This is Apollo Control at 102 hours, 8 minutes and we're about 2 minutes from reacquiring the Command Module Endeavour, assuming that the circularization burn was performed on time. Endeavour should be behind but above the Lunar Module Falcon. The higher orbit that the Command Module would be in, would cause it to pop around the corner so to speak sooner, [to] come into view of radio antennas about 2 minutes prior to the time we'll acquire the signal from the Lunar Module. Just a few minutes ago, Flight Director Glynn Lunney again reviewed the status of the mission with each of his flight controllers, and pointed out that the major activity on this revolution, the last - last revolution prior to the powered descent, will be the landmark tracking, which Al Worden will be performing in the Command Module. Al Worden will be taking marks through the scanning telescope in the Command Module on a 1,000-foot [300-metre] diameter crater, called Index Crater, which is in the landing ellipse - the marks that he takes on this crater are telemetered to ground where we feed them into the computers in Mission Control, and from that compute new orbits for both the Command Module and the Lunar Module, and also compute these orbits with respect to the precise location of the landing site. This information is then fed into the Lunar Module Guidance System - the Guidance Computer on the LM, just prior to the powered descent. Should we not get the landmark tracking on this revolution, the preference would be to wait for 1 revolution to do the lunar landing - slip the landing 1 revolution and attempt to get the landmark tracking on the 14th revolution. At this point we would see no reason for not accomplishing successfully, the landmark tracking on this revolution. And we have had Acquisition Of Signal from the Command Module, which indicates that we did get the circularization burn.
At the present time our radio signal strength from the Command Module is still too weak to permit voice communications. We are starting to get some telemetry data. And we're about 40 seconds away from reacquiring the Lunar Module, Falcon.
INCO says we appear to have lost contact. Madrid reported we had a momentary acquisition of signal, which has since dropped out.
102:12:24 Mitchell: Endeavour, Houston. Standing by for your burn status. [Long pause.]
102:12:44 Mitchell: Endeavour, Houston. Standing by for burn status.
102:12:51 Worden: Hello, Houston. Endeavour. Rog. Stand by one.
102:12:55 Mitchell: Roger. Roger, Al.
102:13:00 Worden: Okay, Houston. The burn got off on time. Burn time, 4 seconds; VGX, minus 0000.9 [fps]; and I trimmed that to 0 at - roll of 0 [degrees], pitch of 107, and yaw of 358. VGX was plus all zero's, VGY was plus all zero's, VGZ was minus 0000.5. Delta-VC was minus 11.2 [fps]; fuel was 29.25 [per cent]; oxidizer, 29.15 [per cent]; and unbalance meter was decreased 50. And I've got me in a 65.2 by 54.8 [nautical mile orbit, 120.7 by 101.4 km].
102:13:44 Mitchell: Okay, Al. We got everything except the item after the burn time. [Pause.]
102:13:54 Worden: Roger. The VGX at shutdown was minus .9. [repeat] 0.9.
102:14:03 Mitchell: Okay. We copy. [Long pause.]
102:14:19 Mitchell: And, Al. I'm ready to give you a P24 PAD, when you're ready to copy. [Long pause.]
102:14:45 Worden: Okay, Ed. Go ahead.
102:14:47 Mitchell: Rog. 15-1; T-1, 102:37:27; T-2, 42:17; TCA, 43:57; T-3, 44:45. The attitude is nominal, and you'll be off track 3 miles to the north.
102:15:21 Worden: Roger. I understand. [P]24 landmark tracking PAD, tracking 15-1; T-1, 102:37:27; 42:17; 43:57; 44:45. Nominal attitude is off track north 3 miles.
102:15:42 Mitchell: Good readback.
102:15:46 Worden: Rog. [Pause.]
102:15:54 Irwin: Ed, I have some AGS Cal numbers for you.
102:15:57 Mitchell: Okay, Falcon. Ready to copy.
102:16:02 Irwin: Roger. The initial values: plus 02, minus 04, plus 03, plus 02, plus 90, minus 07. Cal values: plus 02, minus 04, plus 02, plus 21, plus 81, and minus 15.
102:16:26 Mitchell: Copied all of them. [Pause.] Those numbers look good, Falcon.
102:16:36 Scott: And, Houston; Falcon. We're ready to go with the DPS.
102:16:41 Scott: Okay. And we're ready to go with the DPS pressure checkout any time you are.
