This is Apollo Control at 271 hours, 20 minutes. Shift change is underway in the Control Center. We estimate the change of shift news briefing for 4:15 pm Central Daylight Time.
This is Apollo Control. At this time, we are going to replay the video only of the inflight press conference. This will be seen in the MSC News Center.
271:39:19 Scott: In getting ready for contamination photography, we find that we've got a - a certain number of exposures left in the Nikon. Namely, we're on exposure number 29 in mag Victor, and we think we have 45 total, which would enable us to complete the contamination photography with the Nikon, if you desire, rather than with the DAC, as you changed. [Long pause.]
271:39:52 Parker: 15, they plan on using those last 15 frames or so on Victor for postmission calibration, so we still intend to press on with the DAC, please, Dave.
271:40:04 Scott: All right, understand. Thank you.
271:40:08 Parker: And, Dave, if you'll give us a start time on that, I'll give you a call at the end, because we want you to cycle some extra film through the DAC to give them a little leader there at the end to protect their film or something.
This is Apollo Control. At the present time, we are replaying the video only from the Apollo 15 inflight press conference. The change of shift press briefing is scheduled to start shortly in the MSC News Center Briefing Room. During this press conference, we will, as is our practice, record any conversations with the crew for playback following the change of shift press briefing.
The following is a recording of the change of shift press briefing.
271:47:29 Parker: Rog. We were seeing the Optics drifting around against the hard stops. We'd like to have you bring them back and then zero them in, per the usual procedure. We kind of guess your getting ready for [a P]52 anyway, aren't you?
271:47:42 Irwin: Pretty soon.
Long comm break.
This is the P52 platform realignment which was read up to the crew at 268:39:48.
This is Apollo Control at 271 hours, 51 minutes. We accumulated less than a half a minute of tape during the change of shift briefing. We'll play back the tape conversations with the crew at this time and then I'll leave the lines up live.
272:07:49 Parker: Apollo 15, Houston. If one of you guys is free, we've got some updates we could read to you. [Long pause.]
272:08:06 Worden: Okay, Houston; 15. Stand by one.
272:08:12 Parker: Okay, understand you're ready. What - the first thing is an Entry PAD. So you might whip out your Entry Checklist.
Comm break.
272:09:26 Worden: Okay, Houston; 15. Go ahead on the Entry PAD.
272:09:30 Parker: Roger. Would you believe it, we're going to land in mid-Pacific? And after that, it's 000, 153, 000; 294:41:37, 267, plus 26.12, minus 158.10; 06.2; 36097, 6.50; 1084.8, 36179; 294:58:37; 00:29; Noun 69s are NA; 4.00, 02:13; 00:18, 03:38, 07:44; 04, 140.3, 37.5; 213, down, 09.6, right, 4.7; lift vector, up. Comments: 1. Use nonexit EMS pattern, 2. RET of 90K, 6 plus 06, RET of mains, 8 plus 32; landing, 13 plus 29; constant g, roll right; Moon set time, 294:56:20. Over. [Pause.]
The data passed up for this entry PAD is interpreted as follows:
Purpose: This is a very preliminary entry PAD, intended to give the crew something to get them home should communications be lost. Tomorrow, prior to re-entry in 22 hours time, another entry PAD will be read to them, then they will make a final correction to their trajectory before the final entry PAD is read to them.
Landing target: Mid-Pacific landing site.
IMU gimbal angles required for trim at 0.05g: Roll, 000°; pitch, 153°; yaw, 000°.
Time of the horizon check: 294:41:37.
Spacecraft pitch at horizon check: 267°. This is 17 minutes before time of entry.
Splashdown point: 26.12° north latitude, 158.10° west longitude.
Maximum number of g's during entry: 6.2.
Velocity at 400,000 feet altitude (about 66 nautical miles or 122 km): 36,097 feet/second (11,002 meters/second).
Entry flight path angle at 400,000 feet: 6.50°.
Range to go to splashdown point from 0.05g event: 1,084.8 nautical miles. To set up their EMS (Entry Monitor System) before re-entry, the crew need to know the expected distance the CM would travel from the 0.05 g event to landing. This figure will be decremented by the EMS based on signals from its own accelerometer.
Predicted inertial velocity at 0.05g event: 36,179 feet/second (11,027 meters/second). This is another entry for the EMS. It is entered into the unit's Delta-V counter and will be decremented based on signals from its own accelerometer.
Time of Entry Interface (400,000 feet): 294 hours, 58 minutes, 37 seconds.
Time from Entry Interface to 0.05g event: 0:29 (seconds).
Planned drag level (deceleration or g-force) during the constant-g phase: 4.00.
Time from Entry Interface until their velocity slows sufficiently to allow a circular orbit around Earth: 2:13.
Time from Entry Interface that the communications blackout begins: 0:18.
Time from Entry Interface that the communications blackout ends: 3:38.
Time from Entry Interface that the drogue parachutes will deploy: 7:44.
Sextant star: 04 (Achernar, Alpha Eridani.)
Sextant shaft angle at Entry Interface minus 2 minutes: 140.3°.
Sextant trunnion angle at Entry Interface minus 2 minutes: 37.5°.
The next three items refer to an attitude check made using the COAS sighted on a star two minutes before Entry Interface.
Boresight star: 213. Since this is not a recognised star number from the Apollo list, we have yet to learn what it refers to.
Boresight Star pitch angle on COAS: Down 9.6°.
Boresight Star X position on COAS: Right 4.7°.
Lift vector at Entry Interface: Up.
Comments in addition to the PAD:
The non-exit EMS pattern is to be used, that is, the entry is not expected to skip off the atmosphere and re-enter.
Time to reach 90,000 feet (27.4 km) 6:06 after Entry Interface.
Time of main parachute deployment: 8:32 after Entry Interface.
Time of landing: 13:29 after Entry Interface.
When maneuvering to ensure a constant g force (done after the max-g portion of the entry to assure a constant deceleration), the crew is to roll right.
Moonset: 294:56:20. This provides one more check of the entry progress.
This completes the preliminary entry PAD.
