NASA played conservative when selecting the rendezvous method for the early two vehicle missions. When choosing the best method of rendezvous, the final closure rate between the two spacecraft, and the lighting conditions at rendezvous were primary concerns. They chose the coelliptic rendezvous method, with the LM in the primary, active role, and the CSM calculating and preparing to back up the manoeuvres should the LM run into trouble.
To arrive at these final approach conditions, the rendezvous sequence was broken into three parts, CSI-Coelliptic Sequence Initiation, CDH-Constant Delta Height, TPI-Terminal Phase Initiation. See the diagrams below.
At the time of the first LM apolune following the insertion burn, the CSI manoeuvre effectively circularized the LM orbit. Half an orbit after CSI, the CDH manoeuvre placed the LM in an orbit that was constantly 15 miles (27.8 km) below that of the CSM. This gave the LM time to track the CSM using the rendezvous radar and calculate the parameters for the TPI manoeuvre.
The experience in rendezvous gained during the Gemini, two man, Earth-orbital missions, showed that the terminal phase of the rendezvous should commence approximately 130° behind the optimum location for the final rendezvous and docking. The station keeping and docking needs to take place when the lighting is most appropriate. Also they wanted to have the LM approach from a lower orbit, visible against the lunar surface as seen from the CSM, and the CSM appearing fixed against the celestial background as seen from the LM. Most of the terminal phase took place in darkness, and the final braking phase in daylight, just after the orbital sunrise.
Following the TPI manoeuvre, the LM starts to climb up to the CSM orbital altitude. There are two opportunities to make mid-course corrections if required, before arriving at the final braking phase. Three braking manoeuvres were planned, carried out by the LM. The LM at this stage was very light and extremely responsive to firings of its RCS. The CSM could backup these manoeuvres if required, but was still considerably heavier and less responsive.
During all of these manoeuvres, the crew of both spacecraft monitored to see if there was any need to adjust the orbital plane of the LM, for it to coincide with that of the CSM. Any out-of-plane element could be adjusted for as part of the CSI, CDH or TPI manoeuvres, or a small separate manoeuvre between CSI and CDH.
Diagram of CSI to CDH.
Diagram of CDH to docking.
103:44:50 Young (onboard): Okay.
103:45:17 Cernan (onboard Snoopy): I'm coming up on 35 seconds.
103:45:54 Stafford (onboard Snoopy): We're burning. Gee, you can really feel the acceleration.
103:45:56 Cernan (onboard Snoopy): Okay, here it goes.
103:45:57 Stafford (onboard Snoopy): Open.
APS / RCS interconnect coming open and the RCS SOV vales being closed for the CSI burn.
103:46:05 Stafford (onboard Snoopy): We're burning, John, we're burning. We've got 29 to go, 26 to go.
103:46:07 Young (onboard): Roger.
103:46:08 Cernan (onboard Snoopy): [Garble] to go. Watch the AGS, Tom, it's counting better for you. Okay, I'm closing these right now.
103:46:16 Stafford (onboard Snoopy): You've got it open.
The CSI burn using the LM RCS, draws its propellant from the APS tanks via the interconnect valves. Cernan is now placing the System A & B ASC Feed 1 & 2 switches (4) in the Closed position. These switches are all on panel 1.
He will then put the System A & B Main SOV switches on panel 1, to the Open position, returning the RCS propellant feed from its own tanks.
103:46:18 Cernan (onboard Snoopy): We're okay.
103:46:25 Stafford (onboard Snoopy): Man, you can really feel that.
103:46:27 Cernan (onboard Snoopy): Null them out, babe. You got a light vehicle.
103:46:32 Stafford (onboard Snoopy): That's it.
103:46:34 Cernan (onboard Snoopy): You want to get that one?
103:46:36 Stafford (onboard Snoopy): Yes.
103:46:38 Young (onboard): Snoopy, did you complete the burn? Over.
103:46:52 Stafford (onboard Snoopy): Don't want to use too much - Shit! [garble].
103:46:54 Cernan (onboard Snoopy): Want to take that one out or not? Okay.
103:46:56 Stafford (onboard Snoopy): Okay. All zeros and 4. Go. Proceed.
103:47:14 Cernan (onboard Snoopy): Good burn, John.
103:47:54 Cernan (onboard Snoopy): Gee, I wouldn't give you a nickel in a candy store for the - What?
103:47:58 Stafford (onboard Snoopy): That weird noise is on VHF B.
103:48:01 Cernan (onboard Snoopy): It's a what?
103:48:02 Stafford (onboard Snoopy): It's on VHF B.
103:48:03 Cernan (onboard Snoopy): Is that right?
103:48:04 Stafford (onboard Snoopy): Yes.
103:48:08 Cernan (onboard Snoopy): Okay, Let's go up and get him, Tom. The AGS says he knows where he is.
103:48:18 Stafford (onboard Snoopy): Okay.
103:48:22 Cernan (onboard Snoopy): 76 and 64. Okay, I've got to load the W-matrix as soon as that thing comes out. The AGS needle is 48.2 by 41.6? Shit!
103:49:05 Young (onboard): How do you want to do the plane change, Gene?
103:49:08 Cernan (onboard Snoopy): John, let me pick a number. Any number you pick, if you've got time to figure it out. Let me load the W-matrix here.
103:49:15 Young (onboard): Roger. I show you at 48.2 by 41.
103:49:18 Cernan (onboard Snoopy): That's what we got. 48.2 by 41.6.
Following the CSI maneuver, the AGS calculates that the LM is in a 48.2 x 41.6 nm [89.3 x 77.0 km] orbit.
103:49:58 Stafford (onboard Snoopy): I got a good lock-on.
103:50:17 Cernan (onboard Snoopy): Think you found him?
103:50:33 Cernan (onboard Snoopy): Okay, if you got a good solid lock-on, Tom, you can go ahead to LGC, and it should take it, all the way. Tracker lights should come on. That's him locking on. Okay, that's good.
103:51:03 Young (onboard): I show you at 142.7 miles [264.3 km].
Both vehicles are showing the same range via the rendezvous radar, and the VHF ranging system.
103:51:11 Young (onboard): [Garble].
Page 18 of the LM Timeline Book shows details of the procedures the crew followed between CSI and CDH. The steps to be taken for the cancelled plane change are included. It includes the notations made by the crew at the time. AGS related entries begin with the * symbol.
103:51:17 Cernan (onboard Snoopy): Look at that number. Look at that number. Every time we get a big high number. I'm going to copy that one down.
The crew continue to get an erroneous first readout when they call up P20, which they have to reject.
103:51:19 Young (onboard): When is your CDH time? Over.
103:52:05 Cernan (onboard Snoopy): I just got 104:43:52.71.
103:52:20 Stafford (onboard Snoopy): Okay.
103:52:26 Cernan (onboard Snoopy): Good. After that first one, they're good.
103:52:28 Stafford (onboard Snoopy): Say it to John.
103:52:29 Cernan (onboard Snoopy): Did you get that, John?
103:52:32 Young (onboard): 104:43:57.
103:52:35 Cernan (onboard Snoopy): 104:43:52.71.
103:52:40 Young (onboard): That's right down the alley.
The Flight Plan calls for Young to continue to track the LM using the CSM sextant, taking 3 marks over the next 2 minutes.
103:52:41 Cernan (onboard Snoopy): And I'll pick a plane-change time here right away.
103:53:11 Stafford (onboard Snoopy): I'm going to PGNS now.
103:53:29 Stafford (onboard Snoopy): Hello, Charlie Brown. Snoop.
103:53:33 Young (onboard): Go ahead. Over.