102:16:44 Mitchell: Okay. We're ready. Press on.
102:16:49 Scott: Roger.
102:16:54 Mitchell: Endeavour, Houston. Give us Narrow please on your High Gain [Antenna].
102:18:26 Scott: Okay, Houston; Falcon. We've done the descent start. The ambient pressure is down to 450 but the manifold pressure hasn't moved. [Pause.]
102:18:39 Mitchell: Stand by. [Pause.] Okay, Falcon. We believe you turned your PQM [Propellant Quantity Monitor] Off, and - and that's your PQGS [Propellant Quantity Gauging System] Off, and - probably your problem - your hed - Helium Monitor. I think you got it inadvertently. [Pause.] And, Endeavour, we'll take P00 and Accept. [Pause.]
102:22:53 Mitchell: Endeavour, Houston. We're recommending a half a degree per second for your maneuver. You've got quite aways to go.
102:23:02 Worden: Rog, Ed. [Pause.]
102:23:10 Scott: And, Houston; Falcon. The Landing Radar looks good up here.
102:23:14 Mitchell: Roger. It looks good here. [Pause.]
102:23:25 Scott: Rog.
102:24:48 Mitchell: Falcon, Houston. If you'll let us have P00 and Data, we have uplink for you.
102:24:55 Irwin: Roger.
102:24:58 Mitchell: And I have PADs for Endeavour and Falcon, when you're both ready. [Pause.]
102:25:11 Irwin: Falcon's ready.
102:25:14 Worden: Endeavour's ready.
102:25:17 Mitchell: Okay. Here we go. With Echo, 104:42:30.00; Foxtrot, plus 0108.2, plus all zeros, minus 0050.0; 0144.9, plus 0008.6, 0119.2; 0:36, 000, 270; 0282.5; plus 0108.5, plus all zeros, minus 0049.3; Golf, 107:37:30.00; Hotel, 109:18:45.00. Readback. [Pause.]
102:26:31 Irwin: Okay. Falcon with the readback on no PDI plus 12. 104:42:30.00; plus 0108.2, plus all zips, minus 0050.0; 0144.9, plus 0008.6, 0119.2; 0:36, 000, 270; 0282.5; plus 0108.5, plus all zips, minus 0049.3; 107:37:30.00; and 109:18:45.00.
102:27:20 Mitchell: Okay. You got cut out there. Your AGS Delta-VZ, confirm it's a negative [sign] and [the GET for] Hotel [is] 109:18:45.00. [Pause.]
102:27:36 Irwin: That's confirmed, Ed.
102:27:38 Mitchell: Okay. Endeavour, give us Omni Charlie, please. [Pause.]
102:27:48 Worden: Endeavour on Omni Charlie.
102:27:50 Mitchell: Roger. And did you get the readbacks, Al?
102:27:55 Worden: Endeavour copied them - copied the PADs. Rog.
102:27:58 Mitchell: Okay. Here we go with India PDI PAD: 104:30:10.94; 11:03, plus 0002.9; 002, 110, 310; plus 56922; Juliet: 109:18:45.00; Kilo: 107:27:30.00; Lima: 104:50:49.67; Meco: 109:18:45.00; T-2 is at PDI plus 20:39; Nectar: 106:41:20.05. Readback. [Pause.]
102:29:18 Irwin: Okay. Falcon, with the readback. PDI-1: 104:30:10.94; 11:03, plus 0002.9; 002, 110, 310; plus 56922; Juliet: 109:18:45.00; Kilo: 107:27:30.00; Lima: 104:50:49.67; 109:18:45.00; T-2 at PDI: plus 23:39; and Nan is 106:41:20.05.
102:30:05 Mitchell: Okay. The T-2 time is at 20:39. [Pause.]
102:30:16 Irwin: Roger. 20:39.
102:30:19 Mitchell: Let's try it again - 20:39.
102:30:25 Irwin: 20:39; thank you, Ed.
102:30:26 Mitchell: Good readback. [Pause.] Falcon, computer's yours.
AS15-87-11700 - Area west of the crater Macrobius, The distinct rayed crater is at 20.7°N, 43.3°E - Image by NASA/Johnson Space Center.
The Flight Activities Officer [FAO] reports that Al Worden in Endeavour is nearly in the proper attitude for the landmark tracking. That's scheduled to begin in about 8 or 9 minutes from now. The landmark will first come into view over the horizon at 102 hours, 37 minutes, 27 seconds. And it will be about 4 or 5 minutes after that before Worden actually begins taking marks on the landmark.