272:12:11 Worden: Okay, Houston. Understand. Entry PAD, mid-Pac; 000, 153, 000; 294:41:37, 267; plus 26.12, minus 158.10; 06.2; 36097, 6.50; 1084.8, 36179; 294:58:37; 00:29; 4.00, 02:13; 00:18, 03:38, 07:44; 04, 140.3, 37.5; 213, down, 09.6, right, 4.7; lift vector, up. Comments: nonex - use nonexit EMS pattern; RET 90K is 6 plus 06; RET mains, 8 plus 32; RET landing, 13 plus 29; constant g is roll right, Moon set at 294:56:20.
272:13:27 Parker: Roger, Al. Good readback. And we'd be interested in knowing the status of the EMS check you ran 2 or 3 hours ago, if you have it.
272:13:36 Worden: Yes, sir. The EMS check was just fine.
This check of the EMS was called for by the Flight Plan right after the first set of lunar eclipse photos. This is a range of test built into the EMS to check its performance and calibration, particularly of the scribe which will trace a line across a roll of paper during re-entry in response to the CM's velocity and the g-forces acting on it.
272:13:39 Parker: Okay, that's good to know. At the end of your contamination experiment here, we'll be going into this Mass Spec. boom test. And, if you guys let me know when you're ready, we've got a procedure to read up to you for that. We'll read up to you at that time. I assume you've been told that we aren't going to a midcourse 6, and right now mid-course 7 is looking like .09 [feet per second] which is - makes it kind of problematical as to whether we burn it or not. Weather in the recovery area is currently predicted to be, for your splashdown, 15-knot winds, 4-foot seas, 2,000 scattered, 10 miles - in other words, looking better and better all the time.
272:14:24 Worden: Roger, Bob; that sounds great.
Very long comm break.
With the sixth midcourse correction burn cancelled, their workload is relaxed and they can carry out an extra experiment to try and photograph the cloud of gases generated when they make a water or urine dump. This information is helpful in understanding the results from the Mass Spectrometer.
Also, concerning the Mass Spectrometer's boom, Mission Control want to carry out a test that may determine the cause of the difficulties they have been having in deploying and retracting the boom. This test will occur in twenty minutes.
272:26:56 Parker: Apollo 15, Houston. If you'll give us Accept, we'll give you a very slight clock update to sync you for entry. And be advised we will not be sending a state vector uplink at this time; your vector is still just as good as the one on the ground.
272:27:14 Scott: Rog; understand, and you've got Accept. [Long pause.]
If the calculations made by the onboard computer are to be relevant, its clock must match those on Earth which are making the same calculations.
272:37:33 Parker: 15, Houston. Request you trim back to the original attitude now.
This is the attitude read up at 268:38:02 which they use for the contamination photography.
272:37:40 Scott: Okay.
272:37:46 Parker: And again, if one of you has a couple of minutes, we can tell you a couple of other things.
272:37:53 Scott: Okay, in - in other words, you want us to maneuver back to the original attitude, rather than just damp rates, huh?
272:38:01 Parker: Rog; yeah. We'd like to use the same star backgrounds; so that means going back to the original attitude in the Flight Plan around 271:20 or so.
272:38:15 Scott: Okay.
272:38:16 Parker: Which is what you got called up.
272:38:20 Scott: No, we don't have that called up. All we have is damp rates, but we'll do that. [Realises the Flight Plan has been updated.] Oh, what we have called up here? Yeah, okay.
Comm break.
The fuel cell purge, due about now, is held off until 273 hours.
272:40:31 Parker: And, 15; Houston. If one of you has some time, we'd like to talk about some stowage, please.
272:40:39 Scott: Okay, go ahead.
272:40:41 Parker: Okay, we've gone over the stowage which you read down this morning, and everything's shipshape, except we have one question on one item and that concerns the stowage of the core stems. The core stems should be stowed in the sleep restraint that has the CMP's PGA in it. We understand that it's now stowed in the bag on the side of A-8. I guess our first question is, how many - How long is the core stem at the present time? Did you break it down, or is it still three sections long, which we think it is on the ground.
While on the surface, Dave was unable to break down the six sections of the three-metre-long core stem after he had removed it from the regolith. Three sections are still joined as a pole 1.5 metres long which is difficult to stow in a crammed place like Endeavour's cabin. Compartment A-8 is on the right-hand side of the aft bulkhead (against the heatshield) beneath what is normally Jim's couch position.
272:41:16 Scott: No, it's still three sections long, and we could put it in the sleep restraint. It just seemed like a convenient place to stick it in the bag over there to keep it tied down well.
272:41:24 Parker: Okay. Next question is, how'd you get it in the A-8 bag, which according to our measurements on the ground is only 36 inches [92 cm] long and, therefore, apparently not long enough to hold the three lengths of core stem?
272:41:37 Scott: Well, it's sticking out a little bit, I guess we have to admit, but it's pretty well cinched down.
272:41:42 Parker: Okay, stand by.
272:41:47 Scott: But it's no problem; we can put it any place you like. [Long pause.]
272:42:05 Parker: Okay, Dave, I guess we - I don't think it makes an awful lot of difference, but it'd probably make a lot of other people happy if we ended up putting it in the sleep restraint. They wouldn't worry about that loose end hanging out there - if it's not too much trouble.
272:42:20 Scott: Oh, it's no problem at all; be glad to do that.
272:42:23 Parker: Thank you.
272:42:24 Scott: You know, we know what number one priority on this spacecraft is. [Pause.]
This is a humorous reminder from Dave of what the core stem cost to extract; in terms of time, effort and lost exploration of other regions at Hadley Base. To him, it is a very expensive sample and worth caring for.
272:42:34 Scott: We wouldn't - we wouldn't lose that or misplace it or get it rattled around for anything, Bob. [Pause.]
272:42:44 Parker: No comment. [Pause.]
272:42:51 Scott: And you say everything else is okay, huh?
272:46:21 Parker: And, 15, reminder or a question. Did you guys get the word that they like a pad of about 2 seconds worth of 24 frames per second at the end of those photos to protect these things?
272:46:25 Scott: Roger; we got that, Bob. Thank you. [Long pause.]
272:46:47 Parker: And if you guys'll give me a call when you're ready to do the Mass Spec. boom test, I'll read it up to you.
272:46:54 Scott: All righty, Houston; stand by. [Long pause.]
272:47:36 Worden: Houston, 15.
