Apollo 11 emerges from the far side of the Moon and reports a successful insertion into lunar orbit. The crew get their first good look at the Moon, observing the crater Aristarchus by Earthlight and transmitting television views of their landing site. They prepare for another lunar engine firing which will bring them into a tighter lunar orbit, then make this burn over the far side two revolutions after their first insertion burn.
We pick up the flight 90 seconds before the spacecraft emerges around the limb. Initially, reception is very weak.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
That noise is just bringing up the system. We have not acquired a signal. We're a minute and one-half away from acquisition time.
076:14:17 Collins (onboard): I rolled too slow.
076:14:19 Armstrong (onboard): Doubt that we'll make it.
076:14:23 Collins (onboard): Oh, look at that [garble].
076:14:32 Collins (onboard): Golly damn! A geologist up here would just go crazy.
076:14:40 Aldrin (onboard): You want the Flight Plan?
076:14:43 Armstrong (onboard): Yeah, please.
30 seconds.
076:14:57 Collins (onboard): Okay, we shouldn't take any more pictures on this roll until Earth comes, I don't think. This is...
076:15:01 Armstrong (onboard): About out?
076:15:02 Collins (onboard): ...just about out and it's on our last color roll, so we'll switch to black and white as soon as we get to Earth.
076:15:07 Armstrong (onboard): We might make it in time.
076:15:09 Collins (onboard): Yeah.
076:15:13 Aldrin (onboard): There it is, it's coming up!
076:15:15 Armstrong (onboard): What?
076:15:16 Aldrin (onboard): The Earth.
076:15:16 Armstrong (onboard): See it?
076:15:17 Aldrin (onboard): Yeah. Beautiful.
076:15:21 Aldrin (onboard): It's halfway up.
076:15:23 Armstrong (onboard): We ought to have AOS now. You got your...
076:15:26 Aldrin (onboard): Right over the LM.
076:15:28 Armstrong (onboard): Are you set up?
076:15:30 Aldrin (onboard): Just about to be cut off by the LM. Boy, does that ever look beautiful in the sextant.
076:15:36 Armstrong (onboard): Have you got...
076:15:37 Collins (onboard): Okay, how about MSFN...
076:15:39 Collins/Aldrin (onboard): You got them.
Madrid AOS, Madrid AOS.
076:15:42 Armstrong (onboard): We're in Omni...
076:15:45 Aldrin (onboard): Down Voice Backup.
076:15:46 Armstrong (onboard): ...Bravo.
076:15:48 McCandless: Apollo 11, Apollo 11, this is Houston. Do you read? Over.
076:15:52 Aldrin (onboard): Yeah, we sure do, Houston. The LOI-1 burn just nominal as all getout, and everything's looking good.
076:15:59 McCandless: Apollo 11, Apollo 11, this is Houston. Do you read? Over.
Telemetry indicates that the crew is working on the antenna angles to bring the High Gain Antenna to bear.
076:16:59 Spacecraft: Houston, Apollo 11. Over.
076:17:00 McCandless: Apollo 11, Apollo 11, this is Houston. We are reading you weakly. Go ahead. Over.
076:17:08 Armstrong: Roger. Burn status report follows. Delta-TIG zero, burn time 5:57, [garble] on the PAD. VGX minus 0.1, VGY minus 0.1, VGZ plus 0.1, Delta-VC minus [garble] point eight, fuel [garble] plus 390 [garble]. Over.
076:17:44 McCandless: 11, this is Houston. These residuals, do you have minus 0.17 [garble], VGX minus 0.1, VGY minus 0.1, VGZ 1.1, and a burn time of 5 plus 57. Stand by, maybe the comm will improve a little bit. Over.
Comm break.
076:19:32 McCandless: Apollo 11, this is Houston. Are you in the process of acquiring with the High Gain Antenna? Over.
Comm break.
076:21:37 McCandless: Apollo 11, Apollo 11, this is Houston. How do you read?
076:21:43 Collins: Reading you loud and clear, Houston. How us?
076:21:46 McCandless: Roger. Reading you the same, now. Could you repeat your burn status report? We copied the residuals and burn time, and that was about it. Send the whole thing again, please.
076:21:56 Collins: It was like - it was like perfect!
076:22:00 Armstrong: Delta-TIG zero, burn time 5:57, PAD values on the angles, VGX minus 0.1, VGY minus 0.1, VGZ plus 0.1, no trim, minus 6.8 on Delta-VC, fuel was 38.8, ox 39.0, plus 50 on balance. We ran an increase on the PUGS. Noun 44 showed us in a 60.9 by 169.9.
076:22:35 McCandless: Roger. We copy your burn status report. And the spacecraft is looking good to us on telemetry.
076:22:47 Armstrong: Roger. Everything looks good up here.
Very long comm break.
That burn report was by Neil Armstrong.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
This is Apollo Control. We're showing spacecraft weight in lunar orbit of 72,004 pounds [32,660 kg].
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
076:34:34 Armstrong: Apollo 11 is getting its first view of the landing approach. This time we are going over the Taruntius crater, and the pictures and maps brought back by Apollos 8 and 10 have given us a very good preview of what to look at here. It looks very much like the pictures, but like the difference between watching a real football game and one on TV. There's no substitute for actually being here.
076:35:11 McCandless: Roger. We concur, and we certainly wish we could see it first hand, also.
That was Neil Armstrong.
076:35:32 Armstrong: We're going over the Messier series of craters right at the time, looking vertically down on them, and Messier A, we can see good-sized blocks in the bottom of the crater. I don't know what our altitude is now, but in any case, those are pretty good-size blocks.
076:35:56 McCandless: Okay. Just roughly, it looks like you're about 120 miles or 130 miles right now. Make that 127 [nautical] miles [235 km].
Comm break.
076:37:12 Armstrong: We're approaching PDI point now, over... [Pause.]
076:37:24 Armstrong: There's Secchi in sight. [Long pause.]
076:37:48 Armstrong: We're over Mount Marilyn at the present time, and it's ignition point.
Mount Marilyn was named by astronaut Jim Lovell for his wife and sits at the southeast corner of Mare Tranquillitatis. It is part of a range of low mountains, Montes Secchi, that borders this part of the mare. On 26 July, 2017, the name was officially adopted for the feature by the International Astronomical Union. Up to then, its use was informal.
The Moon, at a similar phase to what it was when Apollo 11 visited. The position of Mount Marilyn is shown along with other features mentioned by Neil. Moon photo by David Woods.
During Lovell's Apollo 8 flight as its Command Module Pilot, one of his tasks was to make sightings of the landmarks along the ground tracks leading to two possible landing sites. Apollo Landing Site 2 was the more westerly of these and it is the site that has been chosen for the Apollo 11 landing attempt.
This image shows Mount Marilyn in relation to other features mentioned by Neil. Image from data gathered by Lunar Reconnaissance Orbiter.
Mount Marilyn is a triangular landform that happens to be 500 kilometres east of the landing site which made it a convenient marker for the start of the powered descent to the lunar surface. As Neil puts it, it marks the ignition point of the manoeuvre, a moment known as Powered Descent Initiation, or PDI.
Mount Marilyn. Image from data gathered by Lunar Reconnaissance Orbiter.
076:37:55 McCandless: Roger. Thank you. And our preliminary tracking data for the first few minutes shows you in a 61.6 by 169.5 orbit [114.1 by 313.9 km]. Over.
076:38:10 Armstrong: Roger.
076:38:12 McCandless: And Jim is smiling.
Comm break.
McCandless is referring to Jim Lovell, who is in the Control Room at this time.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
076:41:29 McCandless: Apollo 11, this is Houston. Over.
076:41:35 Armstrong: Go ahead.
076:41:37 McCandless: 11, Houston. During your SPS burn as played back on tape down here, we've observed the nitrogen tank Bravo pressure in the SPS system dropping a little bit more than we anticipated. It's holding steady right now. We'll continue to watch it and keep you posted if anything comes up. Over.
High pressure nitrogen gas is used to actuate the valves that feed propellant to the SPS engine. During the burn, engineering data from the spacecraft was recorded on the DSE tape recorder. this data, along with crew voice recordings is played back to Earth on an auxiliary radio channel as soon as the spacecraft comes back into view.
076:42:03 Armstrong: Roger. Thank you.
076:42:04 McCandless: Right. And it has held steady...
076:42:05 Armstrong: Currently going over Maskelyne, Mas...
076:42:10 Armstrong: Okay.
076:42:11 Armstrong: And Boot Hill, Duke Island, Sidewinder, looking at Maskelyne W, that's the yaw round checkpoint, and just coming into the terminator. At the terminator it's ashen gray. As you get further away from the terminator, it gets to be a lighter gray, and as you get closer to the subsolar point, you can definitely see browns and tans on the ground, according to the last Apollo limb observation anyway.
076:42:49 McCandless: Roger, 11. We're recording your comments for posterity.
076:42:57 Armstrong: [Laughter.] Okay.
And again, that was Neil Armstrong with the report.
076:43:04 Collins: Did somebody in the background - do they accuse us of being compromisers?
076:43:08 McCandless: Huh! [Long pause.]
076:43:19 Armstrong: And the landing site is well into the dark here. I don't think we're going to be able to see anything of the landing site this early.
076:43:42 McCandless: Apollo 11, this is Houston. When you have a free minute, could you give us your onboard readout of N2 tank Bravo, please. And we'd like to make sure you understand that ever since you stopped thrusting with the SPS, the temperature in this tank has remained steady. Over. Make that the pressure has remained steady.
076:44:07 Collins: Rog. We understand tank pressure has stayed steady. Thank you.