Reviewing our status briefly, we've nearly completed the systems checkouts on the Lunar Module. Everything appears to be in order at the moment both with the LM and the Command Module for the powered descent, which will occur on the next revolution, 14th revolution. And we're standing by now for the landmark tracking which Al Worden will perform from the Command Module Endeavour.
102:34:24 Worden: Houston, Endeavour.
102:34:27 Mitchell: Go ahead, Endeavour.
102:34:32 Worden: Roger, Ed. Just checking over this P24 PAD again. And you didn't update the longitude over 2 on this one. Did you want to do that?
102:34:41 Mitchell: Stand by. [Pause.] Negative, Al. Go with the one in the Flight Plan.
102:34:46 Worden: ...and low altitude. Okay.
AS15-87-11701 - View looking southwest with crater Hill in the foreground, and beyond Carmichael - Image by NASA/Johnson Space Center.
AS15-87-11702 - View looking southwest with crater Hill in the foreground, and beyond Carmichael - Image by NASA/Johnson Space Center.
AS15-87-11703 - View looking southwest with crater Hill in the foreground, and beyond Carmichael - Image by NASA/Johnson Space Center.
102:36:14 Mitchell: Falcon, Houston. Over.
102:36:19 Scott: Houston, Falcon. Go.
102:36:21 Mitchell: Roger. Check your CO2 Sensor circuit breaker. We're showing off-scale low.
102:36:29 Scott: Okay.
102:36:32 Irwin: Circuit breaker's closed, Ed.
102:36:34 Mitchell: Roger. [Long pause.]
102:36:52 Mitchell: Endeavour, standby for T-1 minus 30 seconds.
102:36:57 Mitchell: Mark.
102:36:59 Worden: Rog. [Long pause.]
T-1 is the time at which the landing site landmark will first appear on the horizon.
AS15-87-11704 - View southwest towards the crater Littrow and the massifs of the Taurus Mountains. These surround what will become the Apollo 17 landing site - Image by NASA/Johnson Space Center.
AS15-87-11705 - View southwest towards the crater Littrow and the massifs of the Taurus Mountains. These surround what will become the Apollo 17 landing site - Image by NASA/Johnson Space Center.
AS15-87-11706 - View straight down into the 11-km crater Brewster (formerly Römer L) - Image by NASA/Johnson Space Center.
AS15-87-11707 - View southwest across the southeastern shore of Mare Serenitatis. Crater Clerke is near the centre of the image - Image by NASA/Johnson Space Center.
AS15-87-11708 - View southwest across the southeastern shore of Mare Serenitatis. Crater Clerke is left of centre - Image by NASA/Johnson Space Center.
AS15-87-11709 - The bowl-shaped Clerke, and an unusual light-toned patch within the system of rilles around the edge of Serenitatis - Image by NASA/Johnson Space Center.
AS15-87-11710 - A series of extensional rilles on the eastern side of Mare Serenitatis surrounded by a triplet of simple craters, each probably only a couple of kilometres in diameter. Centre of photo is located at 23.6°N, 29.1°E - Image by NASA/Johnson Space Center.
AS15-87-11711 - A series of extensional rilles on the eastern side of Mare Serenitatis surrounded by a triplet of simple craters, each probably only a couple of kilometres in diameter. Centre of photo is located at 23.6°N, 29.1°E - Image by NASA/Johnson Space Center.
AS15-87-11712 - Dorsum Androvandi on the eastern side of Mare Serenitatis. Centre of photo is located at 23.6°N, 28.8°E - Image by NASA/Johnson Space Center.
AS15-87-11713 - Dorsum Androvandi on the eastern side of Mare Serenitatis. Centre of photo is located at 23.6°N, 28.7°E - Image by NASA/Johnson Space Center.
AS15-87-11714 - Dorsum Androvandi on the eastern side of Mare Serenitatis. Centre of photo is located at 23.6°N, 28.7°E - Image by NASA/Johnson Space Center.
102:41:19 Mitchell: Mark. One minute; T-2 minus 1.
102:41:24 Worden: Rog. [Long pause.]
102:41:45 Mitchell: Standby for 30 seconds.
102:41:47 Mitchell: Mark.
102:42:04 Mitchell: 10 seconds.
102:42:07 Mitchell: Mark.
