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Apollo 15

Day 11: Worden's EVA Day

Corrected Transcript and Commentary Copyright © 2000 by W. David Woods and Frank O'Brien. All rights reserved.

[This section primarily covers the eleventh day of the mission, August 5, 1971. Apollo 15's CSM (Command Service Module), Endeavour, has left the vicinity of the Moon and has begun essentially falling to Earth. The last burn performed by the crew, the Trans-Earth Injection burn, placed them on a path that would have the spacecraft pass over Earth's far side at an altitude of about 35 kilometres, had the planet been devoid of atmosphere. Of course, the Earth does have an extensive envelope of gas which the spacecraft will intercept, losing its momentum through friction and heat. By that time, Endeavour will be travelling at nearly 11 kilometres per second under the pull of Earth's gravity. But now the Moon's gravity is dominant; the spacecraft is only coasting at just over 1 kilometre per second and is slowing as it continues rising away from the Moon.]

[The primary objective of the day is for Al Worden to perform an EVA (Extra-Vehicular Activity) out through the main hatch and along the side of the Service Module to the SIM (Scientific Instrument Module) bay. There he will retrieve film magazines from the Panoramic and Mapping Cameras and take an opportunity to visually inspect the bay. Throughout their time in lunar orbit, the SIM bay has experienced a few problems and since it will be destroyed along with the Service Module when it re-enters the atmosphere, engineers are keen to gather as much information as they can to aid troubleshooting. The eye of a test pilot is a welcome opportunity to see if any mechanical manifestations of the symptoms exist.]

[Despite PAO Announcer's words, the rest period was due to begin at 228 hours exactly. Delays in finishing yesterday's activities delayed its commencement by 50 minutes.]

Public Affairs Officer - "This is Apollo Control. 234 hours, 44 minutes Ground Elapsed Time. 1 hour remaining in the Apollo 15 crew rest period. And, here in Mission Control, got a clock counting down to splash; showing now 60 hours, 26 minutes; which is tentatively the time from now until splashdown in the North Pacific just North of Hawaii. On the seventh of August. Apollo 15 now 26,130 nautical miles [48,393 km] out from the Moon, en route to Earth; velocity, 3,761 feet per second [1,146 m/s]. We'll bring that air/ground circuit live, hopefully prior to the first call to the crew in approximately an hour from now. At 234 hours, 46 minutes Ground Elapsed Time, this is Apollo Control."

[Flight Plan pages 3-345, 3-346 and the current page, 3-347.]

235:45:46 Allen: Good morning, Endeavour. This is Apollo Control in Houston, Texas, tuning the band [i.e. about to play some "wake-up music" to the crew]. Over. [Long pause.]

235:46:21 Scott: Good morning, tuning the band. This is Endeavour. Go.

235:46:30 Allen: Roger. Good morning, Endeavour. This is Houston with CSM consumables and a few good words about your Flight Plan, when you're ready.

235:46:46 Scott: Just stand by one.

235:46:48 Allen: Okay, Dave. And you troops sure start the day early up there, I must say.

235:46:59 Scott: Yes, seems that way, doesn't it?

[Long comm break.]

235:51:13 Allen: Endeavour, this is Houston. Were you calling?

235:51:21 Scott: Roger, Joe. We've located the Flight Plan. Go ahead with your updates.

235:51:27 Allen: Okay, Dave. I guess, let me start with the CSM consumables. At 235 plus 30, RCS total, 41; quad A: 43, 40, 38, 41; H₂ tank 1, 41, 40, 36; O₂ tank 1, 56, 58, 45. And the only immediate other thing I have for you, Dave, is a comment on the maneuver at 236 hours - about the Gamma-ray boom retract. We'd like for you to confirm - I'll be back when...

[Comm break.]

235:53:38 Scott: Last I heard was gamma-ray. Go ahead.

235:53:42 Allen: Okay. The rest of that mysterious transmission is essentially the following, Dave. We've got a funny in that gamma-ray experiment and - so we're going to - to want to modify the use of it a little bit today. It should be no major imposition, but the Flight Plan calls out far the Gamma-ray boom to be retracted at 236 hours. We'd like to modify that by saying, turn the Gain Step, Shield, Off, at that time and we'll want you to retract it about 10 minutes later. We'll give you a cue for that. Over.

235:54:27 Scott: Okay. Gain Step, Shield, Off, at 236 and stand by for your cue for retraction.

235:54:36 Allen: That's correct, Dave. I've got a few other good things here, but there's no hurry on any of them. [I would] be willing to stand by, if you wanted to get squared away and give me a call later, or whatever you'd like to do. It's your preference.

235:54:54 Scott: Well, let's go ahead, Joe. We're getting squared away up here.

[Scott, from the 1971 Technical Debrief - "It seems like, particularly with the SIM bay, that we really never had enough time to do our housekeeping. We were always busy trying to keep up with things. I'm not sure whether it was because of the amount of equipment on board or because we had to constantly pay attention to our SIM bay operations. But it seems like we were always pressed on the housekeeping. We had to eat fast, had to get ready for the next thing fast, and, in general, we never had a lot of time to sit around and wait to get to the Moon; nor did we have a lot of time to sit around and wait to get home. We always had something to do. And it was mostly because the housekeeping took a fair amount of time.]

["One thing we all commented on was that it would be better if, when you awaken, you ate first and took care of your cleanup activities before you got into the operational part of the day. To try and combine operations with eating sort of compromised both. A guy would be halfway through fixing a meal and he'd have to go turn on some SIM bay thing, which means you didn't do either one very efficiently. After waking up, you should eat, clean up and then go to work. You'd be more efficient.]

["There are a number of things you have to do in the spacecraft which aren't really called out in any time line. We have an eat period and then we have a rest period and vice versa. You can't go from an eat period to a rest period. There are a lot of things that have to be done, most of which are called out in the presleep checklist. You can't just go finish your dinner and in two minutes do the presleep checklist and go to bed. You have to have a transition period during which you chlorinate the water, change a canister, everybody take their last urination for the day, and clean things up in general. You have to have a period of time there to get ready to go to bed."]

235:55:25 Scott: Roger. 236:45; X-ray, On.

235:55:27 Allen: Okay. And turning over several pages to 241 plus 25.

235:55:43 Scott: Go.

235:55:44 Allen: Roger. After the step "O₂ heaters 1, 2 and 3 to Auto", add "O₂ tanks 1 and 2, 50 Watt Heaters, Main B, two, to Open."

235:56:31 Scott: Roger. 241:25; O₂ Heater - or O₂ Tank 1 and 2, 50 Watt Heaters, Main B to Open, and O₂ Tank Heater - They're 50 Watt also? Main A, one, Open?

235:56:54 Allen: Stand by, Dave. I'm sorry about this one. Stand by.

235:57:01 Scott: Okay. [Long pause.]

235:57:26 Allen: Okay, Endeavour. Let me try that again. Had a typographical error down here. It should read "O₂ Tank 1, 50 Watt Heater, Main B, 1, Open"; and "O₂ Tanks 2 and 3, 50 Watt Heaters, Main A, 2, Open". Over.

235:57:53 Scott: Okay. O₂ Tank 1, 50 Watt Heater, Main B, 1, Open; and Tanks 2 and 3, 50 Watt Heaters, Main A, 2, Open.

235:58:04 Allen: That's correct, Dave. I apologize for the slow start there. Now I've got some DAP load changes that cover the times from about 247 hours to 252 hours. And - the change is apparently because of a mis - of a mistake in the Flight Plan you have on board that we, in the meantime, have caught down here. And - so there are several deletions and additions during that time. The first one starts at 247 plus 28.

235:58:44 Scott: Go ahead, I've got it.

235:58:48 Allen: Okay. Delete your Verb 48, 11111 and X1111, and add - stand by a second.

235:59:09 Scott: That's twice.

[Dave Scott and Joe Allen work well together and it is likely Dave is teasing Allen about the frequency of his pauses during these updates. Joe is reading up a revised DAP load status. These are the numbers that are entered into the computer to make the DAP operate in a desired fashion.]

235:59:59 Allen: Okay, D.R. [i.e. David Randolph Scott] I'm ready to try it again. You've deleted at 247:28 the line with all the funny number ones, and you're supposed to delete, in the DAP load column, also that same entry. It's in the time column, I guess. And then turn the page.

[Flight Plan page 3-348.]

236:00:15 Allen: Okay. Go to 248 hours, on the next page, and in the note column, change the DAP load status to read 11101. And the rest is the same. And this DAP load status continues through the PTC until 251 hours. And the next change is at 251 hours and 4 minutes.

236:01:10 Scott: Okay. 251:04, and I got the other three changes. Go ahead.

236:01:17 Allen: Okay. Delete the Verb 48 line and the DAP load over in the time column there.

236:01:37 Scott: Okay.

236:01:38 Allen: And the next change is at 251:47. Delete the Verb 48 line and the DAP load in its corresponding time column.

236:01:58 Scott: Okay. And I guess over in the notes column, we're still carrying 11101. Right?

236:02:06 Allen: That's affirmative, Dave. And starting at 252 hours, your DAP load status should read 111 - Stand by. [Pause.]

236:02:29 Allen: Okay. Let me try again. Starting... [Long pause.]

236:02:57 Allen: Okay starting at 252 plus 00 hours, in the notes column, the DAP load status should read 11101 times 1111 [means 11101 X1111]. And this should be carried through the rest period until 261 hours. Over.

236:03:31 Scott: Okay, Joe. You were saying something there about 252:30, as we lost comm. I got the entry at 252:00. Was there any change at 252:30?

236:03:43 Allen: Negative, Dave. The change at 252:00 should just be continued through until 261 hours. And that's just the DAP - DAP load status - should be changed correspondingly through until that time.

236:04:05 Scott: Okay. I see. And then we're - we're just 11101 all the way.

236:04:10 Allen: That's correct. [Long pause.]

[This long series of changes are really intended to make a simple change to the status of the Digital Auto Pilot, the routine in the computer that maintains the desired spacecraft attitude. The setting of the fourth bit to a zero has the effect of changing the deadband from ±5° to ±0.5°, essentially tightening up the control of the PTC rotation and maintaining it throughout the day and rest period.]

236:04:37 Allen: Dave, that's all I've got for the time being. And I think I'd be afraid to go ahead much further, if you're really counting these times. Maybe I should start keeping score on you as well.

236:04:52 Scott: [Laughter.] Okay.

236:05:00 Allen: We're happy for the time being. We're - we're standing by for a crew status report at your convenience. And we'll be watching for the Gain Step Shield to come Off.

236:05:15 Scott: Okay. We'll get right back with you in about 5 or 10.

236:05:18 Allen: Thank you.

[Comm break.]