272:47:37 Parker: Go ahead, 15.
272:47:41 Worden: Okay, you going to read up the procedures real time on the Mass Spec. boom?
272:47:44 Parker: Roger.
272:47:47 Worden: Okay, why don't we go ahead and do that, then, while we're finishing up the contamination photos?
272:47:52 Parker: Okay, stand by. [Pause.] Okay, 15, first step is Mass Spec. boom to Retract, talkback barber pole for 4 minutes or until gray. If talkback fully gray within 4 minutes, deploy boom and return to Flight Plan. Over. [Pause.]
Before Apollo 15 took the first flight example to the Moon, it was expected that the boom carrying the Mass Spectrometer would take about 2 minutes, 40 seconds to deploy and retract. In use it has proved balky; sometimes working perfectly, sometimes stalling before reaching full retraction.
Panel 230
While operating the boom from panel 230, Al has a talkback indicator to inform him of the boom's status. It shows a striped pattern while the boom is on the move, changing to a gray flag once the limit of motion is reached. Stalling of the motor is indicated by a half gray flag.
There is a suspicion that the problem is associated with the temperature of the mechanism and the cable harness surrounding the boom. At their current attitude, the SIM bay is out of the Sun and is being chilled by facing deep space. Mission Control want to try and retract it while cold and are giving it plenty of time to make it.
272:48:22 Worden: Roger. Understand you want retract on the Mass Spec. boom for 4 minutes, and, if it goes gray before then, go back to deploy and return to the Flight Plan.
272:48:32 Parker: That's affirm. And give - give us a call when you get done.
272:52:43 Worden: Okay, there's 4 minutes of Retract, and it's still barber pole.
The motor that drives the boom has stalled.
272:52:47 Parker: Okay, if the talkback is not fully gray in 4 minutes, let's go to Mass Spec. Boom, Off, center, for one minute. That's just to let the motor cool down.
272:52:57 Worden: Okay, it's off now.
272:52:59 Parker: Okay. [Pause.]
272:53:06 Worden: And what at the end of the one minute?
272:53:08 Parker: Okay, at the end of the one minute, we will deploy it for 20 seconds and then Off, center, and then we will retract for 40 seconds or until the talk back is one half barber pole [stalled] or fully gray [retracted] and then Off. Over.
272:53:25 Worden: Okay, got you. [Long pause.]
272:53:37 Worden: Okay, going to extend.
272:53:39 Parker: Okay. [Pause.]
272:53:49 Worden: And do you want to pause it off between extend and retract?
272:53:53 Parker: Stand by. Not necessary to pause between Deploy and Retract on this.
272:54:03 Worden: Okay, it's in Retract now.
272:54:05 Parker: Copy. [Long pause.]
272:54:43 Worden: Okay, Houston, that's the 40 seconds of Retract, and it's at half barber pole, and I've turned it off.
The motor has stalled again.
272:54:49 Parker: Okay. In that case, we'd like you to repeat the 20-second Deploy, 40-second Retract sequence twice more and, if gray talkback is still not obtained, we'll turn it off and wait until 275 hours, at which point we'll give you a call and we'll replay - we'll repeat that. Over.
272:55:08 Worden: Okay, fine. We'll cycle that whole thing twice more.
272:57:16 Parker: 15, Houston. We'd like to proceed with the fuel cell purges now to get those out of the way before the P23s.
272:57:25 Worden: Roger, Houston. [Long pause.]
About now, the fuel cells are to be purged to remove impurities in the H2 and O2 reactants by flowing these reactants through them. Earlier, a heater for the H2 purge line was switched on to ensure that when the purge occurs, only gaseous H2 at a high enough temperature reaches the fuel cell. The H2 is stored at temperatures near absolute zero and it is critical that the cells are not allowed to become too cold.
272:58:19 Worden: Houston, Mass Spec. boom has been cycled three times. All I can get out of it is a half barber pole, and I've got it turned off right now.
272:58:28 Parker: Roger; copy, Al. We'll call you at 275 hours to repeat that, the reason for that is that presently we are sort of sitting in a cold-soak attitude. We're going to repeat it at 275 hours when we're sort of in a hot-soak attitude.
272:58:43 Worden: Okay.
Very long comm break.
At that time, Endeavour will be carrying out some more x-ray astronomy in an attitude which will face the SIM bay towards the Sun.
273:09:41 Parker: Apollo 15, Houston. We'd like to go to Ion Source, Off, and Mass Spec. Experiment to Standby.
273:09:52 Scott: Ion Source, Off, and Mass Spec. to Standby.
273:09:55 Parker: Roger.
Very long comm break.
Al continues with the third of four P23 cislunar navigation sightings he will complete today. As before, he first calibrates the pointing of the optics by sighting on Dnoces, a star, otherwise known as Iota Ursae Majoris but named by the Apollo 9 crew, including Dave, after Edward White the Second, the CMP of the Apollo 1 crew as a memorial to their dead colleagues. "Dnoces" is "second" spelled backwards.
For these navigation sightings, Al measures the angles between Elnath (Beta Tauri) and Earth's horizon furthest from the star, Capella (Alpha Aurigae) and Earth's horizon furthest from the star, and, finally, Alphard (Alpha Hydrae) and Earth's horizon nearest the star. Then, using P23, he can calculate if there needs to be any update to the current state vector, displaying that result as a change in position and a change in velocity.
This is Apollo Control. The crew has completed the program 23 midcourse navigation exercise, aboard the spacecraft, and should be beginning their eat period - or are already into it at this time. Before we put them to bed, they'll have one more set of navigation sightings to take on a series of stars. And we'll put the spacecraft in a Passive Thermal Control mode. The rest period is scheduled to begin at 277 hours, 30 minutes, or about 4 hours from now. Apollo 15 at the present time is 101,214 nautical miles [187,448 km] from the Earth, and traveling at a speed of almost 1 mile per second. We're reading 5,137 feet per second [1,566 m/s].
273:28:48 Parker: 15, Houston. Al, we missed your last Noun 49 [change in position and change in velocity]. [Long pause.]
273:29:08 Worden: Okay, I'll show you this one.
273:29:10 Parker: Thanks.
Very long comm break.