076:44:12 Aldrin: Roger. We're showing the N2 tank pressure in tank Bravo to be 1,960, something like that, and Alpha is, oh, about 22 - about 2,250. Over.
076:44:34 McCandless: Roger. We show 2,249 in Alpha and 1,946 down here.
076:44:44 Aldrin: Okay.
Long comm break.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
076:53:19 Collins: Houston, Apollo 11. How about coming up with some roll, pitch, and yaw angles in which to stop this so-called Orb-Rate that I'm doing.
076:53:45 McCandless: We'll have them for you in a minute, 11.
076:53:51 Collins: Okay. And time to stop also, please.
076:53:55 McCandless: Yes, indeed.
Comm break.
076:56:35 McCandless: Apollo 11, this is Houston. Over.
076:56:41 Aldrin: Go ahead, Houston.
076:56:42 McCandless: Roger. We show you, in the Flight Plan, staying in orbital rate until about 79 hours, 10 minutes. Do you have some particular attitude or reason for wanting to go inertial? Over.
There are two common attitude modes that a spacecraft can have when orbiting a planet or moon; Orbital rate or inertial.
Comparison of orbital rate and inertial modes of orbiting a body.
For orb-rate flight, the spacecraft slowly rotates, usually around its pitch axis, at a rate that matches its orbital period. In this way, one side of the ship always points towards the surface, be it for windows, sensors or cameras. For inertial flight, the spacecraft maintains a constant attitude with respect to the stars, perhaps for the purposes of a major burn.
076:57:00 Collins: No, that's fine. I just wanted to confirm that. Until 79:10, then we'll breeze around here in orbit.
076:57:07 McCandless: Roger. And we've got an observation you can make if you have some time up there. There's been some lunar transient events reported in the vicinity of Aristarchus. Over.
076:57:28 Aldrin: Roger. We just went into spacecraft darkness. Until then, why, we couldn't see a thing down below us. But now, with Earthshine, the visibility is, oh, pretty fair. Looking back behind me, now, I can see the corona from where the Sun has just set. And we'll get out the map and see what we can find around Aristarchus.
076:57:54 Armstrong: We're coming upon Aristarchus right now...
076:57:55 McCandless: Okay. Aristarchus is at Tango Echo 9 on your ATO chart. It's about 394 miles north of track. However, at your present altitude, which is about 167 nautical miles, it ought to be over - that is within view of your horizon: 23 degrees north, 47 west. Take a look and see if you see anything worth noting up there. Over. [Pause.]
076:58:34 Armstrong: Both looking.
076:58:36 McCandless: Roger. Out.
Long comm break.
That was Buzz Aldrin discussing the Earthshine.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
077:03:01 Armstrong: Houston, 11. It might help us a little bit if you could give us a time of crossing of 45 west.
077:03:09 McCandless: Say again, please, 11. [Long pause.]
077:03:23 Armstrong: You might give us a time of crossing of 45 west, and then we'll know when to start searching for Aristarchus.
077:03:32 McCandless: Roger. You'll be crossing 45 west at 77:04:10 or about 40 seconds from now. Over. Thirty seconds from now.
077:03:45 Armstrong: Okay.
Comm break.
077:04:50 McCandless: Apollo 11, when we lose the S-band, we'd like to get Omni Charlie from you. And update my last, that 77:04 was the time when Aristarchus should become visible over your horizon. 77:12 is point of closest approach south of it. Over.
077:05:14 Armstrong: Okay. That sounds better because we're just - just went by Copernicus a little bit ago.
077:05:18 McCandless: Roger. We show you at about 27 degrees longitude right now.
077:05:25 Armstrong: Right-oh.
Comm break.
Location of Copernicus and Aristarchus with respect to Apollo 11's ground track.
Roughly speaking, Apollo 11 is following the lunar equator east to west. Copernicus and Aristarchus are to the north of its ground track.
077:07:07 Aldrin: Houston, when a star sets up here, there's just no doubt about it. One instant it's there, and the next instant it's just completely gone.
077:07:16 McCandless: Roger. We copy.
Comm break.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
077:09:21 McCandless: Apollo 11, this is Houston. We request you use Omni Charlie at this time. Over.
077:09:29 Aldrin: Okay. Going to Omni Charlie.
077:09:32 McCandless: Roger. Out.
Comm break.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
077:11:57 Aldrin: Houston, Apollo 11.
077:12:01 McCandless: Apollo 11, this is Houston. Go ahead.
077:12:06 Aldrin: Roger. Seems to me since we know orbits so precisely, and know where the stars are so precisely, and can time the setting of a star or a planet to a very fine degree, that this might be a pretty good means of measuring the altitude of the horizon.
077:12:32 McCandless: Roger. [Long pause.]
077:12:51 Armstrong: Hey, Houston. I'm looking north up toward Aristarchus now, and I can't really tell at that distance whether I really am looking at Aristarchus, but there's an area there that is considerably more illuminated than the surrounding area. It just has - seems to have a slight amount of fluorescence to it as a crater can be seen, and the area around the crater is quite bright.
Aristarchus is the brightest crater on the face of the Moon.
077:13:30 McCandless: Roger, 11. We copy. [Long pause.]
077:14:23 Aldrin: Houston, Apollo 11. Looking up at the same area now and it does seem to be reflecting some of the Earthshine. I'm not sure whether it was worked out to be about zero phase to - Well, at least there's one wall of the crater that seems to be more illuminated than the other, and that one - if I'm lining up with the Earth correctly, does seem to put it about at zero phase. That area is definitely lighter than anything else that I could see out this window. I am not sure that I am really identifying any phosphorescence, but that definitely is lighter than anything else in the neighborhood.
077:15:15 McCandless: 11, this is Houston. Can you discern any difference in color of the illumination, and is that an inner or an outer wall of the crater? Over.
077:15:34 Aldrin: Rog. That's an inner wall of the crater.
077:15:43 Collins: No, there doesn't appear to be any color involved in it, Bruce.
077:15:47 McCandless: Roger. You said inner wall. Would that be the inner edge of the northern surface?
077:16:00 Aldrin: I guess it would be the inner part of the west-northwest part, the part that would be more nearly normal if you were looking at it from the Earth.
077:16:20 McCandless: 11, Houston. Have you used the monocular on this? Over.
077:16:28 Aldrin: Stand by one.
Comm break.
077:17:59 Collins: Like you to know this quest for science has caused me to lose my lunch. Floating around in here somewhere, but I can't find it.
077:18:08 McCandless: 11, this is Houston. We're - we're hearing only a partial comm. Say again please.
077:18:20 Collins: I think [garble] [Long pause.]
077:18:41 Aldrin: Houston, we'll give it a try if we have the opportunity on next rev, when we're not in the middle of lunch, and trying to find the monocular.
077:18:51 McCandless: Roger. Copied you that time. Expect in the next rev you'll probably be getting ready for LOI-2.
077:19:09 McCandless: So, let's wind - wind this up, and we've got some other things to talk to you about in a few minutes.
077:19:19 Armstrong: Okay.
Long comm break.
Apollo 11 will be in acquisition for another 20 minutes during its first revolution of the Moon.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
077:22:44 McCandless: Apollo 11, this is Houston. Over.
077:22:49 Armstrong: Go ahead, Houston.
077:22:53 McCandless: 11, this is Houston. We're targeting, or planning to make the LOI-2 burn now using bank A only. We'll have the PAD and everything for you next time around. Just trying to economize a little on bank B. Bank B is holding, though.
At 076:41:37, McCandless informed the crew that the pressure within a nitrogen storage tank that is used to operate the propellant valves on the B bank of the SPS engine was lower than expected. He added that the pressure was holding steady. In order to preserve the remaining pressure, they have elected to carry out the relatively short LOI-2 burn, of only 17 seconds, using just the A bank.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
077:31:53 McCandless: Apollo 11, this is Houston. Over.
077:32:02 Armstrong: Go ahead.
077:32:04 McCandless: 11, Houston. In order to improve the communications a little bit here, we'd like to try to get you on the High Gain Antenna. We're recommending a pitch angle of 0, yaw 355 - I say again 355, the Track switch to Manual, and Wide Beamwidth. Over. [Long pause.]
077:32:42 Collins: Okay. You ready to switch to High Gain now?
077:33:09 McCandless: 11, Houston. Do you read? [Pause.]
077:33:19 Aldrin: Roger. We read you. It seems to be rather marginal on the High Gain.
077:33:24 McCandless: Roger. We concur. [Long pause.]
077:33:42 Collins: Houston, Apollo 11. Could you give us a time of crossing the prime meridian 150 west? Over.
077:33:47 McCandless: Roger. Stand by about a half a second, here. Okay. Your time of crossing the 150 west meridian will be 77:50:05. Over.
077:34:10 Collins: Thank you. [Long pause.]
077:34:24 McCandless: 11, this is Houston. We have about 6 minutes remaining until LOS, and in order that we may configure our ground lines, we'd like to know if you're still planning to have the TV up with the beginning of the next pass. Over. [Pause.]
077:34:48 Armstrong: Roger, Houston. We'll try to have it ready.
077:34:50 McCandless: This is Houston. We are inquiring if it is your plan to. Over. [Pause.]
077:35:00 Armstrong: It never was our plan to. But it's in the Flight Plan, so I guess we'll do it.
077:35:54 McCandless: For use in connection with that time on the prime meridian crossing, you have an orbital period now of 2 hours, 8 minutes and 37 seconds. Over.
077:36:10 Collins: Thank you.
077:36:11 McCandless: Roger. Out.
Comm break.
077:38:16 McCandless: Apollo 11, this is Houston. A little over 2 minutes to LOS. All your systems parameters and orbit are looking good from the ground. We have AOS on the other side at 78:23:31. Over.