[The discriminator in the Gamma-ray Spectrometer has been switched off and the crew are waiting for a cue from Mission Control to retract the boom on which it is mounted. Meanwhile, Al Worden stops the PTC rotation and proceeds with a P52 realignment of the spacecraft's gyroscopically stabilised guidance platform. The platform will be realigned to the orientation defined by the PTC REFSMMAT and as a reference, Al will use two stars, Aldebaran and Procyon. The amount by which the three gimbals supporting the platform must be rotated or torqued is to be reported to Earth but Mission Control can see them appear on the CM's DSKY (Display and Keyboard) as it is monitored via telemetry.]

236:18:27 Scott: Rog. Gamma-ray going to Retract now, and stand by on the news.

236:18:39 Allen: Okay. Roger. You can use that for background for the P52, I guess. President Nixon in effect declared U.S. responsibility for offensive ground combat operations in Vietnam at an end. With the draft still in limbo, Selective Service went ahead today with the lottery to determine the order in which next year's nineteen-year-olds will face military service. Secretary of State William P. Rogers plans to go to the United Nat - Nations to push for a more energetic international relief effort for East Pakistan today. The Senate Armed Services Committee completed action on a 21 billion dollar military buying bill that meets most Nixon Administration weapons requests. President Nixon and his family will fly to Manchester, New Hampshire, and then to a private island in Maine this weekend, when visits to New Hampshire also are planned by four Democratic presidential hopefuls and Republican challenger Rep - Paul N. McClosky, Jr. Predicted weather for recovery day is 2,000 feet scattered, 10 miles vis, and waves approaching 6 feet. Wind is north by northeast, 18 knots. I have a long list of baseball scores here, which I'll just glance over. In the American League, New York beat Cleveland 7 to 3. I have here a local request for the Dodgers who lost to the Astros 2 to 0. The American Classic Golf Tournament starts today at the Firestone Country Club in Akron, Ohio. And the winner will get $30,000 dollars. Sounds to me like the pay's pretty good, and I expect the hours are short. The U.S. Pan American Team went on a fantastic Gold Medal spree yesterday, winning 17 - rather 16 of the 17 medals at stake. The only one the Americans escaped getting was the Gold Medal in weight lifting. And the total in the games, which are being held in Columbia, is 78 for the United states, 36 of them gold, and 51 for Cuba, 12 of them are gold. And I'll end with the story comparable all the way to that incredible contest between the Apollo 15 All Stars and the North American Rockets. Last night in the Texas League, 21-year-old right-hander Tom Walker, pitching far Dallas-Fort Worth team, pitched a 15 inning, no-run, no-hit game against Albuquerque. He retired the last 21 men in a row. Only four Albuquerque players got on base and all of them were on walks. Walker got the first 18 batters out before he walked the first one. He threw 153 pitches in the game, and the no-hitter is an all time record in the Texas League and may very well be an all time record in Major League Baseball. Walker's manager told him that if he did not win the game in the 15th inning, he was going to have to pull him out. Walker said his arm felt a little tired, but he felt okay, understandably. Like doing three EVAs I expect. And that's all the news for - for this morning.

236:22:42 Scott: Boy! It sounds like he's as good as our very own Blinky.

236:22:49 Allen: That may well be, Dave. I - That never occurred to me.

236:22:57 Allen: At least the equal thereof.

236:23:02 Scott: Roger. At least almost.

[Comm break.]

[Once the P52 is out of the way, the Flight Plan calls for a period of cislunar navigation exercises. This requires Al to make a series of sightings of the Earth and stars as part of his brief to be able to get Endeavour home should communication with the Manned Space Flight Network be lost. The data from these sightings are processed by program 23 (P23) in the computer. Although a box in the Flight Plan claims that this exercise "will be performed on a non-interference basis with other crew activities", both the crew and flight controllers act as if it is essential. The Flight Plan also has the P23 exercise before breakfast but, as later comm reveals, the crew are getting on with eating to they can get tidied up prior to the EVA.]

[After the final use of the Mapping Camera yesterday evening, the crew found that it would not retract into the SIM bay. After some troubleshooting before the start of the rest period, it was decided that it could be safely left out without danger to the film within its magazine as long as the spacecraft was rotating in PTC and the heat loads spread. However, the PTC has ceased and will not be restarted before Al carries out his EVA. There is some worry that the film may suffer temperature extremes.]

236:26:28 Allen: Dave. That's my understanding, too. I think - the main reason - for wanting to do this if time is available and it's, o - and it's only - would be a nicety - would be it - gives us a warm feeling regarding the film. [Long pause.]

[Journal contributor Dave Edwards suggests that the broken nature of Allen's comm may be due to him relaying information to the CM while listening to the back room engineers. He sorts it out in his head and gives it a second try.]

236:28:02 Scott: Okay. Well, let us see if we can get to it.

236:28:05 Allen: Roger. Just give a whistle.

236:28:10 Scott: Okay. And we sort of flip-flopped that P23 and eat period so that we could take advantage of our setup for eating and all. And we'll get on with P23 as soon as we finish breakfast.

236:28:23 Allen: Sounds good.

[Comm break.]

236:30:06 Scott: Okay, Joe; but I guess the inequality is the stowage situation in here and assuring that we can get properly prepared for the EVA. So - we'll start the P23 in probably about - oh - 5 minutes or so, because we're almost through eating. But we sort of have to take advantage of our configuration in here in order to stay with the time line later on.

236:30:29 Allen: That's fine, Dave. We understand, thank you.

[Very long comm break.]

[As the Commander, Dave uses his situational awareness in the Command Module to ensure they keep ahead of the timeline. His motto, practised while on the Moon, is "Get ahead and stay ahead." He works effectively with the flight controllers to negotiate the best outcome for the mission and its objectives.]

[Meanwhile, Al begins the procedure for navigating the CSM home without Mission Control's help, using P23 and sightings on stars and the Earth.]

[Prior to taking the sightings, he places Endeavour's attitude control to "Free" and back to "Auto". The DAP status bit that determines the deadband is set to narrow it to ±0.5°, then he maneuvers the CSM to the optics calibration attitude. A sighting is made on star 20 (Dnoces) to provide a calibration of the spacecraft's optical system. Finally, he maneuvers the CSM to the sighting attitude. Here he makes three sets of angle measurements from the Earth's horizon to one of three stars; Bellatrix, in Orion; Pollux, in Gemini; Capella, in Auriga. These angles allow the computer to determine the spacecraft's position and velocity in space with respect to the Earth.]

[Worden, from the 1971 Technical Debrief - "We tried to follow the no-comm schedule on the P23s, and there were some periods where we couldn't follow that because of some other things going on. But, I felt that the on-the-job training on the way out was very valuable, because when we started those P23s on the way home, I had a pretty good feeling for what had to be done and how to handle that whole program. Even after the first set of P23s, we had a pretty good feeling about the computation of the onboard state vector because the ground called up and said that they weren't going to update our state vector because our vector was almost as good as theirs.]

["I think the reason the P23s worked out as well as they did was the fact that I'd done considerable work at MIT on their simulator practising P23s. That made a great deal of difference to me. I had a much better understanding of which horizon to look for and mark on and of how to maneuver the spacecraft with minimum impulse, which can be kind of tricky."]

[Scott, from the 1971 Technical Debrief - "Especially with a light spacecraft."]

[Worden, from the 1971 Technical Debrief - "Especially with light spacecraft. It is really responsive to even minimum impulse. The system of doing the P23s, the maneuvering that we did, and the procedures for going through the P23s worked even smoother in flight than it ever had in the simulator."]

[Scott, from the 1971 Technical Debrief - "The overall concept of how the state vectors were updated and continued on board worked very well. It was obvious that we kept our onboard state vector comparable to the ground state vector all the time. There was no question that we could have completed the navigation on board and made a very acceptable, if not precise, reentry with an onboard vector all the way."]

[Worden, from the 1971 Technical Debrief - "Yes. I definitely had that feeling.]

["One more comment about the P23s before we leave that area. The Earth was a very thin crescent when we did the P23s on the way back home. We had some discussion preflight about taking marks toward the limb of the crescent on the Earth. You don't want to get out too far on the limb. All the stars that were picked were pretty much in the center of the crescent. Never had any problem locating the horizon working on that part of the crescent or taking those marks which kind of surprised me. It's a lot easier than I thought it would be."]

236:43:29 Scott: Go ahead.

236:43:31 Allen: Roger. I've got some information about your midcourse [correction opportunity] 5, which is scheduled to come up here [at 238:46]. We have a firm decision that there will not be a midcourse 5 maneuver required and the numbers behind that are a Gamma of minus 6.69 [degrees, with respect to the local horizon at Entry Interface]; your vacuum perigee is 18.4 [nautical miles, 34.1 km], and the midcourse 5 correction that we're showing now would be 3/10ths of a foot per second. The corresponding midcourse 7 correction runs at about 1.8 feet per second. And, based on that new information, we're wondering if you're still interested in doing the UV photography at scheduled time we're waiting until after the - the EVA. And we're also wondering what your choice will be on the solar corona photography. Over.

[The deletion of midcourse correction 5 frees up an amount of time before the EVA. Yesterday evening, Dave asked to delay a session of ultraviolet photography until after Al gets back inside. Now that more time is available, Mission Control wonder if Dave wishes to reinstate the UV session, forgetting that his original reason for delaying it was that the equipment, (UV-capable lens, film) was stowed beneath other items in preparation for the EVA. Once they begin pulling items out, they begin floating about the cabin and almost take on a life of their own.]

[Note that the vacuum perigee, the lowest point of their path around the Earth had there been no atmosphere in the way, has dropped from last night's value of 40 km. This far out, the slightest change in their current velocity has profound influence on their final trajectory. By the same token, the inevitable error range in their knowledge of their state vector (velocity and position), leads to a substantial range of uncertainty regarding that final trajectory. As they approach Earth, the error range will narrow and the size of further midcourse corrections will become better known.]

236:44:47 Allen: Okay, Dave; fine. And no hurry on - on the - on that decision. We would like the Gamma-ray [Gain] Step Shield, On, now, please.

236:45:06 Scott: Okay. Gamma-ray Gain Step, On.

236:45:10 Allen: Thank you. [Pause.]

236:45:15 Scott: And, Joe, I guess on the corona photography, mag R has been ex - expended. And as far as the UV, is not so much a problem of time. It's a problem of stowage. It's stowed way down deep in one of Endeavour's lockers here and to get at it requires quite a bit of manipulation of bags. And that's the reason we wanted to delay that if it was possible.

236:45:41 Allen: Okay, Dave. We understand that. And that - that sounds like it's a far more reason - reasonable to delay that. The timing is not critical as far as we're concerned. We just wanted to give you a balanced workday.

236:45:58 Scott: Okay; fine. We don't mind loading up a little after the EVA, because it really saves us a lot of work in the long run. And you might wonder why we didn't put - the UV stuff somewhere else, but there's just nowhere else to put it but in it's - in its own proper little spot.

236:46:44 Allen: No, we understand. Thank you.

[Very long comm break.]