103:53:34 Stafford (onboard Snoopy): We don't need to show any TV on docking. If you get a chance, just go ahead and put up the docking target.
TV coverage of the rendezvous and docking was left to crew discretion. Stafford wants Young to be able to concentrate on the docking without being distracted by the TV.
103:53:39 Young (onboard): Say again? Over.
103:53:41 Stafford (onboard Snoopy): Roger. We don't need to show them any TV on the docking. If you just put up - if you get a chance, go ahead and put up the docking target.
The CSM docking target, also known as the LM-active docking target is used when the LM has to adopt the active vehicle role in the docking manoeuvre. This was the primary method on Apollo 9, but on Apollo 10 and all subsequent Apollo missions the docking in lunar orbit was planned with the CSM in the active role.
Should a problem be encountered with the CSM, for example with the RCS, the LM can take over the active role for the final docking. Following the rendezvous and station keeping, The commander, viewing through the LM overhead window, using the COAS, would align the two spacecraft using the CSM docking target which the CMP has mounted in the CSM window 4, the right hand rendezvous window. The commander would perform the final closure between the two spacecraft, using the LM controls to complete the docking.
CSM docking target deployment.
CSM docking target.
103:53:48 Young (onboard): Alrighty.
103:54:14 Young (onboard): If you guys [garble] too much [garble] That's the only problem.
103:54:20 Stafford (onboard Snoopy): I can imagine.
103:55:38 Stafford (onboard Snoopy): How you doing?
103:55:39 Cernan (onboard Snoopy): I need a drink of water. Let's take a look at our systems real quick. Everything looks good here.
103:55:49 Stafford (onboard Snoopy): Ascent water is 90 percent; O2 is 95 percent; same for Ascent 2.
103:56:08 Cernan (onboard Snoopy): [Garble] air in this water. Not as much, but there's air in it.
103:56:14 Stafford (onboard Snoopy): I see what may have happened. You know when you stand up like this and you look at a switch? You could nearly say that that's Off. Son of a bitch!
103:56:31 Cernan (onboard Snoopy): That's a mistake anyone could have made, if we made it.
103:56:33 Stafford (onboard Snoopy): Yes.
103:56:34 Cernan (onboard Snoopy): I assume we did, and so what? So what? That's my feelings. So what? So, we made it. We recovered from it.
103:56:38 Stafford (onboard Snoopy): When it started to go, I - I...
103:56:40 Cernan (onboard Snoopy): I was ready to burn in AGS and align our PGNS to our AGS and then do an alignment. That's what we had to do after insertion anyway.
103:56:46 Stafford (onboard Snoopy): Yes.
103:57:03 Cernan (onboard Snoopy): Looking at that damn, dry, gray sand for so long, I don't know where the hell we are.
103:57:08 Stafford (onboard Snoopy): I don't either. It's starting to look like home, nearly, isn't it? Not quite, but...
103:57:16 Cernan (onboard Snoopy): You know, you'd call it more at home if it had more security, but son of a bitch, there ain't much security down there at all.
103:57:22 Stafford (onboard Snoopy): Yes.
103:57:38 Cernan (onboard Snoopy): I don't know how the hell guys have lived with this Velcro as long as they have, but it is the shittiest stuff, I tell you.
103:58:05 Stafford (onboard Snoopy): That Z-axis track's taking more fuel.
Stafford is making the observation that the Z-axis tracking of the CSM by the LM, to point the rendezvous radar at the CSM, is using quite a lot of RCS propellant. However the overall use of RCS propellant by the LM, proved to be 10% less than the pre-flight estimate.
103:58:12 Cernan (onboard Snoopy): Five more marks and we'll get a - Take some inside while the Sun's on us.
103:58:25 Stafford (onboard Snoopy): Yes, that's a good point.
103:58:46 Stafford (onboard Snoopy): You know what the setting is?
Stafford is querying whether Cernan has the correct settings on the 16-mm sequence camera for interior filming.
103:58:48 Cernan (onboard Snoopy): Might could, I guess.
103:58:50 Stafford (onboard Snoopy): Has it got it on there? On the side?
103:58:54 Stafford (onboard Snoopy): No, it's got - is that it on the table?
103:58:56 Cernan (onboard Snoopy): Huh? It doesn't tell you in here.
103:58:58 Stafford (onboard Snoopy): Okay. Go ahead.
This video was compiled by journal contributor Stephen Slater using the 16-mm sequence camera footage taken by Stafford and Cernan of each other within Snoopy's cabin and the DSEA onboard audio. It includes footage of Stafford using the DSKY.
104:00:05 Cernan (onboard Snoopy): There. Take some this way.
104:00:07 Stafford (onboard Snoopy): Yes.
104:00:16 Cernan (onboard Snoopy): Get it as far away over there as you can, and that'll do it. Hello there, from the men in the Moon.
104:00:22 Stafford (onboard Snoopy): [Laughter.]
104:00:26 Cernan (onboard Snoopy): You can't really bounce around when you're tied down like this.
104:00:29 Stafford (onboard Snoopy): No.
104:00:30 Young (onboard): Man [garble].
104:00:32 Cernan (onboard Snoopy): Well, why don't you - why don't you - I flashed up in here, why don't you try and flash back in there. The rest of it, take it outside. Okay?
104:00:43 Stafford (onboard Snoopy): Okay.
104:00:46 Cernan (onboard Snoopy): I'll just take the rest of it outside.
104:00:50 Stafford (onboard Snoopy): I wish I could do this cheaper. John, you ought to hear these thrusters firing in here. It's really like a big garbage can getting banged around.
Maintaining the LM attitude with the plus-X axis pointing directly towards the CSM for the rendezvous radar tracking is using quite a lot of RCS propellant.
104:01:20 Stafford (onboard Snoopy): We ought to record our fuel. We should have recorded that fuel and I didn't.
104:01:24 Cernan (onboard Snoopy): I have been, Tom. I've been recording after every burn.
104:01:26 Stafford (onboard Snoopy): After every burn. Good. Go ahead and do it.
104:01:34 Young (onboard): [Garble] in plane.
104:01:39 Stafford (onboard Snoopy): John, I'm tracking right on the bellyband, and my inertial needles are right zero, babe.
104:01:43 Young (onboard): Yes. Well, I'm not showing you right on zero, but it's nothing to worry [garble] 20 miles [37 km] [garble] something.
104:01:48 Stafford (onboard Snoopy): Yes.
104:02:01 Cernan (onboard Snoopy): John, remember how we said this morning - we all said how good it was to put these suits on for a change? Still feel that way?
104:02:11 Young (onboard): [Garble.]
104:02:13 Cernan (onboard Snoopy): Still good to put these suits on for a change?
104:02:19 Young (onboard): I never said that.
104:02:29 Stafford (onboard Snoopy): I guess I did. I felt like that for a few minutes. I must have lost my mind.
104:02:28 Cernan (onboard Snoopy): Actually, it did feel good for a change.
104:02:44 Cernan (onboard Snoopy): Helium is [garble] Well, that's right because we use more fuel on ascent. Boy, the APS sure didn't use much pressure out of there, did it?
104:02:50 Stafford (onboard Snoopy): No.
104:02:51 Cernan (onboard Snoopy): I recorded it when we started burning and...
104:03:31 Cernan (onboard Snoopy): Tom, we need a backup mark at 36 minutes.
104:03:34 Stafford (onboard Snoopy): Yes.
104:03:36 Young (onboard): You all do the - plane change at 104:15, right, Gene-o?
Provision was made in the Flight Plan for a plane change manoeuvre, should it be required, between the CSI and CDH manoeuvres at a time nominated by the crew. Cernan has suggested 104:15:00, if they feel they need it.
