulsion of ejecta due to the intense shock waves associated with impact. His study was a major step in the understanding that impact has been, and is, a major sculptor of the surfaces of the planets. The rays of Copernicus are still bright though fading and the crater can be an impressive sight in a small telescope. Apollo 15's inclined orbit keeps it away from the direct vicinity of the crater but other Apollo flights did take copious photos of it.]

[AS15-93-12590 shows the 30-km crater Lambert peeking out from behind the edge of the Command Module window and AS15-93-12591 looks across southern Mare Imbrium towards the Montes Carpatus (Carpathian Mountains). The rays from Copernicus, blasted across the mare surface, are clearly visible.]

[Photography is taken up on magazine OO using the 500-mm lens. Down the years, those who have studied the Moon have had a tendency to be attracted to those features which look different from the monotony of craters and mountains, believing perhaps that the secret to that world's past would be revealed there. Now we understand that it is the obvious features, especially those on a large-scale and visible from Earth, that are the key to Luna's story. Yet this does not stop the lunar explorer from being attracted to the unusual and so whoever has the camera with the 500-mm lens shoots off five frames which have been presented here in a single montage taken from frames AS15-92-12452 to 12456. Returning to the ubiquitous, AS15-92-12457 shows Diophanthus B, a small, simple type crater; 12458 and 12459 are of Rima Delisle and the curious y-shaped form it makes. A little rayed crater, Louise, only 1.5 kilometres across and sited between Diophanthus and Delisle is the subject of frame 12460. 30 kilometres northwest of Louise is Mons Delisle, itself 30 km long and captured in a composite of frames 12461 to 12463. The western rim of Delisle is visible at the top of this image and dominates 12464. These images are repeated up to 12468.]

[In frames AS15-92-12469 to 12471, the photographer returns to the "special features", which have been compiled into a single montage. Another montage, produced from frames AS15-92-12472 to 12474 shows a knot of low hills 40 kilometres west of Delisle.]

[Also taken around this time, but using magazine P, are AS15-93-12592, which looks into the washout of zero-phase illumination at Diophanthus on the left, and Delisle to the right, and 12593, a view southwest across Mare Imbrium with Euler E in the foreground and Brayley B, Brayley and Brayley C strung across the distance. Diophanthus was a fourth century AD Greek mathematician and Edward Brayley, 1801-1870, was a professor at the Royal Institution, London.]

215:13:29 Henize: 15, Houston. If you'll give us Accept, we'll send up a new state vector.

215:13:37 Scott: Roger.

[Comm break.]

[Magazines OO and P continue to be heavily used in these final revolutions.]

[Endeavour is heading for the Aristarchus Plateau, a visually and geologically interesting area which marks the boundary between Mare Imbrium to the east and Oceanus Procellarum to the west. Photography of this area is called for in the Flight Plan and whoever has the camera with magazine P and the 80-mm lens lets its viewpoint wander gently across the scenery while the spacecraft passes overhead. It is probably best to look at some of the highlights of the couple of dozen images taken at this time. Marking the eastern rampart of the Aristarchus region is the range of isolated mountains, Mons Harbinger, seen in AS15-93-12594 and more clearly in 12597. In the middle distance is the flooded crater Prinz and beyond, Aristarchus itself. The version of AS15-93-12601 here is one of Kipp Teague's fine scans from the Apollo collection which shows Prinz and Aristarchus and the pattern of ejecta across the intervening mare surface. The distinctive form of the Prinz rilles is beautifully displayed on this image. Beyond Aristarchus is Herodotus and by panning slightly to the north we see Krieger in 12604.]

[AS15-93-12608 is another image from Kipp Teague's collection which looks closer at Prinz and its system of rilles. The right-hand side of this picture displays excellent examples of crater chains strung across the landscape in the distinctive "V" formations that points to their source, Aristarchus. The effect of this crater's ejecta blanket on the older surface, especially the way the Aristarchus Rilles have been partially filled in, is seen in 12612. The 22-km Krieger peeks out of the edge of the Command Module window in 12613, including the little rille that meanders from its breached western rim.]

[Picking up the photography with the 500-mm telephoto lens on the black and white magazine OO, the photographer is spotting details as they catch his eye. The following is a selection from 19 images between AS15-92-12476 and 12494. Frames 12476 and 12480 give an excellent impression of the polygonal outline of Krieger and its little rille. 90 km east of Krieger is the 9.8-km crater Ångström which carried the name of the Swedish physicist Anders Ångström, 1814-1874. His name is synonymous with the measurement of distances at the very small scale. An "Ångström" is equivalent to a tenth of a micron, or one ten-millionth of a metre. His crater is nicely framed in AS15-92-12478. Image 12481 is of Ångström B which sits astride a wrinkle ridge.]

[This set of images also include two triplets across Aristarchus itself, 12482 to 84 and 12490 to 92. The latter triplet has been composited to provide a spectacular oblique of this crater. Forty kilometres wide and fully three kilometres deep, this enormous pit displays all the classic attributes of a crater of its size, even though it is half an aeon old. It has a distinct central peak though in this case it is off to one side. Around the peak is a flat floor of impact melt, rocks from the target which were thoroughly melted by the energy of the impact. Unable to hold such a massive structure in the form of a simple bowl, the walls have collapsed in a series of terraces, aided by the severe faulting of the crust around the impact.]

[El-Baz, from the 1971 Visual Observation Debrief - "Visual observation 11, Aristarchus Plateau. You looked hard for the transient events from Aristarchus?"]

[Worden, from the 1971 Visual Observation Debrief - "Yes. Boy, I'll tell you, in earthshine, that thing really shows up. That's like a really luminous blanket around it. That is really bright, even in earthshine."]

[El-Baz, from the 1971 Visual Observation Debrief - "Now is it also from the rim crest inward or around it?"]

[Worden, from the 1971 Visual Observation Debrief - "No, around it."]

[El-Baz, from the 1971 Visual Observation Debrief - "The ejecta is also as bright?"]

[Worden, from the 1971 Visual Observation Debrief - "The ejecta was the thing that was bright."]

[El-Baz, from the 1971 Visual Observation Debrief - "How about the crater?"]

[Worden, from the 1971 Visual Observation Debrief - "Not the crater itself so much, but the crater was bright. That's an impression you get when you're coming up on it, because the only thing you see is the ejecta pattern. And that comes right straight at you out of the darkness as you're going over it. ... The inside of it is fairly bright too. But the thing that really catches your eye is this ejecta pattern that's out around it, with that big long tail that sticks out to the southwest. ... Cobra-Head looks like nothing but just a sheer cliff around there."]

[El-Baz, from the 1971 Visual Observation Debrief - "A very steep wall?"]

[Worden, from the 1971 Visual Observation Debrief - "A very steep wall - very high. I couldn't even begin to guess how high it looks, but I bet it's 1,000 feet at least."]

[El-baz, from the 1971 Visual Observation Debrief - "Higher than what?"]

[Worden, from the 1971 Visual Observation Debrief - "It's not higher than anything because it's like a natural amphitheater. ... "]

[El-Baz, from the 1971 Visual Observation Debrief - "Did you see the bottom of it or not?"]

[Worden, from the 1971 Visual Observation Debrief - "No, I never did get a very good look at it, because it was always in shadow."]

[El-Baz, from the 1971 Visual Observation Debrief - "It was deeper than you could actually see?"]

[Worden, from the 1971 Visual Observation Debrief - "Yes, it was still dark down around the bottom, but you could see the wall. ... It was just a big steep wall sitting there."]

[The area just around Aristarchus is shown in AS15-92-12485, 12486 and AS15-92-12494. 50 kilometres north of the great crater is the 8-km Väisälä, formerly known as Aristarchus A. It is named after Yrjo Väisälä, 1891-1971, an astronomer from Finland. The crater is shown in AS15-92-12489 where the damage sustained by its rim from Aristarchus ejecta passing from the south is apparent.]

[Sinuous rilles are a common feature of mare landscapes but around the Aristarchus area, they are particularly ubiquitous and many of the rilles are notable by having craters at their source. The Rimae Aristarchus system, seen to the bottom right of AS15-93-12601, has many of these "cobra-head" features and AS15-92-12488 highlights one of these, just east of Väisälä. The very best example of a cobra-head rille is "The Cobra Head", seen obliquely in 12487, and which is the source of Vallis Schröteri.]

215:16:12 Henize: 15, Houston: the computer is yours.

215:16:20 Scott: Roger.

[Comm break.]

[An updated state vector has been sent to the spacecraft, refining the computer's knowledge of where it is at a particular time. The crew can disable the uplink from Earth and have use of the computer again.]

[Returning to magazine P and colour photography using the 80-mm lens, this camera is continuing to take relatively wide-angle, general shots of the Aristarchus Plateau. AS15-93-12617 shows the hummocky, uneven surface of the plateau and Vallis Schröteri to the left. The landscape further to the north is covered by 12618.]

[Frames AS15-93-12620, 12621 and 12622 look ahead to the western side of the plateau and Montes Agricola. A wrinkle ridge, Dorsum Niggli, connects the mountain range at left of frame with the plateau on the right. The next seven frames, 12623 to 12629, are general shots of Vallis Schröteri. A representative selection from these includes 12623, 12625 and 12628, the latter being a scan by Kipp Teague from his Project Apollo Archive website.]

[The 500-mm lens being used with magazine OO images the detail of Vallis Schröteri along its length in two series of consecutive black and white shots. These do not necessarily overlap and are impractical to compose into a single image. The first series starts with AS15-92-12495 of the Cobra's Head. This feature has been heavily pitted and overlain by ejecta from the formation of Aristarchus 30 kilometres to the east. At this point, the large-scale structure of Vallis Schröteri is 10-km wide and appears to represent the erosion of the landscape by the high volume eruption of lava. Within this a smaller sinuous rille, similar in scale to Rima Hadley, is probably the remains of a later and smaller effusion of lava which flowed along the course left by the earlier outpouring. The rille is followed in frames 12496 and 12497 and in the latter shot, some extraordinary meanders are visible as the smaller rille snakes along the floor of the larger. More frames continue the course of the rille: 12498, 12499, 12500 and 12501. AS15-92-12502 completes this sequence where the larger rilles opens out like an estuary and leaves the smaller to carry on into Oceanus Procellarum.]

215:19:10 Henize: Hey Al. I've sort of got an itch to hear what the Aristarchus region looks like in daylight. You got any comments?

215:19:21 Worden: Well, I'll tell you, Karl; we've all been sitting here kind of looking at Aristarchus a little bit in awe. It looks like probably the most volcanic area that I've seen anywhere on the surface. And certainly it's just very covered with rilles, very - quite deep rilles, too, some of them. Schröter's Valley, for instance, is a magnificent big rille which looks like it's worked - been worked twice; of course, the large rille and then a smaller rille inside.

215:19:54 Henize: What about the source of Schröter's Valley?

215:19:56 Worden: Several cones - say again?

215:20:00 Henize: What about the source of Schröter's Valley. Does it look volcanic?