[With the P23 exercise completed, Al maneuvers the spacecraft to an attitude required for the second period of X-ray astronomy, this time aiming the X-ray Spectrometer at a mid-galactic latitude. This area of the celestial sphere will provide control data for subsequent measurements, essentially characterising the background flux of x-rays from space.]

236:57:49 Allen: Go ahead, 15.

236:57:53 Scott: Okay. Have a crew status report for you, and you can have the docs take a look at the LMP bio[medical], see if that's acceptable.

236:58:00 Allen: Okay.

236:58:08 Scott: Ready to copy?

236:58:09 Allen: Go ahead.

236:58:14 Scott: Okay. 7 hours sleep apiece, and PRDs 25028, 23193, 08031.

236:58:29 Allen: Okay, Dave. Thank you. And we see that we've got the X-ray going. We'd like for you to change the setting on the Gain Step. Give us a one-click increase, which will move us from - the position 7 back to position 1. Over.

236:58:50 Scott: Okay. You've got a one-click increase.

236:58:56 Allen: Okay. We see it, Dave, and Jim's Bio looks clean to us down here. Thank you.

236:59:05 Scott: Okay.

[Very long comm break.]

[Flight Plan page 3-349.]

237:15:05 Allen: Endeavour. Give us six clicks on the Gamma-ray Gain [Step] switch, please.

237:15:14 Worden: Okay. Six clicks.

[Very long comm break.]

237:36:04 Scott: Houston, Endeavour. Go.

237:36:06 Allen: Roger, Dave. A couple of miscellaneous items I'd like to ask you about. First of all, the trench sends their congratulations to whoever's doing the P23 for us. The errors are less than one sigma - and they're awarding the honorary Vasco da Gama Navigation Award for excellence in this. Secondly, we're puzzling over your remark about magazine Romeo [the high-speed black and white film magazine], which you reported to us was exhausted. And we're wondering if you just read - the frame number from the mag and, if so, what it read. Over.

237:36:57 Worden: Yes. Joe, this is Al. The last reading of Romeo, I think, was 110.

237:37:10 Allen: Okay, Al. Thank you. And were you doing the P23 for us?

237:37:17 Worden: Si. [Pause.]

237:37:23 Allen: Okay. I'll tell you a little something about Vasco da Gama later on. Another easy item here; you're going to come up on a bat[tery] charge - I guess Bat B charge - starting at 239 hours, and we'd like to delay that to 244 hours, please.

237:37:46 Scott: Okay. Delay the Bat B charge to 244. And be advised - you've got to know that we've got best navigator in trans-Earth lunar space up here.

237:38:00 Allen: At least one of them, I'm sure.

237:38:01 Scott: In fact, the only one.

237:38:03 Allen: Roger. We copy. And, finally, I'd like to get a volunteer to take a whack at this - configuring the Map Camera properly. And it's going to be a few short steps, and if it works, great; we'll have a lot of good engineering data regarding the thermal properties of that beauty. And if it doesn't work, we're just going to turn it off and leave it. And - when somebody's ready to do that, I'll go through the steps. There are not too many.

237:38:36 Scott: Okay, Joe. Somebody'll be ready in just a few minutes.

237:38:40 Allen: Rog. Thank you, Dave.

[Long comm break.]

237:46:49 Allen: Okay, Endeavour. I've got five steps here, and I think it's easiest for me just to read them to you and have you carry them out rather than copying them down. And the first one - first two steps...

237:47:01 Scott: Rog.

237:47:02 Allen: ...on panel 181, verify Logic Power, Main A circuit breaker, Closed.

237:47:16 Scott: Okay, verified.

237:47:17 Allen: And same panel, verify Logic Power switches, two of them, to Deploy/Retract.

237:47:26 Scott: Verified.

237:47:28 Allen: Step 3 on panel 278, the Experiment Covers Deploy circuit breaker, Main A to Closed.

237:47:44 Scott: Verified. Closed.

237:47:47 Allen: Step 4 on panel 230, the Map Camera, verify Standby.

237:47:56 Scott: Verified to Standby.

237:47:59 Allen: Okay, and coming up on step 5 and let me read through this - and - I'll stand by for questions then, if there are some. We want the Map Camera Track to Extend; and, simultaneously, we want the Experiment Cover Map Camera/Laser Altimeter to Open, and we want those two things done simultaneously.

237:48:33 Scott: Okay. Understand. Go to Extend and open the Covers, Map Camera/Laser simultaneously.

237:48:37 Allen: Roger. And a note on that - I guess - on the Map Camera Track to Extend, we'll be watching that for about between 4 and 5 minutes or until you get a gray talkback on there. And - we think this is going to clear up our problem and if it doesn't, we're just going to turn the whole ball of wax off and go ahead and do the EVA as normally planned. Over.

237:49:13 Scott: Okay, Joe. In three seconds, we'll execute.

237:49:18 Allen: Roger, Dave. We're watching. [Long pause.]

237:49:32 Scott: Well, I got a gray on the Mapping Camera. How 'bout that.

[The talkback indicator for the Mapping Camera's Extend/Retract function is meant to show barber pole (striped) while the camera is on the move. When it reaches the limit of its travel, the talkback changes to gray. Since they tried retracting it last night, it has been barber pole. The gray indication Dave has seen means that the camera is fully out again and the short length of time taken implies that it had hardly moved in on retraction.]

237:49:53 Allen: Dave, do you have a gray on the door as well?

237:49:59 Scott: That's affirm, but I did not get a barber pole on the door. It just stayed gray.

237:50:06 Allen: Okay; that's good. That just means that it was open already.

237:50:13 Scott: Right.

237:50:15 Allen: Okay. Then that - that's worked out fine. Apparently, we were having a temperature problem with that thing before, and we're back in business just like normal. We'd like now the Mapping Camera Track to Retract, and that'll take I guess about 4½ minutes.

237:50:38 Scott: Okay. Map Camera Track going to Retract now.

[Long comm break.]

237:57:23 Scott: Okay. Fine. [Long pause.]

237:57:44 Allen: And, Dave, could - could you have someone check the barber pole on our Map Camera, Track, to see if you have the gray-Retract indication, please.

237:58:01 Scott: Roger, Joe. I been watching it. You got about 7 minutes and 20 - 20 seconds now and it's still barber pole.

[The indication means that the Mapping Camera is still stuck, likely near its extended position.]

237:58:28 Allen: Okay, Endeavour. We're satisfied with that Mapping Camera exercise. Two more requests on that. Go to Off with the Extend/Retract switch, and to Off with the Mapping Camera/Laser Altimeter Cover switch, please. And we're finished with that.

237:58:54 Scott: Okay; Extend/Retract to Off; and a Map Camera/Laser Altimeter's going of Off.

237:59:03 Allen: That's right, Dave. And a note for Al. We think that the magazine Romeo, based on the frame count you gave us, still has enough frames left to take the solar corona pictures. And we'll have some special words for Al on how he's to take those pictures. I guess, we'll delete a few of the solar corona requirements. Also, word about the PRD configuration for the EVA. Apparently, we'll want the CMP to have the PRD whose number reads 25028. And, I guess, that's the one you've been carrying, Dave. And, Jim, we'll - we'll use the one that reads 08031, but we would like to have him reconfirm this number before he starts the EVA. Over.

[Flight Plan page 3-351.]

238:00:22 Allen: Roger. We want Al to wear the PRD that's now reading 25028. That will distinguish it from the other two with no ambiguity. And Jim to take the one that begins 080, and we want him to give us the full reading off of that before he start the EVA, though.

238:00:46 Scott: Well, we'll have to give it to you now, because it will be in the suit and we won't be able to get to it.

238:00:50 Allen: That's fine. Any time. Any time. [Long pause.]

238:01:28 Scott: Okay. The one Jim will wear will be 08037.

238:01:37 Allen: Okay, Dave. Thank you. And if you'll give us P00 and Accept, we'll let you have a new state vector.

238:01:49 Worden: Rog. You've got it.

[Comm break.]

[Program zero-zero is the computer's 'do-nothing' state which is appropriate for those times when Mission Control were updating areas of its memory by radio link. Apollo crews usually referred to this program as P00, pronounced "Pooh" as in the classic children's character invented by A. A. Milne.]

238:04:37 Irwin: Roger.

[Comm break.]

238:06:13 Allen: Standby. [Long pause.]

[These are deletions intimated by Allen ten minutes ago.]

238:07:41 Scott: All right. I got all that. Thank You.

[Long comm break.]

[From this point, the crew can begin their preparation for the EVA. The only other item prior to that are the taking of a few images to calibrate the solar corona pictures taken earlier in the mission.]

238:14:37 Allen: Hello, Endeavour, this is Houston.

238:14:43 Scott: Houston, Endeavour. Go.

238:14:45 Allen: Be advised at my mark, you are leaving the sphere of lunar influence; and it's downhill from here on in.

238:14:54 Allen: Mark.

238:14:59 Scott: Roger, Thank you, Joe. That's nice to know.

238:15:07 Allen: Did you notice anything there, Dave? Discontinuity in velocity or anything like that?

238:15:17 Scott: Well, Joe. That's one of the mysteries that we'll probably have keep to ourselves.

238:15:22 Allen: I was afraid of that.

[Long comm break.]

[After 7¼ days having the Moon as its chief gravitational influence, Endeavour now "feels" the gravity of Earth as the stronger force and its velocity begins to increase. Trajectory computations are changed over to be Earth-centric and the Moon's velocity in its orbit is taken out of the reckoning.]

[The conversation between Joe Allen and Dave pokes gentle fun at the news media's inability to fully grasp the concepts behind this imaginary boundary. Many continued to believe that there was a physical jump felt by the crew, a belief perhaps fed by the jump in the velocity numbers due to the change in reference frame.]

[Woods, from 2000 correspondence - "Was this the inspiration behind this exchange?"]

[Scott, from 2000 correspondence - "Well, that's one of those little mysteries that we'll have to leave for future researchers....!!!! It all goes along with the culture of lunar exploration!"]

238:22:02 Scott: Go ahead.

238:22:03 Allen: Roger, Dave. We're looking down the line here towards the EVA. And the Surgeon's getting good biomed data on Al now, except one of the three EKG sensors is apparently marginal, and there's some noise creeping in. We're just wondering what your standard procedure is regarding sensoring before the EVA exercise. If he's going to resensor, it's probably no problem; if he's not planning to, maybe we ought to talk it a little. Over.

238:22:37 Scott: Okay. We're all three all sensored, ready to go. If they have a problem, let's get it squared away right now.

238:22:45 Allen: Okay. Do you have, - Maybe Al could try pressing down on the three EKG leads, one at a time, for us; that may help us out.

238:23:01 Scott: Okay. Here we go. The upper right.

238:23:17 Allen: Okay.

238:23:22 Scott: Okay. The upper center is being pressed.

238:23:36 Allen: Okay.