AS15-87-11715 - View WSW across Mare Serenitatis towards Montes Apenninus and the Apollo 15 landing site - Image by NASA/Johnson Space Center.
Flight Activities Officer [FAO] reports that Worden has begun taking marks and we're seeing those here on our data displays here in the Control Center. We'll get a qualitative assessment from Worden following the landmark tracking.
102:44:54 Worden: Okay, Houston. It's out of sight.
102:44:56 Mitchell: Roger, Endeavour. How did you feel about them, Al?
102:45:03 Worden: Oh, I felt good about them, Ed. Right on.
102:45:05 Mitchell: Very good. Thank you.
102:45:08 Worden: No question about the landmark. And every mark, I had the - the crater centered, Crater Index.
102:45:17 Mitchell: Very, very good. Thank you. And I have an update to the PDI abort PAD, when Endeavour and Falcon are ready. [Long pause.]
102:45:37 Irwin: The Falcon's ready. [Pause.]
102:45:46 Worden: Endeavour's ready.
102:45:47 Mitchell: Okay. It's item Kilo. Should be 107:20:30.00. [Pause.]
102:46:02 Irwin: Okay. Falcon copied Kilo as 107:20:30.00.
102:46:02 Mitchell: Good readback.
102:46:08 Worden: Endeavour copies.
AS15-87-11716 - Hadley Rille and the Apollo 15 landing site. Mount Hadley Delta is on the left - Image by NASA/Johnson Space Center.
AS15-87-11717 - Hadley Rille and the Apollo 15 landing site. Mount Hadley Delta is on the left - Image by NASA/Johnson Space Center.
AS15-87-11718 - Hadley Rille and the Apollo 15 landing site. Mount Hadley Delta is on the left - Image by NASA/Johnson Space Center.
AS15-87-11718b - A labelled version of 11718 to show the primary features of the site - Image by NASA/Johnson Space Center.
AS15-87-11719 - Hadley Rille and the Apollo 15 landing site. Mount Hadley Delta is on the lower left - Image by NASA/Johnson Space Center.
AS15-87-11720 - Hadley Rille at the Apollo 15 landing site. The landing site is at the lower right and Mount Hadley Delta is on the lower left - Image by NASA/Johnson Space Center.
AS15-87-11721 - Hadley Rille and the area of Palus Putredinus west of the Rille - Image by NASA/Johnson Space Center.
102:50:51 Mitchell: Endeavour, Houston. Omni Delta.
The Flight Dynamics Officer [FIDO] has confirmed Al Worden's assessment of the landmark tracking. He reports that we appear to have gotten sufficient information from the landmark tracking to update the location of the landing site, and this would appear to clear the way for carrying out the landing on the planned revolution on the next rev. We'll be giving a Go for the powered descent on reacquiring at the beginning of the 14th revolution. The Command Module, Endeavour, now in a more or less circular orbit. Al Worden reported that the onboard computations of the orbit following the circularization burn were 65.2 by 54.8 [nautical miles, 120.8 by 101.5 km], which is very close to what we had anticipated and we'll be getting a ground computation of that orbit before too much longer. But it would appear from the information passed - passed down to the ground by Worden that the circularization maneuver was almost precisely as planned. Both crews, Irwin and Scott aboard the Lunar Module, and Worden aboard the Command Module, are presently involved in making the final alignments of their guidance system platforms prior to the powered descent.
102:56:44 Mitchell: Falcon, Houston. [Pause.]
102:56:50 Irwin: Alright. Go ahead, Ed.
102:56:51 Mitchell: Let's see if you can reach Endeavour and ask him to bring the High Gain [Antenna] up. Flight Plan angles, please. Minus 69 and 114. [Pause.]
102:57:05 Irwin: Roger. Endeavour, this is Falcon. How do you read? [Pause.] Roger. Houston would like you to bring up the High Gain [Antenna] to a minus 69 and a 114.
103:09:38 Scott: Okay, Houston; Falcon. How's the P63 look?
103:09:42 Mitchell: Okay, Dave. It looks very good. Time's okay. And be advised, both Endeavour and Falcon, that the P24 looked good. There will be an update, but we feel very confident about it. [Pause.]
103:10:00 Scott: Okay, Falcon here. Very good.
103:10:04 Mitchell: And, Falcon, we'd like to see a Verb 47 down to the AGS, please. And be advised that your platform, both gyros and PIPA [Pulsed Integrating Pendulous Accelerometers]'s, are [in] good shape. No updates to them.