077:38:40 Aldrin: Rog. 78:23:21.
077:38:43 McCandless: Roger. That was 31 on the end.
077:38:50 Armstrong: Okay.
Very long comm break.
This is Apollo Control. We've had Loss Of Signal from Apollo 11 on its first lunar revolution. We will acquire the spacecraft on the next revolution at 78 hours, 23 minutes, 31 seconds. The orbital period for Apollo 11's present orbit; 2 hours, 8 minutes, 37 seconds; and as you heard we passed up to the crew information that we would perform the LOI-2 burn using only bank A. The banks are the drive mechanisms for the ball valves in the Service Propulsion System. They open and close these ball valves and the valves allow the fuel and oxidizer to flow into the engine. There are redundant valves and redundant banks, banks A and B. There was apparently - they are driven by nitrogen and that was the reference to the pressure drop there. There was apparently a leak in nitrogen tank B during the LOI-1 burn. This burn was performed with both banks open. The engine can be operated with only one bank. It's apparent that the tank leaked only during the burn while the bank was actuated. Pressure has held steady since the end of the burn and the experts are reducing the data and looking at the leak rate, determining whether it was constant throughout the burn, what - precisely what the situation is. We're showing pressure in tank B of 1,960 psi [13.5 MPa]. In tank A 2,250 psi [15.5 MPa]. Both of these are well above the red lines of 400 pounds psi [2.8 MPa].
From the 1969 Mission Report (page 16-1): "During the lunar orbit insertion firing, the gaseous nitrogen in the redundant service propulsion engine actuation system decayed from 2307 to 1883 psia (see fig. 16-1), indicating a leak downstream of the injector pre-valve. The normal pressure decay as experienced by the primary system is approximately 50 psia for each firing. Only the one system was affected, and no performance degradation resulted. This actuation system was used during the TransEarth Injection firing, and no leakage was detected.
Mission Report: (continued) "The fuel and oxidizer valves are controlled by actuators driven by nitrogen pressure. When power is applied to the service propulsion system in preparation for a maneuver, the injector pre-valve is opened; however, pressure is not applied to the actuators because the solenoid control valves are closed. When the engine is commanded on, the solenoid control valves are opened, pressure is applied to the actuator, and the rack on the actuator shaft drives a pinion gear to open the fuel and oxidizer valves. When the engine is commanded off, the solenoid control valve vents the actuator and closes the fuel and oxidizer valves.
Mission Report: (continued) "The most likely cause of the problem was contamination in one of the components downstream of the injector pre-valve, which isolates the nitrogen supply during nonfiring periods. The injector pre-valve was not considered a problem source because it was opened 2 minutes before ignition and no leakage occurred during that period. The possibility that the L regulator and relief valve were leaking was also eliminated since pressure was applied to these components when the pre-valve was opened.
Mission Report: (continued) "The solenoid control valves have a history of leakage, which has occurred either because of improper internal air gap adjustment or because of seal damage caused by contamination. The air gap adjustment could not have caused the leakage because an improper air gap with the pre-valves open would have caused the leak to remain constant. Both of the solenoid control valves in the leaking system had been found to be contaminated before flight and were removed from the system, rebuilt, and successfully retested during the acceptance test cycle.
Mission Report: (continued) "It is concluded that the leakage was due to a contamination-induced failure of a solenoid control valve. The source of contamination is unknown; however, it was apparently removed from the sealing surface during the valve closure for the first lunar orbit insertion maneuver (fig. 16-2). A highly suspect source is a contaminated facility manifold at the vendor's plant. Although an investigation of the prior failure indicated the flight valve was not contaminated, the facility manifold is still considered a possible source of the contaminants."
077:41:15 Collins (onboard): That's why I'm trying to get it out.
077:42:16 Armstrong (onboard): No alignment this rev, huh?
077:43:02 Aldrin (onboard): Mike, I guess the name of the game is to go back to - B Omni?
077:43:10 Collins (onboard): Huh?
077:43:12 Aldrin (onboard): Go back to B in Omni?
077:43:17 Collins (onboard): Well, let's see - when we come over the hill next time, we're supposed to have them on the High Gain, I think.
077:43:25 Armstrong (onboard): Not sure of that.
077:43:29 Collins (onboard): [Garble].
077:43:31 Aldrin (onboard): Did you use this thing?
077:43:33 Armstrong (onboard): No.
077:43:34 Aldrin (onboard): Well, let's get rid of it then. I can't see a crapping [garble].
This appears to refer to the monocular.
077:44:26 Aldrin (onboard): 77:44 - okay - LOS is right on schedule.
077:44:35 Collins (onboard): 77:50, we'll be at the prime meridian. Now, I can set that map up so it'll tell us where we are.
077:44:43 Armstrong (onboard): Okay.
077:44:45 Aldrin (onboard): We - we're ahead on this eat period - we're behind on the last eat period or something. We got a [garble].
077:45:15 Collins (onboard): I think, Buzz, if you put - put the High Gain to Manual and go pitch 20 - yaw 360 - pitch minus 20, I guess...
077:45:26 Aldrin (onboard): Minus 20; yes, that would be better.
077:45:28 Collins (onboard): ...and yaw 360...
077:45:29 Collins (onboard): That's okay assuming I'm at the right attitude, but I ain't going to be at the right attitude - not without wasting a lot of gas. Put...
077:45:36 Aldrin (onboard): That's fine, but...
077:45:42 Armstrong (onboard): If you did, it would be very interesting that way.
077:45:46 Aldrin (onboard): Yep. Oh, crap.
077:45:55 Aldrin (onboard): We get High Gain and we get TV at the same time...
The high bandwidth of the TV signal demands that a radio link to Earth with a low signal to noise ratio be established. At lunar distance, Apollo can only achieve this using the High Gain Antenna. Being mounted on one side of the Service Module at its base, the HGA has a limited range of articulation of about a hemisphere. It can't work through the body of the spacecraft so their attitude must be such to have Earth within that hemisphere. Since the HGA is on the opposite side of the CSM from the windows, then if it can see Earth, the windows are likely to be facing the Moon.
077:45:58 Collins (onboard): Well, I better start maneuvering then. Doggone it, I've been yawed out of plane somehow. Let's see, we're pitched down - we want to pitch back up - pitched down, doggone it. Accel Command, pitch down.
077:46:17 Armstrong (onboard): Okay, well - are we going to unlock the camera store and get all that claptrap put together?
077:46:23 Aldrin (onboard): Yep.
077:46:24 Armstrong (onboard): Okay.
077:46:42 Aldrin (onboard): Which window you want to operate out of, so I can figure out how to put the monitor on?
077:46:48 Armstrong (onboard): Well, I suppose the best one would be the center window, don't you think?
077:46:57 Aldrin (onboard): Probably, I don't know; wait until we get into attitude.
077:47:01 Armstrong (onboard): Get into attitude - see what we think.
One could get the impression that the crew are not overly keen on the upcoming TV show.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
This is Apollo Control, Houston at 77 hours, 48 minutes now into the flight of Apollo 11. Here in Mission Control Center, Houston, we're in the process of changing shifts. Cliff Charlesworth Green Team of flight controllers very shortly will be leaving their consoles. Meanwhile Apollo 11 passing over the far side of the Moon, out of acquisition. Our last orbital parameter readings on our flight dynamics orbital digital displays indicated an apogee of 168.5 nautical miles [312.1 km], a perilune of 1 - correction, perilune of 61.2 nautical miles [113.3 km]. We're currently planning a change-of-shift briefing at approximately 2:30 Central Daylight Time or as soon thereafter as is practicable. The change-of-shift briefing will include only Flight Director Cliff Charlesworth. It's expected to be of short duration since we will have a TV pass soon after reacquisition of the spacecraft. At 77 hours, 50 minutes into the flight of Apollo 11; this is Apollo Control, Houston.
077:48:19 Collins (onboard): Oh, shit! This pitch here is no good. 32, huh? Pitch 315 I want to be at, huh? Alright. They keep - all they do is they say Orb-rate and that little attitude right there and right there applies to the rest of this page, all of that page, and over to this page.
077:48:46 Armstrong (onboard): Okay, so that's the one we'll do.
077:48:50 Collins (onboard): Okay, that's the way I'm rolling.
077:48:51 Armstrong (onboard): And we'll take the - we'll have High Gain...
077:48:54 Collins (onboard): Yep.
077:48:55 Armstrong (onboard): ...and we'll get the camera out of the center window, if that looks reasonable.
077:49:02 Collins (onboard): Okay.
077:49:06 Armstrong (onboard): We'll have to give them pictures of the Moon.
077:49:07 Collins (onboard): [Garble]. I've been plotting on them [garble]. 50:05.
077:49:14 Collins (onboard): We'll have a gauge as to where we are.
077:49:22 Collins (onboard): 55...
As intimated earlier, they should be passing over the 150°W meridian at 077:50:05. This is roughly coincident with the eastern rim of the large (437-km diameter) walled plain, Korolev and is nearly antipodal to the Apollo 11 landing site. This meridian is also very near the current sunset terminator, just as the landing site is reaching the sunrise terminator.
077:50:35 Aldrin (onboard): Outside, huh? Alright, the switch is set for outside.
077:50:41 Collins (onboard): Could I have that map that y'all were looking at before, that lunar map? Thank you.
077:51:03 Armstrong (onboard): Hmmm - here comes the Moon.
077:51:16 Aldrin (onboard): Really beautiful.
077:51:29 Armstrong (onboard): Hey, you...
077:51:30 Collins (onboard): I wonder where we are.