238:23:41 Scott: Okay, the lower left. [Long pause.]

238:23:57 Allen: Okay. Stand by.

238:24:02 Scott: Okay. [Long pause.]

238:24:56 Allen: Dave, it looks to us like it's one of the two top sensors, and we were wondering how difficult it would be to reseat both of them now.

238:25:11 Scott: Okay. I'll tell you what we'll do. A little further down the line here, we'll take care of both of those. We'll just reseat them and everything.

238:25:24 Allen: Okay, fine. Thank you.

238:25:29 Scott: And thank you for thinking ahead on that one.

[Very long comm break.]

[Preparation for the EVA will begin with powering down the instruments in the SIM bay, retracting the booms and closing covers.]

238:43:28 Scott: Houston, Endeavour. Go.

238:43:30 Allen: Roger. I've got an update to your corona - window calibration photography and the UV photographs, when you're ready.

238:43:45 Scott: Okay. Stand by one.

[Comm break.]

[Deployment of the Mass Spectrometer's boom has been an increasing problem throughout its use. The problem is correctly suspected to be caused by the mechanism being affected by cold. The spacecraft is being held in a constant attitude and if heat from the Sun cannot get in to warm the boom's systems, they quickly radiate their heat into space.]

238:46:53 Scott: Okay. And we're going ahead with the dumps, if that's okay?

238:47:05 Allen: Okay. [Long pause.]

238:47:17 Scott: And if you'd like a visual check of just exactly where that's hanging up, why we can give it to you in a couple of hours. We'll have Al go out and take a look.

238:47:26 Allen: That's not a bad idea. Does he know about this plan yet?

238:47:32 Scott: Well, I don't know. We'll check with him. Yeah, he nods his head like he'd probably be obliged to do it.

238:47:40 Allen: Okay. Break it to him gently, though.

238:47:44 Scott: Okay.

238:47:46 Allen: And, Dave. While I got you here, I do want to comment that the first change in the Flight Plan is to delete the step at 238 plus 23 that says "enable all jets." We think that there is a - a certain chance that Map Camera may be stuck out, and we particularly don't want RCS jets A4, A2, B1 and B4 to be enabled, because they may give us trouble with that camera.

238:48:30 Scott: Okay. Understand, Joe. We'll scratch that step and make sure A4, A2, B1 and B4 stay off.

[The four RCS thrusters mentioned are those whose exhaust would, if used, most likely impinge upon the Mapping Camera. A photograph taken of Endeavour during the rendezvous shows the relationship of this camera to these jets.]

238:48:48 Scott: Go ahead. I've got the Flight Plan out.

238:48:55 Allen: Okay. If you'll turn to page 3-352, which is the Corona Window Calibration and UV photos procedures page.

238:49:11 Scott: I've got it.

238:49:15 Allen: Okay. The attitude involved in the corona photographs should read 057, 005, 025. And the time on that, 239 plus 08. And the High Gain [Antenna] numbers, pitch, minus 48; yaw, 238.

238:50:03 Scott: Okay, Joe. 057, 005, 025 at 239:08. Minus 48 and 238 for the High Gain.

238:50:13 Allen: That's correct, and moving down a couple of lines, the shutter speed should be changed from 1/500th to 1/125th. And change the inhibit jets line to read "damp rates for 5 minutes." CMC Mode to Free.

238:50:58 Scott: Okay. Understand. Scratch inhibit jets, and substitute damp rates for 5 minutes, and then CMC, Free, and the 1/125th replaces the 1/500th on the camera.

238:51:11 Allen: That's correct, Dave. And moving down a little further, delete the line, "cycle 1 frame, change shutter" and delete the line "cycle 1 frame." And finally, change the last line, enable all jets to read, "CMC Mode, Auto."

238:52:44 Scott: Okay, delete line, "cycle 1 frame" and "cycle 1 frame"; and CMC Auto, replaces "Enable all jets".

238:52:52 Allen: That's correct and assuming you're going to take the UV photographs after the EVA, I have a photo PAD for that, if that assumption is correct.

238:53:06 Scott: Looks like that assumption is probably correct, Joe, and we'll take the photo PAD later on. Let us get on with corona [photography], or we won't make it.

238:53:14 Allen: Okay. Sounds good.

[Long comm break.]

238:57:34 Scott: Houston, 15. Go.

238:57:36 Allen: Roger, Jim. We understand you are going to delete [means postpone] the UV photographs, but after you complete the corona window calibration, you will have to do the first step in the UV photos trans-Earth coast procedures, there. And that first step is Verb 49 maneuver to Earth UV photo attitude, and it lists the attitude there. We need this for thermal reasons.

238:58:08 Scott: Roger. We'll do that.

[Long comm break.]

[Since the Passive Thermal Control was stopped three hours ago, the spacecraft has adopted various stable attitudes which have tended to heat one side of the spacecraft and chill the other. During the planning for the morning's activities, thought has been given to the temperature extremes sustained by Endeavour's systems, carefully balancing operational requirements with thermal ones. Mission Control want to ensure that after an extended period of pointing the X-ray Spectrometer to deep space, the heat load will be shared around the spacecraft's body. Therefore, the crew will maneuver to the UV photo attitude as planned even though they are not carrying out the photography. Once the SIM bay film magazines are retrieved, the thermal constraints will lessen.]

[Flight Plan page 3-353.]

239:05:45 Allen: Go ahead, 15.

239:05:50 Worden: Hey, Joe. Just a point of clarification on the backing to be used for the corona. I don't know whether you are aware or not, but the backing that fits into window 4, which is the right-hand rendezvous window, has two different mounting pads for the camera, one is 250 and the other is 80. And the 80 is pointing 12 degrees below the X-axis, and I just wanted to check and see if you wanted us - if that's the proper PAD or if you wanted us to use the 80 or the 250 pad.

239:06:23 Allen: Al, use the 80. The one pointing 12 degrees above the X-axis.

239:06:30 Worden: Okay, Joe. Thank you.

[Very long comm break.]

[The procedures for the EVA begin on page 3-1 of the CSM Systems Checklist.]

[Long comm break.]

[Comm break.]

[Mission Control want the LCG (Liquid Cooled Garment) that Dave was wearing three days ago when he and Jim Irwin returned from the Moon's surface. After re-entering the Command Module and while preparing to jettison the Lunar Module Falcon, he had trouble sealing the water connection to the LCG and had to use a plug instead. If returned to Earth, then analysis of the problem, believed to be caused by dust contamination, can be made in time for the next flight.]

239:52:19 Henize: Roger. [Long pause.]

239:52:45 Scott: Well, Houston, I guess that it's a good reason we're about an hour ahead. So we'll go ahead and dig it out.

239:52:58 Henize: That's your choice, Dave.

239:53:04 Scott: Well, we're sort of ahead, and expecting little things like that to pop up.

239:53:08 Henize: Fine.

[Comm break.]

[Woods - "Suited and unsuited in the Command Module in weightlessness. Is that a particularly difficult task. Is it easier or more difficult than doing so on the Moon. You got three guys in a small space and no gravity."]

[Scott - "The only added difficulty in weightlessness is sort of getting to a position where the other guy can help you get in the suit and hold the suit. That's no big deal. The work on the suit is getting it zipped, getting it plugged, getting it checked. All that stuff. Yeah it was probably a little more difficult than... [laughs] They're both hard. If I say weightlessness is more difficult than one-sixth-g then the implication is that one-sixth-g is easy. Not easy. Very, very hard."]

239:54:30 Henize: Roger; Dave. That's fine. That's the one we'd like.

239:54:35 Scott: Okay. Okay. [Long pause.]

239:54:56 Henize: And 15, whenever Al has a quiet moment, I have several prebriefing questions to send up to him about what to look for on the V over H sensor.

[The V over H sensor is part of the Panoramic Camera's system. The sensor optically determines the rate at which the landscape is passing below, allowing the camera to adjust for the smearing that would occur if uncorrected.]

239:55:12 Henize: Very good.

[Long comm break.]

[Flight Plan page 3-354.]

[Endeavour has probably been maneuvered to the required attitude for Al's EVA. Appropriate angles are given in the Flight Plan for aiming the HGA (High Gain Antenna). To use them, the crew assume manual control of the antenna's mounting gimbal and dial in the given angles using two knobs to the lower right of the Main Display Console, panel 2. Nearby gauges let them monitor the antenna's actual orientation.]

[Now that the spacecraft is in the proper attitude, the A and B thruster quads are disabled. These are adjacent to the SIM bay and would pose a danger to Al as the spacecraft constantly fires thrusters to maintain its attitude. Guard rails are installed over the centre of the Main Display Console to ensure that controls, particularly those concerning the RCS, are not nudged. The three crew don their suits, Dave and Jim wearing their surface EVA suits, and get connected to the spacecraft's suit oxygen circuit. Al's 7.4-metre umbilical is different in that it includes a tether connected between a fixing on the CM and a waist belt he will wear around the outside of his suit. The umbilical also carries wiring for communication and biomedical telemetry. Jim also has a waistbelt and a shorter, 2.2-metre tether as he will stand in the CM hatch during the EVA, helping control Al's umbilical, operate the TV and 16-mm cameras and bring the film cassettes into the cabin.]

240:01:59 Scott: Okay. Go to Manual.

[Very long comm break.]

[During this hour of communications silence, the crew continue their preparations for the EVA.]

[Scott, from the 1971 Technical Debrief - "On the night after TEI, Al started configuring the cabin, stowage-wise, so that we'd be set up for the EVA. I think he put at least 2 hours into configuring the cabin the night before."]

[Worden, from the 1971 Technical Debrief - "Yes. There was a lot of detail stuff, like putting things into the EVA bag, getting the purge valve out, and getting a lot of the little stuff out of the stowage containers. We tied the rock bags up to the sides of the spacecraft, rather than tying them down on top of the lockers. That way we could get in and out. Rearranging the stowage was kind of the detail part of some of the EVA prep that we did the night before."]

[Scott, from the 1971 Technical Debrief - "The point is that when we got into the EVA day - when we got up that morning for the EVA - the cabin was already in good shape. Everything was set up so that we could proceed into the EVA prep according to the checklist with a minimum amount of shuffling. At the outset, I'd like to say that the checklist was excellent. The procedures ran very smoothly. I don't think anything was out of order. We had a very complete set of procedures overall. Everything got done according to the book, and it was very good. The only problem was time. We got up that morning and we had a few SIM bay things to do. Al had some P23s to do, and as soon as he finished his P23s, we started into the checklist and the portion called "Cabin Prep for EVA." We started that at 237:30 GET. It's really called in the Flight Plan to start at 239:30, so we started 2 hours early in the cabin prep for EVA. We went through every step line-by-line to make sure it all got done. It flowed very smoothly with no hitches, and it just took a little time to get everything done. We ended up just about on time for the pressure integrity checks. That means that it took us almost 2 hours longer than preflight planning. We were very happy that we had started early. We were glad that we had Al configure the cabin the night before to take care of the little details. I think it will pay off if you get started early on the EVA, because it really takes a lot of time making sure that you get everything done."]