215:20:08 Worden: Well, that whole area in there looks volcanic, yeah. And that certainly comes from - from up on the plateau there. I would guess that the Cobra Head is the source for Schröter's Valley. The elevation is - is a little subtle from this - from this vantage point, but I - I guess that would be my guess. And as far as where the - think we've found something interesting anyway about the - the ends of the rilles, particularly around the Schröter's Valley area, it looks quite distinctly like the rilles - the - the mouths of the rilles - or the delta's have been covered with rising maria - mare materials - from the lower - from the - from the lower elevation. Almost as if there was a - a - a rille with a delta-like deposit at one time, but then the mare - the elevation of the mare - or the height of the mare came up into the rille far enough to - to cover all that delta area. So all you see now is what would look like a - a - a river into a lake who's elevation has increased.

215:21:23 Henize: Ah, ha! Very interesting thought.

[Comm break.]

[The implication of what Al is saying is that the top surface of the mare was formed some time after the rille itself, perhaps from lavas that flowed from another source.]

[The final batch of photography before reaching the terminator is on magazine P with the 80-mm lens. Two similar frames, AS15-93-12630 and 12631 look to where the southwest edge of the Aristarchus Plateau meets Oceanus Procellarum, which is also where Vallis Schröteri runs into it. The blast marks from Aristarchus' ejecta are apparent across the mare surface. 12632 shows the southern tip of the Montes Agricola range with Dorsa Burnet running alongside. This is rephotographed soon after in frames 12636 and 12637 with the EVA floodlight visible in the foreground. The 24-km crater Schiaparelli dominates the foreground of the western mare in 12633 with the rim of Seleucus rising out above the terminator. From this image of Schiaparelli, it appears that the crater was formed before the last of the mare basalts had flowed as lava across this area as they seem to form a shoreline around the ejecta blanket. This effect can sometimes give a clue to the age of the mare and, indeed, this area is thought to be particularly young relative to the profound antiquity of the lunar surface. While most of the lunar surface is believed to be between 3 and 4 aeons old, older than almost every rock on the surface of the Earth, there is a crater to the northwest of Schiaparelli called Lichtenberg. This crater has a fading ray system indicating it formed less than 1 aeon ago, yet some of those rays have been obscured by lava which makes them younger still and the youngest recognised basalts on the Moon. Finally, AS15-93-12638 shows a triplet of small craters right next to the terminator, the largest two of which are Schiaparelli C and E.]

[The current period of Mapping Camera photography comes to an end with the arrival of the terminator and another will commence once they reach lunar sunrise.]

215:23:23 Henize: 15, this is Houston. I'm turning you over to Joe now. I'll see you on the way home tomorrow.

215:23:31 Scott: Okay, Karl. Talk to you tomorrow. Thanks for coming out so early for us.

215:23:38 Henize: It was a pleasure, believe me.

[Comm break.]

[One of the tasks just before sunrise is to photograph the solar corona using the DAC (Data Acquisition Camera), their movie camera, and a Hasselblad, both using very high speed black and white film. In preparation for this the spacecraft is maneuvered to an attitude given in the Flight Plan which will aim the forward-facing rendezvous windows in the required direction.]

215:24:43 Allen: Good morning, Yankee Clipper; this is Houston. [No answer.]
[Comm break.]

[Yankee Clipper was the name given to the CSM of the Apollo 12 mission. The CMP on this flight was none other than Dick Gordon, the backup commander of Apollo 15. The links between these two flights are very strong as Scott, Worden and Irwin, an all-Air Force crew, were backups to Conrad, Gordon and Bean, an all-Navy crew, who were renowned for the lighthearted slant they gave to their flight. While Conrad and Bean moved on to Apollo Applications (Skylab), Gordon stayed behind to the end of the lunar program.]

215:25:10 Allen: Good morning, Endeavour; this is Houston.

215:25:16 Scott: Good morning, Houston; this is Endeavour. How are you today?

215:25:19 Allen: Just fine, Dave.

215:25:27 Allen: The devil in the backup commander made me do the other.

215:25:36 Scott: Well, we're not surprised. [Long pause.]

215:26:02 Scott: Seems like that other fellow is hung up on that other flight [Apollo 12] for some reason or another.

[Long comm break.]
Public Affairs Officer - "This is Apollo Control. Some 8 minutes remaining in this 70th lunar revolution front side pass. Handover under way between Gene Kranz's flight team of flight controllers taking over from Milt Windler, maroon team. ... The lunar surface TV panoramic viewing test this morning began at about 3:53 with good quality pictures. The test was abruptly terminated about 12 minutes later when the lunar communications relay unit FM downlink went off. At the time the LCRU FM downlink was lost, small increment iris open commands were being transmitted to the camera. The LCRU does not respond to Power On commands. Troubleshooting is now under way, and an attempt to determine the reason for the loss of the Lunar Surface TV signals. Apollo 15, now in a 52.3 by 66 nautical mile orbit. Present height 54.4 nautical miles, velocity 5,373 feet per second. With some 6 minutes, 52 seconds remaining before Loss Of Signal, we'll continue to stay up live for the remainder of this front side pass. At 215 hours, 29 minutes Ground Elapsed Time, this is Apollo Control up and live."
[As part of the regular housekeeping aboard Endeavour, a fresh lithium hydroxide canister, number 18, is placed in receptacle A of the cabin ECS circuit, replacing 16 which is stowed in compartment A3, one of a row which lies across the base of the Command Module against the curve of the aft heatshield.]
215:31:38 Allen: Endeavour, this is Houston. We're about 4 minutes from LOS. You look to be in good shape to go around the corner.

215:31:48 Scott: Roger. Thank you, Houston.

[Very long comm break.]
Public Affairs Officer - "This is Apollo Control at 215 hours, 35 minutes. Apollo 15 has gone behind the Moon on its 70th revolution, out of range of ground stations now. Here in the Control Center, the handover is complete. Flight Director is Gene Kranz, CapCom, Joe Allen. At 215 hours, 36 minutes; this is Mission Control, Houston."

215:35:22 Irwin (onboard): ...

215:35:27 Worden (onboard): What?

215:35:28 Irwin (onboard): ...

215:35:30 Worden (onboard): Yes, he'll ... Follow those numbers. As long as we're in Free, it don't really make any difference whether you got P30 running or not, as far as P20 is concerned. Anyway, they don't care about it as long as we don't run it more than a half an hour.

215:36:43 Worden (onboard): No, he wanted to run the P20 through.

215:36:46 Scott (onboard): ...

215:36:49 Worden (onboard): Yes.

215:36:51 Worden (onboard): You want to do a P20 first.

215:36:54 Worden (onboard): Yes, you don't need to do that until - They - they need to have us inertial for a while. Yes. We do that calibration in this attitude. And then at...

215:37:07 Irwin (onboard): ...?

215:37:08 Worden (onboard): Yes. At 55, then we can go ahead and do a P20, and - and get into attitude and then do the P30.

215:37:22 Irwin (onboard): (Yawn) ... time for ...?

215:37:27 Worden (onboard): Hey; you know, it is. What time is that thing happening? Not for a while yet, I bet.

215:37:45 Worden (onboard): ... another 3 and a half hours.

215:40:27 Worden (onboard): Yes, ...

215:40:33 Irwin (onboard): ... What ... do? Let's see ... We're ... that bag ... Put them away...

215:40:57 Scott (onboard): Stand by and ... Come on. ... Logic ...

215:41:02 Irwin (onboard): 8700? The rest of them ...

215:41:08 Scott (onboard): ... still too ...

215:41:11 Irwin (onboard): Yes, I know.

215:41:13 Scott (onboard): Got to ... these goddam ...

215:41:18 Irwin (onboard): ...

215:41:22 Scott (onboard): ... this ...?

215:41:23 Irwin (onboard): ...

215:41:28 Worden (onboard): Yes, it's not much of a lineup - from a ...

215:41:38 Scott (onboard): ...

215:41:41 Irwin (onboard): ... What are you trying to do? ...

215:41:53 Scott (onboard): Well, if you want to get - well, what I really want to do is make sure we got helmets and gloves ... Be right back.

215:42:00 Irwin (onboard): Where you going?

215:42:01 Scott (onboard): I got to put your - I got to put my helmet ... my EV gloves. The rest of your helmet, Jim, will go with my helmet and your ...

215:42:21 Irwin (onboard): Yes, put them down there. ...

215:42:32 Scott (onboard): ... out?

215:42:33 Irwin (onboard): ... umbilical and ...

215:42:44 Scott (onboard): ... going to do it just like you used to do it with a checklist back when ...

215:42:49 Worden (onboard): Try to find that checklist ... It's part of the requirement. ... do. You're going to have to punch all these goddam switches, pardner.

215:42:59 Irwin (onboard): ... for the ... switches, let me know.

215:43:16 Worden (onboard): Who doesn't?

215:43:19 Scott (onboard): ...

215:43:28 Irwin (onboard): Just have to see.

215:44:00 Scott (onboard): We'll have to stow this stuff for TEI. ... umbilical. All this stuff for the EVA configuration, ... really ... trouble.

215:44:20 Scott (onboard): ...

215:44:21 Worden (onboard): Well, we are going to have to photograph the EVA, too. (Cleared throat)

215:44:27 Scott (onboard): I know that.

215:44:29 Worden (onboard): Okay.

215:44:30 Irwin (onboard): ..., too ....

215:44:34 Scott (onboard): Yes.

215:44:42 Worden (onboard): We better not use - use your attitude. ... The rates are low. ... I think once we get ...; otherwise, maybe we could arrange a TEI ... (Laughter)

215:44:57 Irwin (onboard): Yes.

215:44:58 Worden (onboard): Well, TEI, all we really need to do is ...

215:45:05 Scott (onboard): Sounds like you're trying to get out of EVA ... Tomorrow, ... take a little...

215:45:10 Worden (onboard): Yes.

215:45:11 Scott (onboard): ...reshuffling. So, if you can go now, ... some reasonable point ... EVA prep. We can try it, anyhow; because tomorrow, when I'm trying to get things squared away for the EVA prep, by the time we can ... the EVA prepping ... It'll be late tomorrow before we even ...

215:46:04 Irwin (onboard): Yes. We can get all that stuff done ...

215:46:08 Scott (onboard): Yes.

215:46:13 Worden (onboard): Got lots of stuff to be ...

215:46:15 Irwin (onboard): ... for these? Oh! ...

215:46:23 Scott (onboard): ... Yes. Well, we can't really use those on this EVA. ...

215:46:30 Irwin (onboard): Yes.

215:46:34 Worden (onboard): Watch it now. ... coming up ...

215:46:40 Scott (onboard): ... Where will we have to go with - Well, let's put it in this ...

215:46:48 Worden (onboard): It's getting ...

215:47:02 Scott (onboard): ...

215:47:04 Irwin (onboard): What?

215:47:05 Scott (onboard): I said, "Why don't we ...?"

215:47:08 Irwin (onboard): Yes.

215:48:01 Worden (onboard): Well, we got the pan camera figured out for the new whole show, huh?

215:48:04 Irwin (onboard): Really?

215:48:08 Worden (onboard): (Laughter).

215:48:10 Irwin (onboard): Stop laughing, you son of a gun, you ...

215:48:12 Worden (onboard): I - I'm happy that it's even ready to come to, it's such a complicated bunch of shit.

215:48:25 Worden (onboard): Okay, these return pictures should come out in the ... see what happens ...

215:48:57 Worden (onboard): Another - Yes. As soon as we get through this other color, you can hand me that other mag, and I'll get set up for the Earth pictures. I think I'll keep holding it. ... your problem. Why don't...