104:03:44 Cernan (onboard Snoopy): I hope there is none though. Boy that's a long time in - Look at this.
104:04:27 Cernan (onboard Snoopy): That recycle is taking forever!
104:04:31 Stafford (onboard Snoopy): Yes.
104:04:42 Young (onboard): [Garble].
104:04:45 Stafford (onboard Snoopy): What, John?
104:04:49 Young (onboard): Our REFSMMAT's slipped.
104:04:51 Stafford (onboard Snoopy): Yes.
104:04:55 Cernan (onboard Snoopy): John, this consistently is saying we're about 152 to 154 miles [282 x 285 km]. It looks like TPI has gone 54 seconds away from us, made it a little bit longer.
Young is calculating the required plane change solution independently with the CMC using routine 36.
104:05:09 Young (onboard): Roger.
104:05:22 Cernan (onboard Snoopy): We got real good numbers, plus 0.30, 0, and plus 1.9 on our first cut.
The 1st calculation of the required Delta-V at CDH is: plus-X, 0.3; plus-Y, 0.0; plus-Z, 1.9 fps (plus-X, 0.1; plus-Y, 0.0; plus-Z, 0.6 m/s) relative to the LVLH framework, Plus-X is the direction of flight, the orbital plane, Plus-Y is perpendicular to the orbital plane, to the right, Plus-Z is vertically down towards the Moon's center.
104:06:49 Young (onboard): [Garble] I'm showing a plus point - I'm showing minus 1.1 for the plane change. That looks good.
104:06:59 Cernan (onboard Snoopy): Wait a moment and I'll take a look at what ours says here in a minute.
104:08:24 Cernan (onboard Snoopy): We show minus 3.1, which is again the opposite direction. We will not do it, John.
The crew are erroneously applying a sign change to the CSM out of plane value, thus believing that the out-of-plane values obtained by the two spacecraft are in opposite directions, and they believe to some degree cancel each other out, so they have decided to delay the out-of-plane correction at this time.
From the Apollo 10 Mission Report: "A crew misunderstanding of the sign notation for this parameter existed and apparently resulted from the fact that all Command-Module mirror-image solutions for rendezvous require a sign reversal when used by the Lunar Module crew. Since the determination of Lunar Module out-of-plane velocity is a separate routine in the Command Module Computer and not a mirror-image solution, this parameter should not be reversed in sign when used for comparison. This fact had not been made clear enough before flight, and the crew was acting on what they believed to be the correct comparison procedure. No difficulties were encountered by this misunderstanding and subsequent delay in the out-of-plane correction, since errors of this type do not increase (propagate)."
Actually, the agreement in sign of the out-of-plane velocity solutions was valid, since each vehicle computed precisely the same parameter, the out-of-plane velocity of the Lunar Module.
104:08:34 Young (onboard): Okay.
104:09:08 Stafford (onboard Snoopy): Okay. Minus 36 minutes. Okay. There's 126 - 7 (nautical miles, 235 km). Let's see how this compares to the nominal.
Stafford is recording the range to compare with backup manual charts in order to fine tune them for subsequent missions.
104:09:29 Cernan (onboard Snoopy): 23 and 10.
104:09:57 Cernan (onboard Snoopy): Hey, John, if you can, when we get back, see if you can get a picture of the ascent stage only, will you?
104:10:02 Young (onboard): Okay [garble].
104:10:06 Cernan (onboard Snoopy): Okay. Great.
104:10:12 Stafford (onboard Snoopy): Look at the boulders on that.
104:10:21 Young (onboard): You guys said you weren't going to do that plane change?
104:10:24 Cernan (onboard Snoopy): No. We are not going to do it. If you can, when we get back - Don't sweat it - but if you can, see if you can get some ascent-only pictures. Ascent-stage-only pictures.
104:10:42 Young (onboard): Yes, I will.
104:10:44 Cernan (onboard Snoopy): Okay.
104:10:53 Young (onboard): [Garble] I got you on the other frame, but I don't know if this dang camera was in the right focus for up there, or the right setting. But I was really hopping.
104:10:58 Stafford (onboard Snoopy): We got it all taped up for you.
104:11:00 Young (onboard): Your Hasselblad ain't taped up.
104:11:09 Cernan (onboard Snoopy): It should be f:8 at 250th, something like that.
104:11:12 Young (onboard): Yes. That's what I had it set on. I think I need [garble].
104:11:20 Cernan (onboard Snoopy): I got to call for another Verb 93 here and initialize, even though we don't do the plane change. I'll do it about plane-change time.
Verb 93 initializes the W-matrix. The W-matrix is used by the PGNS to allow for slight imperfections in the loaded state vector.
104:11:29 Stafford (onboard Snoopy): Look at our rendezvous radar.
104:11:51 Cernan (onboard Snoopy): Want some water, babe?
104:11:52 Stafford (onboard Snoopy): Yes. Do you want some grape juice?
104:11:57 Stafford (onboard Snoopy): Think I'll have some grape juice. All we got to do is get back in dock and get that tunnel pressurized and we're home, Gene-o. [garble] hours to go.
104:12:17 Cernan (onboard Snoopy): One more big burn after that. Boy, I'll tell you those burns sure settle that crap that's laying around here, don't they?
104:12:25 Stafford (onboard Snoopy): Yes. Boy, that ascent burn was wild, and we're the first ones that's had an evaluation of it. See, 9 only burned it for a couple of seconds. But that thing was whoo, whoo.
The only manoeuvre made using the APS on Apollo 9 whilst it was manned, was the CDH burn. Its duration was 2.9 seconds. Apollo 9 did burn the APS again during the ascent engine burn to depletion for 362.3 seconds, once the LM ascent stage was finally separated from the CSM.
104:12:33 Cernan (onboard Snoopy): Is that right?
104:12:34 Stafford (onboard Snoopy): Yes.
104:12:35 Cernan (onboard Snoopy): Boy, it - it was rocking, I thought...
104:12:36 Stafford (onboard Snoopy): Boy, it rocks.
104:12:41 Cernan (onboard Snoopy): John, could you see our plume when we fired?
104:12:47 Young (onboard): Yes, I could on the descent burn.
Young observed the DOI, DPS burn, using the CSM sextant. He could see an orange plume.
104:14:42 Stafford (onboard Snoopy): Look at that crater, Gene-o. See those black things where it slumps down? Right near the rim is black stuff and halfway down is black. See that?
104:14:51 Cernan (onboard Snoopy): Yes.
104:14:52 Stafford (onboard Snoopy): In that region down there?
104:14:53 Cernan (onboard Snoopy): Boy, that is something.
104:15:06 Cernan (onboard Snoopy): Hey, John, you ain't never seen so many Master Alarms and warning lights as you've seen on this bird.
104:15:17 Young (onboard): Strange things, we got computers going on in here, too. You wouldn't believe some of them.
Young uses program P33 to compute a solution for the CSM to backup the CDH burn should the LM fail to perform this manoeuvre.
104:15:27 Stafford (onboard Snoopy): On that phasing burn, we had the master caution on three times with the Descent Quantity going low twice and the Gimbal light's coming on. Also our fuel pressure showed zero. Other than that, it was a pretty nominal burn, John.
104:15:52 Stafford (onboard Snoopy): You can see how these craters are formed? How the sides slump in and leave these tailings in the back?
104:15:57 Cernan (onboard Snoopy): Yes, yes, I sure can.
104:16:03 Cernan (onboard Snoopy): There's that one that Jack may wanted.
104:16:15 Young (onboard): When is the ground supposed to pick us up?