[Worden, from the 1971 Technical Debrief - "Most things you do on board take a little longer than you would expect them to preflight. That's because you take a little bit more care with what you're doing in flight. You do it much more methodically than you do preflight. That was particularly true of the EVA prep. We went through the checklist very carefully, very methodically, and we never rushed at any time. It flowed very smoothly but a little slower than we anticipated."]

[Scott, from the 1971 Technical Debrief - "Which I think was good in that case, because it was the first time through for that EVA. It was nice to have a comfortable time pad all the way through. We knew we had a good time pad all the way through, so perhaps we were not operating at maximum efficiency relative to time. We were taking our time because we knew we had the pad."]

[So that Mission Control, and the public too, can watch the progress of Al's excursion along the Service Module, a pole has been provided so that the colour TV camera and the 16-mm movie camera can be mounted far enough from the CM main hatch to gain a reasonable view of his activities around the SIM bay. The pole will be attached to the inside of the open hatch.]

[When Dave and Jim walked and drove on the Moon, they each carried a backpack called a PLSS (Portable Life Support System) which provided all the required consumables to keep them alive and fit for over seven hours. The PLSS provided oxygen, cooling water and scrubbed CO₂ out of the air. If, however, a suit were to be punctured for some reason, the flow-rate from the oxygen supply would likely not be high enough to sustain the crewman against the falling pressure. For this contingency, both Dave and Jim carried an extra package on top of the PLSS called the OPS (Oxygen Purge System), the prime component of which was a very high pressure bottle of O₂ which could be quickly released through a regulator. Though the PLSS's were discarded on the Moon, the two OPS units were retained in case Dave and Jim needed to transfer to the CM by an EVA. Now one unit will provide Al with his emergency supply during his EVA.]

Public Affairs Officer - "This is Apollo Control at 240 hours, 37 minutes. The crew is busy with preparations for EVA and Apollo 15 is 173,670 nautical miles [321,636 km] from Earth. Velocity 2,935 feet per second [895 m/s]."

[Flight Plan page 3-355.]

241:00:04 Henize: 15, this is Houston. Go ahead.

241:00:11 Scott: We're all suited up, and down to the comm check portion of the EVA prep, and we're ready to talk to you about whatever you'd like to talk about.

241:00:21 Henize: Roger. Stand by.

241:00:34 Henize: I guess the main thing we have to talk about is the inspection of the V over H sensor of the Pan Camera. Are you ready to listen, Al?

241:00:48 Scott: Okay. He can read you, but he's got to reconfigure his panel in order to talk to you, so we'll do that.

241:00:56 Worden: Okay, Karl, how do you read me now?

241:00:57 Henize: Loud and clear, Al. Hey, on this V over H sensor, I have a set of five steps, or five questions that we'd like to have for you to have in your mind.

241:01:09 Worden: Okay. Go ahead.

241:01:11 Henize: Okay. Number 1 is, inspect the general area - this is sort of a general point of view - inspect the general area around the V over H sensor and comment on any evidence of thermal or mechanical degradation. And 2, 3, 4, and 5 are sort of more specifically. Number 2. Is there any evidence of V over H sensor lens cracking, or debris on the lens? In other words, have a good check of the lens itself. Number 3. Is any large amount of the black paint around the V over H sensor opening missing? Number 4. Is the plume shield in place around the V over H sensor opening? And the plume shield is what I'd generally call the - or - the - it's the guard around the lens sticking out about 3 inches [75 mm] there. And, number 5. Is anything obviously obstructing the V over H sensor field of view?

[This illustration, taken from the J-mission Apollo News Reference, shows the layout of the SIM bay. The V over H sensor is to the lower right of the Panoramic Camera's lens. Though difficult to see on this picture, its plume shield is like a lens hood projecting forward. During the EVA, Al will engage his feet in the foot restraint to the left. Facing right, he will have access to the majority of the bay, particularly the film cassettes which he must retrieve.]

241:02:29 Henize: Okey doke. No other special questions at the moment. Stand by.

241:02:40 Worden: Okay.

241:02:42 Scott: Okay. We'll proceed on here then.

241:02:46 Henize: Incidentally, I guess we're - we both understand each other on the status of the Mapping Camera? So far as you know, it hasn't retracted. Is that correct?

241:02:58 Worden: That is our understanding at this point. I'll let you know when I get out.

241:03:02 Henize: Roger. [Pause.]

241:03:11 Henize: Oh, Al. One more point that I overlooked down here, and that is, the people here would like to have you look at the Mass Spec. boom, Al, if it's at all feasible. If it's not convenient to look down at the base of that boom and look at the coils, forget it; but if you can get a look in there, we would expect to find a coil crossover jamming down in the base there, and we'd like to have your visual confirmation of that.

241:03:39 Worden: Roger, Karl. I had intended to do that.

[Towards the latter part of the spacecraft's time in lunar orbit, Al began having problems retracting the boom carrying the Mass Spectrometer. This problem is discussed more fully earlier in this journal but its essence is that the boom mechanism sticks when it becomes cold.]

[The next exchanges are the crew's comm checks. Dave and Jim will use a PTT (Push to Talk) switch. Al will be on VOX, his transmissions being made automatically by a voice-operated switch.]

241:04:04 Scott: Net comm, Off.

241:04:05 Worden: Net comm, Off.

241:04:06 Scott: S-band T/R.

241:04:07 Worden: S-band T/R.

241:04:08 Scott: [Garble.]

241:04:09 Worden: Normal.

241:04:10 Scott: Intercom T/R.

241:04:11 Worden: T/R.

241:04:12 Scott: [Garble.]

241:04:13 Scott: Off. [Long pause.]

241:04:53 Worden: Roger.

241:04:55 Scott: Houston, Endeavour. I guess the comm's acceptable to you down there on - with Al on VOX. Is that correct?

241:05:02 Henize: Roger. We're reading him loud and clear.

241:05:07 Scott: Roger. [Pause.]

241:05:14 Worden: Press Alarm, On; tone on.

241:05:17 Scott: [Garble] Off?

241:05:18 Worden: Off. [Long pause.]

241:05:38 Worden: On. [Long pause.]

241:06:13 Scott: Go ahead.

241:06:22 Worden: 900.

241:06:42 Scott: Roger.

241:06:43 Worden: Repress to Off. [Pause.]

241:06:51 Scott: Flashlight. Flashlight. Yes, got it. It's okay. It's off. Panel 600.1. Go.

241:07:16 Worden: Emergency O₂ Valve, Closed.

241:07:20 Scott: Closed. [Long pause.]

241:07:49 Worden: No, I'm negative. [Garble] panel 8, front.

241:08:09 Worden: [Garble.] [Long pause.]

241:08:23 Worden: Just...

241:08:30 Henize: 15, we'd like to have Omni Charlie.

241:08:43 Scott: Roger. Omni Charlie.

[Comm break.]

241:09:53 Scott: It's On.

241:09:57 Scott: It's on. [Long pause.]

241:10:42 Scott: Good.

[Very long comm break.]

241:21:05 Scott: Roger. We'll do that.

241:21:08 Worden: Okay. Stand by. I'll get the High Gain. [Long pause.]

241:21:38 Worden: Okay. High gain?

241:21:40 Henize: Roger; and thank you.

241:21:41 Scott: You should have it. [Pause.]

241:21:50 Worden: Negative. Coming unstowed.

241:21:58 Worden: They're installed.

241:21:59 Unknown Speaker: [Garble.]

241:22:03 Worden: [Garble.]

241:22:05 Unknown Speaker: [Garble.]

241:22:09 Worden: It's attached.

241:22:09 Scott: Don OPS. Connect straps to adapter bracket.

241:22:13 Worden: In work. [Long pause.]

241:22:58 Worden: Okay. Wait. [Long pause.]

241:23:11 Worden: Wait a minute. Let's get the straps up. [Long pause.]

241:23:45 Worden: Okay.

241:23:47 Scott: Okay. Snap all the flaps.

241:24:01 Worden: Now, I'm on SCU whenever - Whenever you're ready.

[Comm break.]

241:25:31 Worden: All verified. Roger. Got you. [Pause.]

241:25:44 Worden: Okay.

241:25:55 Scott: You can leave them off. [Long pause.]

241:26:52 Scott: Down in the left-hand LEB, Jim. Bring it up with gloves and helmet, gloves inside. [Long pause.]

241:27:35 Scott: Cabin pressure, 5.2 [psi].

241:27:40 Worden: Yes.

[Comm break.]

[Comm break.]

241:31:53 Scott: Cabin pressure is approaching 6, and I'll crack the side hatch valve just a bit.

241:31:59 Irwin: Yep.

[Comm break.]

[Worden, from the 1971 Technical Debrief - "There was a lot of discussion about cracking the side hatch valve to maintain the cabin pressure during the EVA prep. That's particularly true when I was flowing through the umbilical. I thought that operation worked very well. I didn't see any problem at all with opening the side hatch valve just a little bit to relieve the cabin pressure."]

[Scott, from the 1971 Technical Debrief - "Except that it was easier for me to do it than it was for you."]

[Worden, from the 1971 Technical Debrief - "That's right."]

241:33:08 Irwin: Roger. [Long pause.]

241:33:26 Worden: All locks.

241:33:28 Scott: Okay.

241:33:33 Worden: You guys do your integrity check before I put my helmet and gloves on. [Pause.]

241:33:49 Worden: In case I'd have something closed.

241:33:51 Scott: Cabin pressure, 5.4. [Long pause.]

241:34:13 Scott: Okay. O₂ Flow High, pegged.

241:34:17 Irwin: Your light's on. [Pause.]

241:34:30 Worden: O₂ Flow High, pegged. [Pause.]

[Comm break.]

241:36:20 Scott: Vents.

241:36:22 Irwin: Vents all closed. [Long pause.]

Public Affairs Officer - "Heart rates now in the 60's with Dave Scott occasionally dropping down into the 50's."

241:37:19 Irwin: It's ready.

241:37:22 Worden: Side hatch valve coming on pull. [Long pause.]

241:37:56 Scott: Roger. That and my SCM. Okay? That'll hold steady.

[Comm break.]

241:39:54 Worden: Yeah.

241:39:55 Scott: ...suit pressure reading?

241:39:58 Worden: Suit pressure's reading about - pound and a half above cabin. [Long pause.]

241:40:28 Worden: Cabin pressure's running about 5.9.

241:40:37 Scott: I'll pump it down a little bit. [Long pause.]

241:41:00 Worden: Jim. Stand by one. Get the cabin pressure down.

241:41:10 Scott: Okay. [garble] valve's, closed. SCS, closed. [Long pause.]

241:41:58 Scott: Houston, 15. The suit circuit looks pretty good up here. How does it look to you?