215:49:12 Irwin (onboard): You know, this thing's ... about 30 degrees ...

215:49:17 Scott (onboard): That right?

215:49:21 Worden (onboard): ... that thing somewhere.

215:49:28 Irwin (onboard): ...

215:49:41 Irwin (onboard): ... would you hold that thing?

215:49:43 Scott (onboard): Damn right. Just sitting there, looking at the Moon.

215:50:12 Scott (onboard): ...

215:50:19 Worden (onboard): ... all right? ... What'd I do with my mag. Here it is.

215:50:27 Scott (onboard): Did you take that cover off?

215:50:29 Worden (onboard): No, not lately ....

215:50:30 Irwin (onboard): ...

215:50:32 Worden (onboard): Huh?

215:50:33 Irwin (onboard): Take that ...

215:50:45 Irwin (onboard): ...

215:50:48 Worden (onboard): Move it up a little.

215:50:51 Irwin (onboard): ...

215:51:00 Worden (onboard): ... Yes, take these a little bit later.

215:51:11 Worden (onboard): How's that?

215:51:13 Irwin (onboard): That's about the only way you can get them.

215:51:15 Worden (onboard): ...

215:51:21 Irwin (onboard): Try to move them.

215:51:25 Worden (onboard): What?

215:51:26 Irwin (onboard): Try to move them up one.

215:51:28 Worden (onboard): Yes. No?

215:51:37 Irwin (onboard): Just going to leave these tied down.

215:51:45 Worden (onboard): ... vertical?

215:51:57 Scott (onboard): Hey, watch the ... Be sure you don't get any of the crap out of that one.

215:52:06 Worden (onboard): Yes.

215:52:07 Scott (onboard): You ...?

215:52:10 Worden (onboard): Yes, that was my Hasselblad pack right here.

215:52:12 Scott (onboard): Well, that wouldn't ...

215:52:18 Irwin (onboard): Really need to take a Hasselblad mag with you.

215:52:20 Worden (onboard): Yes, give me a Hasselblad mag ...

215:52:24 Irwin (onboard): ...

215:52:29 Worden (onboard): Yes, you're right.

215:52:30 Irwin (onboard): ...

215:52:43 Irwin (onboard): ...

215:52:46 Worden (onboard): Yes.

215:53:03 Worden (onboard): ...

215:53:08 Irwin (onboard): All you really need ...

215:53:12 Worden (onboard): ...

215:53:14 Irwin (onboard): Yes.

215:53:15 Worden (onboard): Okay.

215:53:25 Irwin (onboard): Mine's here. ...

215:53:31 Worden (onboard): Here are mine, okay. ...

215:53:37 Irwin (onboard): ...

215:53:40 Worden (onboard): I'll take them.

215:53:47 Irwin (onboard): ...

215:53:50 Worden (onboard): How you like them? Okay?

215:53:52 Irwin (onboard): ...

215:53:59 Worden (onboard): Look for yours, pal.

215:54:00 Irwin (onboard): (Laughter).

215:54:04 Worden (onboard): You should be proud - you should be proud of yourself, Jim.

215:54:16 Worden (onboard): Do you intend ignoring that question? Are you a naive ...?

215:54:24 Irwin (onboard): I answered it. Hey, you got to get your...

215:54:26 Worden (onboard): God! What a posthole digger.

215:54:29 Irwin (onboard): Chief priority. Time to do the P20 .... do it?

215:54:37 Worden (onboard): ...

215:54:44 Irwin (onboard): Oh ....

215:55:17 Irwin (onboard): ...

215:55:25 Worden (onboard): Jim, how long has it been since weight? ... says part 1 - part 2, part 2. All the rest of you ready?

215:55:36 Irwin (onboard): Yes.

215:55:38 Worden (onboard): DAC should be set for right now. Got to notify the ...

215:55:50 Irwin (onboard): ...

215:56:07 Worden (onboard): Y'all noticing that all that noise is gone?

215:56:11 Irwin (onboard): What?

215:56:12 Scott (onboard): I don't know if ...

215:57:13 Worden (onboard): You ignoring that Flight Plan?

215:57:15 Irwin (onboard): Cut it.

215:57:17 Worden (onboard): Aw, you ain't that bad. Catch it, son.

215:57:23 Irwin (onboard): ... won't come down. Help me?

215:57:45 Worden (onboard): All right, God damn you, come help me.

215:57:49 Scott (onboard): Boy, oh, boy.

215:57:51 Irwin (onboard): All these mags ... 2 and a half by 2 millimeter. ...

215:58:01 Worden (onboard): ... bracket.

215:58:03 Irwin (onboard): Got a ... bracket.

215:58:04 Worden (onboard): That's 80 millimeter ... up there.

215:58:10 Irwin (onboard): No .... I gave it to you.

215:58:33 Worden (onboard): Hope you don't roll the ... back in there.

215:58:38 Irwin (onboard): Can't believe it.

215:58:42 Worden (onboard): Ahl Okay, 2.8, 1/500th, and click one off - which I just blew.

215:59:00 Worden (onboard): Okay .

215:59:14 Scott (onboard): Hey, what time did...

215:59:17 Worden (onboard): Yes.

215:59:18 Scott (onboard): Got that one?

215:59:19 Worden (onboard): Yes, that at the - T-start time, yes.

215:59:21 Scott (onboard): Yes.

215:59:26 Worden (onboard): That solar corona is kind of interesting. You might watch it out the window there. You - you can really - you can really see it.

215:59:42 Worden (onboard): That's right.

215:59:44 Scott (onboard): Are you going ... from here?

215:59:46 Worden (onboard): Well, Enter. That doesn't work right. Oh, you're trying to Enter on Noun 18.

216:00:00 Scott (onboard): Oh, my. I've got to have a Noun.

216:00:09 Worden (onboard): Noun 18 is attitude. Gimbal angles. There's time.

216:00:19 Scott (onboard): Well, ...

216:00:20 Worden (onboard): You loaded - you loaded gimbal angles, to drive to, for some reason.

216:00:25 Scott (onboard): ...

216:00:27 Worden (onboard): Is it going there? You changed the gimbal angles in - in P20.

216:00:33 Scott (onboard): Why didn't I get a P50?

216:00:38 Worden (onboard): Because you were probably already - you were probably just getting to the P20 attitude.

216:00:41 Scott (onboard): ... each time. Why don't we both do 20? You've taken up enough pictures.

216:00:48 Worden (onboard): Did you Enter on the re - Did you Enter on it when you got to the attitude?

216:00:54 Scott (onboard): No.

216:00:55 Worden (onboard): Well, that - Okay. Call up P20 again and go through that. Okay.

216:01:03 Scott (onboard): I get a Noun 18 ... Noun 78. ... Noun 18.

216:01:12 Worden (onboard): What'd you do?

216:01:13 Scott (onboard): ... option 5?

216:01:16 Worden (onboard): Yes. Option 5. Yes.

216:01:24 Scott (onboard): You ... another 20?

216:01:26 Worden (onboard): Okay? Go.

216:01:28 Scott (onboard): 5.1. ... ?

216:01:29 Worden (onboard): Yes...

216:01:30 Scott (onboard): ...? 5.2?

216:01:31 Worden (onboard): That's good.

216:01:32 Scott (onboard): ...?

216:01:37 Worden (onboard): Oh, it wasn't to the attitude yet, Dave. No wonder. You're in - you're in Hold over there.

216:01:46 Scott (onboard): Sure enough.

216:01:48 Worden (onboard): Oh! Blew it!

216:01:53 Scott (onboard): Well, all I know is I got that needle.

216:01:54 Worden (onboard): Sure. We're in Low Rate.

216:01:58 Scott (onboard): ... needle ...

216:02:09 Irwin (onboard): All I know is...

216:02:10 Scott (onboard): Can I load P30 now?

216:02:11 Worden (onboard): No.

216:02:12 Scott (onboard): ...

216:02:13 Worden (onboard): No. Not when we're in maneuver. They won't let you in.

216:02:22 Scott (onboard): So that's what I did wrong.

216:02:24 Worden (onboard): Yes. That's why you - that's why you loaded...

216:02:25 Scott (onboard): I heard...

216:02:26 Worden (onboard): ...the Noun 18.

216:02:27 Scott (onboard): Well, I thought you said...

216:02:28 Worden (onboard): It'll come up in a major mode but you won't get...

216:02:29 Scott (onboard): Oh, I thought...

216:02:30 Worden (onboard): ...You won't get a time display. Yes. You can't; it shuts off the power to display, like a Noun 18.

[Flight Plan page 3-328.]

[While Endeavour is in the darkness of lunar night, two cameras are prepared with very high speed black and white film for photography of the solar corona as it appears just prior to sunlight. The DAC with magazine H and a Hasselblad with magazine R are mounted in brackets looking out of window 4, the right hand rendezvous window.]

[At 216:03:55, the mission timer is started which will provide a reference for taking shots. When it reaches 5 minutes, the DAC is started at 1 frame per second and a shutter speed of 1/125th of a second. At 6:40 on the timer, its shutter speed is changed to 1/500th. At 6:50 and every 10 seconds thereafter, a frame is taken on the Hasselblad starting at 1 second exposure, then 1/4 then reducing the exposure by one stop with every frame until they get to 1/500th. At 8 minutes on the timer, the DAC is stopped, both cameras are cycled to fresh film and the Hasselblad prepared for colour photography during the coming daylit pass. 13 images are catalogued in the Apollo 15 Hasselblad Index but were not available for this Journal at the time of writing.]

[Orbit 71 begins about 23 minutes before AOS at about 215:56 and the spacecraft meets the sunlight 14 minutes later. At 216:18:30, as the spacecraft crosses the terminator, the Mapping Camera begins an hour-long period of photography looking to the south, 40° away from vertical.]

216:03:01 Worden (onboard): That T-start is right now, too.

216:03:04 Scott (onboard): ...

216:03:07 Worden (onboard): Uh...

216:03:12 Scott (onboard): 216.

216:03:14 Worden (onboard): 216:03. That's right.

216:03:16 Scott (onboard): We have 15 minutes.

216:03:18 Worden (onboard): No, we're at 216:03 right now.

216:03:23 Scott (onboard): ... We'll never complete ...

216:03:28 Worden (onboard): Yes, we will. That's been all - Well, let's see. Let's get the stick and put in a higher rate in the DAP. Jim?

216:03:35 Irwin (onboard): Get the stick?

216:03:36 Worden (onboard): Yes.

216:03:50 Worden (onboard): What the hell's that 111. Okay.

216:04:03 Worden (onboard): Okay. I think that does it. I should have played a 3 while I was at it. Huh.

216:04:12 Irwin (onboard): What?

216:04:13 Worden (onboard): I should have put in a 3 and really zapped it around.

216:04:26 Scott (onboard): Three ...

216:04:28 Worden (onboard): Yes.

216:04:29 Scott (onboard): Three is a what? ...?

216:04:31 Worden (onboard): Three is 2 degrees per second. We better do it.

216:04:34 Scott (onboard): ...

216:04:35 Worden (onboard): I don't know if I can hit the stick again, only -

216:04:41 Scott (onboard): How about the boom? Is that extended?

216:04:43 Worden (onboard): We got the boom now?

216:04:44 Scott (onboard): I don't know.

216:04:46 Worden (onboard): Well, what's the Flight Plan say?