104:16:18 Stafford (onboard Snoopy): Pick us up at 24 and 25.
104:16:21 Young (onboard): Roger, after CDH.
104:16:22 Stafford (onboard Snoopy): Yes.
104:16:23 Young (onboard): No, [garble].
104:16:25 Stafford (onboard Snoopy): Yes.
104:16:39 Cernan (onboard Snoopy): There's an update after the - after the - initialize the W-matrix.
104:16:48 Stafford (onboard Snoopy): What was it?
104:17:17 Cernan (onboard Snoopy): Okay. Now it's taking one. The first mark after you initialize the W-matrix...
104:17:20 Stafford (onboard Snoopy): Is that the [garble].?
104:17:21 Cernan (onboard Snoopy): [garble] is [garble] Look at that.
104:17:23 Stafford (onboard Snoopy): Zero.
104:17:37 Cernan (onboard Snoopy): Look at that - on AGS Min Deadband. Look at how close the AGS thinks that is to it. Look at it.
104:17:56 Stafford (onboard Snoopy): (Laughter) Want to do this in PGNS, or we do it in AGS Attitude Hold? Let's do it in AGS Attitude Hold and see what we get.
This is Apollo Control at 104 hours, 18 minutes. We're not quite 2 minutes away from acquisition of the Command Module. We'll try to give you a - an explanation of what happened during the staging sequence. The backup guidance system, the AGS or Abort Guidance System mode control switch was in Auto because the - the radar had been used to track the Command Module, and they were using the Auto mode for Reaction Control System attitude control. Now at - the - this mode control switch should have been placed in Attitude Hold for staging, but it was not because that step had been omitted from the checklist. So the control system maneuvered the Lunar Module to lock on to the Command Module as the computer directed, but that was not the proper attitude for staging, and the crew were not sure whether they went to pulse mode or to manual, straight manual control, but they went to one of those two modes to get out of that situation, and the staging went well. We're about 30 seconds away from acquisition now.
Young is continuing to take optical marks of the LM through the CSM sextant.
104:18:04 Cernan (onboard Snoopy): Yes, let's do it. Let's try it. We owe it to the vehicle to...
104:18:42 Cernan (onboard Snoopy): Either these oxygen gauges don't work, or we just ain't using any.
104:18:46 Stafford (onboard Snoopy): Our cabin pressure is holding real good. Real tight.
104:18:52 Cernan (onboard Snoopy): It's warm in here, but not exceptionally hot.
104:18:55 Stafford (onboard Snoopy): Yes.
104:18:56 Cernan (onboard Snoopy): Turn that cabin fan on; see how much noise it makes.
104:19:26 Cernan (onboard Snoopy): We'll make one more recycle after five marks and then let it go to 12 minutes. Oh, Tom, 23 minutes, I need a backup.
104:19:33 Stafford (onboard Snoopy): Okay.
The altitude at staging was 33.4 nautical miles (61.9 km).
104:20:34 Cernan (onboard Snoopy): AGS is right on. Look, 105.5 miles (195.4 km) and 129 feet per second (39.3 m/sec). That's not bad. 23 minutes, T.P.
Gene Cernan was the only crewman in the LM being monitored by the flight surgeon, and his heart rate during that staging sequence ranged from 105 to 129.
104:20:47 Stafford (onboard Snoopy): Okay. Mark it. R-dot is 126.
104:20:57 Cernan (onboard Snoopy): 126. Is that all?
The current PGNS range rate, is 126 fps (38.4 m/s), which compares very closely with that for the AGS.
104:21:01 Stafford (onboard Snoopy): Yes. About what it's supposed to be. Yes. That's within a foot per second of the nominal.
104:21:35 Stafford (onboard Snoopy): I still don't hear José out there. Were they there when they burned CSI? The ground wasn't in contact, were they?
104:22:08 Cernan (onboard Snoopy): I'm sorry, Tom, I - I didn't hear you.
104:22:10 Stafford (onboard Snoopy): We were out of contact with the ground when we burned CSI, weren't we?
104:22:15 Cernan (onboard Snoopy): Yes. We need another backup mark at 10 minutes.
104:22:23 Stafford (onboard Snoopy): Yes.
104:22:26 Young (onboard): You guys got 21 minutes and counting, about?
104:22:27 Cernan (onboard Snoopy): Yes. Yes.
104:22:28 Stafford (onboard Snoopy): Yes. About 21:20.
104:22:31 Stafford (onboard Snoopy): Mark.
104:22:33 Young (onboard): Okay.
104:22:38 Stafford (onboard Snoopy): How's the burn over there doing on RCS fuel, John?
104:22:42 Young (onboard): Well, I was doing okay until the last hundred miles or so, and I had to put it tight deadband; because when we started talking about things like plane changes, I want to be able to go back and look at the ball. I think we're fat right now.
Young is confirming that the SM has been frugal in its use of RCS propellant during the spacecraft solo operations.
Prior to the LM insertion manoeuvre, CSM attitude control was performed primarily either with the DAP in wide deadband at rates of 0.2 or 0.5 deg/sec or with the pulse mode of the Stabilization and Control System (SCS). With the wide deadband mode, additional pilot attention to spacecraft roll was required to maintain the preflight angles for nominal High Gain Antenna acquisition and lock-on and still provide the proper line-of-sight coverage for the rendezvous radar transponder.
104:22:51 Stafford (onboard Snoopy): Yes.
104:22:53 Young (onboard): I think we're in [garble], right now.
104:22:54 Stafford (onboard Snoopy): Yes. Here comes the Earth! Beautiful. I'll get it. It really comes up.
104:23:00 Duke: Charlie Brown, Houston. We're standing by. Over.
104:23:05 Young: Roger.
104:23:07 Young (onboard): Burn was nominal. Your burn was 45.3 and you burned [garble] was 46.9 [garble].
104:23:18 Duke: Charlie Brown, Houston. How did the CSI go?
104:23:22 Cernan (onboard Snoopy): Isn't that phenomenal?
104:23:34 Young: Boy, this tracking the LM against the background of the Moon or something down there is really fantastic.
104:23:46 Duke: We copy, Charlie Brown.
104:23:49 Stafford (in Snoopy): This is Snoopy. How do you read me?
104:23:50 Cernan (onboard Snoopy): Let me get them on High Gain, babe.
104:23:55 Duke: Hey. Snoop. Houston. We're reading you four-by-four. Over.
104:24:00 Stafford (in Snoopy): Roger. We had a nominal burn. Everything went good, and we had a beautiful Earthrise as you came up from behind the horizon.
104:24:10 Cernan (onboard Snoopy): Golly.
104:24:12 Duke: Roger. Need you Noun 81 numbers, Houston. Need you Noun 81 numbers and your residuals. Over.
104:24:20 Stafford (in Snoopy): Roger. Stand by.
104:24:26 Cernan (in Snoopy): Okay. For CSI the Noun 81 numbers were 45, 43, 00. Residuals were 0, minus 0.4, and 0.
104:24:41 Duke: Roger, Snoop. We copy 45, 43, 00. Residuals: 0, minus 0.4, 0. Thank you much.
Noun 81 displays the Delta-V applied to the LM by the CSI manoeuvre relative to the LVLH framework: plus-X, 45.0; minus-Y, 0.43; plus-Z, 0.0; all in fps (plus-X, 13.7; minus-Y, 0.13; plus-Z, 0.0 m/s).
104:24:50 Cernan (in Snoopy): Now we're going to try and put you High Gain.
104:24:55 Duke: Roger.
104:24:57 Young: We copy that. Go.