103:10:19 Scott: Very good. [Long pause.]
103:10:26 Scott: Houston, Falcon. While that's running through there, we're going back through notes, checking over the activation. And one thing we missed there was, just before undocking, we ran the suit pressure integrity check, and the first time around, we got a greater than 3/10ths decrease in one minute. So we cycled through both regulators, did that test, and came back and ran the suit integrity check again, and it was just fine. It was about 1/10th in a minute.
103:11:38 Mitchell: Okay, Falcon. We copy that. Thank you.
103:11:44 Scott: Okay.
103:12:56 Mitchell: Falcon, Houston.
103:13:01 Scott: Houston, Falcon. Go.
103:13:03 Mitchell: Rog, Dave. Talk about reviewing notes, we did so, also, and we found one we'd like to pass to you before LOS.
103:13:12 Scott: Okay.
103:13:14 Mitchell: Dave, we - working out a procedure down here that we simmed [that is, ran in the simulator], and it's in the event of a low thrusting DPS during PDI. We're prepared to call to you - an RCS thrust augmentation for one minute, at about one minute or a minute and a half into the burn. And recommend doing it on the LMP's TTCA [Thrust/Translational Control Assembly], if we have to do it at all. What do you think?
103:13:47 Scott: That's fine. We'll try that if we need it.
103:13:50 Mitchell: Okay, the procedures are very simple. We'll call it to you as we've measured the thrust.
103:13:57 Scott: Okay. And I guess you'll call "On" and call "Off" with the TTCA, is that correct?
103:14:03 Mitchell: We can. That'll just be a one minute - a one minute burst.
103:14:11 Scott: Okay, fine. And by the way, when we went by PD - PDI-0, we took a couple of hacks at the altitude. It showed 10 [nautical] miles even.
103:14:20 Mitchell: Very good.
We're about three minutes away now from loss of radio contact with the Lunar Module. However we won't be losing contact with the Command Module due to its higher orbit for about 7 minutes - 7½ minutes. The contingency procedure which Ed Mitchell passed up to Dave Scott related to the use of the Reaction Control System thrusters on the Lunar Module in the unlikely event that the LM descent engine is significantly below normal in thrust. Normally that engine should produce about 9,900 pounds of thrust. If the thrust level should be about 260 pounds low or more, it would be possible to make up the difference by turning on the Reaction Control System thrusters, firing the 4 thrusters in the plus-X direction, adding to the thrust of [the] descent engine. These 4 thrusters each provide about 100 lbs of thrust and we found by simulating this technique, if the thrusters are applied early enough in the powered descent, a normal landing can be carried out.
103:15:53 Mitchell: Falcon, Houston. You're about a minute and 40 seconds from LOS. We'd like to see your 400 plus 30000 before LOS.
103:16:06 Irwin: Rog. In work.
We're about 1 minute now from Loss Of Signal with the Lunar Module. And would like to reemphasize that that technique for using the Reaction Control System thrusters is a backup technique. The normal procedure would be to use only the Descent Propulsion System for the braking required for the landing. The Reaction Control System thrusters would be used solely for attitude control. And in the unlikely event that we have a low thrust engine once we turn on the Descent Propulsion System, then we'll have up the sleeve the possibility of using the Reaction Control System thrusters.
103:17:19 Mitchell: Falcon, Houston. LOS in 30 seconds.
We've had Loss Of Signal with the Lunar Module, Falcon. We're getting weak signal strength from the Command Module, although we do have about 3 minutes left before we lose radio contact with Endeavour. And as Falcon went around the corner behind the Moon, we were showing the Lunar Module in an orbit, 60.6 [nautical miles, 112.2 km] at its high point; 60.6 nautical miles, and with a low point of 8.5 nautical miles [15.7 km] above the lunar surface.
103:21:30 Mitchell: Endeavour, Houston.
103:21:36 Worden: Houston, Endeavour. Go ahead.
103:21:37 Mitchell: Rog, Al. Your a minute from LOS. We recommend, on the next pass, check your S-Band Squelch Switch, Off.
103:21:50 Worden: Ah, Rog. [Laughing.]
103:21:52 Mitchell: Thank you.
103:21:53 Worden: Thank you. It was On.
AS15-87-11722 - Earth - Image by NASA/ASU.
AS15-87-11722 - Earth, cropped from full image - Image by NASA/ASU.