Endeavour has been holding attitude to a ±0.5° deadband all day. Now, with the P23s out of the way, the DAP can be reconfigured to change this to a ±5° deadband, which is less fuel hungry. This is done by entering all ones into the registers called up by Verb 48.
273:39:30 Parker: 15, Houston. Looks like a good set of P23s again, Al. And your gamma, right now, on your vector, is 6.5. [Pause.]
This means that the predicted re-entry angle, based on Al's current state vector, is 6.5°. This is considered to be the ideal angle.
273:39:48 Worden: It sounds like, after a while, we might get along without you, huh, Bob.
Which, after all, is the object of the exercise.
273:39:55 Parker: No comment.
Dave then rubs it in.
273:39:59 Scott: As a matter of fact, if you guys keep working on your ground [calculated] vectors, they might even converge to the onboard vectors pretty soon.
274:06:16 Worden: Rog; want us to - delete the Logic Power, two, if we're going to do the Mass Spec. at 275? [Pause.]
274:06:28 Parker: 15, that's affirm.
274:06:33 Worden: Okay. [Long pause.]
274:06:44 Parker: And, 15; Houston. You got any more updates to our Flight Plan?
274:06:51 Worden: No, but I'll scan it over; and, if I find any, I'll let you know.
Very long comm break.
At 274:15 GET, the SIM bay, and therefore the X-ray Spectrometer, are aimed at the north galactic pole for a 30-minute period of data gathering. As has been done twice before, the intention of aiming the instrument at this arbitrary direction, rather than at a specific known source of X-rays, is to measure the background X-ray flux, see how strong it is in comparison with the other arbitrary directions to which the instrument was aimed, and to look for any variability in these readings which gives a control reading against which any variability seen from the known sources can be compared.
274:37:35 Parker: Roger; we have an update to the Flight Plan, if you guys are ready to copy.
274:37:41 Worden: Roger. We're ready to copy.
274:37:43 Parker: Okay. The attitude that we maneuver to at 274:46 there, for the second set of X-rays should be changed - that Verb 49 maneuver, should be changed to 196, 346, 012. [Pause.] Over. [Pause.]
274:38:14 Worden: Roger. Understand the Verb 49 maneuver to the X-ray pointing attitude should be changed to 196, 346, 012.
274:38:25 Parker: Roger. And, before we start that Verb 49 maneuver at 274:45 or thereabouts, we'd like to cover the ex - We'd like to close the experiment covers, Alpha/X-ray, to Close. That's the one on panel 278. And then after we get to attitude at about 275:00, we'll go ahead and open those covers again, the Alpha/X-rays. [Long pause.]
274:39:03 Worden: Roger. Understand, you want the Alpha/X-ray covers closed before the maneuver and opened after the maneuver.
274:39:09 Parker: Roger. These - the new position I sent you up on that - Those two steps there in the procedure are to keep from getting sunlight right in on some of the stuff to protect it. And...
274:39:19 Worden: Okay.
274:39:20 Parker: ...and, also at this time, you may terminate the battery A charge.
274:39:26 Worden: Okay, terminating the battery A charge. [Long pause.]
274:40:16 Worden: Houston, 15.
274:40:18 Parker: Go ahead, 15.
274:40:21 Worden: Roger, Bob. Do you want us to go to Standby on X-ray while the door is closed, or is it okay to leave it in 'On'?
274:40:29 Parker: Rog. You can leave it on - Dave.
274:40:34 Worden: Okay.
Long comm break.
At 274:45, the spacecraft is maneuvered around to face the X-ray Spectrometer towards a point in space opposite the centre of the galaxy. As requested five minutes ago, the instrument's cover will be closed prior to the maneuver as there is a possibility that as the spacecraft is rotated around, sunlight might impinge on it. The change in attitude also affects which omni-directional antenna is best placed for communication with Earth.
Once the spacecraft is settled at its new attitude, a 1-hour period of measurement with the X-ray Spectrometer begins. Once again, this is a control reading rather than of a discrete, known source. Meanwhile, the crew begin the last meal of the day.
275:07:09 Scott (onboard): Anybody else like chicken stew?
275:07:14 Irwin (onboard): Chicken stew, huh? Yes, I do. I didn't know we had any. Is that what you have up there?
275:07:31 Worden (onboard): Yes.
275:07:32 Scott (onboard): No, uh-uh.
275:07:44 Irwin (onboard): If you want to eat here, I'll be happy to come down the re.
275:08:31 Irwin (onboard): Hey, throw me some beef steak. Well, I guess some turkey and gravy.
275:08:50 Scott (onboard): [Garble].
275:08:52 Irwin (onboard): Go back where? Yes, man, you aren't kidding.
275:08:58 Worden (onboard): Thought you wanted to go back to the Moon?
This is Apollo Control at 275 hours. Apollo 15, at the present time, is 96,347 nautical miles [178,434 km] from Earth, and traveling at a speed of 5,342 feet per second [1,628 m/s]. A short while ago, the recovery room here in the Control Center reported that the prime recovery ship is headed toward the target point in the Pacific Ocean - north of Hawaii. Seas in the predicted landing point are 4 feet, clouds are 2,000 feet and broken, and we expect to have 15-knot winds at splash time tomorrow - generally very good weather predicted in the recovery area. The crew is scheduled to begin an eat period at this time. Following that, they have one more set of star sightings to take - mid-course navigation. Prior to putting the spacecraft in the Passive Thermal Control mode - after eating, rather, they'll put the spacecraft in the Passive Thermal Control mode prior to beginning their 9-hour rest period. And on the clock that's counting down toward splashdown, we show 20 hours, 9 minutes, 40 seconds now until splashdown.
275:09:26 Irwin (onboard): I'll trade with you, Dave.
275:09:27 Scott (onboard): All right.
275:09:28 Irwin (onboard): I'll go down there.
275:09:31 Scott (onboard): Down here?
275:09:32 Irwin (onboard): Yes.
275:10:37 Irwin (onboard): This is our new garbage can down here, huh? Good.
275:10:49 Irwin (onboard): You want to get those readings now, Al, or after supper?
275:10:52 Worden (onboard): I don't care.
275:10:54 Irwin (onboard): Get them now?
275:11:03 Worden (onboard): Okay. Start out with 5-C.