077:51:31 Armstrong (onboard): ...we're going to stop here pretty soon, right?
This is Apollo Control, Houston; at 78 hours, 18 minutes now into the flight of Apollo 11. Apollo 11 still passing around the far side of the Moon. We're less than 5 minutes now away from time of acquisition on this, this second revolution for Apollo 11. The station to acquire on this pass will be the Goldstone wing site which will feed the television to Mission Control Center, Houston, and thence to all parts of the country. We would expect to come up with television perhaps some several minutes after acquisition since we must first lock up on the downlink and have the scan converter in full operation. So at 78 hours, 19 minutes continuing to monitor; this is Apollo Control, Houston.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
Mark. 2 minutes now from time of predicted acquisition in Mission Control Center. We're standing by.
078:22:10 Armstrong (onboard): ...and you could be busy getting up supplies if you...
078:22:16 Collins (onboard): About a minute from AOS.
078:22:19 Aldrin (onboard): Okay, let's get out of this. Let me get Verb 62. Okay, Mike?
Verb 62 will display the total attitude error. This is essentially the difference between their present attitude and the attitude that they want to get to.
078:22:22 Collins (onboard): Oh, I really need these [garble], Buzz. I really need these goddam [garble].
078:22:26 Aldrin (onboard): Well, we're not going to have much of a TV unless we get High Gain.
078:22:30 Collins (onboard): Alright.
Mark. 1 minute now from time of predicted acquisition. Continuing to stand by in Mission Control Center, Houston.
078:22:32 Aldrin (onboard): I'll give it back to you - [garble].
078:22:50 Armstrong (onboard): You got yourself some rates going about, like, what you want?
078:22:55 Aldrin (onboard): You got - you got High Gain right now, I mean the angles, right now.
078:23:00 Collins (onboard): And we're 23 - we're 30 seconds from AOS, so those angles should be okay. You reading them?
078:23:08 Armstrong (onboard): Minus 30 pitch...
078:23:10 Collins (onboard): Yes.
078:23:11 Armstrong (onboard): ...150 yaw, okay.
078:23:12 Aldrin (onboard): No, that's not 150 - that's 15. Isn't it?
078:23:14 Armstrong (onboard): Just a second. Yes, minus - I'm sorry, minus 31 and plus 15. Right. You got it?
078:23:27 Collins (onboard): Yes.
Mark. 10 seconds away now. Standing by for acquisition. We've - we've had AOS by Goldstone. Television is now on. That's Bruce McCandless, our Cap...
078:23:34 Armstrong (onboard): I don't know what f-stop I ought to be at. Well - see what it's doing, Mike?
078:23:42 Collins (onboard): [Garble].
078:23:44 Armstrong (onboard): The flicker I don't know about, the white dot is...
078:23:47 Aldrin (onboard): Yes, the flicker...
078:23:48 Armstrong (onboard): ...the flicker is what I'm - Nothing I can...
078:23:50 Collins (onboard): Okay, we got it solid.
078:23:52 Armstrong (onboard): ...nothing you can do about the flicker?
The colour wheel in front of the TV camera's imaging tube means that each TV field (60 per second) is a sequential analysis of the scene in red, blue then green; in that order. If the scene contains areas of colour, those will appear to have a 20 Hz flicker and this may be what Neil is referring to. It is not until the signal gets to Earth that it gets converted to a standard colour television signal.
TV transmission from the spacecraft begins at 078:23:55, very soon after AOS. The landscape is lit by a near vertical Sun so only albedo details are visible. There is almost no sense of the landscape's topography.
078:23:55 McCandless: Apollo 11, this is Houston. Over.
078:23:55 Collins (onboard): Got it solid on Auto.
078:24:09 Aldrin: Houston, Apollo 11. Are you picking up our signals okay?
078:24:11 McCandless: Apollo 11, this is Houston. Affirmative. We're reading you loud and clear on voice and we have a good clear TV picture, a little bright crater in the...
078:24:23 Aldrin: ...No, no, no. That's...
078:24:24 McCandless: ...the bottom of the picture. I guess that's the spot on the tube.
078:24:30 Aldrin: I'm sorry about that one.
The TV camera is looking to the south side of their path as they travel east to west. Two distinctive craters are visible at the bootom of the screen at this time, Saha J to the left and Saha N to the right
078:24:33 McCandless: And if you could give us P00 and Accept, we'll uplink a new state vector and target load to you.
078:24:45 Collins: Okay. [Long pause.]
Mission Control will upload the following into the computer's erasable memory: a revised state vector based on the most recent tracking as the spacecraft passed across the Moon's near side on the previous orbit; details of what the upcoming LOI-2 burn should be aiming for in terms of Delta V.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
078:25:30 Aldrin: Houston, Apollo 11. One of the larger craters on the back side - I noticed a small, dark speck on the outer wall, and putting the monocular on it, I was able to see - oh, an area maybe a quarter of a mile in diameter. It was really a fresh looking dark-colored pit, and that seems to be in contrast with all the other fresh little craters or holes that you can perceive on the walls of any of these craters. Around this particular one there seems to be two or three of these - especially the one that caught my attention. Quite remarkable. Over.
078:26:24 McCandless: Roger. Do you have a location on that one? [Pause.]
078:26:34 Aldrin: No, not a precise one. I've got several pictures of it, though.
078:26:38 McCandless: Roger. We copy. [Pause.]
This - That was Buzz Aldrin making a report, geological report on back-side pass.
078:26:47 McCandless: We're getting a beautiful picture in down there now, 11. The color's coming in quite clearly, and we can see the horizon and the relative blackness of space, and without getting into the question of grays and browns, it looks, at least on our monitor, sort of a brownish-gray.
The TV camera is zoomed in on a light spot in the distance. This is a small, fresh impact crater on the eastern rim of Hirayama M.
078:27:10 Aldrin: That's a good, reasonable way of describing it. It appears to me as though it made a difference just sitting back in the tunnel and gazing at all windows; it makes a difference which one you're looking out of. For example, the camera right now is looking out the number 5 window, and it definitely gives a rosier or tanner tinge, especially when you look straight through it and not at an angle. Over.
078:27:45 McCandless: Roger.
The camera zooms out to reveal Hirayama Y in the central foreground and the smaller, brighter Hirayama T to the right.
At this point in the air-ground recording, the Flight Director's microphone finds its way onto the recorded audio.
078:27:53 Flight: GNC, Flight. [Under Aldrin] Okay, your tank - nitrogen tank [garble] is okay? Still holding?
078:27:53 Collins: Oh, we're about 95 or 100 degrees east. Coming up on Smyth's Sea.
078:27:54 Flight: Okay.
078:28:02 McCandless: Say again, 11?
078:28:07 Collins: I'd say again we're about 95 degrees east, coming up on Smyth's Sea.
078:28:11 McCandless: Roger. And for your information, we show you at an altitude of about...
078:28:15 Aldrin: Houston...
McCandless (continued): ...92 miles [170 km] above the surface right now.
078:28:21 Aldrin: Okay.
Mare Smythii appear on the right of the TV coverage as a darker landscape.
078:28:22 Aldrin: Houston, Apollo 11. Did you observe a difference in the N2 pressures before LOI? It seems to me as though the two were not equal on the [garble]...
078:28:33 Flight: Standby.
Aldrin (continued): ...B tank was a lower pressure. Over. [Long pause.]
078:28:40 Flight: Yeah, I think that's right. Ah...
078:28:57 Collins: I'm flying it in SCS minimum impulse, Houston, and it's rather difficult to keep it on a constant theta. The LM wants to wander up and down. I'm not sure if it's in response to mascons or what, but I can get it completely stabilized in theta and let it alone, and in another couple of minutes it will have developed its own rate.
Mike is flying the stack in 'orb-rate' so that the windows stay facing the Moon as they go around. In this mode, the angle between the spacecraft and the flight path is called 'theta' and is similar in concept to an aircraft's pitch angle. However, there is a phenomenon called gravity gradient stabilisation whereby a spacecraft with an uneven mass distribution (the CSM and LM being a pretty good example) will eventually align itself with its long axis radial to the planet it is orbiting.
Mascons are areas on the Moon where there is a mass concentration. These are high density areas below the surface, often beneath lunar maria, which perturb the flight path of orbiting spacecraft. In this case, they have nothing to do with what Mike is experiencing.
078:29:22 McCandless: This is Houston. Roger.
That was Mike Collins making that report.
In this part of the TV coverage, the dark circle within Mare Smythii is crater Warner, named after Worcester Reed Warner (1846-1929), an American astronomer, engineer and businessman.
078:29:30 Aldrin: Houston, we'll be moving shortly from the side window to the hatch window, and we'll try and pick up some of the landmarks that we'll be looking at as we approach powered descent. Over.
078:29:47 McCandless: 11, this is Houston. Roger. And we're through with the uplink; the computer is yours. You can go to Block and we'll have the information on nitrogen for you shortly. Over.
078:30:01 Aldrin: Roger. Copy. [Pause.]
The camera is now zoomed into Hirayama T with its bright inner slopes.
078:30:08 Collins: Okay, Houston. Several minutes ago I was exactly steady on theta, and since then I have been moving toward the LM, pointed straight down toward the radius vector, and that's been despite a number of down minimum-pitch impulses.
078:30:30 McCandless: Roger. [Long pause.]
The next target for the TV camera is Gibbs, a prominent 76-km crater near the horizon whose north rim is particularly bright owing to the ray system of a small crater that formed there.
078:30:49 Collins: We're over Smyth's Sea right now.
078:30:51 McCandless: Roger.
078:30:56 Collins: We're about 88 degrees east, I would estimate.