241:42:05 Henize: Roger, 15. It looks good to us down here.

241:42:11 Scott: Okay. Thank you. [Long pause.]

241:43:06 Irwin: SCU is done. 603 is On. Verified.

241:43:39 Worden: Okay. Let's get the helmet on first.

241:43:49 Irwin: Okay. Purge valve.

241:43:55 Worden: Got it. It's activated.

241:44:07 Irwin: Rog.

241:44:10 Scott: Pull the OPS down there, would you, Jim?

241:44:18 Worden: Hold it. Hold it up in front.

241:44:29 Worden: Okay. [Long pause.]

241:44:53 S/C: Can you [garble]?

[Comm break.]

241:46:20 Worden: Got it. [Long pause.]

241:46:55 Scott: Okay. Down and locked.

241:47:05 Scott: O₂ coming off. [Long pause.]

241:47:40 Irwin: Locked. [Pause.]

241:47:48 Scott: Okay. I'll be pressurizing. [Long pause.]

241:48:16 Scott: [Garble.] [Long pause.]

241:48:51 Worden: [Garble] 3. [Long pause.]

241:49:10 Worden: Okay. [Long pause.]

241:49:28 Scott: Okay. Stable at 3.9.

241:49:36 Worden: Turn it off.

241:49:40 Irwin: [Garble] Verified, off.

241:49:43 Scott: Yes, it's okay.

241:50:05 Scott: 6. [Pause.]

241:50:14 Scott: Got it? Okay. It's off.

241:50:23 Irwin: Locked.

241:50:26 Scott: High. You've got the temp. Can you reach it? Hook that strap in for me, too, would you, please? No.

241:50:52 Henize: 15, Houston. We note that your cabin pressure's up to 6. You might consider dumping it down.

241:51:01 Scott: Roger, Houston. [Long pause.]

241:51:20 Irwin: Hooked.

241:51:38 Scott: Tell me when my temp [garble] anyone.

241:51:51 Irwin: Yeah. [Long pause.]

241:52:43 Scott: Okay. [Pause.]

241:52:50 Irwin: Reading 4.0.

241:52:55 Scott: Okay.

241:53:11 Worden: It's off. Warning tone's on.

[Comm break.]

241:54:30 Scott: Reading 4 on stable.

241:54:32 Worden: Off. [Pause.]

241:54:43 Irwin: Reading 300. [Long pause.]

241:55:04 Scott: Okay, Houston; 15. We've got a good integrity check on the CMP, and standing by for a Go for depress from...

241:55:23 Worden: Dave, would you turn my [garble] valve, please.

241:55:31 Henize: We copy, 15. And you have a Go for depress.

[The main, or side hatch has a depressurisation valve built into it. It is operated by releasing a handle and winding the valve open. The crew are only 4 minutes behind their planned timeline.]

241:55:38 Worden: Are they vertical now? [Pause.]

241:55:50 Worden: Other side too. Two of 'em.

241:55:52 Scott: Yeah. [Pause.]

241:56:02 Scott: Okay. You guys ready? Okay. Houston, 15. The side hatch dump valve is coming open.

241:56:14 Henize: 15, Houston copies. [Long pause.]

Public Affairs Officer - "Cabin pressure coming down."

241:56:47 Worden: Rog.

241:56:54 Scott: Want to stop there?

241:56:58 Worden: Well, okay. Think it's probably easier than I can. [Long pause.]

241:57:37 Scott: Reading 4.0. Go to 'em.

[Comm break.]

Public Affairs Officer - "Cabin is 1½ pounds per square inch."

241:59:21 Worden: Reading 3.8 on mine. [Long pause.]

Public Affairs Officer - "Half a pound cabin pressure now."

242:00:16 Worden: Roger. Fine. [Long pause.]

242:00:35 Scott: Okay.

[Comm break.]

[Flight Plan page 3-356.]

242:01:38 Worden: Yeah. It makes a difference. It's still flowing into the cabin.

242:01:42 Scott: How can you read me? You read me okay? Good.

242:01:42 Worden: You hear my VOX cut in and out? Good.

Public Affairs Officer - "Heart rates: Worden and Irwin in the 70's, Scott in the 60's."

[Mention of the crew's heart rates brings up the point that after the flight Dave had concerns as to whether Jim should have gone through the hatch for this EVA in light of the heart rhythm irregularities seen by the ground]

[Scott - "I think we should have had a discussion. We had a private loop. We could have had a comms loop discussion with the Flight Director and whoever, and they could have said, 'Jim's got a problem,' and we probably would have changed the EVA procedures.]

[Scott - "We could have switched - I just sat in the left couch. I didn't do anything. Jim didn't have a big job but he was standing in the hatch, helping Al. Suppose he had had a heart attack and died? Would have been a bad day. Would have been better to put Jim in the left couch and let him just relax, and let me do his job, which wasn't a big deal. But nevertheless, I'd have switched it."]

[Woods - "Had something happened, you would have been in a more secure position."]

[Scott - "Yeah. I mean if I had known Jim had a problem, then I would have said, 'Let's switch roles for Al's EVA and you just sit there in the couch and watch the world go by.'"]

[Harland - "Well you'd done a head-out-of-the-hatch on [Apollo] 9 so you know what's involved there."]

[Scott - "Yeah. I'd understand the hatch. Yeah. At the very least, we'd have had a nice discussion with the Flight Director, 'nice' being full disclosure of the situation and full discussion of what's the best thing to do."]

242:02:28 Scott: I suspect that SCU is forward enough to keep it there. [Long pause.]

242:03:01 Worden: It'll hold. Now. [Pause.]

242:03:12 Worden: It's released. It's in the yellow?

242:03:18 Worden: No. We've missed it.

242:03:20 Scott: Yeah. I can't see it. Jim, can you see the indicator?

242:03:23 Irwin: I can't either, can you?

242:03:27 Scott: Stand by one.

242:03:30 Worden: Roger. [Garble.]

242:03:39 Scott: Houston, 15. We're getting ready to open the hatch. How does everything look to you down there?

242:03:49 Henize: Roger, Al. Everything's looking good to us here.

242:03:53 Worden: ...out, Dave.

242:03:56 Scott: Okay? Unlatch. Unlatch. Ready? Rog.

242:04:19 Worden: No.

242:04:23 Henize: 15, Houston. We don't see the TV camera on yet.

242:04:25 Worden: The hatch is open.

242:04:29 Scott: Huh. Oh, we haven't got it out yet. We'll have it out there in a minute. It should be on though.

[Al's EVA has been described as the first interplanetary spacewalk, in an age that placed much prestige on space "firsts". Apart from the three Apollo EVAs to retrieve SIM bay film cassettes, every other EVA from a spacecraft in freefall has taken place in low Earth orbit, never more than about 600 kilometres away from the home planet. This was still true at the time of writing thirty years after the event.]

[Scott, from the 1971 Technical Debrief - "Hatch opening occurred about 5 minutes after the planned hatch opening. The integrity checks went very well. The procedures played just exactly as they were laid out in the checklist and just like we've seen them in the chamber. I'm glad we ran those chamber runs because that helped us, Jim and I, to understand what you were doing with your equipment."]

[Worden, from the 1971 Technical Debrief - "I think so, too. We were all well prepared for the EVA."]

242:04:39 Scott: Roger. Roger.

242:04:46 Worden: Okay. [Long pause.]

242:05:09 Worden: Okay. [Garbled.]

242:05:16 Worden: [Garble] zero. Clips.

242:05:32 Worden: Jettison bag is gone. And jettison bag number 2.

242:05:50 Worden: Okay. [Long pause.]

[Worden, from the 1971 Technical Debrief - "After getting the hatch open, the first thing I did was take the TV and the DAC and mount them on the bracket in the hatch. The hatch didn't get fully opened the first time. When I got part way out, I guess you opened the hatch the rest of the way so that the camera was pointing down along the SIM bay. I just went outside the hatch, grabbed the first handrail, and positioned myself just outside the hatch until Jim got in the hatch to observe and to watch the umbilical."]

[Later in the Technical Debrief, when the crew discuss simulations, Al discusses the training he did in the WIF (Water Immersion Facility). This technique, where an EVA crewmember dons a spacesuit, modified for use underwater and weighted to give neutral buoyancy, to give an impression of how the body moves in a zero-g environment has become the preferred method of training for the lengthy EVAs performed almost routinely in low Earth orbit.]

[Worden, from the 1971 Technical Debrief - "I thought the training program for the EVA was just right. There wasn't too much. I thought there was an adequate amount of training. The sessions in the WIF could have been reduced somewhat because the sensation of neutral buoyancy is sufficiently removed from zero-g that with too much training in the WIF, it almost turns out to be negative training. The operation is so much more difficult in the WIF than it is in flight or in the zero-g airplane that fewer sessions in the WIF would have been in order. Maybe one or two sessions in the WIF, instead of a large number of them, would be perfectly adequate. The zero-g airplane was invaluable. The one-g trainer going through the prep and the post was completely adequate. I thought that particular training program was outstanding."]

242:06:16 Scott: Okay, Houston. You should be getting a picture about now.

242:06:21 Henize: Roger, 15. We're getting a signal. [Long pause.]

242:07:04 Worden: Okay. [Pause.]

242:07:12 Worden: Okay. Fine. First thing is that the map - the Mapping Camera is all the way out.

242:07:27 Scott: Okay. [Pause.]

242:07:34 Scott: Okay. [Long pause.]

242:07:52 Henize: 15, this is Houston. We're getting a clear picture now, but the aiming of the TV camera is poor. Is it possible to open the hatch wider?

242:08:10 Scott: Yeah, that's what - we're - we're looking at that, too. Stand by one, and we'll do that. [Pause.]

242:08:44 Worden: Yes, I can see the TV is pointed right at the Command Module there. Right at the interface.

Real Video file (142K)

[This Real Video file is taken from NASA's post-mission documentary on the mission.]

242:08:57 Scott: Push it back a little there, Jim. Okay.

242:09:11 Henize: That's excellent.

242:09:13 Scott: You should have a picture at a man in space.

242:09:15 Henize: Very good. [Pause.]

242:09:20 Worden: Okay. You ready, Jim? I'll work my way down. Okay, it's reading 4. Okay. [Long pause.]

Public Affairs Officer - "Distance 171,000 [nautical] miles [316,691 km]."

[This illustration outlines how Al is to progress along from the CM hatch to the foot restraints in the SIM bay. Having exited the CM (1), he uses handholds mounted all along the side of the Service Module (2) until he is over the bay (3). Further handholds surrounding the SIM bay allow him to rotate (4) until his feet are in the correct position to engage them in the foot restraint (5), giving him full access to the bay.]

[Worden, from the 1971 Technical Debrief - "I went hand-over-hand down the SIM bay and to the left around the Mapping Camera. I just floated myself over the Mapping Camera instead of going around it down into the SIM bay. I put my feet in the foot restraints and just stood there for a minute, resting and looking at the SIM bay, and waiting for Jim to get himself positioned in the hatch."]