104:25:14 Duke: Charlie Brown, Houston. Did Snoop do a plane change? Over.
104:25:21 Duke: Charlie Brown, Snoop. Correction, Charlie...
104:25:14 Cernan (onboard Snoopy): Wonder if I can call Noun 75 up?
Verb 06 Noun 75 displays the Delta-altitude, the time between CDH and TPI, and the difference in time between the nominal TPI and the latest TPI ignition time update. See the entry at CDH -18:00 on page 18 of the CSI to CDH Timeline Book.
104:25:29 Young: We thought we could do it then. It's at the plane-change time; and at the plane-change time, which was 104:15, I had minus 1.1 and they had plus. They had one in the opposite direction, so we decided not to do it there.
104:25:45 Duke: Roger. We copy.
104:25:59 Stafford (onboard Snoopy): What was that?
104:26:34 Cernan (in Snoopy): Hello Houston. This is Snoopy on High Gain. How do you read?
104:26:37 Duke: Roger. We got you on High Gain, Snoop.
104:26:45 Cernan (onboard Snoopy): Okay. This High Gain stuff is a piece of cake. I don't know what you were all so worried about.
104:26:52 Duke: Wish we could say the same about the Omnis.
104:26:53 Stafford (onboard Snoopy): [Laughter.]
104:26:55 Cernan (in Snoopy): Yes, all I did was look at you coming over the horizon, and I pointed High Gain up and down my Z-axis like I hoped I could; and man, there you were, and she locked on.
104:27:07 Duke: Roger. We got you, and we got you counting down, and we see you 16 45.
104:27:13 Cernan (in Snoopy): Okay. Seems like every time we initialize or call a P20 for the first time, the first Mark we have to reject because it's got horrendous 5-digit numbers in it.
When in P20, the crew call up Verb 06 Noun 49 to display on the DSKY the Delta-R - range, XXXX.X nm, and Delta-V - rate of closure, XXXX.X fps. The initial P20 LGC readout of range rate from the RR, is displayed as a set of random and very large values.See explanation at 101:08:47.
104:27:29 Duke: Roger. We copy.
Showing range 97 miles [180 km].
104:27:43 Cernan (onboard Snoopy): Charlie Brown, this is Snoopy.
104:27:45 Young (onboard): Go ahead. Over.
104:27:52 Cernan (in Snoopy): It looks like TPI - My last recycle [Noun 75], TPI moved away from us 2 minutes and 40 seconds. I'm going to go and try calculating out plane-change here and compare it with yours, but it looks like we're in good shape. I got Delta-H of 14.9 [nautical miles, 27.6 km].
104:28:04 Young (onboard): Roger.
104:28:09 Duke: Roger, Snoop. We copy. Houston.
That Delta-H is the differential in altitude between the Command Module and the Lunar Module, and Gene Cernan reads it as 14.9 nautical miles [27.6 km]. We'd like to be right around 15 nautical miles (27.8 km), so that's very good.
104:28:34 Young (onboard): Okay. I got you at 96.25 miles (178.3 km) now. That sound about right?
In this next maneuver, the CDH...
104:28:42 Stafford (in Snoopy): Roger, Charlie Brown, Snoop. We're locked on with you all the way. Right together.
Stafford is confirming they have good rendezvous radar lock-on on the CSM Charlie Brown.
104:28:47 Young (onboard): I show you're flying right straight down the bellyband, too.
104:28:51 Stafford (in Snoopy): Roger. You're right in plane with us, Charlie Brown.
104:28:55 Stafford (onboard Snoopy): Go back through.
104:29:04 Stafford (in Snoopy): Hello, Houston. This is Snoopy. One thing that looks real good to us, is the Rendezvous Radar temperature has kept fairly cool. In fact, where it is now, at 80, is about as hot as it's gotten all day. Over.
104:29:19 Duke: Roger, we copy, Tom. Thank you much.
104:29:33 Stafford (onboard Snoopy): Okay, we'll Proceed at 12 minutes.
Page 19 of the LM Timeline Book shows details of the procedures the crew followed between CSI and CDH. It includes the notations made by the crew at the time. AGS related entries begin with the * symbol.
104:29:45 Cernan (in Snoopy): Charlie Brown, this is Snoop. Our plane change is NG, so we're not going to burn ours. We'll wait for yours. If it sounds good, we'll look at it.
104:29:54 Young (onboard): Roger.
104:30:09 Cernan (onboard Snoopy): Listen to that antenna move around. You know, with the - between that and the radar, and the...
104:30:39 Young (onboard): Snoop, say again the CSI - the CDH time
104:30:43 Cernan (in Snoopy): CDH time is 104:43:52.71.
104:30:53 Duke: Roger. We copy.
104:30:54 Young: CDH: 104:43:52.71.
104:30:59 Cernan (in Snoopy): That's it, Charlie Brown.
104:31:02 Cernan (onboard Snoopy): Isn't that magnificent, Tom? Would you believe it? North pole is on the righthand side.
104:31:12 Stafford (onboard Snoopy): Right.
104:31:53 Cernan (onboard Snoopy): Better get the 13th Mark.
104:31:57 Stafford (onboard Snoopy): We got beaucoup.
104:32:02 Young: Okay. I'm showing a minus 4.2.
Young has computed his own value for the LM out-of-plane; minus-Y, 4.2 fps (1.28 m/s). At this point the crew have little confidence in these values, so they decide to delay any out-of-plane correction until TPI.
104:32:08 Cernan (onboard Snoopy): John, you don't want to burn it, do you?
104:32:10 Stafford (onboard Snoopy): No.
104:32:11 Cernan (onboard Snoopy): Let...
104:32:12 Young (onboard): I don't believe it.
104:32:11 Stafford (in Snoopy): I don't either, John. We're going to ignore it here.
104:32:17 Young: You can take it out quite easily.
104:32:20 Stafford (in Snoopy): Yes.
104:32:22 Cernan (in Snoopy): Let's not burn it. Ours was in the opposite direction even with the sign changed, but let's not burn it. You're right down to belly band, babe.
The crew are still under the misapprehension, that the out-of-plane values for the CSM have the sign reversed. Young is pointing out that any out-of-plane errors can still be taken out during later manoeuvres.
104:32:35 Cernan (onboard Snoopy): 13th mark will get it.
104:32:39 Stafford (onboard Snoopy): We'll see.
104:32:42 Cernan (onboard Snoopy): 10 minutes, Tom, I need a mark.
104:33:47 Cernan (onboard Snoopy): Isn't that just fantastic, Tom?
104:33:48 Stafford (onboard Snoopy): Stand by.
104:33:50 Stafford (onboard Snoopy): Mark.
104:33:51 Cernan (onboard Snoopy): Okay.
104:33:52 Stafford (onboard Snoopy): 124 feet per second (37.8 m/sec).
Stafford is recording the minus 10-minute range for the backup manual chart comparison.
And we're 10 minutes away from the CDH maneuver burn that will make the differential altitude constant. Be a very small maneuver on the order of 2 to 2½ feet per second (0.6 to 0.76 m/sec). The ground solution is 2.3 feet per second (0.7 m/sec). The crew is now getting solution from their computer.
104:33:53 Cernan (onboard Snoopy): 124. What about - That's all I need.
104:33:57 Stafford (onboard Snoopy): Yes, the [garble] is [garble].
104:33:59 Cernan (onboard Snoopy): That's all I need. 0.1 and 137.9. 0.1...
104:34:31 Stafford (onboard Snoopy): You want me to Proceed? Get it?
104:34:36 Cernan (onboard Snoopy): Okay. I got plus 1.2 Delta-VZ, and X is plus 0.2.