AS15-87-11723 - Earth - Image by NASA/ASU.
AS15-87-11723 - Earth, cropped from full image - Image by NASA/ASU.
And, we've had Loss Of Signal now with the Command Module. When next we reacquire the Lunar Module, Falcon, will be about 25 minutes away from the scheduled time of the powered descent, the beginning of the powered descent to the lunar surface. And as both spacecraft went around the corner, everything appeared to be normal. At this point we see nothing that would interfere with a normal landing. We'll be getting the - taking a final look at the status of the trajectory in both spacecraft on reacquiring, and at that time a decision for the powered decent will be made. However, as we say at the present time we see nothing that would stand in - stand in the way of a normal landing on the 14th revolution. At 103 hours, 24 minutes; this is Apollo Control, Houston.
AS15-87-11724 - Mare Ingenii, caught just before the Sun sets on it. The flooded ring which dominates this south-facing photograph is the crater Thompson which forms part of the mare - Image by NASA/Johnson Space Center.
AS15-87-11725 - Mare Ingenii - Image by NASA/Johnson Space Center.
AS15-87-11726 - Crater Tsiolkovsky - Image by NASA/Johnson Space Center.
AS15-87-11727 - Crater Tsiolkovsky - Image by NASA/Johnson Space Center.
AS15-87-11728 - Crater Tsiolkovsky - Image by NASA/Johnson Space Center.
AS15-87-11729 - Crater Tsiolkovsky - Image by NASA/Johnson Space Center.
This is Apollo Control. We're now about 4 minutes from reacquiring the Lunar Module Falcon, now on its 14th revolution of the Moon. On reacquisition of the Lunar Module, the crew will be in final preparations for the powered descent. The Flight Dynamics Officer [FIDO] reported that results of the landmark tracking were all satisfactory. And we're, as far as the trajectory is concerned, in good shape for the powered descent. We will have to steer out about 3.3 miles - nautical miles of cross-range error and this will be taken into account in the targeting for the powered descent. I would like to run over the major sequence of events which will occur in the powered descent. At about 3 minutes prior to the initiation of the maneuver, Scott and Irwin will yaw 50 degrees left; this is to clear the Lunar Module antennas so that we have good lock-on, good communications during the early portions of the powered descent when the LM body tends to block the antennas without the yaw maneuver. Initiation of the powered descent is scheduled to occur at 104 hours, 30 minutes and 11 seconds Ground Elapsed Time; and the nominal burn time would be about 12 minutes to the landing. For the first 26 seconds of the burn on the Descent Propulsion System engine, the throttle will be at Minimum; this is to allow the engine gimbal to trim up, get everything going in the right direction before full - full thrust is applied. At about 26 seconds, the guidance system throttles the engine to full thrust which is about 9,900 pounds of thrust and is also the thrust level that is maintained throughout a good portion of the braking phase. After 3 minutes of burn time, the crew will yaw face up which is the normal attitude for landing radar acquisition. At this time, they will be in a position facing upward with their feet, so to speak, in the direction of travel and the LM will be gradually pitching into a more upright position throughout the powered descent maneuver. At about 4 minutes into the burn, we can expect to get landing radar data. This landing radar updates will begin feeding into the guidance system, improving its knowledge of how far above the lunar surface the Lunar Module is. And at about 7½ minutes into the burn, Lunar Module Falcon will pass over the Apennine Front, clearing the mountains at a height of about 10,000 feet, passing about 10,000 feet above the mountains which at that point have an altitude of about 12,000 feet above the landing site. And at about 9 minutes, 24 seconds; we would reach the point designated "High gate," at which the Lunar Module pitches forward to give the crew their first visibility of the landing site. And at this point, they will be switching to Program 64 in the guidance logic which will carry them from an altitude of 7,000 feet down to the altitude of about four or five hundred where they'll switch to Program 66 for the final descent. At this point, Dave Scott will most likely be flying with Automatic Attitude Control and he will be controlling the rate of descent manually from probably about 4 to 500 feet vertically down to touchdown. Because of the nature of this landing site, there are several opportunities during the powered descent to update the guidance system's knowledge of where it is with respect to the landing site. We have had Acquisition of Signal with the Lunar Module. We'll stand by for a call to the crew.
104:05:42 Mitchell: Falcon, Houston. [No answer.]
104:06:00 Mitchell: Falcon, Houston.
104:06:05 Scott: Houston, Falcon. Go.