078:31:04 McCandless: We show you about south of the - southwest of the crater Jansky right now. [Long pause.]
The TV camera zooms into a distinctive, bright, 28-km crater on the southern margin of Mare Smythii. Though it is unnamed, it lies adjacent to the northeastern rim of Crater Kiess.
078:31:28 Collins: Smyth Sea doesn't look very much like a sea. It - The area which is devoid of craters, of which there's not very much, is sort of a hilly looking area. It's not like the maria at all.
078:31:41 McCandless: Roger. We copy that about the sea, and it looks like you were just giving us a view of the crater Neper, the large crater on the left, and Jansky on the right. [Long pause.]
That exchange between CapCom Bruce McCandless and Mike Collins aboard the Apollo 11 spacecraft.
Neper and Jansky are craters north of Mare Smythii. McCandless has not realised that the camera is looking south.
078:32:06 Collins: We think you're close, but no cigar.
Comm break.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
Apollo Control, Houston. We acquired TV at 78 hours, 24 minutes, 11 seconds. Currently our orbital parameters show 104 altitude [193 km] - an apolune of 170.2 [315.2 km], a perilune of 61.3 [113.5 km] - nautical miles, those are.
TV transmission from the spacecraft continues in this clip starting at about 078:33:00. As the spacecraft comes further around the Moon, the lighting gradually lowers its angle, bringing out some of the landscape's topography.
078:33:20 McCandless: 11, this is Houston. Would you care to comment on some of these craters as we go by?
The TV camera is looking back in an easterly direction and zooms into the crater Haldane, a 38-km fractured-floor crater with Mare Smythii. The crater has an inner semicircular feature that, at this high sun-angle, gives it a distinctive double-walled look.
078:33:29 Armstrong: Roger. We're approaching the approach path to ignition. This is equivalent to 13 minutes before ignition, and we're at about 80 degrees east, I guess - 83 degrees east. [To crewmate] That correspond to the location you're holding there presently?
078:33:59 McCandless: Roger. We're showing your present position as about 77 - 76 degrees east looking back towards the east. [Pause.]
078:34:16 Collins: Hey, you should be looking back at Smyth Sea now.
078:34:19 McCandless: Roger.
The camera has settled on two craters on the northwest margin of Mare Smythii. On the left is Schubert (54 km) and to its right is Back (35 km, formerly Gilbert U). Note that Schubert is not named after the music composer but after an astronomer who lived around the turn of the 19th century.
We've now heard from all three Apollo 11 crewmembers during this television pass. The individual talking earlier was Neil Armstrong.
078:34:23 Armstrong: Okay.
078:34:25 Aldrin: Houston, what you're seeing in the middle of the screen now is the crater Schubert and Gilbert U is in the center right now; and this comes up at about - a little over 12 minutes before powered descent. Instead of me looking - Instead of looking back at it, we'd be looking straight down at that time.
078:34:50 McCandless: Roger.
078:34:55 McCandless: And we show you at an altitude now of about 110 [nautical] miles [204 km]. And, of course, you'll be considerably lower at the initiation of powered descent. [Long pause.]
When the LM comes in towards its landing, it will be in an orbit that is about 110 kilometres or 60 nautical miles in altitude around the far side of the Moon, the same as the current stack. However it will be heading down to only about 15 km or 8.5 nm altitude above Mount Marilyn. At the moment the stack's nearside altitude is 313 km (169 nm) and it is climbing towards that high point.
078:35:18 Collins: Okay, Houston. Look at register 3 on the DSKY data. This data is increasing toward my desired of 315; and I'll let the hand controller alone here, and I'll bet you it reverses itself. [Long pause.]
078:35:46 McCandless: Roger, 11. We're watching the DSKY now, and it's still coming in beautifully on the TV. [Pause.]
078:35:59 Armstrong: Okay. There's - on the right side of the screen at the present time, there's a triple crater with - with a small crater between the first and second; and the one at the bottom of the screen is Schubert Y. [Long pause.] Zoom in - it does have a central peak in Schubert Y. Actually, several of them, and you can observe those, plus the rim craters at the bottom of your screen.
The crater that the camera zooms into, which Neil calls Schubert Y, is now called Nobih.
078:36:36 McCandless: Roger. We're seeing the central peak quite clearly now. [Long pause.]
078:36:53 Armstrong: Okay. We're zooming in now on a crater called Schubert N. Schubert N, very conical inside walls and the bottom appears to be nearly flat.
This crater is now called Liouville (16 km diameter).
078:37:11 Collins: Look at data on the DSKY. It's stabilized and is holding steady now.
078:37:19 McCandless: Roger.
078:37:20 Armstrong: Looking out the window I can see a number of small craters on the bottom of Schubert N.
078:37:32 Collins: We're coming up on the Foaming Sea where I'll be doing some P22 marking on a crater of my choice; name of crater, KAMP.
Crater KAMP is not a formal lunar feature name. Rather, it was named by Mike similar to how Jim Lovell named a peak near the crater Secchi as Mount Marilyn. Mike will use KAMP as a navigational landmark at around 082:37:04. KAMP honours Mike's family, being the initials of his three children and his wife: Kate, Ann, Michael and Patricia. The Foaming Sea, Mare Spumans, is on the eastern limb of the Moon as viewed from Earth.
078:37:41 McCandless: Okay. We'll be watching for KAMP.
078:37:49 Collins: And notice register 3 has reversed itself, and it's heading back the other way now without any pitch thruster firing.
078:37:56 McCandless: Roger, Mike. We confirm that you've changed the direction of your pitch rate. [Long pause.]
078:38:28 Collins: Generally speaking the...
078:38:30 Aldrin: The crater...
078:38:31 Collins: ...The tendency seems to be to pull the LM down toward the center of the Moon as in a gravity gradient experiment.
078:38:40 McCandless: Roger, 11. We copy...
078:38:43 Collins: It may have something to do with mascons or it may...
078:38:46 McCandless: Roger. We copy...
078:38:47 Aldrin: [Garble.]
078:38:48 Collins: It may have something to do with Mascons or it may just be the peculiarity of the DSKY display.
078:38:51 McCandless: Okay. We've observed the behavior of your DSKY, and I think we've got the data here to work on it. Let us grind around a little while on it, and we'll report back to you, probably in a rev or two.
078:39:08 Collins: Okay. Well, in the meantime, I'm going to pitch down toward 315.
078:39:14 McCandless: Roger. [Pause.]
078:39:25 Armstrong: Three craters - three horizontal craters that you now have in the field of view are immediately underneath the ground track. The right-hand, and the largest crater that you see, is Dubiago P. [Pause.]
Also in the TV frame at this time is Dubiago Q on the left. The conical crater between them is unnamed. The western side of Mare Spumans is across the bottom of the frame.
078:39:49 McCandless: Roger. We concur on the identification of that crater. [Pause.]
078:40:01 McCandless: And we show you coming up on landmark Alpha 1 here shortly.
078:40:11 Armstrong: Roger. Mike's having his first look at Alpha 1 at the present time. [Pause.]
078:40:22 Collins: Yeah. It's a great bright crater. It's not a large one but an extremely bright one. It looks like a very recent and, I would guess, impact crater with rays streaming out in all directions which should make my... Correction - the Foaming Sea easy to see coming up on it now. Crater KAMP is one of the smaller ones out on the - on the floor of the Foaming Sea. [Long pause.]
We've been some 17 minutes now into this television pass and standing by, continuing to monitor.
078:41:34 McCandless: Here we show you over the Sea of Fertility now, and we ought to have Langrenus down south of track a few degrees, about 9 degrees south of track.
078:41:48 Aldrin: Now the crater that's in the center of the screen now is Webb. We'd be looking straight down on it at about 6 minutes before powered descent. It has a relatively flat bottom to the crater, and you can see maybe two or three craters that are in the bottom of it. On the western wall, the wall that's now nearest to the - the camera, near the bottom of the screen, we can see a dimple crater, just on the outside. And then coming back toward the bottom of the screen and to the left, you can see a series of depressions. It's this type of connected craters that give us most interest to discover why they're in the particular pattern that they're in. I'll zoom the camera in and try and give you a closer look at this.
078:42:48 McCandless: Roger. We're observing the dimple crater now. The central peak we can see on the Orbiter photos doesn't seem to stand out very well here.
078:43:02 Aldrin: Well, they're not central peaks. They're depressions in the center.
078:43:05 McCandless: Roger.
Crater Webb, and to its left, the series of depressions or 'connected craters' mentioned by Buzz. Image from data gathered by Lunar Reconnaissance Orbiter.
Most crater chains on the Moon are thought to be formed from one of two mechanism. In one type, a lava tube below the surface has collapsed along its length. These are usually characterised by the chain following the sinusoidal route of the tube. The other type is from the sequential impacts of a series of objects that once were bound together but were pulled apart by tidal forces when passing a large body, probably Earth, prior to hitting the Moon.
078:43:08 Collins: And you'll notice on the pitch thruster activity, I've still - I've put in, oh, a dozen minimum impulses in pitch down, and I'm still far from correcting back to 315.
078:43:20 Aldrin: We're moving the camera over to the right window now to give you Langrenus, its - its several central peaks and...
078:43:29 McCandless: Roger. We got Langrenus in our screen now. [Long pause.]
Langrenus (132 km) is a large and quite spectacular crater on the southeast margin of Mare Fecunditatis, Among its major features are a heavily terraced rim and central peaks up to 1-km tall.
078:43:54 McCandless: Okay, 11. This is Houston. We're getting a beautiful picture of Langrenus now with its rather conspicuous central peak.