Cernan has obtained these CDH values from the onboard backup charts.
104:34:40 Stafford (onboard Snoopy): You want me to Proceed?
104:34:48 Young: Okay. My [Noun] 81 and a minus 0.5, 0, and minus 2.9 for P33.
Young is computing the LM CDH values using the P33 in the AGC in the CSM. His computed values are; minus-X, 0.5; plus-Y, 0.0; minus-Z, 2.9; all in fps (minus-X, 0.15; plus-Y, 0.0; minus-Z, 0.88 m/s), all relative to the LVLH framework.
104:35:01 Cernan (onboard Snoopy): Okay, John, that's good. We'll burn ours. Ours is plus 0.1, 0, and plus 3.0.
104:35:06 Duke: Snoop, Houston. We see your solution. It looks prima. Over.
104:35:13 Cernan (onboard Snoopy): Charlie Brown, did you read me? Houston may have cut you out - it's plus 0.1, 0, and plus 3.0.
104:35:28 Young (onboard): Roger.
104:35:29 Cernan (onboard Snoopy): That's plus 0.1, 0, and plus 3.0.
104:35:34Cernan (onboard Snoopy): Okay, and the backups gave me plus 0.2 and plus 1.2, so we're in good shape.
Cernan is comparing the PGNS CDH values with those derived from the onboard backup charts, and they are in close agreement.
104:35:35 Young: Roger. They both look great. Yes.
104:35:41 Stafford (onboard Snoopy): Okay, we'll make this AGS, Attitude Hold, and let's make sure we get the right one.
104:35:43 Cernan (onboard Snoopy): Okay. We're all set?
104:35:47 Stafford (onboard Snoopy): We're set.
104:35:48 Cernan (onboard Snoopy): Okay.
104:35:49 Stafford (onboard Snoopy): Call P00.
104:35:50 Cernan (onboard Snoopy): Let's get this thing updated? Verb 47.
Cernan is calling up Verb 47 to initiate routine 47-AGS initialization. This will copy the current LM state vector form the LGC to the AGS.
104:36:41 Stafford (onboard Snoopy): We're coming over the old craters.
104:36:42 Cernan (onboard Snoopy): Okay, babe, call up 41 and get me an 06 86.
104:36:56 Stafford (onboard Snoopy): Plus 0.1, zip, plus 3.0.
Cernan is calling for P41, to compute the IMU orientation and preferred vehicle attitude for the upcoming CDH RCS manoeuvre, then calling Verb 06 Noun 86, the LGC displays the velocity to be gained in the three axis (in the Local Vertical framework), X, Y, Z during the CDH burn. The values displayed are plus-X, 0.1; plus-Y, 0.0; plus-Z, 3.0; all in fps (plus-X, 0.03; plus-Y, 0.0; plus-Z, 0.9 m/s).
104:37:33 Young: This is the nicest CDH - This is the nicest CDH solution we ever got.
Using P33, Young has computed the CSM CDH solution for the final time, if required.
104:37:36 Stafford (in Snoopy): Thats right, John. Looks like our CSI solution and the total targeting was just fantastic.
104:37:56 Stafford (onboard Snoopy): Oh, I wish I had a...
The Control officer reports that all of the LM consumables are in good shape. We're showing a range now of 87 miles (161 km) between the LM and the CSM.
104:38:07 Stafford (onboard Snoopy): Look at them. Boo. See out there.
104:38:08 Cernan (onboard Snoopy): Yes, yes, you can see across both of them...
104:38:12 Cernan (onboard Snoopy): ...see across both of them.
104:38:13 Stafford (onboard Snoopy): Okay. Let's make sure we get the right AGS stuff this time. Go to Enter, to [garble].
104:38:21 Young: Going to do this in AGS. Right?
104:38:23 Stafford (in Snoopy):Yes. We'll give the old AGS a try again. [Laughter.] We'll make sure we're at Attitude Hold. We knew what was wrong before.
The crew want to ensure they don't make the same mistake with the attitude control switch settings, that they made at LM staging.
104:38:31 Stafford (onboard Snoopy): Okay. What's the procedure now?
104:38:33 Young (onboard): The procedure is, babe, just go to AGS, Attitude Hold for the burn.
104:38:39 Stafford (onboard Snoopy): Yes.
104:38:40 Cernan (onboard Snoopy): AGS Mode Control, Attitude Hold; Guidance Control, AGS; and that's it.
104:38:46 Stafford (onboard Snoopy): What about Deadband?
104:38:48 Cernan (onboard Snoopy): Deadband, Min - Deadband, Min; AGS, Mode Control, Attitude Hold and Guidance Control, AGS.
104:39:06 Young (onboard): I'm not sure they weren't taking a wild guess at them answers anyway. I'm not sure - they could have been wrong.
104:39:07 Duke: Charlie Brown, Houston. Over.
104:39:26 Duke: Hello, Charlie Brown. Houston. Over.
104:39:29 Young (onboard): Go ahead. Go ahead, Houston.
104:39:39 Cernan (in Snoopy): Houston, go ahead. Charlie Brown's reading you.
104:39:45 Duke: Roger, Snoop. I'm not reading him at all. Notice - We noticed he bypassed his roll maneuver at about 104:33. We recommend he manually roll 180 before he does his P20 Auto maneuver over, out to the burn.
The CSM Flight Plan calls for Charlie Brown to roll 180° just before AOS.
104:40:00 Young (onboard): Roger.
104:40:03 Cernan (in Snoopy): He got that.
104:40:05 Duke: Okay. We barely heard him. Thank you.
104:40:08 Cernan (in Snoopy): John, we're at 3:43, 3:42, counting down to the burn.
104:40:22 Cernan (onboard Snoopy): You want to make sure you key those in - You put them in Pulse and then key them and then go to...
104:40:30 Stafford (onboard Snoopy): We don't have Z-axis track anymore, do we?
104:40:32 Cernan (onboard Snoopy): Sure we do. Here.
104:40:36 Stafford (onboard Snoopy): Yes. Okay.
104:40:38 Cernan (onboard Snoopy): Sure you do.
104:40:42 Stafford (onboard Snoopy): How come we're pitching up like that.
104:40:48 Cernan (onboard Snoopy): Oh, I'm sorry, you do not have Z-axis track.
104:40:53 Stafford (onboard Snoopy): You better believe it, babe.
104:40:56 Cernan (onboard Snoopy): Wait a minute. In - We went through and we killed 20, but we didn't kill P00; but we got radar discrete but no Z-axis track.
104:41:43 Cernan (onboard Snoopy): Down and aft. Down...
104:41:46 Stafford (onboard Snoopy): Aft and left.
104:41:50 Cernan (onboard Snoopy): Down and aft, but that's down, that's the main thing.
Young is now preparing the CSM in case he has to make the CDH manoeuvre He calls up P41, RCS thrusting program and aligns the GDC.
104:42:00 Cernan (in Snoopy): That's 2 minutes, John.
104:42:01 Young (onboard): Roger.
104:42:14 Young (onboard): What's your first hack at TPI?
104:42:28 Cernan (onboard Snoopy): John, our hack at TPI that we put in back there at...
104:42:32 Stafford (onboard Snoopy): Oh, what...
104:42:34 Stafford (in Snoopy): José, are you maneuvering now? Okay, we just lost lock.
104:42:39 Cernan (onboard Snoopy): Okay, you ought to go to...
104:42:41 Stafford (onboard Snoopy): Slew.
104:42:42 Cernan (onboard Snoopy): It's going to be about 2 minutes later than what we had, John. And that first hack at TPI that they updated us on was 105:21:01.00.