216:04:51 Scott (onboard): Yes, better not.

216:04:52 Worden (onboard): Better not. Yes.

216:04:54 Scott (onboard): You want the ..., don't you? ...

216:04:58 Worden (onboard): Yes, we're almost there.

216:05:00 Scott (onboard): Okay.

216:05:01 Worden (onboard): Yes, we don't have to start here until - Got 5 minutes left - 80 - 8:55.

216:05:11 Scott (onboard): Why is that coming up? Why didn't it come down?

216:05:14 Irwin (onboard): Because the mission timer starts .... Flight Plan ...

216:05:18 Worden (onboard): Yes, because - yes, because of that one.

216:05:20 Scott (onboard): ...?

216:05:21 Worden (onboard): No, this is the mission timer. That - this was - this - Yes?

216:05:26 Scott (onboard): Mission timer, do you set the start and T-stop ...?

216:05:29 Worden (onboard): That's right. No. We're not doing it because we're using P30 instead.

216:05:33 Scott (onboard): Be cool if we set the mission timer anyway.

216:05:35 Worden (onboard): Oh, yes. Sure.

216:05:37 Scott (onboard): And use our GET?

216:05:38 Worden (onboard): You can get it off the DSKY. Hell, the goddam thing's already stopped twice - on its own.

216:05:45 Scott (onboard): What? This one stopped twice?

216:05:46 Worden (onboard): Yes.

216:05:47 Scott (onboard): Really?

216:05:48 Worden (onboard): Yes.

216:06:03 Worden (onboard): You can't read that DET from over here.

216:06:06 Scott (onboard): What?

216:06:07 Worden (onboard): You can't read it from over here to begin with.

216:06:14 Irwin (onboard): I got a good idea.

216:06:16 Scott (onboard): ... fails if you move.

216:06:21 Worden (onboard): Well, you - you got the date.

216:06:24 Scott (onboard): ...

216:06:26 Worden (onboard): Yes. You tried G&N and comp fail?

216:06:30 Scott (onboard): Yes.

216:06:31 Worden (onboard): You tried G&N and comp fail? You're screwed anyway.

216:06:36 Scott (onboard): Better start getting our ... TEI.

216:06:43 Worden (onboard): Well, I think that's - kind of pushing the rules.

216:06:56 Irwin (onboard): Y'all are getting freaked up.

216:06:58 Worden (onboard): Yes. We might.

216:07:05 Scott (onboard): Need a piece of tape. Ought to be a piece of tape around here somewhere.

216:07:13 Irwin (onboard): Yes.

216:07:14 Scott (onboard): Okay.

216:07:15 Worden (onboard): Are you there?

216:07:16 Scott (onboard): Okay.

216:07:17 Worden (onboard): Yes, call up P30 and put those numbers in the -

216:07:45 Scott (onboard): Yes ... zero.

216:07:47 Worden (onboard): I'd just - Yes, I'd just leave all those in there or just load it zero. Okay .... Doesn't make any difference.

216:08:12 Scott (onboard): Got 417.

216:08:16 Irwin (onboard): ... Free? You want to let it be for a while?

216:08:20 Worden (onboard): Yes, we should. On, no, wait. No, that's okay. Those maniacs can wait on Dave. It won't damp.

216:08:28 Scott (onboard): Huh?

216:08:29 Worden (onboard): It won't damp because we're in Orb Rate.

216:08:31 Scott (onboard): You want to go Free?

216:08:32 Worden (onboard): Yes. Okay. Okay, now - look at those times and remember them, Dave.

216:08:43 Scott (onboard): Okay.

216:08:44 Worden (onboard): It starts - Well, the first one's at 5 minutes and then we go 6:40 and every 10 seconds after that. Okay?

216:08:51 Scott (onboard): You ... for that?

216:08:52 Worden (onboard): Yes.

216:08:55 Scott (onboard): Got it.

216:08:56 Worden (onboard): Okay, you ready? Okay.

216:08:59 Scott (onboard): Mark. One cycle.

216:09:35 Scott (onboard): Oh!

216:09:40 Worden (onboard): Now turn out all the MDC lights, and just let - watch the DSKY LEB - if - if you can find one down there.

216:09:48 Scott (onboard): Mark. Forty.

216:09:50 Worden (onboard): Yes.

216:10:15 Scott (onboard): Forty.

216:10:16 Worden (onboard): Okay.

216:10:24 Scott (onboard): Thirty.

216:10:34 Worden (onboard): Okay.

216:10:35 Scott (onboard): Mark.

216:10:36 Worden (onboard): Okay, I got the time. You can watch, if you want.

216:10:41 Scott (onboard): You want a mark at 2:50?

216:10:42 Worden (onboard): Yes. No, I'll - I'll get it. Just watch out the window.

216:10:45 Scott (onboard): Mark. 2:50.

216:10:46 Worden (onboard): Enjoy the scenery.

216:11:46 Worden (onboard): If that time is good enough, boy, you wait. At 8 minutes, the Sun'll show.

216:11:51 Scott (onboard): Fifty-five.

216:11:52 Worden (onboard): Yes.

216:11:53 Scott (onboard): Ga! Boy!

216:11:55 Worden (onboard): Isn't that something?

216:11:56 Scott (onboard): Woo-hooo!

216:11:57 Worden (onboard): Isn't that something?

216:11:58 Scott (onboard): Yes, man!

216:11:59 Worden (onboard): (Laughter)

216:12:00 Scott (onboard): Woo-hoo-hooo!

216:12:01 Worden (onboard): I thought you'd like that (laughter).

216:12:02 Scott (onboard): That's something again! (Laughter) Wheeel

216:12:04 Worden (onboard): Okay - DAC off.

216:12:07 Scott (onboard): That's something ...

216:12:09 Irwin (onboard): ... Cycle one frame.

216:12:11 Scott (onboard): Okay (laughter). Boy, I love stuff like that.

216:12:19 Worden (onboard): Now that's pretty spectacular.

216:12:21 Scott (onboard): It sure is. That's just right between the eyeballs.

216:12:23 Worden (onboard): Yes. You don't expect it. Oh, yesl Okay. Okay, lift the ... away. Oh, we got - we got a little time. No - there's no big rush.

216:12:46 Irwin (onboard): Okay, remove DAC from window, cover lens, and run at 24 frames per second.

216:12:49 Worden (onboard): Yes.

216:12:51 Irwin (onboard): Shutter speed, 1/500th, for 2 seconds.

216:12:54 Worden (onboard): Yes.

216:13:04 Irwin (onboard): Cover lens?

216:13:05 Worden (onboard): Yes.

216:13:12 Irwin (onboard): CMC Mode, Auto. Record the mag.

216:13:25 Worden (onboard): Okay, we're down to about - oh, 60 percent of the frame, I guess.

216:13:33 Irwin (onboard): Sixty percent?

216:13:34 Worden (onboard): Sixty percent of the MAG, yes.

216:13:35 Irwin (onboard): How about your frame?

216:13:46 Worden (onboard): 100.

216:13:49 Irwin (onboard): Okay.

216:13:56 Worden (onboard): Yes.

216:13:58 Irwin (onboard): ... what?

216:14:00 Worden (onboard): Now, which one you want to use? Use this one?

216:14:27 Worden (onboard): Okay, we got 1/125th, got...

216:14:29 Irwin (onboard): What's your mag number? Need that.

216:14:31 Worden (onboard): ... Yes.

216:15:18 Worden (onboard): Okay ... get it up there and get it going , we'll be all right .... Why don't you run one across this way? Now hold it.

216:15:58 Worden (onboard): Okay, I want back ... Yes, that ought to do it. Run this one down through here.

216:16:05 Irwin (onboard): ...

216:16:08 Worden (onboard): What?

216:16:09 Irwin (onboard): I don't think you guys'll make it, frankly.

216:16:11 Worden (onboard): No (grunt).

216:16:35 Worden (onboard): ... back it off. Oh, yes, that's right. We don't move now, anyway.

216:16:52 Worden (onboard): Okay.

216:17:10 Irwin (onboard): ...

216:17:15 Worden (onboard): Did you let the ... down?

216:17:18 Scott (onboard): No.

216:17:21 Irwin (onboard): ...

216:17:22 Worden (onboard): Yes.

216:17:23 Irwin (onboard): ...

216:17:24 Worden (onboard): Huh! (Sigh) Okay.

216:17:44 Irwin (onboard): ...

216:17:46 Worden (onboard): Yes, we got it. Is that what you got on there?

216:18:00 Scott (onboard): ...

216:18:07 Worden (onboard): Rate's down.

216:18:13 Scott (onboard): ...

216:18:17 Worden (onboard): Yes. That's - that's about right, Dave.

216:18:21 Scott (onboard): ...

216:18:22 Worden (onboard): Huh?

216:18:24 Scott (onboard): ...

216:18:35 Worden (onboard): Yes. Okay.

Public Affairs Officer - "This is Apollo Control at 216 hours, 20 minutes. We're about a minute away from Acquisition Of Signal. At approximately 9 o'clock this morning, on the television monitors in the news center, we will replay the video tape of this morning's test of the lunar surface television camera. This will be a video tape replay - will be video only, no audio. This test started at 3:53 a.m. Central Daylight Time, this morning, lasted for approximately 12 minutes when the FM downlink from the lunar communications relay unit was lost. The LCRU has not responded to Power On command since that time, and this problem is still being studied. We'll stand by now for AOS on Endeavour."

216:25:37 Scott (onboard): Did we do a P20?

216:25:38 Worden (onboard): Yes.

216:25:41 Scott (onboard): I thought we called P20 now, Al.

216:25:43 Worden (onboard): Yes, just recall P20. It should do it itself. No, if you get the Uplink Activity light, that means it's gone outside the 10-degree dead band, in which case you have to do a Verb 58 - to get back in.

216:26:21 Allen: Hello, Endeavour, this is Houston requesting Reacq and Narrow on the High Gain [Antenna]. [No answer.]

216:26:43 Allen: Apollo 15, Apollo 15. Houston requesting Reacq and Narrow on the High Gain.

[Comm break.]

[The routine procedure each time Apollo 15 reaches AOS is for the crew to position the HGA (High Gain Antenna) to angles given in the Flight Plan. These are based on the expected spacecraft attitude at AOS. The beamwidth of the antenna is set to Wide so that some signal will be received even with pointing errors. Once a crewmember gets the antenna within range of Earth and sees an appropriate indication on a meter, he switches it to Reacq(uire) and Narrow (beamwidth) whereupon it automatically homes in on its target. Houston are getting a weak signal and believe that the crew have not selected Reacq.]

216:28:40 Worden: Hello, Houston; 15.

216:28:42 Allen: Hello, 15; this is Houston.

216:28:47 Worden: Okay, Joe. We're reading you and we were in Reacq and Narrow and couldn't seem to pick you up, so we're back in Manual and Medium [beamwidth] now.

216:28:58 Allen: Okay, Al; we copy that. Thank you. While we're thinking about that one, we've got a couple of requests for you here. We'd like for you to turn on your RCS Propellant, Secondary. We're expecting a crossover in the D and C quads during the shape ullage, and we can, I guess, use those on now. And I've got some small changes to your Flight Plan when you are ready to copy.