104:06:08 Mitchell: Roger, Falcon. We're ready for your Ascent Bat On time and your ED Bat report. [Pause.]
104:06:18 Irwin: Roger, Ed. The Ascent Bats were On at 103:50:45, and I'll check the ED Bats now. [Long pause.]
104:06:53 Irwin: And, Houston, this is Falcon. ED batteries both check at 37 volts.
104:06:53 Mitchell: Copy; 37 volts. And I have an update to your PDI PAD. [Pause.]
104:07:06 Irwin: Roger. Go ahead.
104:07:08 Mitchell: And, Falcon, give us P00 and Data, and we'll give you an uplink. [Pause.]
104:07:20 Scott: P00 and Data. Go ahead with the PAD.
104:07:22 Mitchell: Roger. India: 104:30:08.54.
104:07:32 Irwin (onboard): Yes? Okay.
Mitchell (continued): Noun 61 crossrange, plus 0003.3 and your DEDA's 231 entry, plus 56943.
104:07:57 Irwin: Ed, if you're reading us, you ought to call us after the - the uplink. We cannot read you.
104:08:13 Scott (onboard): Locked up yet?
104:08:14 Irwin (onboard): No.
104:08:18 Scott (onboard): Here it comes; don't change it. It's coming in.
We're coming up now on 20 minutes until ignition for the powered descent. The landing point for Apollo 15, in a plains area boxed in by mountains on one side, actually on two sides and a rille on the third side. We'll put Falcon down about 1 mile from the Hadley Rille. They'll be coming in about 2 miles to the south, rather to the north of the point where Hadley Delta begins to rise abruptly to an altitude of about 13,000 feet above the landing site, and approximately 6 miles behind their approach path, about 6 miles from the touch down point to the east, the Apennine Front itself begins to rise up to about 12,000 feet, with the highest peaks in that Front about 15,000.
And here in Mission Control, we've switched over from the large display of the lunar surface that we've had up on our front plot board since going into lunar orbit. We now have the analog displays which will tell the Flight Dynamics Officer [FIDO] how well the descent trajectory is progressing and includes abort lines that will tell him if any of the parameters or the characteristics of the trajectory are approaching unsafe limits.
104:10:18 Scott (onboard): Did you check the RCS? Okay. ECS look all right?
104:10:27 Irwin (onboard): Yes.
104:10:52 Irwin (onboard): If we should be up-linked, Dave, I'll need a - Verb 47.
We're coming up now on 10 minutes until the beginning of this 12-minute powered burn to the lunar surface. At the initiation of this maneuver, the Command Module Endeavour will be about 350 nautical miles [650 km] behind the Lunar Module. The Command Module will pass overhead at just about the time the Lunar Module is touching down. Aboard the Lunar Module Falcon the crew has completed updating their backup guidance system with the same information that has been loaded into the Primary Guidance [and Navigation] System.
104:20:37 Scott: Hey, Houston, Falcon on Vox. How do you read?
104:20:40 Mitchell: Loud and clear, Dave.
104:20:44 Scott: Okay.
104:20:47 Scott: [Garble] off. [Long pause.]
And the crew has now switched on the guidance program - program 63 which will guide the Lunar Module during the initial portion of the power descent, the principal braking phase.
A last look at the Lunar Module orbit showed it to be in an orbit with a high point of 60.6 nautical miles [112.2 km] and a low point of about 8.1 nautical miles [15.0 km]. The Command Module Endeavour, that was in an orbit of 64.6 by 53.8 [nautical miles, 119.6 by 99.6 km]. And we're now coming up on about 6 minutes prior to the beginning of the powered descent. Everything continuing to progress very smoothly, and rather quietly here in Mission Control at the moment.
104:25:11 Irwin: Five minutes.
104:25:12 Scott: Okay. [Garble].
104:25:13 Irwin: [Garble, may be landing radar] breaker is in. Altitude transmitter.
104:25:18 Scott: Altitude transmitter is 3.7; velocity's 3.8.
104:25:23 Irwin: Stand by for 4 minutes for [garble]. [Pause.]
104:25:36 Irwin: Reading me any better, now?
104:25:37 Scott: Yep. [Long pause.]
Flight Director Glynn Lunney, at this moment getting a final status for powered descent.
104:26:09 Scott: Okay. Go for the final trim.
104:26:11 Mitchell: And, Falcon, you are Go for PDI.