242:09:58 Henize: We copy.

242:09:59 Scott: Yes. [Long pause.]

242:10:07 Scott: Okay. [Long pause.]

242:10:40 Worden: Okay. I'm in the front restraint.

242:10:45 Henize: Yes, that's good work up there, Al. [Long pause.]

242:11:37 Worden: Okay, the Pan Camera cassette is tethered. There's the pip pin.

242:12:32 Scott: Good.

[Comm break.]

[Worden, from the 1971 Technical Debrief - "The Pan Camera went just as I had anticipated it would go. I pulled the metallic cover off the Pan Camera and released it. Then, I pulled the fabric cover off. The force that it took to pull both of those covers off was just as I had expected and remembered from preflight. It was the same operation. I pulled the pin on the Pan Camera cassette, tethered myself to it, and pulled the release handle. It came out even easier than I had expected. The mass of the Pan Camera cassette was a little bit more than I had expected, but it was no problem handling it. I just very carefully drifted it back towards the hatch, keeping my hand on the handle and maneuvering myself back. I did release it at one time, because I had to use both hands to maneuver myself over the Mapping Camera. But I didn't release it clear to the end of the tether. I just let go for a minute, repositioned myself, and then grabbed it with the handle again. I thought that went very smoothly."]

Public Affairs Officer - "Irwin's heart rate 116, Scott's 71. There's the film cassette."

242:13:43 Scott: Get it inside there, if you can, Jim. Get it inside. [Long pause.]

242:14:26 Irwin: Okay.

242:14:30 Worden: Rog. Would you like to exchange - would you like to get hold of it? [Laughter.]

242:14:42 Worden: That's the Pan Camera [cassette], right. Okay, Houston. The Pan Camera is safely inside. Over.

[Worden, from the 1971 Technical Debrief - "The transfer back through the hatch went just as we'd done before, too. I handed the Pan Camera cassette back in through the hatch. You tethered it and then released my tether. That was pretty much as we'd done before; no problems there."]

[Scott, from the 1971 Technical Debrief - "I put it down in the LEB and it stayed. I left it on the tether and it never got in your way. No problem."]

242:14:53 Henize: Beautiful job, Al baby. Remember - remember, there is no hurry up there at all.

242:15:02 Worden: Roger, Karl. I'm enjoying it. [Long pause.]

Public Affairs Officer - "Going back for the Mapping Camera cassette now."

242:15:35 Worden: Okay, Houston. Rest break. We'll take a look at the V over H sensor.

242:15:41 Henize: Very good.

242:15:48 Worden: Uh, hum, I see nothing on the V over H sensor. There's no back - black paint missing. There's nothing obscuring the field of view. The glass is not cracked.

242:16:13 Worden: The shield is not obstructing the field of view. There's nothing in the way, Karl.

242:16:21 Henize: We...

242:16:22 Worden: It's perfectly clear.

242:16:23 Henize: We copy your report, Al. Thank you.

242:16:29 Worden: Okay. And as I look around, the Mass Spec. is - oh, it looks like about - not quite in - the cover. It looks like maybe it's the cover that's jammed. Yes, in fact, it is the cover that's jammed. See?

242:16:57 Henize: Roger, Al. We copy. That was most unexpected news.

242:16:59 Worden: No, I can't tell from here. I can't really - I can't really tell from here, Karl, whether it's the cover or not. I thought the cover was jammed. One corner of the cover is overlapping a - side section of insulation which I wasn't expecting it to. But it doesn't seem to be - it doesn't put any force on it - on the Mass Spec. If I could get around and take a look at it. The Mass Spec. is in the guide pins, and the Mass Spec looks like as it is fully retracted. The Mass Spec. is fully retracted, Karl.

242:17:57 Henize: Roger, Al. We're reading you loud and clear.

242:17:59 Worden: Any - any diffi - any difficulties with the talkback has to be associated with that cover, because the cover is not closed. How far through the slot should the guide pin come on the - on the reel?

242:18:18 Henize: Stand by, Al.

242:18:21 Worden: Okay. 'Cause I can see a guide pin coming through. You do that, and I'll get the map - Mapping Camera.

[Worden, from the 1971 Technical Debrief - "The Inconel cover on the Mass Spectrometer was cocked about 30 degrees from the closed position. I reached over and grabbed the cover and moved it a little bit. It's a fairly flimsy cover, but I wanted to see if it was jammed against anything. One corner seemed to be hung up. I released it, but the cover stayed where it was. I really couldn't close it. Then, I looked down inside the Mass Spec. itself and noticed that the guidepins were through the guide slots in the experiment itself, indicating that it had at least positioned itself on the base of the boom itself. I wasn't sure at the time. That's something I hadn't looked at preflight. I wasn't sure just how far those guidepins should come through the slots to indicate that the Mass Spectrometer was fully retracted. So I called down to the ground and said that the tip of the guidepins were just through the guideslot. They called back and said that it wasn't fully retracted then, because the guidepins should be through the slots far enough so that the cylindrical part of the guidepin could be seen. So, that indicated to me that the Mass Spectrometer wasn't fully retracted. That was all I could see on it. I couldn't see around the Mass Spectrometer. I couldn't see down into the SIM bay at that point because the cover was obscuring the view."]

242:19:39 Worden: Okay, Jim. I'm ready to bring the other one back.

242:20:03 Henize: Hey, Al. It looks like you're running a pass up there. That's beautiful. [Long pause.]

Public Affairs Officer - "And there was the Mapping Camera cassette."

242:20:27 Worden: Okay. [Long pause.]

[Worden, from the 1971 Technical Debrief - "I pulled the cover off the Mapping Camera, I noticed that that particular cover was a little more difficult to release than I had anticipated. That particular cover is set under a flange on either side. It's held down by some pins at the release end of the cover. I had to twist it a little bit and pull it a lot harder than I had anticipated to release it from the flanges on the side. But, it did come off all right; there was no problem. The fabric cover underneath got hung up on one corner. The fabric has a rubber slot that it fits into around the edges, and it's almost an airtight seal. That rubber-slotted flange hung up in one corner, and I had to pull it three or four times before I got it released. After that, everything was just as I had anticipated."]

["I tethered the Mapping Camera cassette, released it, and it was a very easy operation after that. I brought it back into the hatch, as we had practised preflight."]

242:21:25 Scott: Okay, Houston. The Mapping Camera cassette is inside.

242:21:30 Henize: We copy. [Pause.]

242:21:42 Worden: Houston, is there anything else you want me to check in the SIM bay before we go back in?

242:21:52 Henize: Al, we'd be...

242:21:53 Worden: Is there anything on the Mapping Camera I can check?

242:21:55 Henize: Al, we'd be pleased to have any general comments you had about the SIM bay experiments, otherwise than what we specifically asked you. Did everything look in order?

242:22:05 Worden: Okay. Well, everything looked good, as far as I could tell, all except for the cover on the Mass Spec., and the fact that the Mapping Camera is up. Maybe I could make another quick check back here and see if I can see anything on the Mapping Camera.

242:22:23 Henize: Rog. [Long pause.]

[Worden, from the 1971 Technical Debrief - "I think the concern at the time was that the Laser Altimeter/Mapping Camera contamination cover was binding against the side - forcing it to stay in the Extend position. I went back out and looked, and there was about three-fourths of an inch to maybe 1 inch clearance between the cover and the Mapping Camera itself. From that, I concluded that the cover hadn't anything to do with it. I looked underneath the Mapping Camera, and I looked around all of the edges to see if there was something binding, maybe something that had lodged alongside the Mapping Camera. Everything looked clean to me. There was nothing that was impinging on the Mapping Camera at all. The stellar shield was still out, but of course, it would be with the camera extended. At that point, it was maybe 12 to 15 inches away from the SIM bay mold line. So, there was nothing I could tell from there that would shed any light on why the Mapping Camera did not retract."]

242:23:16 Scott: All right. [Long pause.]

Public Affairs Officer - "Worden's heart rate 85 now."

242:23:40 Worden: Oh, just a second. I've got get the mask and get the TV.

242:23:54 Worden: Okay. TV coming in. Got it, Dave? Okay.

242:24:03 Scott: Okay, take your time.

242:24:05 Worden: I - I'm doing fine. [Long pause.]

242:24:20 Worden: Okay. [Pause.]

242:24:33 Worden: Hung up - on something. [Long pause.]

242:24:58 Scott: Ah, yes, it's about the same place it was when we opened the hatch. [Pause.]

242:25:15 Worden: Okay. Hatch is locked.

[Worden, from the 1971 Technical Debrief - "I went back in the hatch, pulled the quick release on the TV camera bracket, which we had decided to do preflight. Rather than releasing the handle itself, we pulled the Marmon clamp, releasing the pole. I sent the pole in the hatch, backed into the hatch myself, and pulled the hatch closed. I thought that went very easy. It took hardly any force at all to close the hatch. It operated very smoothly and very freely. I pulled it right down to the point where it was closed. A couple of pumps on the handle, and the latches were over and off. It was very simple operation."]

242:25:35 Worden: Can you do it, Dave? Okay.

242:25:40 Henize: 15, Houston. You can turn off the TV anytime you like.

242:25:47 Scott: Let us get depr - pressurized first, Karl.

242:25:52 Irwin: Okay. [Pause.]

[Worden, from the 1971 Technical Debrief - "Once we got the side hatch open, from that point to the time we closed the hatch, the whole operation went almost exactly as it had in preflight training, both in the zero-g airplane and the Water Immersion Facility. I don't recall anything during the EVA that I thought was off-nominal. As a matter of fact, it was so much like preflight, that I really had no anxieties about the EVA at all. The whole thing went just as smooth as it could."]

["It was just as we practised. That's the key to the whole thing - good solid practice before flight. Be well prepared for what's going to be out there and for the kind of body motions that are required to get back into the SIM bay and into the foot restraints."]

["In true zero-g it was really much easier than it had been even in the zero-g airplane. I think there's some rotation that you get in the zero-g airplane that does effect your motions a little bit. True zero-g is just much easier. If you can do it in a zero-g airplane and in the Water Immersion Facility, in flight it is easy."]

242:26:00 Worden: Okay.

242:26:01 Scott: Very good. [Pause.]

242:26:10 Worden: Okay. [Long pause.]

242:26:41 Irwin: Tell me when to close it. That's it.

242:26:47 Worden: [Garbled.] Take it down here before it's too - okay, okay.

242:27:09 Scott: Okay?

Public Affairs Officer - "Cabin pressure coming up now."

242:27:11 Worden: I said, I wish I were back outside. It's hell in here. Okay.

242:27:18 Irwin: Closed.

242:27:24 Worden: I can't. No. Yeah. That's okay, Jim.

242:27:43 Irwin: How's that? There we go. Now we should get our positions straight. You see it now, Dave? Okay. Make sure we got a good seal.