[Allen's request about the spacecraft's RCS propellants highlights some of the interesting ways in which consumables are managed by Houston. Remaining propellant quantities in the four jet clusters are not directly measured (a difficult thing to do in a zero-g environment). Instead, indirect methods are used based on telemetered readings from the helium pressurisation system, thruster usage, system history and the like. However, by this stage of the mission, errors in these methods may have built up and it would be desirable to have some way to firm up their knowledge of what is left.]

[The propellants for each RCS quad are stored in two pairs of tanks; primary fuel and oxidiser and secondary fuel and oxidiser; four tanks in all. The quantity of propellant in the secondary tanks comprises 39.5% of the total available and so when they switch to it, they know this is the quantity remaining. It gives them an accurate data point to work from as they keep track of the RCS quantities for the rest of the mission. To avoid running the primary tank to empty, this 'crossover' is carried out when the total has been calculated to have reached 43% remaining.]

[Houston estimate that the C and D quads will require switching over to the secondary tanks during the RCS burn that settles the SPS propellants prior to the upcoming orbit shaping burn, therefore Houston wants all the quads switched over.]

[This coming near-side pass is the crew's last major photo opportunity before they begin preparing to come home. The picture taking begins on magazine P and the 80-mm lens with AS15-93-12639, a stark portrait of the crescent Earth. It continues with an 18-frame sequence of the 207-km crater Humboldt, photo target 13 in the Flight Plan, looking to the south with the Sun illuminating from the west. A composite image of frames AS15-93-12640, 41, 43, 44, 45 and 46 shows the crater well and the features within. To the east is a triplet of craters, one of which is an unusual double crater. In the centre, part of a mountain range forms the focus of a splendid network of rilles, both radial and arcuate. Humboldt shares some common features with Alphonsus, another large, flat-floored crater. Both have dark patches on their floors and both have been the site of "Transient Lunar Phenomena", unexplained activity seen from Earth. Subsequent images in this sequence, AS15-93-12647 to 12657, essentially cover the same ground seen in the composite. Paul Spudis is a geologist at the Lunar and Planetary Institute in Houston.]

[Paul Spudis, from 2000 correspondence - "Humboldt is one of a class of features on the Moon known as 'floor-fractured craters' These craters have anomalously shallow floors and extensional features (cracks) on the floor. Often, they are partly filled with later, volcanic lava."]

["The thought is that these craters were originally normal impact craters, but have been modified by internal processes. Specifically, liquid magma, injected underneath the crater floor, would (1) shallow the crater; (2) uplift and dome the floor; (3) create an extensional stress field, resulting in cracks; (4) possibly permit lava to reach the surface, accounting for the partial lava flooding."]

["The 'double-crater' on the floor of Humboldt is an unrelated feature. It's not known how these 'doughnut craters' form, but there are several scattered around the Moon. For small craters (a few hundred meters in diameter), they indicate a solid, bedrock substrate beneath a fragmental over-layer, but the one in Humboldt is quite large (almost 10 km in diameter) and I suspect instead that these double craters represent impacts of clots of debris or clouds of fine debris, either a broken up, fragmented asteroid or it is a secondary crater."]

216:29:34 Worden: Okay Joe, I'm ready to copy the changes in Flight Plan.

216:29:40 Allen: Okay, Jim. I assume you're reading me loud and clear. You're still a little bit - have a little noise in the background. If you have your Flight Plan in front of you, the first entry is at 217 plus 17 and it is an addition. "Retract Map Camera". The next one is at 217 plus 21. Addition: "Close Map Camera and Laser Experiment Covers". The third is at 217 plus 58; delete those two lines: "O2 heater, three, Auto; O2 heaters 1 and 2, Off". Those are two deletions. Another deletion...

216:30:53 Worden: Okay. Let me read that back to you, Joe.

216:30:54 Allen: Okay, fine, Jim.

216:31:00 Worden: You have 217:17, retract the Mapping Camera and 217:21, close Map Camera and Laser Covers. And then the deletion at 217:58 of the O2 heaters, three, and O2 heaters 1 and 2.

216:31:24 Allen: That's correct, Jim. And the next change is - it's a deletion at 218:02, and that is delete the "PCM cable" line, there. And down a couple of inches, at 218:08, an addition: "Map Camera and Laser Experiment Covers to Open, and extend Map Camera". Read back.

216:32:11 Worden: Okay. I understand to delete the PCM cable at 218:02, and then at 218:08, Map Camera and Laser Covers Open, and Extend Mapping Camera.

216:32:23 Allen: The readback is correct and the next - next change is at 219:07; and once again, delete the "PCM cable" line. And at 219:17 add "Laser Altimeter, Off; Close Map Camera and Laser Experiment Covers", and delete Map Camera extension. And the last addition, that is to say the last change, is at 220 plus 05, delete the "PCM cable" line. Over.

216:32:33 Worden: Okay. I copied 220:05, delete the PCM cable, and go on back to [the] page fore - before, we deleted the PCM cable there at 219:07. And 219:17, a new item, Laser Altimeter, Off. Close Mapping Camera and Laser Experiment covers, and then delete the next line - the "Map Camera Track to Extend".

216:34:05 Allen: Sounds good, Jim, and that's all I have for the moment. We do want a verification that all four propellant secondaries are opened on your RCS, please.

216:34:26 Worden: Okay. That's verified. Just opened them.

216:34:29 Allen: Okay. Thank you.

[Comm break.]

[This is a reminder that the valves to the secondary tanks in each RCS quad are still to be opened.]

216:37:00 Allen: Endeavour, this is Houston. We'd like Auto on the High Gain [Antenna], please, and we show your optics in the CMC Mode. We'd like that zeroed at your convenience, please.

216:37:19 Worden: Auto, and zeroed.

[Very long comm break.]

[An additional task at this point is to power up the Panoramic Camera to allow Mission Control to monitor it. It will be switched off when the ground lets them know they are happy.]

[Endeavour is coasting across the prominent crater Langrenus to the south east of Mare Fecunditatis. On magazine P and a 250-mm lens, frame AS15-93-12658 looks WNW across the mare. Langrenus FF (nearest camera) and FE (beyond and to the right) lead to the largest crater in the picture, the 13-km Lindbergh. Various light rays sweep across the mare and the light feature near the horizon and to the right is Messier. AS15-93-12659 looks down to the western rim of Langrenus showing the extensive slumping that has taken place. Using the 500-mm lens on magazine OO, AS15-92-12510 and 12511 cover the central peak cluster of Langrenus.]

[At 216:40, the Panoramic Camera is powered for a few minutes while Mission Control check its health by telemetry. Once happy, they will ask for it to be switched off again.]

[On magazine P, AS15-93-12660 is another view WNW across Mare Fecunditatis with the Messier twins and their double ray becoming more dominant. To the right of the twins is Messier B. AS15-93-12661, 12662 and 12663 are taken at the end of the double ray from Messier, where it meets the highlands bordering Fecunditatis. A distinctly pear-shaped crater, Lubbock H, is visible along with an extension to the Rimae Goclenius system of rilles. Frames AS15-93-12664 and 12665 are a view west to the shore of Mare Tranquillitatis and the bright ray crater Censorinus.]

[Censorinus is also the subject of four images, AS15-92-12512 to 12515, taken on magazine OO with the long telephoto lens. Within Mare Tranquillitatis is a ring of hills which are the remnants of an inundated crater, Maskelyne F. Under the very high Sun, these hills stand out light-coloured against the mare, as seen in a compilation of AS15-92-12516 to 12518. Frames 12519 to 12522 pinpoint areas northwest of Maskelyne F which come under the heading of special features showing pits, mounds and a crater. Frames 12523 to 12525 are of a small, 6-km pit formerly called Maskelyne H but now named after Otto Wallach, 1847-1931, a chemist from Germany. Wallach is sited about 90 km from Maskelyne next to a cluster of low hills.]

[Another assortment of features on Mare Tranquillitatis are brought together in a montage comprising AS15-92-12526, 28, 29, 31, 33, 34, 35 and 37. These are all in the region of Carrel, a 16-km crater whose southwestern rim is shown in AS15-92-12532. Frame AS15-92-12538 shows an elongated crater, Arago E, and to its west a wrinkle ridge. This ridge is part of a system of radial ridges across the mare which emanate from the ghost crater Lamont which itself only exists as a circular series of wrinkle. All these ridges arise from compression stresses in the basalt sheet that form the mare. Those that form Lamont may be purely due to the distribution of these stresses or they may betray the presence of a subdued impact structure.]

[The photo index places AS15-92-12539 as showing part of crater Sosigenes but I have been unable to correlate it on the maps. A 30-km ridge stretching south-southwest from Al-Bakri is shown in three frames, AS15-92-12540, 41 and 42. The northeast rim of Al-Bakri itself along with a small, bright crater are seen in AS15-92-12543.]

[Returning to the colour film on magazine P, four frames, AS15-93-12666 to 12669, look northwest across Mare Tranquillitatis with the Montes Haemus range on the horizon and Mare Serenitatis beyond. The major craters visible in this montage begin with Carrel, formerly Jansen B but now named after Alexis Carrel, 1873-1944, a French biologist who became a Nobel Laureate for Medicine in 1912. Ross D lies in the middle ground and to its left, only partially visible is Ross itself. The bright patch this side of the mountains is Al-Bakri. The camera is then turned to the SSW for a 5-frame pan of the southern shore of Mare Tranquillitatis, including Moltke on the left and Sabine partially visible on the extreme right using frames AS15-93 12670 to 12674. Frame AS15-93-12675 and 12677 show Sosigenes A and the expansion-induced rille system at the western margin of the mare. An unusual elongated feature crosses the rilles nearly perpendicular to them. This may be a collapsed volcanic lava feature rather than an impact scar. The rilles continue south past Ariadaeus, seen in AS15-93-12676. This is part of a double crater as it directly abuts Ariadaeus A. Ariadaeus E is the flooded embayment just in front of the pair and at the bottom of the photograph is Sosigenes C.]

216:49:12 Allen: Endeavour, Pan Camera Power, Off, please.

216:49:20 Worden: Roger. Pan Camera, Off.

216:49:23 Allen: Thank you.

[Comm break.]
216:51:29 Allen: Hello, Endeavour. This is Houston with photography PADs and a TEI-73 PAD, when you're ready.

216:51:43 Irwin: Okay, Joe. I'm ready to copy the photo PADs.

216:51:50 Allen: Okay, Jim. I've got a Map Camera photo PAD, a Pan Camera PAD, and a Terminator photo PAD for you. And before I start, just a word of explanation. Because of your change of trajectory from what we considered a nominal one, we've got some details to add to the PAD that involve image-motion setting changes and exposure changes. And I'll read those in detail, in a moment. I just wanted to give you a word of explanation on it. The first PAD is the Map Camera photo PAD copied at 217 plus 10; and at 217 plus 10 it is T-start: 218 plus 16 plus 59, T-stop: 219 plus 16 plus 44. Over.

216:53:01 Irwin: Roger. Copy. 218:16:59; 219:16:44.

[As Jim continues with his secretarial duties, Al and Dave are busy with a camera each shooting off their excess film.]

[Woods, from 2000 correspondence - "Was there a sense of wanting to use up film rather than bring home unexposed stock?"]

[Scott, from 2000 correspondence - "Probably a sense of capturing the spectacular scenes before we departed - our high inclination ground track presented us with a great variety of superb views. And of course, why return with unexposed film?"]