078:44:07 Collins: The Sea of Fertility doesn't look very fertile to me. I don't know who named it.
078:44:12 Armstrong: Well, it may have been named by a gentleman whom this crater was named after, Langrenus. Langrenus was a cartographer to the King of Spain and made one of the - one of the early reasonably accurate maps of the Moon.
To flesh Neil's story out a little more, although Michael Florent van Langren, a 17th century Flemish astronomer and cartographer, was one of the first telescopic mappers of the Moon, almost every name he gave to its surface features failed to stick. Much of the Moon's major nomenclature, including Mare Fecunditatis (Sea of Fertility), is attributed to Giovanni Riccioli and only one name has survived from Van Langren's map, the self-named major crater Langrenus.
078:44:39 McCandless: Roger. That's very interesting...
078:44:41 Collins: I'll have to admit it sounds better for our purposes than the Sea of Crises.
078:44:46 McCandless: Amen to that.
078:44:52 McCandless: Okay. It looks like you're coming inside now on the camera.
078:44:59 Aldrin: Well, I can't get behind to see the monitor. I'll bring the focus in, but we're going to be looking down past one of the LM quads and one of the antennas, almost straight down at the ground track that we'll be seeing coming in now. I guess this is maybe 2 or 3 minutes before powered descent. [Long pause.]
078:45:37 Aldrin: Alright, that should put the LM structure about in focus, and I'm going to move it out to infinity and then expand the field of view. [Long pause.]
078:46:00 Collins: Crater Secchi is out my window now, window number 2. [Pause.]
078:46:09 McCandless: Apollo 11. This is Houston. We show you coming up on the terminator at 78:53, about 7 minutes from now, and we've also got the LOI-2 and TEI-5 PADs ready for you after the TV, whenever you want to terminate. Over.
078:46:31 Armstrong: Roger.
078:46:33 McCandless: And we're getting a good view of the track leading into the landing site now. [Long pause.]
The Secchi Rilles on the western margin of Mare Fecunditatis come into view
078:46:58 McCandless: Okay. And it looks like we got Secchi K, went by about 10 seconds ago. Coming up on Apollo Ridge. [Long pause.]
078:47:36 McCandless: And in the right-hand portion of our screen right now, we can see Messier Alpha and Bravo with the light-colored rays streaming off in one direction. [Long pause.]
The two Messier craters mentioned by McCandless are now known as Messier (for the elongate eastern crater) and Messier A.
The two Messier craters, Messier on the right and Messier A with the two rays emanating from it on the left. Image from data gathered by Lunar Reconnaissance Orbiter.
078:48:00 Collins: I don't know if you can make out, but in the Sea of Fertility there are a number of craters that are just barely discernible. Old, old craters whose outlines are just barely able to be seen.
078:48:14 McCandless: Roger. I think we can make them out. The color really enhances our ability to discern features and craters over what we see in real time on our black and white monitor.
The TV pictures do not show these structures well. They may be craters that are completely submerged under the lavas that form Mare Fecunditatis and which are now only visible by their rims encouraging the formation of wrinkle ridges around their outline. There are two of them that lie on the south side of the Messier rays.
078:48:31 Collins: Right. The - At these low Sun angles, there's no trace of brown, it's now returned to a very gray appearance and, like the 8 crew said, it has a look of plaster of Paris to it at this Sun angle, which is completely lacking at higher Sun angles.
078:48:49 McCandless: Roger. [Long pause.]
The camera's view has now settled on the range of mountains known as Montes Secchi, including Mount Marilyn to which the camera zooming in.
We're now some 25 minutes into our television pass.
078:49:06 Armstrong: Okay. This is very close to ignition point for powered descent. Just passing Mount Marilyn that - that triangular-shaped mountain that you see in the center of the screen at the present time with crater Secchi Theta on top of the far northern edge of the mountain.
078:49:32 McCandless: Roger. We're getting a good view of Mount Marilyn and of Secchi Theta. [Pause.]
TV transmission from the spacecraft continues in this clip starting at about 078:49:32 when the crew are zoomed into Mount Marilyn at the southeast corner of Mare Tranquillitatis. Coverage will continue across the mare until they reach the terminator with its low-angle illumination.
078:49:45 Armstrong: And now we're looking at what we call Boot Hill; occurs 20 seconds into the descent. [Long pause.]
Neil is somewhat confused when calling this feature Boot Hill. It does, however, seem to be in the right place to be a 20-second position check. In just over three minutes, at 078:52:58, Neil will correctly use the name for a feature now generally recognised as Boot Hill.
Watching this pass with a great deal of interest in Mission Control Center is Pete Conrad, the commander for the Apollo 12 mission.
078:50:08 Armstrong: The bright, sharp-rimmed crater at the very right edge of the screen, Censorinus T. [Pause.] Now passing the - the 1-minute point in powered descent.
078:50:30 McCandless: Roger. And for your information, your current altitude is 148 nautical miles [274 km] above the surface. [Pause.]
078:50:52 Armstrong: [Garble].
078:50:43 Collins: I'm unable to determine altitude at all looking out the window. I couldn't tell whether we were down at 60 or up at 170 [111, 315 km resp.].
078:50:50 McCandless: I bet you could tell if you were down at 50,000 feet.
078:50:57 Collins: I wouldn't be surprised. [Long pause.]
078:51:11 Armstrong: We're passing some steep ridges here, the edges of old craters that were photographed by Apollo 10. And those - the crew of Apollo 10 was very impressed with the steepness of these ridges when they came over them at about 50,000 feet.
078:51:36 McCandless: Roger. We can observe they're also steep even from this altitude. You got quite a shadow being cast by the Sun at these low angles.
078:51:47 Armstrong: The entire surface is getting considerably darker than the surface that we looked at previously when the Sun was quite high above us. The crater in the - bright crater in the center of the screen, - well, the smaller one is Censorinus.
Censorinus is notable because, despite having a major name, it is very small at only 3 kilometres diameter. What makes it stand out is the bright ray system that surrounds it, indicating that it is a relatively young.
The 3-km bright ray crater, Censorinus. Image from data gathered by Lunar Reconnaissance Orbiter.
Nearly all of the nearby craters that take their name from it are larger. For example the previously mentioned Censorinus T at 5 km and the adjacent Censorinus A at 7 km. Only Censorinus U is a small.
078:52:09 McCandless: Roger. And we show you a little over 1 minute from the terminator at the present time. [Long pause.]
078:52:24 Aldrin: How's the brightness of the picture you're receiving? You think we ought to open up the f-stop some as we approach the terminator?
078:52:34 McCandless: Yeah. The brightness is still doing quite well. You can go ahead and open it up a stop or two. The automatic light level compensation seems to be working beautifully. [Long pause.]
078:52:58 Armstrong: There's a good picture of Boot Hill.
078:53:02 McCandless: Roger. We're...
078:53:03 Armstrong: Three minutes and 15 seconds into the descent.
078:53:08 McCandless: Roger. We're seeing Boot Hill now.
Neil correctly names this boot-shaped feature as Boot Hill. It sits near to another low hill that the astronauts have named Duke Island. The CapCom for tomorrow's landing attempt will be astronaut Charlie Duke.
078:53:10 Armstrong: And the next crater coming into the bottom, that's Duke Island right there, and to the left, the crater - the largest of the craters near the center of the picture right now is Maskelyne W. This is a position check during descent at about 3 minutes and 39 seconds, and it's our downrange position check and cross-range position check prior to yawing over face-up to acquire the landing radar. Past this point, we would be unable to see the surface below us until getting very near the landing area.
078:53:57 McCandless: Roger. I imagine you get a - you'll get a real good look at that tomorrow afternoon. [Pause.]
The Apollo 11 landing attempt is unique among the Apollo landings because the initial part of the descent was flown with the windows facing the surface. This gave Neil the opportunity to check the descent trajectory by noting the time when they would pass landmarks and compare them to prediction. In the event, he would determine that the descent had begun late and that they would overshoot their planned site. After a few minutes, he would rotate the LM to a windows-up attitude. Subsequent missions dispensed with this check. Alternative means had been found to ensure the accuracy of a landing.
078:54:14 Armstrong: Sinuous Rille is the one that was referred to in Apollo 10 as Sidewinder.
078:54:21 Collins: That's a good name, too: Sidewinder and Diamondback. It looks like a couple of snakes down there in a lake bed. [Long pause.]
078:54:42 Armstrong: And we're approaching the terminator now. See the...
078:54:48 McCandless: Roger.
078:54:49 Armstrong: ...contrast has increased and only the sunlit side of these ridges remain illuminated, while the dark sides and the shadow will become completely black.
078:54:59 McCandless: 11, this is Houston. The picture's getting a little grainy now. You might go ahead and open up the f-stop. [Long pause.]
078:55:19 Collins: Landing point is just barely in the darkness. That one crater, the upper part of which you see, lower part completely in darkness - the small, well-defined crater is Moltke, which is about abeam of the landing site.
078:55:32 McCandless: Roger. We can just see - it looks like a little less than half of its rim right now. [Pause.]
078:55:45 McCandless: And we can make out, just barely, some features on the surface, maybe from Earthshine. [Pause.]
078:55:58 McCandless: Are you wide open on the f-stop at this time?
078:56:03 Collins/Aldrin: Affirmative, we are.
078:56:06 Aldrin: Yeah. And it looks like we're just about to get the Sun coming into the lens, so we'll have to move the camera away.
078:56:12 McCandless: Roger.
078:56:14 Collins: We can't see any Earthshine or any surface features at all in Earthshine now, due to the fact that the LM is very bright and is causing our pupils to contract.
The camera's view goes to look towards the horizon where the very low sun angle brings out the topography of teh surface in dramatic tones.