Cernan is using program P34 to update the TPI ignition time. He is letting Young know that the time the LGC is giving is approximately 2 minutes later than the ignition time voiced to them as part of the CSI PAD update at 103:14:21.
104:43:25 Cernan (in Snoopy): John, we're within 35 seconds.
104:43:27 Young (onboard): Roger.
104:43:36 Cernan (onboard Snoopy): Down 3 and aft.
104:43:37 Stafford (onboard Snoopy): Yes.
104:43:45 Cernan (in Snoopy): 10 seconds. We're in AGS, Min deadband attitude hold. 4, 3, 2, 1.
104:43:53 Cernan (onboard Snoopy): Burning. Skoshi more. That ought to get it. Watch it slip - flip.
104:44:09 Stafford (onboard Snoopy): Okay, 0...
104:44:11 Cernan (onboard Snoopy): 0.10 and minus 1.
The actual residual errors following the CDH burn relative to the LVLH framework were plus-X, 0.1; plus-Y, 0.0; minus-Z, 0.1; all in fps (plus-X, 0.03; plus-Y, 0.0; minus-Z, 0.03 m/s).
104:44:18 Stafford (in Snoopy): Burn was good.
104:44:18 Young (onboard): Excellent.
Planned spacecraft attitude from CDH (Constant Delta Height) to docking.
104:44:22 Duke: Roger, Snoop. We copy.
104:44:27 Stafford (in Snoopy): And did you copy the residuals?
104:44:29 Duke: That's affirmative. We got it all. Over.
104:44:33 Stafford (in Snoopy): Alright. Okay, go back up, John, and we'll be all set to track.
104:44:40 Young (onboard): Roger.
Stafford wants Young to maneuver the CSM back to radar tracking attitude.
104:45:39 Stafford (in Snoopy): And we have a solid lock-on, John.
104:46:23 Stafford (in Snoopy): Okay, Charlie Brown. This is Snoopy. I've had you in reflected sunlight out there - for about - for about 90 miles (167 km) on. It was just very clean. It's just about the same as around the Earth when we used to see the Agena, but I've got you as a little yellow dot out there, and Ive been tracking you since about 90 miles (167 km). Over.
104:46:53 Stafford (in Snoopy): And Ive got only one eye power.
104:47:00 Cernan (in Snoopy): Hey, John, after aligning this platform with the AOT, I can see why your eyes are - why you're saying what you're saying. I'll tell you.
104:47:15 Stafford (in Snoopy): Hello, Houston. This is Snoopy. We're right over by Moltke and the landing site again. Getting a view of it now from 45 miles and again - just extrapolated from below. It looks like we got about 25 to 30 percent clear area in there. Over.
104:47:38 Stafford (in Snoopy): Roger. We're coming up to the craters Sabine and Ritter, and we can see U.S. 1 here, and the sides of U.S. 1 again are rounded and [garble] but the whole thing is dropped down just like reported before.
104:47:51 Duke: Roger. We copy, Snoop.
104:47:53 Cernan (in Snoopy): Houston, do you have a good gouge on...
104:47:55 Duke: Go ahead.
104:47:56 Cernan (in Snoopy): Do you have a good gouge on the setting for internal film to use outside?
Cernan believes he may only have internal colour film for the 16-mm sequence camera, and needs to know the f-stop offset for using it to shoot outside views.
104:48:00 Duke: Stand by.
104:48:10 Duke: Roger. Use two f-stops higher, Snoop, on that film; and, Tom, if you've got a chance to talk a minute, could you describe Landing Site 2 from 8 miles (14.8 km)? We didn't have you in communications at that time.
104:48:35 Stafford (in Snoopy): Okay, Houston. Go ahead. You were cut out. Say you want me to describe the Landing Site 2 again?
104:48:41 Duke: Roger. We can get it later, Snoop. It's a little busy now. We'll get it later. We were out of communications with you at that time, but we will get it later. Over.
104:48:53 Stafford (in Snoopy): Yes. Okay. The approach end looks lots smoother than some of the Orbiter photos show. It's still estimate 25 to 30 per cent, say, semi clear area for - if the LM has enough hover time, at least from what we can see at 50,000 feet, it should not be a problem. However, if you come down in the wrong area and you don't have the hover time you are going to have to shove off.
104:49:17 Duke: We copy.
104:49:20 Stafford (in Snoopy): Roger. Okay. We got solid lock-on now, and we're working on P34.
Range is 71 miles (131 km). We're showing constant Delta altitude of 14.94 miles (27.67 km) between the two vehicles.
104:49:50 Duke: Snoop, Houston. We don't read Charlie Brown. Would you relay that, if he's done his 180 roll, to try the High Gain for us.
104:50:02 Stafford (in Snoopy): Roger. Charlie Brown, this is strictly as a relay. If youve done completed your 180 degree roll, will you try your High Gain for Houston? Over.
104:50:33 Young: Houston, Charlie Brown. On the High Gain.
104:50:36 Duke: Roger, Charlie Brown. We read you. How you doing?
104:50:50 Young: Houston, Charlie Brown. On High Gain Antenna.
104:50:54 Duke: Roger. Charlie Brown, Houston. We're reading you five-by.
104:51:24 Duke: Hello, Snoop. Houston. If you use any different f-stops on the film, we'd like for you to mark it so we can process it right. Over.
104:51:39 Cernan (in Snoopy): That ought to be a ball.
104:51:43 Duke: Roger.
104:51:59 Cernan (in Snoopy): I'll try, Charlie; I'll do my best.
104:52:02 Duke: Okay, Gene-o. I was just - had- Don't worry about it. Sorry.
104:52:19 Cernan (in Snoopy): No, don't be sorry. Hey, you guys are floating on the world out there sideways.
104:52:18 Duke: Okay.
104:52:23 Stafford (in Snoopy): As the Earth came up, on this Earth day, I guess you would call it, the north pole was to the right and the south pole was to the left, and looks like - see a lot of clouds over the Pacific Ocean. We were kind of busy. Didn't take much time to notice, but it was a beautiful sight. Over.
104:52:43 Duke: Roger. We're here and still spinning.
104:52:49 Stafford (in Snoopy): Okay.
104:52:55 Cernan (in Snoopy): Charlie, I don't know how the Big Man must see things, but if his view is any better than ours, it's got to be fantastic.
104:53:03 Duke: Copy.
104:53:35 Young: Houston, Charlie Brown. I'd like to get a sunset time. Over.
104:53:39 Duke: Roger, Charlie Brown. Stand by.
104:53:44 Young: Oh, never mind. It happens so fast around here, I ought to be instantaneously aware of it.
104:53:59 Duke: Charlie Brown, Houston. We got a time for you for sunset: 104 and 58. Over.
104:54:10 Young: 104:58? Over.
104:54:13 Duke: Affirmative.
104:54:17 Young: Roger.
104:54:35 Young: I show you at 64.89 miles (120.18 km). How do you agree with that, Snoop? 64.7 (miles) (119.8 km).
104:54:43 Stafford (in Snoopy): Roger. You're right on the money. We show you about 64.6 (miles) (119.6 km) now.
104:54:48 Young: Roger.
104:54:50 Stafford (in Snoopy): We're correlated right down there. That VHF is working beautiful. Just like the radar.
104:54:59 Young: That's mighty good gear.
104:55:00 Stafford (in Snoopy): Sure seems to be.
104:55:03 Cernan (in Snoopy): Hey; Houston, Snoopy.
104:55:04 Duke: Go ahead, Snoop.