275:11:13 Irwin (onboard): 5-C reading 4 - 4.2.
275:11:19 Worden (onboard): All right; 5-D?
275:11:23 Irwin (onboard): 3.9.
275:11:25 Worden (onboard): 6-A?
275:11:26 Irwin (onboard): You writing them down?
275:11:28 Worden (onboard): Yes.
275:11:30 Irwin (onboard): 6-A is 4.1.
275:11:34 Worden (onboard): Okay; 6-B?
275:11:37 Irwin (onboard): 4.2.
275:11:42 Worden (onboard): 6-C?
275:11:45 Irwin (onboard): Greater than 5.
275:11:48 Worden (onboard): No kidding. Huh. Okay...
275:11:57 Scott (onboard transcript gives Worden): Houston, 15. Go ahead.
275:11:59 Parker: Roger. Remember back aways, we were talking about doing some more Mass Spec. boom tests at 275 hours, which is gone by. We're right now talking about delaying that until 276 hours, approximately, or at least until before you start your Verb 49 maneuvers for the next set of P23s. Over.
275:12:23 Scott (onboard transcript gives Worden): Okay, fine.
275:12:21 Worden (onboard): Okay, fine. 6-D.
The final series of P23 navigation sightings is due at 276 hours, right after the current period of x-ray data collection and the crew's meal break is over.
275:12:25 Parker: We're just letting it [the Mass Spectrometer's boom] heat-soak a little bit longer. [Long pause.]
275:12:26 Irwin (onboard): Is that okay on 6-C, the fact that it's...
275:12:28 Worden (onboard): I don't know; we'll tell them.
275:12:30 Irwin (onboard): Okay, 6-D is 45.
275:12:36 Worden (onboard): Okay.
275:12:39 Worden: And, Houston; 15. I have some Command Module RCS injector temperatures for you.
275:12:45 Parker: Ready to copy.
275:12:48 Worden: Okay, these are readings off the Systems Test Meter. 5-A is 4. - or 5-C is 4.2; 5-D is 3.9; 6-A is 4.1; B is 4.2; C is greater than 5; and D is 4.5.
275:13:08 Parker: Roger. Copy 4.2, 3.9, 4.1, 4.2, greater than - and 4.5.
275:13:16 Worden: Roger.
Very long comm break.
At 274:50 in the Flight Plan there is a call for the temperatures of the injector valves for four of the Command Modules RCS engines to be read, using the Systems Test Meter. While they need to be warm enough to accept propellant tomorrow during re-entry, it is unknown at the time of writing why they are being measured now. The Systems Test Meter is a simple way of allowing the crew to access many of the less important readings from the vast array of sensors that monitor the overall health of the spacecraft. The meter is mounted on panel 101, next to the spacecraft optics controls in the Lower Equipment Bay.
Panel 101 - the Systems Test Meter.
The two rotary switches give access to a 'seven by four' matrix of signals allowing 28 different measurements to be available to the crew. The outputs of the spacecraft's sensors are normalised by the Signal Conditioning Equipment such that the required range of each sensor is expressed between zero volts and five volts. This preparation to a standard form makes it easy to telemeter the voltages to Earth, and it allows the crew to access a wide variety of readings using a single voltmeter without taking up precious space in the instrument panels. The drawback is that reference must be made to spacecraft handbooks to interpret the readings. To take the first reading, for example, at position 5-C, this setting gives the injector temperature of the secondary pitch-down thruster on the Command Module. The full range of 0V to 5V represents a temperature range of -50° to +50° Fahrenheit (-45.5° to +10° Celsius). The nominal value for this is greater than 28°F or a reading greater than 3.9V on the meter. In the event, all the readings read down by the crew are nominal.
275:13:30 Irwin (onboard): Here, put it on there, I'll give you a squirt. How many do you want?
275:13:37 Scott (onboard): Is that the soup?
275:13:41 Worden (onboard): Chicken stew.
275:13:42 Irwin (onboard): How many do you want?
275:13:43 Scott (onboard): Three of them.
275:13:44 Irwin (onboard): Ready?
275:13:45 Scott (onboard): Yes.
275:14:01 Scott (onboard): Shit.
275:14:04 Irwin (onboard): Screw it in there?
275:14:05 Scott (onboard): Good.
275:14:06 Worden (onboard): [Garble].
275:14:13 Scott (onboard): Yes. Roger.
275:14:16 Worden (onboard): [Garble].
275:14:30 Irwin (onboard): Yes.
275:14:39 Scott (onboard): Well, we have a lot of drinks for breakfast.
275:14:42 Irwin (onboard): Okay, I ought to change the LiOH. Which one was it, Al?
275:14:48 Worden (onboard): Okay, 23 to B and 21 to A-5.
275:14:52 Irwin (onboard): Okay, going into B.
275:14:54 Worden (onboard): 23 into B.
275:14:56 Irwin (onboard): Okay.
275:16:22 Irwin (onboard): I wonder if any of this food is - the - the irradiated food.
275:16:26 Scott (onboard): Could be ....
275:16:33 Irwin (onboard): One way of preserving food these days is to...
275:16:37 Scott (onboard): [Garble] radiation.
275:16:39 Irwin (onboard): And it preserves it. At certain times, radiation preserves it.
275:18:01 Irwin (onboard): Okay. Canister change is complete.
275:18:03 Scott (onboard): Okay. Very good.
275:19:22 Scott (onboard): [Garble].
275:19:25 Irwin (onboard): That's wrong, Dave.
275:19:27 Scott (onboard): [Garble]...
There is a break in the onboard recording.
275:30:27 Scott (onboard): Al, you going to monitor comm? I'm going to get off the headset here.
275:30:29 Worden (onboard): [Garble].
275:32:09 Scott (onboard): Come forward, Al. Thank you very much. [Garble]. Just ruined the whole thing.
275:36:48 Worden (onboard): Oh - damn!
275:36:51 Scott (onboard): Oh, my God.
275:37:09 Worden (onboard): Freaking DAC won't come off.
275:37:15 Scott (onboard): You need one of these, too? That okay?
275:37:20 Worden (onboard): Okay. Okay.
275:37:27 Scott (onboard): There you go. Can I get that for you?
275:37:32 Worden (onboard): Thank you.