078:56:25 Aldrin: It's a very fantastic view to see the terminator as you look along the edge of it. I think you'll agree that some of these craters that you're seeing in the picture now are really accentuated by the lengthening of the shadows as they approach the terminator.
078:56:42 McCandless: Yes. It's a very beautiful and a rugged sight that we've got on the screen now. [Pause.]
078:56:52 Collins: And I think you've got some interesting data on thruster firings versus pitch angle. It looks like that LM just wants to head down towards the surface, is all.
078:57:01 McCandless: Roger. I have a comment here that says that's what the LM was built for.
078:57:12 Collins: I believe! [Long pause.]
078:57:45 Aldrin: And as the Moon sinks slowly in the west, Apollo 11 bids good day to you.
The TV transmission comes to an end.
078:57:50 McCandless: Roger. We sort of thought it was the Sun setting in the east.
There you have it. Our first glimpse of the lunar surface during the Apollo 11 mission. The eleven crew took us on a guided tour of the front side, plus talked their way through the powered descent that lies ahead in tomorrow's activities. At 78 hours, 58 minutes into the flight of Apollo 11; this is Apollo Control, Houston, continuing to monitor.
078:58:00 Collins: Well, it depends on your point of view.
078:58:04 McCandless: Roger. Out.
078:58:20 McCandless: Apollo 11, Houston. When you're ready to copy, I have an LOI-2 PAD and a TEI-5 PAD. Over.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
078:58:58 McCandless: Roger on the inertial. And here we go on the LOI-2 PAD. LOI-2, SPS/G&N: 38320, plus 1.66, minus 0.81; TIG 080:11:36.03. Noun 81; minus 0140.8, minus all balls, minus 0074.3. Roll, all balls, 196, 359; 0065.7, plus 0053.7. Delta-VT; 0159.2, 0:17, 0153.1. Sextant star; 23, 116.0, 13.8. The rest of the PAD is NA. GDC align; Vega and Deneb, 243, 183, 012. Ullage; two jets, 19 seconds. Remarks: On your DAP load, we would like in R1, 20101 vice the value which appears in the Flight Plan. In making the sextant star check, this must be done between GET of 79:30:10, at which time the star comes above the horizon, and 79:52:10, which is your local sunrise due to the fact that this star is relatively close to the Sun. Your burn orientation is heads down, retrograde, pitched up 28 degrees with respect to local horizontal. The calculated values for Noun 42 are HA 65.6 and HP 54.6, both of those being plus. Read back. Over.
079:01:55 Aldrin: Roger, LOI-2: SPS/G&N: 38320, plus 1.66, minus 0.81; 080:11:36.03; minus 0140.8, minus all balls, minus 0074.3. All zeros, 196, 359; 0065.7, plus 0053.7; 0159.2, 0:17, 0153.1; 23, 116.0, 13.8. Vega, Deneb, 243, 183, 012; two jet, 19 seconds. DAP; R1, 20101. Sextant star between 79:30:10 and 79:52:10. Attitude is heads down, retrograde pitched up 28 degrees. HA after the burn - Was that Noun 42 for HA and 64.6 and HP 54.6? Over.
079:03:19 McCandless: Roger. On the Noun 42 value, the last stuff you gave, HA is 65.6, HP is 54.6. Otherwise, I readback correct. I'm standing by with your TEI-5 PAD. Over.
079:03:37 Aldrin: Roger. HA 65.6 for Noun 42. And ready to copy.
The PAD is interpreted as follows:
Purpose: The LOI-2 PAD gives the necessary parameters for their second burn to properly insert into lunar orbit at about 110-km (60-nm) altitude. Their first LOI burn brought them into lunar orbit but was deliberately made slightly short so that any overburn errors would not put the spacecraft at risk of impacting the Moon. LOI-2 is a relatively small burn and will leave the CSM in the orbit it will keep for the remainder of its time at the Moon.
Systems: The burn will be made using the large SPS (Service Propulsion System) engine at the rear of the Service Module, under the control of the Guidance and Navigation system.
CSM Weight (Noun 47): 38,320 pounds (17,382 kg).
Pitch and yaw trim (Noun 48): +1.66° and -0.81°. The SPS engine is mounted on gimbals and can be aimed so that its thrust vector (the direction in which it pushes) acts through the spacecraft's centre of mass. These angles represent a calculated initial direction for these gimbals. Once a normal automatic burn begins, the TVC (Thrust Vector Control) system will automatically adjust these angles to account for shifts in the stack's centre of mass.
Time of ignition, TIG (Noun 33): 80 hours, 11 minutes, 36.03 seconds. The burn will occur about halfway around the far side as the spacecraft reaches its perilune, the lowest point in its orbit.
Change in velocity (Noun 81), fps (m/s): x, -104.8 (-31.9); y is zero; z, -74.3 (-22.6). Since the change in velocity is expressed relative to the Local Vertical/Local Horizontal frame of reference, we can see that this burn is largely a retrograde burn and therefore meant to slow the spacecraft down with respect to the Moon.
Spacecraft attitude: Roll, 0°; Pitch, 196°; Yaw, 359°. The desired spacecraft attitude is measured relative to the alignment of the guidance platform. The current alignment of the platform was set per the Landing Site REFSMMAT.
HA, expected apocynthion of resulting orbit (Noun 44): 65.7 nautical miles (121.7 km).
HP, expected pericynthion of resulting orbit (Noun 44): +53.7 nautical miles (+99.5 km). The inclusion of the plus sign is a welcome confirmation that their perilune is above the surface of the Moon and not below it.
Delta-VT: 159.2 fps (48.5 m/s). This is the total change in velocity the spacecraft would experience. (It is a vector sum of the three components given above.)
Burn duration or burn time: 17 seconds.
Delta-VC: 153.1 fps (46.7 m/s). This value is entered into the Delta-V display of the EMS (Entry Monitor System) panel. This figure will descend to zero as the engine burns. If the Guidance and Control System fails to stop the burn, the EMS will do so but it has to be given a low Delta-V figure to take account of the engine's tail-off thrust after shutdown.
Sextant star: Star 23 (Denebola, Beta Leonis) visible in sextant when shaft and trunnion angles are 116.0° and 13.8° respectively. This is an attitude check.
Other parameters on the PAD sheet are not applicable to this manoeuvre.
GDC Align stars: Stars to be used for GDC Align purposes are Vega and Deneb.
There are a bunch of comments at the end of the PAD, some of which are self-explanatory. An ullage burn of 19 seconds using two of the aft-facing thrusters is required to settle the contents of the SPS propellant tanks. The next note concerns the Digitial Auto-Pilot (DAP). The values entered into a particular register adjust how the computer controls the spacecraft's attitude. There is then a note about when a particular star can be used as an attitude reference. Next is a brief description of their attitude during the burn and finally a note about the calculated values for their orbit's apocynthion and pericynthion according to Noun 42. It is unclear why Noun 42 gives slightly different values than Noun 44 given in the PAD.
079:03:44 McCandless: 11, this is Houston. TEI-5 SPS/G&N: 37201, minus 0.60, plus 0.47; TIG 086:09:36.66. Noun 81; plus 3352.1, plus 0344.1, minus 0145.8; roll NA; pitch, 032. The rest of the PAD is NA. Ullage; two jets, 16 seconds, undocked. Over. [Pause.]
079:04:44 Aldrin: Roger. TEI-5 SPS/G&N: 37201, minus 0.60, plus 0.47; 086:09:36.66; plus 3352.1, plus 0344.1, minus 0145 - 458, NA, 032. The rest is NA. Two jets, 16 seconds, undocked. Over.
079:05:16 McCandless: Apollo 11, this is Houston. Readback is correct. Out. [Long pause.]
The PAD is interpreted as follows:
Purpose: The PAD is for a contingency burn to return to Earth at the end of Rev 5.
Systems: The burn would be made using the SPS engine, under the control of the Guidance and Navigation system.
CSM Weight (Noun 47): 37,201 pounds (16,874 kg).
Pitch and yaw trim (Noun 48): -0.6° and +0.47°.
Time of ignition (Noun 33): 86 hours, 9 minutes, 36.66 seconds.
Change in velocity (Noun 81), fps (m/s): x, +3,352.1 (+1,021.7); y, +344.1 (+104.9); z, -145.8 (-44.4). The large positive number in the X direction implies a large prograde component, essentially adding to their orbital velocity, exactly what would be expected from an escape manoeuvre.
Spacecraft attitude: Roll, NA; Pitch, 32°.
All the subsequent items on the form are not applicable to this PAD. The final comments are that there should be an ullage manoeuvre prior to the burn whose duration would be 16 seconds using two rearwards-facing thrusters, and that the manoeuvre would be made after undocking from the LM.
079:05:42 McCandless: Apollo 11, this is Houston.
079:05:44 Collins Houston, you want us back on downvoice backup? Over.
079:05:49 McCandless: Apollo 11, this is Houston. That's affirmative on the downvoice backup. We'd like you to confirm your Uptelemtry switch in the Normal position. Over.
079:06:04 Collins: Roger. It's in Block. Did you get us the - You got us a new CSM state vector and an LOI-2 target load in between all that television, didn't you?
079:06:13 McCandless: That's affirmative.
079:06:16 McCandless: And what I'm asking for is the switchover to...
079:06:17 Collins (under McCandless): Thank you.
079:06:18 Aldrin: The Up-telemetry switch is in Normal. Over.
079:06:22 McCandless: Roger. Out.