[On magazine P, a sequence of four southwest-facing images pan across Boscovich, to the east of Mare Vaporum. These are AS15-93-12679 to 12682 and Boscovich is the dark, degraded bowl to the left, one of a scattering of dark-floored depressions or "lacus" (lakes) which mottle the terrain between Mare Vaporum and Mare Serenitatis. Frame 12683 features an unusual sight, a crater with a dark ejecta blanket - the vast majority have light ejecta - which may be caused by the excavation of dark subsurface material. Frames 12684 and 12685 is of the Haemus mountains, seen under a high Sun with the slopes only recognisable by the light colour of their slopes.]

[The 500-mm telephoto lens is still being used with the black and white magazine OO. Frame AS15-92-12544 looks very obliquely across some of the lakes between Mare Vaporum and Mare Serenitatis. To the left is Lacus Doloris (Lake of Suffering) with the 9-km flat-floored crater, Bowen, on its northeastern shore which is named after Ira Bowen, 1898-1973, an American astronomer. To the right is Lacus Odii (Lake of Hate). A small bright crater is the subject of the next seven images, the best of which is 12548. Frame 12552 is of a softened circular wall which is crater Menelaus S, and Menelaus itself is partially seen in frame 12553. The subsequent five images are of various small bright craters, the most interesting of which is 12558 which displays a dark streak among the much lighter crater walls.]

216:53:11 Allen: That's correct, Jim. And if you'll turn the page now, I want you to delete two lines, one at 218 plus 35 and that is "Map Camera, Image Motion, Increase, talkback barber pole, on". Delete that, and delete the line at 218 plus 55 which reads, "Map Camera, Image Motion, Increase, talkback barber pole plus four steps" et cetera. And, instead, put in the instructions: At T-start - it should be barber pole plus four. At 218 plus 39 plus 00, barber pole plus three; and at 218:49 plus 00, barber pole plus four. Readback, please.

216:54:49 Irwin: Okay, the instructions are that at T-start, it should be barber pole plus four; at 218 plus 39 plus 00, barber pole plus three; at 218 plus 49 plus 00, barber pole plus four.

216:55:08 Allen: That's correct, Jim. And those are your image-motion settings, and you're to delete the other two image-motion instructions in the Flight Plan. One at 218:35 and the other at 218:55, and I know you got that. The second...

216:55:29 Irwin: Yes, I made those two deletions.

216:55:31 Allen: Okay, the second is the terminator photo PAD to copy at 218 plus 07. And it is T-start: 218 plus 15 plus 19. Over.

216:55:54 Irwin: 218:15:19.

216:55:55 Allen: Roger. And finally, the Pan Camera photo PAD. Copy at 218 plus 39. T-start: 218 plus 52 plus 55. T-stop: 219 plus 16 plus 44. And delete the two Pan Camera exposure lines. The first one at 218 plus 57. Delete that. And the second one at 219 plus 03. Delete that. And instead, use these exposure instructions. At 219 plus 00 plus 13, decrease. At 219 plus 00 plus 50, normal. At 219 plus 06 plus 35, decrease. At 219 plus 07 plus 28, normal. Readback please.

216:57:55 Irwin: Okay, I understand the instructions on the Pan Camera. Exposure at 219 plus 00 plus 13, it's decrease; 219 plus 00 plus 50, it's normal; 219 plus 06 plus 35, it's decrease; 219 plus 07 plus 28, it goes back to normal.

216:58:15 Allen: That's right, Jim. And give me the T-start and T-stop times, please.

216:58:24 Irwin: Okay, T-start was 218:52:55, and 219:16:44.

216:58:32 Allen: Sounds fine, and I'm holding TEI-73 PAD when you're ready for that.

216:58:44 Irwin: Stand by one, Joe.

[Comm break.]

[Flight Plan page 3-329.]

[Photography continues on two cameras and the long telephoto with black and white film yields details of the landscape in and around the Apennine Mountains. Frames AS15-92-12559, 12562 and 12563 focus on a bright crater within the Apennine Bench Formation, just inside the arc of the Apennine Front. Two other shots that look at this area are 12560 and 12561, though these are somewhat difficult to place. Frames AS15-92-12564 and 12565 look down upon the Apennine Front about 50 km west of the Crater Conon and about 150 km southwest of the landing site at Hadley. AS15-92-12566 is of a curved depression at the southwestern edge of the Apennine Bench Formation.]

[Few images are taken with the 250-mm lens and colour film at this time and AS15-93-12686 and 12687 are the only two that look down to the Apennine region at this point. Soon after, this camera is trained on one of the great lunar craters, Eratosthenes, becoming visible to the crew as the Moon's rotation brings their inclined orbit over new territory.]

[Composited together from AS15-93-12688 and 12689, this view of the 58-kilometre crater is looking almost directly south. With wall terracing, flat floor and central peak, its morphology is classic for its size. However, the montage shows the rays from Copernicus, about 250 km WSW, blasted across it and its surroundings, indicating that Eratosthenes is the older formation. At one time, it would also have displayed an impressive ray system of its own but we believe that rays fade away after about an aeon or so. Both Copernicus and Eratosthenes lie on the margins of Mare Imbrium and as they both overlie the mare, they are known to be younger. All this and other evidence had lead lunar geologists to classify the ages of all lunar features as follows:

Copernican System: Applies to features up to about 1 aeon (billion years) old; impact craters with ray systems which defines them as being relatively fresh, all geological units which can be linked to these in age.

Eratosthenian System: Applies to features about 1 to 3 aeons old; slightly eroded impact craters without rays and other features that obviously postdate the maria.

Imbrian System: This includes the formation of the Imbrium and Orientale basins about 3.8 aeons ago, the filling of these and all the other basins during the major mare-laying epoch up until about 3 aeons ago and the features that can be associated with this timeframe.

Nectarian System: Applies to those features formed at the same time as the major basins, between the formation of the Nectaris and Imbrium basins.

Pre-Nectarian System: Applies to everything formed prior to Nectaris.]

217:00:01 Irwin: Okay, Joe. I'm ready here for the TEI PAD.

217:00:15 Allen: Roger, Jim. It's TEI-73, SPS/G&N: 36188; plus 0.63, plus 0.98; 221:47:42.81; plus 2883.3, minus 0661.3, minus 0195.5; 179, 128, 350. All the rest is NA. Ullage, four jets, 12 seconds. Other: the PAD assumes no shape maneuver, and it assumes the lift-off REFSMMAT. Over.

217:01:38 Irwin: Okay, Joe. TEI-73, PAD readback. SPS/G&N; 36188; plus 0.63, plus 0.98; 221:47:42.81; plus 2883.3, minus 0661.3, minus 0195.5; 179, 128, 350. Four-jet, 12 seconds; PAD assumes no shape burn, and lift-off REFSMMAT. Over.

217:02:11 Allen: Okay, Jim. Right on. Thank you.

[Comm break.]

[Interpretation of the TEI-73 PAD is as follows.

Purpose: TEI-73 is the last abort TEI PAD that will be sent to the crew, and is intended to get the crew headed home one orbit earlier than planned. The next PAD, the preliminary TEI-74 PAD, is the first estimate for the scheduled burn to get them home. :

System: The maneuver would use the Service Propulsion System, and the primary Guidance and Navigation system.

CSM Weight (Noun 47): 36,188 pounds (16,415 kg).

Pitch and yaw trim (Noun 48): +0.63° and +0.98°.

Time of ignition, Tig (Noun 33): 221 hours, 47 minutes, 42.81 seconds.

Change in velocity (Noun 81), fps (m/s): x, +2,883.3 (+878.8); y, -661.3 (-201.6); z, -195.5 (-59.6). These velocities are expressed with respect to the local vertical/local horizontal frame of reference.

Spacecraft attitude at Tig: Roll: 179°, Pitch: 128°, Yaw: 350°.

SPS propellants are settled in their tanks by firing the plus-X thrusters on all four of the Service Module RCS quads for 12 seconds.]

217:04:09 Allen: Endeavour, this is Houston.

217:04:17 Irwin: Go ahead, Joe.

217:04:19 Allen: Roger, Jim. Just for your own thinking, we'd like to advise you that we have reviewed the cue card F-K1 for the plane change burn that Al copied, and it's update is still valid for your shape burn later on. We're in the process of going over your SPS thrusting procedures on G5-1 in the checklist, and we see very - only very minor changes that we'll be coming up to you with regarding your burn later on today, so I think things are pretty well in hand down here. Over.

217:05:07 Worden: Okay, we copy. Thank you, Joe.

217:05:13 Allen: Another item regarding that, FAO wants me to urge you again just to follow the Flight Plan items regarding SIM bay operation before and after these burns coming up, and we'll get no - we'll get into no problems at all. Over.

217:05:35 Worden: Roger. Understand.

[Very long comm break.]
[Photography on this pass is completed on magazine P using the 250-mm lens. Twenty frames, AS15-93-12690 to 12709, are taken looking north, essentially letting the spacecraft's motion alter the point of view, and it is probably best to present the highlights from this selection. This is Photo Target 27 and is the area in which the Soviet-built Luna 17 landed carrying a Lunokhod unmanned rover after being launched from Earth on 10 November 1970. The Lunokhod 1 rover is still operating while Apollo 15 carries out its exploration and will finally expire in October 1971, having traversed 10.5 kilometres of Mare Imbrium.]

[Frame AS15-93-12691 looks north across Mare Imbrium with Montes Jura, the mountain range that forms the rim of Sinus Iridum, on the horizon. In the foreground are two small craters, Carlini A nearest the bottom of frame, Carlini S in the middle distance. Lighting is from the east. After a bit, Promontorium Heraclides (Hercules Promontory) comes into view in 12697. This represents the southwestern cusp of Sinus Iridum. The largest crater visible is Caroline Herschel C with Caroline Herschel U to its 4 o'clock in the picture. The wrinkle ridge adjacent to Caroline Herschel U which runs north to Sinus Iridum is shown better in 12702. In frame 12707, the camera has moved across to the light-coloured terrain that forms the northwestern margin of Mare Imbrium, just southwest of Sinus Iridum. The two major craters visible are Mairan E (smaller and near the centre) and Mairan A (larger and to the left). The tip of this light terrain ends near the crater Gruithuisen, where the basalts of Mare Imbrium and Oceanus Procellarum meet and frame 12709 shows some of the interesting features in this region. At the bottom left of the picture is Gruithuisen H and centre-right is Gruithuisen B with a branch of Dorsum Bucher running between. Beyond and to the left of Gruithuisen B are two dome-shaped hills. Nearest the crater is Mons Gruithuisen Delta and beyond is Mons Gruithuisen Gamma. Though impossible to spot in this small reproduction, this latter hill has a 900-metre craterlet at it peak, giving it a look of a unusually domed volcano.]