275:37:36 Scott (onboard): Ready for it now?
275:39:42 Scott (onboard): [Garble]. Move over some. [Garble].
275:39:52 Worden (onboard): If I were you, I'd go over to the lab and pick one up out of there - a perfect sample.
275:39:58 Scott (onboard): They don't have them.
275:39:59 Worden (onboard): They don't?
275:40:00 Scott (onboard): No.
275:40:08 Irwin (onboard): Dammit, why don't you buy a set of them? ...
275:40:14 Worden (onboard): I might buy them.
275:40:16 Irwin (onboard): Yes, but you'd be taking all that guff.
275:40:30 Irwin (onboard): Feast over his favorite rock.
275:40:34 Worden (onboard): Right.
275:40:39 Scott (onboard): [Garble].
275:40:40 Irwin (onboard): How come?
275:40:41 Worden (onboard): [Garble].
275:40:53 Worden (onboard): [Garble].
275:41:05 Worden (onboard): On the ball.
275:41:12 Scott (onboard): [Garble].
275:41:30 Worden (onboard): [Garble] to surprise [garble].
275:41:40 Scott (onboard): [Garble] 330 [garble].
275:41:49:Worden (onboard): (Clears throat) You going to do anything else down there? Are you going to do anything down there? All right.
275:41:58 Scott (onboard): ...
275:42:02 Worden (onboard): Well, I've got a P23 to do in 3 minutes, and then we got to ... the daytime. I got to clean up and change my long johns and take my biomed off, while I got the chance.
275:42:17 Scott (onboard): Okay.
275:42:58 Worden (onboard): Okay.
275:44:37 Irwin (onboard): Dave, I hope we're going to be able to see them unload all those rocks.
275:44:42 Scott (onboard): Yes, I think we should.
275:44:43 Irwin (onboard): Okay.
275:44:44 Scott (onboard): [Garble] time [garble].
275:44:48 Irwin (onboard): I hope so. Yes. They'll just have to hold up the - the rocks until we're there.
275:44:58 Scott (onboard): [Garble] going to have a ball [garble]. Is that why you [garble]?
275:45:07 Irwin (onboard): Yes.
275:45:12 Scott (onboard): [Garble].
275:45:15 Irwin (onboard): Yes.
275:45:19 Scott (onboard): [Garble] mind working some long hours.
275:45:29 Irwin (onboard): How long does the medical take on the ship?
275:45:33 Scott (onboard): [Garble].
275:45:34 Irwin (onboard): [Garble] ship until about what - 6 o'clock tomorrow night? We'll be taking that physical until 10 tomorrow night ?
275:45:42 Scott (onboard): Ten their time is all I know.
275:45:48 Irwin (onboard): Oh, that's right. It's 4 our time, which is...
275:45:54 Scott (onboard): On board the ship.
275:45:56 Worden (onboard): Yes. [Garble].
275:46:03 Irwin (onboard): Yes.
275:46:04 Scott (onboard): [Garble].
275:46:24 Worden (onboard): [Garble] we're laughing.
275:46:46 Scott (onboard): [Garble].
275:46:59 Scott (onboard): I think we might look [garble].
275:47:35 Irwin (onboard): I had it under control. I had it under control.
275:47:41 Scott (onboard): [Garble].
275:48:00 Worden (onboard): We're all having his.
275:48:05 Irwin (onboard): Man, we're down low. The cupboard's bare. Bacon squares.
275:48:27 Irwin (onboard): I don't know if we have enough in there for two more. Yes, I guess we do.
275:48:52 Scott (onboard): [Garble].
275:48:57 Irwin (onboard): Yes, you need a reinfo - forced toe section.
275:50:55 Worden (onboard): I'll take that and get this - Going to use the camera.
275:51:26 Irwin (onboard): Have a 9-hour rest period.
275:51:42 Irwin (onboard): Make sure I'm turned on there, will you, Dave? My power on?
275:52:00 Worden (onboard): [Garble].
275:52:02 Irwin (onboard): What? Yes, if you want to dig it out, it's in the - I put it in that bag. Dave, could you get - Dave, could you get - There's a bag in my TSB. One of the white towel bags that has all my gear it in.
275:52:38 Irwin (onboard): Thank you. It's in here, Al.
275:55:14 Parker: Rog. If one of you fellows has the time, we might like to continue on with the Mass Spec. boom retract test.
To recap, on occasion the Mass Spectrometer boom fails to retract. Mission Control suspect that this problem is temperature sensitive. Three hours ago, while the SIM bay was being chilled by being pointed towards deep space, a controlled attempt was made to retract it which was unsuccessful. This next attempt to retract it will be made with the boom's mechanism having been warmed in the Sun for nearly an hour.
275:55:23 Irwin: Okay. Is it something I should write down, or can I just do it real time?
275:55:27 Parker: I'll give it to you real time. It's not that complicated, Jim.
275:55:32 Irwin: Okay. Go ahead.
275:55:34 Parker: Okay. We need the Experiment switch to On down there in the Alpha - Excuse me, the Mass Spec. Experiment switch to On; and the Ion Source, On. Over. [Pause.]
275:55:49 Irwin: Okay. I understand Mass Spec. Experiment, On; and Ion Source, On. Stand by. [Long pause.]
275:55:47 Irwin (onboard): David, can you get a couple of switches over there? The Mass Spec. Experiment, On; and the Ion Source, On.
275:56:10 Irwin: Okay, Bob. They're both On.
275:56:13 Parker: Okay. And then next, you go down to the other panel, and we go Deploy for 20 seconds on the Mass Spec. boom, and then Retract for 40 seconds, or until we get a gray indication. Over. [Pause.]
275:56:34 Irwin: Understand you want Deploy for 20 seconds and then - on the Mass Spec. boom, and then Retract, until we get gray, or 40 seconds.
275:56:44 Parker: Roger. Whichever occurs first.
275:56:49 Irwin: Okay.
Comm break.
275:56:50 Irwin (onboard): Okay, Dave. On that Mass Spec. Boom, we go Deploy for 20 seconds. If you want, I can give you a mark.
275:56:59 Scott (onboard): That's okay.
275:57:21 Scott (onboard): They're Off.
275:57:23 Irwin (onboard): Go to Off and then I'll have you - and then Re - and then Retract it for 40 seconds...