242:28:22 Scott: Okay, Houston; 15. It looks like we got a good seal. How's it look down there?

242:28:38 Henize: 15, Houston. Your seal looks good to us.

242:28:44 Scott: Okay, thank you. Is 601 open?

242:28:52 Irwin: It's open.

242:29:03 Irwin: and it looks zero now, Dave?

242:29:10 Scott: Rog. [Long pause.]

Public Affairs Officer - "Cabin pressure 2 pounds."

242:29:58 Scott: [to Worden] You should have stayed longer.

[Comm break.]

[Al gets a question along the same lines during the inflight press conference tomorrow. When asked why he came in so soon, he answered that he came in when the job was done.]

[Woods - "Al seemed to spend an awful short time outside. You told him you should have stayed there longer. He was all for get out there, do the job, get back in. That seems a bit of a shame from his point of view."]

[O'Brien - "I would imagine that you would have a little bit of free time, but this wasn't time critical. You were plugged into the CSM. You weren't in a rush."]

[Scott - "Weren't in a rush, but on the other hand, the purpose was to get the film and get back in. I think Al did the right thing. Came back in. I mean, it'd be nice to stay out and float around and look around but, why? So if you stay out and float around and look around and then something goes wrong during that period, then you say, 'Why did I do that?' So I think what you do is you do your job and you get back in and close the hatch and say, 'Gee, that was wonderful. I had a great time. I did my job.' I think to float around out there is exposing yourself to an unnecessary risk. It's low risk, but on the other hand, it's high risk. So what if that last minute is a time you popped a leak for some reason? Eh? So shoot, get the job over. As sort of an analogy, we used to fly airplanes in bad weather. Rule was always; go to your destination, finish your mission and then play around because if you got to get down, you got fuel."]

[Woods - "You say to him here, 'You should have stayed longer.'"]

[Scott - "He got it done very quickly and very efficiently and came back in and the comment is, 'Geeze, you were having a good time. Why didn't you stay a while?' But I didn't really mean that. I meant it in a positive way. 'You should have stayed out there and stayed longer. You were doing really great, terrific.' But if you look at the seriousness of it, he did exactly right. He got his job done and he got in."]

[Woods - "On both of your Apollo flights, somebody went out through the main hatch of the Command Module. That's an impressive piece of engineering, an outgoing door that holds against 5 or 6 psi. After the Apollo 1 tragedy, were you involved at all in the redesign of that?"]

[Scott - "Yeah. They had all these working groups to fix all the problems. Not just the fire-related problems. All the problems kind of stuff. And I was on the working group with the probe and drogue and with the hatch and with the EMS and something else. But, yeah, I was pretty much in the middle. And in the hatch thing, they brought McDonnell Douglas guys in to really help them with that."]

[O'Brien - "Really?"]

[Scott - "Yeah, well, Gemini had an outward-opening hatch, right? They brought in the MacDac guys to help the Rockwell guys redesign the hatch."]

[Woods - "And as it happened, you were the first person to really test it on Apollo 9."]

[Scott - "Ah, but it worked. It was really a good hatch."]

242:33:00 Henize: 15 - 15, Houston. As long as we have the TV camera on, go - go to Average, and we should get a better picture down here.

242:33:11 Scott: Well, it's just down in the LEB sort of stowed away, but we'll do that.

242:33:26 Scott: We're just not in a position to get the panel 3 switch right now.

242:33:31 Henize: We - we copy, and that's fine. [Pause.]

242:33:50 Scott: You may have something on your picture, now. I'll check.

[Long comm break.]

242:37:18 Worden: Cabin pressure rate is coming up.

242:37:22 Irwin: They're out of lockup.

[Comm break.]

Public Affairs Officer - "Apollo 15 distance from Earth now 170,172 nautical miles [318,158 km]. Velocity 3,016 feet per second [919 m/s]."

242:40:37 Irwin: I'll get it. [Long pause.]

242:41:02 Scott: Got it.

242:41:03 Worden: PGA pressure. [Long pause.]

242:41:23 Worden: [Garbled.]

242:41:25 Scott: Yes.

242:41:26 Worden: [Garbled.]

Public Affairs Officer - "This is Apollo Control. The EVA clock here in control center recorded 39 minutes, 56 seconds [total EVA time]."

242:41:31 Scott: On.

242:41:35 Scott: Why don't you do it so I don't get my gloves dirty. Get my helmet. Get that stuff off and leave them.

[Comm break.]

[EVA times are measured from the time cabin pressure indicates less than 3.5 psi until it rises above this figure again. Although nearly 40 minutes were clocked for the EVA, the hatch was only open for twenty of those, though the Flight Plan had 53 minutes set aside for it.]

242:46:09 Scott: Okay; we'll do that. Thank you.

[Long comm break.]

[The crew are raising the cabin pressure by bleeding the contents of the OPS oxygen bottle. The Flight Plan calls for them to do this until the bottle is depleted. However, on this occasion, this is providing too much air. With the cabin repressurised, they can doff their suits and begin configuring the cabin for the rest of the journey home.]

242:52:38 Scott: Houston, 15. We're prepared to maneuver to the thermal attitude a little early if you'd like us to go over there.

[This is an attitude to mitigate the effects of solar heating on one side of the spacecraft and the chill of space on the other. However, the version of the Flight Plan used in the compilation of this journal does not show a change in attitude until 245:30, when there is a further period of x-ray astronomy using the SIM bay's X-ray Spectrometer.]

242:52:53 Scott: Roger.

[Long comm break.]

242:58:18 Scott: Roger. Going Auto. Over.

[Very long comm break.]

[If they were to place the HGA's Track switch from Reacq to Auto slowly, it would pass through the Manual position, whereupon it would begin to slew to the positions set on the HGA's position dials and go off lock. Since the HGA is already correctly pointed, they want to keep that position, perhaps to keep a solid telemetry record.]

[Flight Plan page 3-357.]

243:25:57 Henize: 15, this is Houston.

243:26:07 Scott: Go ahead, Houston; 15.

243:26:10 Henize: After some discussion down here, we'd like to disable your jets A2 - Alpha 2 and Bravo 1, mainly because the Mapping Camera's still out and our concern is that the plume will be deflected down into the SIM bay and possibly damage some of our electrical wiring or some of the - the N2 plumbing, which may give us other problems.

243:26:36 Scott: Roger. That sounds like a good idea. If there's any other particular configuration you want, just let us know.

243:26:42 Henize: Roger.

243:26:47 Scott: And A2 and Bravo 1 are disabled.

243:26:51 Henize: Thank you.

[Very long comm break.]

[Flight Plan page 3-358.]

244:01:42 Henize: 15, go ahead.

244:01:47 Scott: Rog. The OPS pressure is 2,000 [psi] and we'll be off comm for about 5 or 10 minutes here while we reconfigure the suits and everything.

[Since the OPS was not bled to depletion, Dave reports the source pressure reading on the bottle instead. Before use, its pressure gauge read 5,800 psi (40,000 kPa) and is now reading 2,000 psi (14,000 kPa).]

[Other items to be completed are a dump of the excess water produced by the spacecraft's fuel cells and a purge of those cells with oxygen. There is an additional item which is to charge battery B, delayed from before the EVA but the crew will delay all these items a little longer. The spacecraft's batteries are regularly charged during quiet periods to replenish them after any discharge that might have occurred during heavy usage in the meantime.]

244:01:59 Scott: Go.

[Very long comm break.]

244:34:31 Henize: 15, this is Houston. How do you read? [No answer.]

[Comm break.]

244:36:43 Henize: Apollo 15, this is Houston. How do you read? [No answer.]

[Comm break.]

[Comm break.]

244:39:46 Henize: Roger, 15. We're ready for the battery charge; and, while we're about it, the experimenters are getting a little fidgety about the waste water dump because that will impact their Mass Spectrograph work, so we would like to get the dump and the O₂ fuel cell purge started also.

244:40:04 Scott: Roger. We'll get on it right away. [Long pause.]

244:40:56 Henize: And, 15, whenever Al has a couple of minutes, we have a few questions about the SIM bay that we'd like to debrief on.

244:41:09 Scott: Okay, give - give him another 15 to 20 minutes here.

244:41:13 Henize: Rog.

[Very long comm break.]

[Flight Plan page 3-359.]

245:04:19 Henize: 15, this is Houston.

245:04:25 Scott: Houston, 15. Go ahead.

245:04:28 Henize: We need to make a small change in the Flight Plan, because there's a need now to turn the X-ray experiment on. If you'll go down to that group of steps at 245:30, we'd like to do four of them. We'd like to get the "Data Systems - On - switch to On." We'd like to "Disable the jets." We'd like to get "S-band AUX, TV to Science."

245:04:48 Worden: Hey, stand by one.

245:04:50 Henize: Rog. [Long pause.]

245:05:12 Worden: Okay. Go ahead.

245:05:14 Henize: Roger. Four of those steps down at 245:30 we want to do right away, if possible. We want to get the "S-band AUX, TV to Science." We want the "Data System On switch to On." We want to "Disable all jets except -" and we want "X-ray Experiment, On."

245:05:39 Worden: Okay. Understand at 45:30 - 245:30, you want "S-band AUX, TV to Science, Data Systems On to On, disable all jets, and X-ray Experiment, On" immediately.

245:05:54 Henize: That's correct.

[Very long comm break.]

245:17:29 Henize: Apollo 15, this is Houston. How do you read?

245:17:39 Worden: Hello, Houston; this is 15. Loud and clear, and I got your first message, Karl. I'm sorry.

245:17:44 Henize: Hi, Al. Yeah, we've got some sort of problem on ground circuits here. Just wanted to make sure we were in contact with you.

245:17:54 Worden: No, we're here.

245:17:55 Henize: Roger; very good. [Long pause.]

245:18:53 Henize: Al, we have some questions for you on the SIM bay experiments, whenever you have some time to answer them.

245:19:04 Worden: Okay, Karl. Tell you what, I'll give you a call back in about 10 minutes when I'm ready.

245:19:10 Henize: Very good.

[Very long comm break.]

[The SIM bay power and communications links were re-established early and the X-ray Spectrometer started. Now Endeavour is maneuvered to aim the X-ray Spectrometer in the direction of the Scorpius X-1 x-ray source for 35 minutes. This was the first x-ray source to be discovered outside the solar system by a sounding rocket in 1962 at a time when many had believed there would be little to detect in x-rays above the atmosphere apart from the Sun. Later observations showed Scorpius X-1 to be a close binary star system in which material from a normal star accretes onto the surface of an extremely dense, collapsed star; probably a neutron star. The extreme temperatures reached in the process generate a prodigious x-ray flux.]

[The rest of the bay's instruments are also to be brought online. Associated with the X-ray instrument is the Alpha Particle Spectrometer. The Mass Spectrometer is deployed on the end of its boom and