[East of the two domes is a low hill, seen in frame AS15-93-12710, near Caroline Herschel E, known as the Epsilon Prominence. A few more images of the Gruithuisen domes are taken before a sequence looking back towards the north. Montaged from AS15-93-12714, 12715 and 12716, this view has Sinus Iridum to the right and Mairan A on the left. The Gruithuisen domes are seen better in 12717 with Gruithuisen B to the right. The 900-metre craterlet atop Mons Gruithuisen Gamma is easily apparent. The 16-kilometre crater after which so many of these features are named is nicely framed in AS15-93-12719. Franz von Paula Gruithuisen, 1774-1852, was a German astronomer who pioneered lunar study in two opposing ways. He was the first to postulate an impact theory to explain the lunar craters, an idea now very widely accepted. However, through his active imagination, he announced the discovery of buildings and cities on the Moon, writing a book on the subject. Centuries later, there are still people who claim to detect non-human intelligent artifacts through close study of the imagery from manned and unmanned photography of the lunar surface, a concept that is very widely rejected. To the northwest of Gruithuisen is a large, dense cluster of small craters. These are likely to be secondary craters formed by the impact of a loose clump of debris, themselves ejected from a large, distant impact.]

[The final 17 images from this pass can be summarised in three montages and a frame from the Gruithuisen area. Looking vertically down at the terrain beneath them, AS15-93-12720, 12721 and 12723 show part of the Montes Harbinger range and Rimae Prinz collection of rilles. A montage made from AS15-93-12724, 12727 and 12728 shows an unnamed wrinkle ridge which runs north/south between Oceanus Procellarum and Mare Imbrium. For reference, the two craters at the very top-left corner are Gruithuisen R and S. These two craters are also shown on frame AS15-93-12733, a picture which is representative of four other frames, 12730, 31, 32 and 12734. Another montage of the two Gruithuisen domes completes the photography for this pass. Made from AS15-93-12735 and 12736, these show the domes well, including Mairan A in the distance.]

Public Affairs Officer - "This is Apollo Control at 217 hours, 17 minutes. Flight Dynamics Officer Bill Stovall has just passed to Flight Director Gene Kranz, the latest computed times for the shaping burn, and for the subsatellite jettison. These times will be updated later and they may change in the seconds, but they're very close to what the times will be. Present computation shows the shaping maneuver will be performed at 221 hours, 20 minutes, 49 seconds with the delta-V of approximately 66 feet per second. Subsatellite jettison at 222 hours, 39 minutes, 34 seconds. The resulting satellite orbit is expected to be 76.5 by 55.1 nautical miles. The longitude of perilune on that orbit, 47.6° west."
[At 217:18:15, just as the spacecraft reaches the terminator, the Mapping Camera finishes a sequence of southward facing oblique photography. Immediately after, Al maneuvers Endeavour into the "Plus-X Forward SIM Attitude" which has the spacecraft flying pointy-end forward.]
217:28:53 Allen: Endeavour, this is Houston. We have no problems at all as you come up on 5 minutes before LOS. Al, we do have a question for you, if this is a good time to ask it. Over.

217:29:09 Worden: Yes; go ahead, Joe.

217:29:11 Allen: Roger. Alfredo, we're sitting down here wondering if, perhaps, at sometime over the past few days you've gotten a visual on the Mass Spectrometer boom and unit, and if so, has it been possible at all to determine which direction the Mass Spec. might be twisting as you move through the orbit over the Moon? Over.

[As described earlier in the journal, the boom which carries the two extendible instruments is made of thin sheet metal with a natural curl to it. Its resistance to twisting forces is limited and, in the case of the Mass Spectrometer which has a directional intake, any twist might be relevant to the results obtained from the instrument.]
217:29:37 Worden: Yeah. I have seen that, Joe, and I've - haven't watched a great deal of twisting and, as a matter of fact, I was rather surprised that there wasn't more twist than what I observed. I may not have picked up the maximum deflection, but I only observed about a - maybe a 5- or 10-degree rotation of the end on the boom, and, as I recall, as I was looking at it from inside the spacecraft, the rotation was counter-clockwise.

217:30:07 Allen: Okay, Al. That's interesting information. We don't necessarily expect it to have rotated more, but just wondering if you had some good visual data for us, and that's excellent. Another comment, and it's more in the way of a reminder; during your EVA, we're going to ask you to look very closely at the V over H sensor, and the symptoms we've had concerning that sensor down here, is as though it has a small crack in the lens or perhaps there's foreign contamination of some kind down in the barrel. And we're going to ask you to look particularly for either a crack, or contamination in the barrel during the EVA. Just wanted to lay that one on you now in case we forget it later on. We'll most likely remind you of it later on.

[Mission Control are mentioning this because they have had problems with the Panoramic Camera's V over H sensor throughout the flight. Poor contrast in this device has meant that many of the frames from this camera have been slightly smeared. Al's EVA tomorrow is an opportunity to get a close look at what might be the problem, something that can very rarely be done during any space flight.]
217:31:01 Worden: Roger, Joe. I understand that one. [Long pause.]

217:31:34 Allen: Endeavour, we'd like a Pro on the P20 now, please.

217:31:48 Worden: Okay, that's in work, Joe.

[This is the maneuver, controlled by P20 in the computer, to change the attitude of the spacecraft.]
217:31:51 Allen: Roger; Jim. Thanks.

217:31:58 Worden: Yeah.

217:31:59 Allen: And, Endeavour, requesting you configure DSE now, please.

217:32:15 Worden: Okay.

217:32:39 Scott (onboard): Back to normal now.

217:32:40 Worden (onboard): Okay ....

217:32:41 Scott (onboard): Okay.

217:33:11 Scott (onboard): ...?

217:33:13 Worden (onboard): No, ... 15.

217:33:17 Allen: Endeavour. Recall the 50 18 and get the attitude, please.

[Very long comm break.]

[The "5018" refers to the computer display Verb 50, Noun 18, meaning "Please perform an Auto maneuver" though in this case they are only using it to recall the attitude angles.]

Public Affairs Officer - "This is Apollo Control at 217 hours, 34 minutes. Endeavour has gone behind the Moon on the 71st revolution and we've had Loss Of Signal."
[Endeavour's seventy second orbit of the Moon commences at about 217:55 GET. The crew's main task during this far-side pass is to get in some exercise and have their lunch. A sequence of terminator photos is to be taken on magazine R. These are AS15-98-13387 to 13397 but copies were not available at the time of writing. The Mapping Camera begins operation for the coming daylit pass at 218:17 GET and at about the same time, the Gamma-ray Spectrometer is retracted in preparation for a later test.]
217:33:27 Irwin (onboard): Well, I can do it. But...

217:33:40 Irwin (onboard): But my needles are not close to center. The needles are not very close to center.

217:33:50 Scott (onboard): I can't hear you.

217:33:51 Irwin (onboard): You can't hear me?

217:33:52 Scott (onboard): No.

217:33:54 Irwin (onboard): Well, you're not on comm. Yes.

217:34:08 Irwin (onboard): We're off about - 20 degrees in pitch.

217:34:55 Irwin (onboard): Enter.

217:34:50 Scott (onboard): ...

217:34:58 Irwin (onboard): As soon as you get the 50 18, you hit the Enter.

217:36:13 Scott (onboard): ...?

217:36:15 Irwin (onboard): Yes.

217:36:20 Scott (onboard): Now ....

217:36:34 Irwin (onboard): What?

217:36:36 Scott (onboard): ...

217:36:40 Irwin (onboard): I can't hear you. Can you get SQUELCH, ENABLE on? There's so much noise in the S-band. I can't hear anything. Yes, I can hear you now.

217:37:04 Scott (onboard): ...

217:37:12 Irwin (onboard): Why'd they tell us to PRO, then? That wasn't the right thing to do, was it?

217:37:15 Scott (onboard): ...

217:37:17 Irwin (onboard): Yes.

217:37:19 Scott (onboard): ...

217:37:21 Irwin (onboard): Yes.

217:37:23 Scott (onboard): ...

217:37:24 Irwin (onboard): Well, we had a 50 18 - flashing. But we'd already gone past the l0 degrees, apparently. And they told us to Pro.

217:37:31 Scott (onboard): ...

217:37:33 Irwin (onboard): Yes.

217:37:34 Scott (onboard): ...

217:38:55 Irwin (onboard): Dave, if you want to put this away, you can. It'd be down in - in R-13, in the camera compartment on that side. There's a bag there - you know, the mag bags from the LM.

217:39:06 Scott (onboard): ...

217:39:07 Irwin (onboard): No, let's see. Okay, yes. Right in there. See that mag bag with six in it?

217:39:19 Scott (onboard): ... right in there ...

217:39:21 Irwin (onboard): No. We have B and A, and - and that one, and there's another one that was good in there.

217:39:33 Irwin (onboard): The others just won't drive.

217:41:09 Irwin (onboard): Not bad. Did real well, Dave.

217:41:43 Irwin (onboard): I'd better be watching the Flight Plan for this page, because there are a lot of little notes I put in there that...

217:41:49 SC ...

217:41:51 Irwin (onboard): Kind of hard to understand, yes.

217:43:18 Scott (onboard): Need it now?

217:44:13 Scott (onboard): Think you can ... tomorrow? Think you ... tomorrow?

217:44:19 Irwin (onboard): That won't be hard to do.

217:44:20 Worden (onboard): ...

217:44:30 Irwin (onboard): A little tennis.

217:44:34 Scott (onboard): ...

217:44:37 Irwin (onboard): I'm going to be worried, too, if I don't have that FCS ... on. I should say the FCS - (laughter). Should say the FCS. All day, Al. We'll be in those suits and won't be able to take a crap.

217:44:54 Worden (onboard): Okay ....

217:45:33 Irwin (onboard): I'll look it up there. The menu today - Today is...

217:45:45 Worden (onboard): We're ready to ...

217:45:50 Irwin (onboard): We have turkey and gravy, wet pack. Cranberry - orange - pineapple fruit cake. Vanilla pudding, which we had yesterday (laughter). And citrus beverage.

217:47:08 Scott (onboard): Okay. ... down below.

217:47:12 Irwin (onboard): Yes. I can cut, if you want to put water in them.

217:47:52 Worden (onboard): ... don't see why ... camera for terminator photos.

217:47:56 Worden (onboard): ...

217:48:15 Scott (onboard): Okay.

217:49:43 Worden (onboard): ... shave.

217:49:46 Scott (onboard): Is it? ...

217:50:06 Worden (onboard): ... wet pack, turkey and gravy.

217:50:35 Worden (onboard): ... minus 5 ...

[Flight Plan page 3-330.]
218:11:01 Irwin (onboard): Okay. We need Gamma-Ray, Boom, Retract.

218:11:19 Irwin (onboard): After about 3 minutes 15 seconds, it should be gray, and then we'll turn it off.

218:11:41 Worden (onboard): ..., Jim. ... one whole week ...

218:11:45 Irwin (onboard): I'll take the cheese.

218:11:49 Worden (onboard): ... all right ...

218:12:07 Irwin (onboard): No. No. I - there'll be plenty of time for canned.

218:12:12 Worden (onboard): ...

218:12:13 Irwin (onboard): No. No, this tube was good.

218:12:18 Scott (onboard): ... camera went out ... right, Al?

218:12:31 Worden (onboard): ... mapping camera ...

218:12:51 Irwin (onboard): Y'all want to try the tube?

218:13:38 Worden (onboard): ... mapping camera right now ....

218:13:46 Irwin (onboard): Hope so.

218:14:08 Worden (onboard): ...

218:14:13 Irwin (onboard): One minute to terminator photos, Dave.

218:14:16 Scott (onboard): ...

218:15:04 Irwin (onboard): 15, 19.

218:15:18 Worden (onboard): How long?