Comm break.
The mechanical problem, believed to be caused by the cable harness stiffening up when cold, has been stopping the boom retracting the final few centimetres where it would give a gray indication on the talkback. This time, it works flawlessly.
275:58:17 Irwin: Okay, Bob. It [the talkback] went gray after thirty seconds.
275:58:20 Parker: Roger; copy. Stand by. [Long pause.]
275:58:46 Parker: Okay, 15. Looks like it's a cold soak problem, then, Jim. We'll just deploy it all the way out and leave it there.
275:58:56 Irwin: Okay. You want us to deploy it all the way now, huh?
275:58:59 Parker: Right. After we did all that work and succeeded in retracting it, now we'll deploy it.
This is Apollo Control. Jim Irwin just reported that the Mass Spectrometer boom, on this attempt, retracted fully. And it was the indication of gray on the talkback, the indicator in the spacecraft. Previously, the indicator had gone half gray, half barber pole, indicating that the boom had not extracted fully. At that time, we suspected that it was possibly because the spacecraft was in an attitude where the boom was not exposed to solar heating. In the attitude at which it was attempted this last time, the Service Module bay was exposed to heating from the Sun, which would seem to verify the theory we've had that the problems in retracting that boom were due to cooling. At 276 hours, Apollo 15 is 93,232 nautical miles [172,665 km] from Earth and traveling at a speed of 5,480 feet per second [1,670 m/s].
276:13:10 Parker: Roger, Al. Recommendation from the ground here. They'd like to see - maybe as many as five optics calibration marks the next time, instead of the two. It's just to give them some data.
When Al calibrates the spacecraft optics in preparation for his navigation duties, he has been taking only a couple of marks. For the upcoming P23, he should take five marks. However, Al misinterprets this request and give five marks for all the sightings rather than the three normally required.
276:13:26 Irwin: Okay, I'll relay that information to our navigator.
276:13:29 Parker: Sorry about that, Jim. You sound like Al these days.
276:13:33 Irwin: Oh, we're getting so we all sound alike up here.
Long comm break.
Now that Al has calibrated the optics, he continues with his final navigational exercise of the day. Once again, the angles are measured between Elnath (Beta Tauri) and Earth's horizon furthest from the star, Capella (Alpha Aurigae) and Earth's horizon furthest from the star, and, finally, Alphard (Alpha Hydrae) and Earth's horizon nearest the star. With the amount of change in his state vector calculated, Al can bring it up on the DSKY as Noun 49.
276:42:39 Parker: Apollo 15, Houston. Over. [No answer.]
Comm break.
276:43:53 Parker: Apollo 15, Houston. Over.
276:43:58 Worden: Go ahead, Houston.
276:43:59 Parker: Roger. Guidance says thank you to Al [for the P23s]. And if - a couple of other things here, if one of you guys has a chance, we'd like a mag sta - magazine status read-out tonight, and we're seeing some noise on Dave's biosensors. He might want to check them or push them down a little bit or something.
276:44:23 Scott: Okay, I'll do that. And you want a magazine status read-out. What do - What do you mean by that exactly.
276:44:29 Parker: Roger. That means how many picture's been taken in some of the magazines there. I think Al's been doing it. He probably knows what's going on, if he can tell you. [Long pause.]
276:44:56 Scott: Okay. I - I guess we don't have a good answer for you on that, Bob. They're all stowed away. And they've all been recorded as we've gone along. Is there any particular need for them before tomorrow sometime?
276:45:13 Parker: Negative, Dave. That's a good answer, it turns out.
276:45:18 Scott: Okay. I think you'll find them all neatly tucked away and recorded when - when you get them on the ship. [Long pause.]
276:45:38 Scott: If you're wondering how many pictures we took, at last count, night before last, it was something like 1,840 some.
276:45:49 Parker: Understand, 1,847.
276:45:53 Scott: Or somewhere around the ball park.
276:45:56 Parker: Is that plus or minus one?
276:45:59 Scott: I think that was LM though, maybe yeah. Then you have to add that to the Command Module.
276:46:05 Parker: You mean like a mile of Pan Camera film, huh?
276:46:09 Scott: Something like that. It looks like it ought to hold a mile by the size of the thing.
Comm break.
About now, the discrimination shield on the Gamma-ray Spectrometer is switched off for a 10-minute period to check its function.
276:48:17 Scott: Well, I had - had the log out here, and I took a look at it, and at last count last night, we were 2,631 on Hasselblad pictures, total.
276:51:12 Parker: Roger, Dave. The interest in the mags was in reference to the UV - the mags for the UV photography tomorrow. So the interest was in the number of frames remaining on magazine Mike and magazine Papa, try - trying to determine which of those would be usable for tomorrow's UV photography.
276:51:35 Scott: Okay. I think we've got that log in the Flight Plan. Stand by 'til Al finishes his P23s, and we'll take a look.
276:51:41 Parker: Roger; understand. No big rush. [Pause.]
276:51:49 Scott: [I] think we'll use a mag that has some film in it.
276:51:53 Parker: Say again, Dave.
276:51:56 Scott: I said, at - at any rate, we'll use a mag that has some film in it tomorrow.
This is Apollo Control at 277 hours, 7 minutes. Al Worden is presently completing a series of star sightings - midcourse navigation exercise, using program 23 in the onboard computer. This will be the last major activity before the crew begins it's 9-hour rest period. After completing this, they'll go through the presleep checklist, get the systems set up for their sleep period and put the spacecraft in its Passive Thermal Control attitude, rotating at about the rate of 4 revolutions per hour. Apollo 15, at this time, is 89,626 nautical miles [165,987 km] from the Earth. The spacecraft velocity is 5,646 feet per second [1,721 m/s]. And we're now 18 hours, 3 minutes away from splashdown.
277:15:55 Parker: Roger. Congratulations, Al. You've just been voted to receive a second Vasco da Gama award for that. We were afraid you were going to do them all the way through the rest period.
277:16:07 Worden: Well, they're fun enough. I wouldn't mind.
277:16:10 Irwin: So were we.
277:16:12 Parker: [Laughter.] Okay; and...
277:16:19 Worden: It wouldn't have taken nearly so long if you hadn't wanted five marks per each star. [Pause.]