Very long comm break.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
This is Apollo Control, Houston at 79 hours, 9 minutes now into the flight of Apollo 11. We currently read an apolune of 170.2 nautical miles [315.2 km], a perilune of 61.2 nautical miles [113.3 km]. Those listing of figures that you heard passed up to the crew were maneuver PAD updates. The first group for LOI-2. We're now looking at the time of burn of 80 hours, 11 minutes, 36 seconds; which should revise our orbital parameters to 65.7 nautical miles by 53.7 nautical miles [121.7 by 99.5 km]. A Delta-V of 159.2 feet per second [48.5 m/s], and a burn duration of 17 seconds, some 17 seconds. So at 79 hours, 9 minutes into the flight of Apollo 11; continuing to monitor; this is Apollo Control, Houston.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
Mike has carried out a P52 platform realignment exercise ahead of the upcoming engine burn. For this P52, Mike's sightings were to star 33 (Antares, Alpha Scorpii) and star 41 (Dabih, Beta Capricorni). The angles through which the platform had to be rotated return it to match the Landing Site REFSMMAT were +0.100° in X, +0.159° in Y and +0.044° in Z. The star angle difference was 0.02°, indicating that Mike's marking accuracy was acceptable.
This is Apollo Control, Houston; at 79 hours, 18 minutes now into the flight of Apollo 11. A quiet period at this time, as the Apollo 11 spacecraft continues its pass around the front side of the Moon. Our current altitude, very close to apolune, now reading 166.7 nautical miles [308.7 km]. Our orbital parameters; 170.2 by 61.2 nautical miles [315.2 by 113.3 km]. Current spacecraft weight in orbit; 71,622 pounds [32,487 kg]. We'll continue to keep the line up and continue to monitor the Apollo 11 crew. No doubt, at this time, preoccupied very probably with the alignment of their G&N platform. At 79 hours and 19 minutes into the flight of Apollo 11; this is Apollo Control, Houston.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
079:21:51 McCandless: Apollo 11, this is Houston. Over.
079:21:57 Collins: Go ahead, Houston.
079:21:58 McCandless: Roger. During the LOI-1 burn, your engine burned a little bit more propellant than we predicted, and consequently, we'd like to update - or send you a new TEI-4 PAD. Over.
079:22:19 Collins: Okay.
079:22:23 Collins: Our chamber pressure onboard was higher that time, too. It's all on the onboard tape, the time entry, and the chamber pressure. But to make a long story short, it worked its way up to 100.
079:22:34 McCandless: Roger.
079:22:39 McCandless: And down here, we showed a chamber pressure of, on the order of, 103 to 104 psi during your burn on playback.
079:22:50 Collins: Okay.
079:22:52 Armstrong: Go ahead with the TEI-4.
079:22:54 McCandless: Roger. TEI-4 revised: SPS/G&N: 38320, minus 0.55, plus 0.60; 084:30:27.49; plus 3138.0, plus 0347.5, minus 0103.2; roll NA: pitch, 034. Rest of the PAD is NA. Ullage, two jets, 16 seconds, undocked. No LOI-2. Over. [Pause.]
079:23:52 Armstrong: Understand; TEI-4 SPS/G&N: 38320, minus 0.55, plus 0.60; 084:30:27.49; plus 3138.0, plus 0347.5, minus 0103.2; NA, 034. All the rest of the PAD's NA. Two jets, 16 seconds, undocked. No LOI-2.
The PAD is interpreted as follows:
Purpose: The PAD is a revised version of a contingency burn to return to Earth at the end of Rev 4.
Systems: The burn would be made using the SPS engine, under the control of the Guidance and Navigation system.
CSM Weight (Noun 47): 38,320 pounds (17,382 kg).
Pitch and yaw trim (Noun 48): -0.55° and +0.6°.
Time of ignition (Noun 33): 84 hours, 30 minutes, 27.49 seconds.
Change in velocity (Noun 81), fps (m/s): x, +3,138 (+956.5); y, +347.5 (+105.9); z, -103.2 (-31.5).
The large positive number in the X direction implies a large prograde component, essentially adding to their orbital velocity, exactly what would be expected from an escape manoeuvre.
Spacecraft attitude: Roll, NA; Pitch, 34°.
All the subsequent items on the form are not applicable to this PAD. The final comments are that there should be an ullage manoeuvre prior to the burn of 16 seconds using two rearwards-facing thrusters, that the manoeuvre would be made after undocking from the LM, and it assumes the crew would not have made the LOI-2 manoeuvre.
079:24:29 McCandless: 11, this is Houston. Readback correct. Out.
Long comm break.
This is Apollo Control, Houston; at 79 hours, 25 minutes. That maneuver PAD that was transmitted to the crew - that was TEI for Trans-Earth Injection burn for the fourth revolution, is a contingency PAD only, only to assure that it is properly onboard the spacecraft, if in the unlikely event it should become necessary to return. At the present time we read an altitude of 157.7 nautical miles [292.1 km] descending from apolune at this time. And our orbital parameters read 170.2 nautical miles [315.2 km], 61.2 nautical miles [113.3 km]. We're some 23 minutes away at the present time from Loss Of Signal. At 79 hours, 26 minutes into the flight of Apollo 11; this is Apollo Control, Houston.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
079:32:19 McCandless: Apollo 11, this is Houston.
079:32:24 Aldrin: Roger. Go ahead, Houston.
079:32:26 McCandless: Roger. We've been looking at your systems data on playback, and everything is looking good. In particular, the SPS looks good. We'd like to remind you, though, of a request to perform this burn on the Bank A ball valves only, and you are Go for LOI-2. Also, we have currently in the Flight Plan, you scheduled tomorrow to start entering the LM at about 96 hours GET, and we'd like to know if you have any plans to initiate this ingress into the LM earlier. If so, we can call the people in ahead of time. Over. [Pause.]
079:33:15 Aldrin: Well, we didn't have any plans to, no. We just wanted to be ready at that time.
079:33:20 McCandless: Roger. We just wanted to make sure that we were ready when you were ready. Over.
079:33:27 Aldrin: Okay. And to get the sextant star in LOI-2, that's roll zero. Is that affirm?
079:33:38 McCandless: That's affirmative. Roll zero.
079:33:43 Aldrin: Okay.
Long comm break.
This is Apollo Control, Houston. We're some 14 minutes away now from Loss Of Signal with the Command and Service Module of Apollo 11. At 79 hours, 34 minutes; this is Apollo Control, Houston, standing by.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
This is Apollo Control, Houston; at 79 hours, 38 minutes now into the flight of Apollo 11. Apollo 11 now 130.4 nautical miles in altitude [241.5 km]. Current velocity reading; 5,131 feet per second [1,564 m/s]. Orbital parameters: apolune, 170.2 nautical miles [315.2 km] with a perilune reading 61.3 nautical miles [113.5 km]. Apollo 11, at this time, has completed its platform alignment and is maneuvering the spacecraft to its burn attitude. We're some 33 minutes away now from time of ignition for the Lunar Orbit Insertion number 2 burn; and we're 9 minutes, 40 seconds away from Loss Of Signal with the Apollo 11 spacecraft. So at 79 hours, 39 minutes; this is Apollo Control, Houston.
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
079:43:30 McCandless: Apollo 11, Houston. Five minutes 'til LOS. And with respect to your request for the nitrogen bottle pressures pre-burn. Just before the burn, we were showing 2,270 pounds per square inch [15.7 MPa] on bottle Alpha and 2,350 [16.2 MPa] on bottle Bravo. Over.
079:43:58 Aldrin: Apollo 11. Roger. Thank you.
079:44:00 McCandless: Roger. Out.
Comm break.
At 076:41:37, McCandless reported to the crew a pressure loss in the 'B' nitrogen tank. Its internal pressure provides the force to open the engine's B bank of propellant valves and it had gone low during the LOI-1 burn. After the burn, it had stabilised at 1,960 psi [13.5 MPa]. Compare this to the other tank, that for the A engine bank at 2,250 psi [15.5 MPa]. The values just supplied by McCandless refer to the tank pressures before the burn. Therefore, while tank A decreased by only 20 psi [138 kPa] during the burn, tank B fell by 390 psi [2,690 kPa].
Download MP3 audio file. PAO loop. Clip courtesy John Stoll, ACR Senior Technician at NASA Johnson.
079:46:23 McCandless: Apollo 11, this is Houston. Two minutes to LOS. Your AOS on the other side is 80:33:21, and the friendly White Team will see you when you come out from behind the Moon.
McCandless (continued): ...Your friendly White Team CapCom will see you when you come out from behind the Moon. I think it's basically the Maroon Team here, and we Greenies are leaving.
079:46:56 Collins: Okay. I don't blame you, Hank.
079:47:06 McCandless: I'd rather be up there.
Very long comm break.
Mark. 30 minutes - 30 seconds now from predicted time of Loss Of Signal. Standing by.
079:48:01 Collins (onboard): Another 5 minutes, Neil babe.
079:48:05 Armstrong (onboard): Okay.
10 seconds.
079:48:20 Aldrin (onboard): This pitch angle is quite a bit off nominal; 196 instead of 212.
079:48:24 Collins (onboard): Umm.
079:48:26 Aldrin (onboard): 16 degrees.
079:48:28 Collins (onboard): Yes, Shaffer screwed up - got to get his eccentric orbit.
Phil Shaffer was Flight Dynamics Officer. He died in 2007. The eccentric orbit post-LOI-2 was done to compensate to some extent for the lunar mascons. The hope was that by making it eccentric in the first place, it will circularise itself by the time of rendezvous with Eagle's ascent stage.
Apollo 11 should now be passing out of range.
Apollo 11 slips out of radio communication with Earth and prepares to refine its parking orbit with a 17-second burn around the far side.