218:15:20 Irwin (onboard): One minute and 40 seconds.

218:15:28 Irwin (onboard): Something on my window. I don't know why they put...

218:15:39 Irwin (onboard): Al, would you turn the Laser Altimeter, On? Laser Altimeter, On.

218:16:09 Irwin (onboard): And Mapping Camera, Image Motion, On. Barber pole plus 4. Yes.

218:16:25 Irwin (onboard): No, I just want it On now. They don't want it - don't want it - you to do that until after you turn it On.

218:16:33 Irwin (onboard): Yes, but it doesn't say Image Motion, Increase, until after we turn it on - turn the Mapping Camera, On.

218:17:24 Irwin (onboard): Okay, Al. If you'll turn the Mapping Camera, On. Yes.

218:17:32 Worden (onboard): ... want?

218:17:33 Irwin (onboard): And Image Motion, Increase to barber pole plus 4.

218:18:45 Irwin (onboard): Yes.

218:19:53 Irwin (onboard): See that crater out there - I don't know whether you can see it out your window, Dave. The one I mentioned looked like it had a contact right through it; one half of it was gray and the other half was white.

218:20:02 Scott (onboard): ...

218:20:05 Irwin (onboard): It's right out here. Just east of - that good Russian crater, Svodska [sic] - Sovolska [sic].

218:20:18 Worden (onboard): ... it's a Russian crater.

218:20:23 Irwin (onboard): Sbodska [sic].

218:20:25 Scott (onboard): Sklodowska.

218:20:26 Irwin (onboard): Sklodowska.

218:20:29 Scott (onboard): ...

218:20:53 Irwin (onboard): Yes.

218:21:07 Irwin (onboard): Okay, we're supposed to configure the DSE. Stop, Command Reset, and REWIND.

218:21:13 Scott (onboard): All right.

218:21:24 Irwin (onboard): It's on the - the Rewind, right - the Record ...

218:25:06 Allen: Hello, Endeavour; this is Houston. [No answer.]

218:25:13 Scott: Hello, Houston; this is Endeavour.

218:25:19 Allen: Roger, Dave. Looking downstream a little bit here, I know you'll be interested to know that both the shape burn and the satellite jett[ison] will be coming up very close to the nominal times in your Flight Plan. And we've got the photo PADs here when you're ready to copy, and there are only a few lines. Over.

218:25:47 Scott: Okay, Joe. Go ahead.

218:25:50 Allen: Roger. The first is a terminator photo PAD to go in at 220 plus 05; and it reads T-start, 220 plus 13 plus 45. Over.

218:26:21 Irwin: Roger, Joe. T-start, 220:13:45.

[Note that there is no record of these photos having been taken in the Apollo 15 Index of 70-mm Photographs.]
218:26:25 Allen: Thank you, Jim. And I've got a milestone for you to add here - a Pan Camera photo PAD, with a T-start of 220 plus 15 plus 25. And the instructions on that are: "Run the Pan Camera to film depletion." And your indication is talkback barber pole. That's a lot of feet of film. And finally an entry at 221 plus 59 - it's an addition which reads "circuit breaker O2 Tank 100W Heaters, three, Main B, closed". Over.

218:27:45 Irwin: Okay; on the last one, it was 221:59, "circuit breaker O2 Heaters - 100 watt Heaters, three, Main B closed". And then going back to the entry for a - a T-start time of the Pan Camera of 220:15:25, and run the camera to film depletion, talkback barber pole.

218:28:08 Allen: Right on, Jim. Thank you.

[Very long comm break.]
Public Affairs Officer - "This is Apollo Control at 218 hours, 39 minutes. Apollo 15 has 33 minutes remaining in acquisition during the 72nd lunar revolution. It's been a quiet pass..."

218:39:12 Allen: Endeavour, this is Houston requesting [Mapping Camera] Image Motion to talkback plus 3.

218:39:22 Irwin: It's in work right now, Joe.

218:39:24 Allen: Okay; thank you. And if you give us Accept, we'll update a REFSMMAT to you. [Long pause.]

[REFSMMATs (reference to a stable member matrix) are used to define a set of orientation vectors to be used by the inertial measurement unit to define, essentially, "which way is up". In theory, any set of coordinates could be used, but those that represent well defined and easily measured references are best. Several are rather obvious; the launch pad at the Kennedy Space Center, the landing site of the LM, and the lift-off site of the LM. What is apparent here is that on a rotating body such as the Moon, Falcon's site on the Moon at lift-off has moved quite a bit since the landing.]

[Al will soon do a double P52 platform realignment and two REFSMMATs are important for this. The "lift-off" REFSMMAT, which has been used since Falcon's return to orbit, will be used for the first P52 realignment to check on the platform's drift since it was last realigned. The "TEI" REFSMMAT, which will define the orientation needed for the burn to return to Earth, will be employed for the second P52.]

[Joe Allen is referring to the TEI REFSMMAT that is being uplinked to the spacecraft about 20 minutes earlier than planned.]

218:40:19 Allen: And, Endeavour; Houston again with a couple more items.

218:40:32 Irwin: Go ahead, Joe.

218:40:33 Allen: Roger, Jim. Coming up on our TEC partial Gamma-ray [boom] extension, and looking downstream towards that, we are requesting that you time the Gamma-ray boom extension, which you're going to do at 219 plus 19 - and we'll be standing by for that time. And also requesting - that you get on the biomed via the Flight Plan, please.

[Some time during the Trans-Earth Coast, the Gamma-ray boom will be partially extended. The way they plan to do this is to time how long a full extension takes. Then, later, they will be able to give a time for extension which will give a proportionate distance from the spacecraft.]
218:41:10 Irwin: Okay. [Long pause.]

218:41:30 Allen: And, Endeavour, it's your computer.

[Very long comm break.]

[At 218:52:55, the Panoramic Camera is operated for the penultimate time and will run until they reach the terminator.]

[Flight Plan page 3-331.]

219:02:36 Allen: Endeavour, please terminate battery Bravo charge.

219:02:44 Irwin: Roger. Battery Bravo terminating.

219:02:54 Scott: Except we were charging battery Alpha. [Long pause.]

[Joe Allen was mistaken. It was battery A that was charging.]
219:03:22 Allen: We copy that, Dave, and agree with it. Thank you.

219:03:29 Scott: Roger. It's terminated.

219:03:32 Allen: And you have - you've got a gotcha on the gentleman sitting next to me.

219:03:41 Irwin: Ought to hit one once in a while.

[Long comm break.]
219:12:56 Allen: Endeavour, Houston. Turn the Map Camera back On, please. And it's not necessary to extend it.

219:13:12 Worden: Map's On.

[Long comm break.]
219:17:21 Allen: Hello, Endeavour. This is Houston.

219:17:28 Irwin: Go ahead.

219:17:30 Allen: Roger, troops. We'd like to tag up with you on the recommended TEI procedures. And, Al, I guess maybe you'll be doing this. And we - we're interested in reverifying the entries which you've made in your P40 SPS Thrusting Checklist, pages G5-1 through to the end. And we've got, I guess, two new entries to put in, but we want to reverify the entries that you've already got in there. Your choice, if you want to read those entries to us, or if you'd like to have us to read them to you. Over.

[Mission Control want to verify the items on the cue cards in light of the short circuit discovered in the SPS on the second day of the mission. Dealing with the fault, which is in the primary control circuit, requires that they use the secondary, or "B" circuit to start and stop the engine, bringing the A circuit in manually in the middle of the burn.]
219:19:14 Irwin: Okay. Let's get Al up on the headsets. Stand by one, please.

219:19:18 Allen: Roger.

219:19:23 Allen: Endeavour, Houston. Requesting Pan Camera Power, Off, please.

219:19:30 Worden: Roger. Doing it right now. [Long pause.]

219:19:51 Worden: Okay, Houston. We had a continuous barber pole on that Pan Camera there.

219:19:59 Allen: Roger. Copy that. That's a lot of film across those rollers.

219:20:06 Worden: Rog.

[Long comm break.]
219:23:13 Allen: Endeavour, Houston.

219:23:21 Scott: Go ahead.

219:23:23 Allen: Roger. A question on your Pan Camera. When you turned the power off, was it already barber pole or was it gray and then went to barber pole as you threw the switch? Over.

219:23:36 Scott: It was already barber pole.

219:23:38 Allen: Okay, thank you. And we're standing by for Al on the headset.

219:23:46 Scott: Okay; let's - let us get all this SIM bay stuff cleaned up first.

219:23:49 Allen: Roger. [Long pause.]

[Having reached the terminator, they are busy getting the cameras in the SIM bay configured off and someone is timing the deployment of the Gamma-ray boom.]

[Right now, Al is busy in the Lower Equipment Bay performing two realignments of the guidance platform using the stars Acamar (in the constellation Eridanus - the River) and Fomalhaut (in the constellation Piscis Austrinus - the Southern Fish). The first reorientation will be to the landing site REFSMMAT. Once a good alignment is achieved, Mission Control will know by how much the platform has drifted since the previous realignment. Then the platform will be realigned to the TEI orientation, using the REFSMMAT sent to the spacecraft earlier and the same stars, Acamar and Fomalhaut.]

219:24:13 Allen: And, Endeavour; this is Houston. You're coming up on 8 minutes to LOS. And we'll just go over the TEI procedures on the next rev. No hurry on that at all.

219:24:30 Worden: Okay, that sounds like a good idea. [Pause.]

219:24:49 Worden: And, Houston. Gamma-ray Boom Deploy was 2 plus 33.

219:24:56 Allen: Say again that time, please?

219:25:02 Worden: 2 minutes and 33 seconds.

219:25:05 Allen: Copy. Thank you. [Long pause.]

219:25:59 Allen: And, Endeavour; this is Houston with instructions on the Pan Camera. You can start the Pan Camera power using the normal procedures at T-start. And if you get an incorrect indication, namely continuous barber pole, just leave it in the normal configuration until AOS. Over.

219:26:27 Worden: Roger. Understand. Start it normally at T-start, and if it is in barber pole, just leave it till AOS.

219:26:34 Allen: That's right; thank you.

[Comm break.]
219:27:39 Allen: And we have the torquing angle. Thank you.

219:27:45 Worden: Roger.

[Long comm break.]

[Prior to Al carrying out the P52 realignments, the spacecraft's attitude control is taken away from P20 so it is no longer in its orb-rate motion. With the realignments completed, control is given back to P20.]

219:30:10 Worden (onboard): Good.

219:30:13 Irwin (onboard): Got them?

219:30:16 Worden (onboard): Got them. Okay. Okay, and I'll go ahead and torque those out on the minute. Just give me a mark.

219:30:24 Irwin (onboard): Okay.

219:30:58 Irwin (onboard): Stand by, Al.

219:30:59 Worden (onboard): Okay.

219:31:00 Irwin (onboard): Mark.

219:31:05 Worden (onboard): Okay, we'll just check it out here.

219:31:17 Allen: Endeavour, you're looking good at LOS minus 60 seconds. Configure the DSE for us, please. And we see you've done that. Thank you.

219:31:28 Worden: Roger. Just did it.

[Very long comm break.]
Public Affairs Officer - "This is Apollo Control at 219 hours, 32 minutes. We've had Loss Of Signal on the 72nd revolution. ... At 219 hours, 32 minutes this is Mission Control Houston."

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