277:16:31 Parker: Rog, Al. I'll tell you about that some time. And, 15, we're configured for the E-mod dump, if you fellows want to give it to us.
A dump to Earth of the data in the Erasable Module (the 2-kwords of memory used by the computer) is part of the pre-sleep checklist. The crew status reports and read-outs from the onboard gauges are still to come. The fans in the H2 tank will be stirred and the crew's potable water supply will be chlorinated. Then, once a set of switch positions are verified, the communications system will be configured for the rest period.
Another task for the end of the day is to set Endeavour rotating in the PTC maneuver. Once the spacecraft gets to the PTC attitude, Al uses P20 in the computer to set the rotation going, essentially getting Endeavour to track a rotating vector. The rate of rotation is to be a little faster than previously. Al will enter 0.42° per second (entered as 04200) instead of 0.35° per second. Angles for dialling into the HGA controls are given. The antenna's control system will be operated overnight in the Reacq mode, whereby it tracks Earth as long as its gimbal system can keep it pointing at it. When the spacecraft's rotation takes it out of range, it will move to preset angles which have been calculated to bring Earth back into the antenna's beam as the PTC rotation continues.
277:16:45 Scott: Okay, it[the E-mod dump]'s coming. Does the bio data look any better?
277:16:48 Parker: Rog. Yes, it does.
277:16:52 Scott: Okay.
277:16:56 Parker: And, as you get ready for PTC, we'd like to do the PTC at 0.42 [degrees per second] there again tonight as last night, although it's changing the Noun 79 value there at 277:14. [Pause.]
277:17:16 Worden: Rog, Bob. I guess we use that as standard procedure now, the 4200.
277:17:21 Parker: Rog. You don't have to do it tomorrow night that way, though.
277:17:25 Scott: Okay. Use a different number tomorrow night.
Comm break.
Of course, tomorrow night, they will not be in space.
277:18:34 Parker: And, Apollo 15, be advised that tomorrow when you're taking your P23 marks, five marks on the cal[ibraton star] and then 3 marks on the [other] stars with the P23 itself will be sufficient.
277:18:48 Worden: Okay, understand. 5 marks on the cal and 3 on each star.
277:19:34 Scott: The crew's all ready for bed, no medications, and the onboard read-out: Battery C, 37; Pyro Bat A, 37.1; B, 37.1; RCS A, 55; B, 50; C, 48; D, 52. And I guess everything else is done. You've got your E-memory dump, and we're ready to power down as soon as we get the PTC going.
277:20:06 Parker: Roger, Dave. As far as we're concerned, we're all finished also. We will not be uplinking a state vector to you. We might have to do that sometime just for practice, but so far we haven't needed to uplink one to you. You guys are doing pretty super on those P23s.
277:20:24 Scott: Compensating errors. [Pause.]
277:20:35 Parker: I can't believe that was a unanimous vote, Dave. [Pause.]
277:20:41 Scott: No, it was only two to one.
277:20:51 [Unintentional key] MCC: Okay, G&C. Let me know when he's in his rate amp.
277:30:31 Scott: Okay. Listen, potable tank inlet valve is open and has been the whole flight. What prompted the question?
277:30:39 Parker: Stand by. [Pause.]
277:30:44 Scott: We're just curious. [Pause.]
277:30:56 Parker: 15, we saw a drop in the potable at the same time that the waste tank was staying stable, and we were - just concerned that it might have gotten out of configuration. We certainly expected it to be open; we just wanted to check it before you went to sleep, so we didn't have to wake you up.
This is Apollo Control at 278 hours, 2 minutes. Flight Surgeon reports that Dave Scott, the only crewman on whom we have biomedical data tonight, appears to be nearing sleep, at least beginning to drop off, and we expect that he'll be sleeping shortly. During this sleep period, we don't expect any further conversation with the crew. The Passive Thermal Control mode appears to be stable. We're watching the attitude excursions, the movements that the spacecraft is making about its axis and it appears to be quite stable. Looks as if it will hold throughout the sleep period. At the present time, Apollo 15 is 86,650 nautical miles [160,475 km] from Earth. The spacecraft velocity is 5,789 feet per second [1,764 m/s]. Checking with the science support room, we have some statistics on the temperature excursions experienced by the lunar surface experiments packages at the Apollos 14 and Apollo 15 sites. The Apollo 14 station went through the largest temperature swing during the eclipse. It started at 173.9° above zero Fahrenheit [78.8°C], and during the maximum point of the eclipse, it was down to 150.6° below zero [-101.4°C], for a temperature swing of 324.5° [180.2°]. The Apollo 15 station measured a somewhat smaller swing. It started at 140° above Fahrenheit [60°C] and dropped down to 143.2° below Fahrenheit [-97.3°C]. These temperatures were measured on the top of the sun shield above the central station on both ALSEP packages. During the crew rest period we'll take the air to ground lines down, keep the tape recorders running and play back any conversations that we might have with the crew, should any arise. At 278 hours, 4 minutes; this is Apollo Control, Houston.
This is Apollo Control at 278 hours, 36 minutes. At the present time, we're replaying the video and audio from the inflight press conference today. This can be seen in the MSC News Center.
This is Apollo Control at 281 hours, 27 minutes. The crew of Apollo 15 asleep at this time. Five hours and two minutes remaining until they will be wakened for preparations for entry and Earth-landing later this afternoon. Splashdown clock showing 13 hours, 43 minutes until splash. The spacecraft, at this time, is 74,650 nautical miles [138,252 kilometres] out in space approaching Earth. Velocity continuing to increase; now showing 6,435 feet per second [1,961 metres per second]. Current vector on the spacecraft still showing entry angle and Entry Interface at minus 6.5 degrees. The vacuum perigee, 21.1 nautical miles [39.1 km]. Maroon Team of flight controllers here in the control center settled in for the graveyard shift watching the replay of yesterday's in-flight press conference. At 281 hours, 29 minutes; this is Apollo Control.
- Tape - For replaying telemetry from tape to Earth
- Down Voice Backup - A spare communications channel
- TV - For relaying television pictures to Earth
- Science - For the real-time relaying of data from the SIM bay to Earth
Mission Control want to receive data from the SIM bay at this time.