104:55:08 Cernan (in Snoopy): Okay. For the record, we have been operating with Charlie Brown the whole time while he's been on VHF ranging, in ICS/PTT, and our hot mike apparently does not bother John at all; and we've had such good luck S-band with you folks down there that we've had hot mike a very short period of time.
The ICS/PTT (Intercommunication subsystem/Push to talk) communication setting only allows voice transmission on the voice actuated circuit (VOX) when the PTT switch on either the astronauts umbilical carrier or ACA hand controller is depressed. This mode was selected on the audio Mode switch on panel 8 for the CDR or panel 12 for the LMP, was placed in the ICS/PTT position. The term 'hot mike' refers to when the crew are transmitting voice in VOX.
Cernan's statement that the use of a 'hot mike' in the LM does not bother the CMP, is not quite borne out by the mission report. The VHF ranging system was being operated by the CMP. The mission report states 'All acquisitions were performed with a "hot-mike" configuration in the Lunar Module, which resulted in two false acquisitions. Both false indications were readily noted by the Command Module Pilot and reacquisition was accomplished normally'.
104:55:28 Duke: We copy all that. Thanks a bunch.
104:55:44 Cernan (in Snoopy): That S-band antenna makes noise, but it sure does track.
104:55:49 Duke: Okay.
104:57:42 Young: Roger. I see you. Very good.
104:58:19 Stafford (in Snoopy): Okay. Houston, this is Snoopy. We're at 60 nautical miles (111 km) closing and R dot looks real fine. I'm sure you're reading it down there. Everything looks real good from here, and I still don't have his flashing light from this distance of 60 miles (111 km). Over.
CSM Rendezvous beacon location.
CSM Rendezvous beacon on display spacecraft at KSC.
Rendezvous beacon on the Apollo 17 CSM America.
104:58:35 Duke: Roger, Tom. We copy. We got you plotting right down the line on your charts. Over.
104:58:42 Stafford (in Snoopy): Roger. Thank you, Charlie. It's looking good here.
104:58:47 Young: Okay. They're on. I'll turn on these running lights and EVA lights too, Tom. Maybe you can - can see them when you get closer.
During the final rendezvous and docking, the LM crew need to be able to make a gross determination of the CSM attitude. This is aided by the CSM running lights. The running lights consist of 8 lights on the service module, two green, two red, and four amber. Four of these lights are located on the forward bulkhead, approximately half way between each of the axes. The remaining four lights are located 6 inches (150 mm) forward of the service module rear bulkhead, also half way between the axes. The two lights in the upper right quadrant are green, the two lights in the upper left quadrant are red, and the four lights in the lower quadrants are all amber. The LM crew can determine the CSM attitude depending on what combination of lights they can see.
CSM running lights
CSM running lights on the Apollo 17 CSM America.
104:58:56 Stafford (in Snoopy): Okay.
R-dot is the range rate. We show that as 120 feet per second (36.6 m/sec) and closing.
105:00:23 Young: Snoopy, you got a later TPI time?
105:00:35 Young: Roger.
105:10:51 Cernan (in Snoopy): Hello, Houston. This is Snoopy. AGS comes out with a TPI at an angle of 26.51, of 24.4 to initiate, 55.9 to total, and that time is just about the same time I'm looking at right now of 105:23:20.
Cernan has been using the AGS to calculate a TPI solution. To call up the TPI Execute Routine, he called up address 410 on the DEDA, and made an entry of +40000. Then he called up address 310 and enters the TPI ignition time.
The AGS can now display the values it has calculated. Calling address 303 will display the line of sight (LOS) angle between the LM local horizontal at TPI ignition and the CSM, 26.6° being the optimum angle. Address 267 displays the total Delta-V required from the TPI manoeuvre to initiate the final climb to rendezvous, and address total Delta-V to be gained from the TPI burn and the following midcourse corrections. Finally address 373 displays the AGS calculated TPI ignition time.
105:02:17 Duke: We Copy, Snoop. Thank you much.
105:03:57 Cernan (in Snoopy): John, our new TPI time is 105:23:06.01; 105:23:06.01.
Using program P34, the LGC calculates the TPI ignition time for the desired LOS elevation angle.
105:04:06 Young: Roger. I got it.
105:04:14 Cernan (in Snoopy): That's only moved up towards us about 12 seconds.
105:05:04 Stafford (in Snoopy): Okay, John. Coming up on 52, say, 0.3 miles [96.9 km] or so. I still don't have you in the sight. No problem. We're locked-on solid.
105:07:15 Young: Did you get your final TPI time? Over.
105:07:19 Stafford (in Snoopy): Stand by.
105:07:26 Young: Go ahead.
105:07:28 Cernan (in Snoopy): John No. We're not going to push final Comp until 12 minutes, but the latest one we got is what I just gave you.
The final computation of the precise TPI ignition time is made at ignition minus 12 minutes, using P34.
105:07:33 Young: Okay. That will be fine.
105:07:35 Cernan (in Snoopy): Is that converging with you?
105:07:37 Young: Well, that thing is still calculating. It really takes a while.
105:07:46 Stafford (in Snoopy): Charlie Brown, Snoop. We've suddenly seen on this last recycle through 6 feet per second [1.8 m/sec] out of plane.
105:07:54 Young: Roger. Wait a second. [Garble].
105:08:10 Stafford (in Snoopy): Hello, Houston, Snoopy. Do you have somebody that can read our erasable - check what our radar angle bias is? Over.
105:08:18 Duke: Roger. Stand by.
105:08:20 Young: Hey! My TPI time - my TPI time - this later, is 105:23:16.79. How's that for a good correlation.
Young is independently calculating the LM TPI ignition time, using the CMC program P74.
105:08:49 Duke: Snoopy, Houston. Your radar bias is in the noise. Over.
105:08:55 Stafford (in Snoopy): Okay. Real fine, Charlie. Thank you very much.
105:08:59 Duke: Roger. And Charlie Brown, Houston. Over.
105:09:05 Young: Go ahead. Over.
105:09:06 Duke: Roger. If you get a chance, we'd like to look at...
105:09:10 Duke: Okay, Charlie Brown. We'd like you to bring your Logic up so you can dock anytime. And so we can give you a Go for the arm and also, I did you get a chance to cycle through the tunnel vent valve to LM Press? Over.
105:09:28 Young: No. Negative. Not yet.
MCC-H are checking whether Young has had a chance to cycle the docking tunnel vent valve, in the vain hope that whatever is blocking it will be ejected.
105:09:32 Duke: Okay.
105:09:35 Young: Okay. The - you want the - SECS breakers are coming On, and the Pyro A and B battery breakers are going In.
105:10:03 Duke: Charlie Brown, Houston. You are Go for Pyro Arm at your convenience. Over.
The SECS (Sequence Events Control System) circuit breakers on panel 8 provides DC power from battery bus A to the logic A bus (and battery bus B to logic bus B) in the master event sequence controller when the Seq Events Control System switches 1 & 2 are placed in the Logic position. The Arm, A & B circuit breakers, also on panel 8, apply DC power from battery bus A & B to the Seq Events Cont Sys-Pyro Arm switches A and B.
Once the circuit breakers are pushed in, MCC-H can confirm the connections to the buses are satisfactory and give the Go for Pyro Arm.
The CMP, nearer to the time of the final rendezvous and docking, will place the Seq Events Cont System, Logic switches in the 1 & 2 position, and the Pyro Arm switches in the A and B position. This action energizes the motor switches in the Lunar Docking Events Controller, which controls the docking probe retraction.
SECS Logic and Arm circuit breakers on panel 8.
105:10:10 Young: Roger. Thank you.
105:10:55 Cernan (in Snoopy): Charlie Brown, Snoop. When you get your solution, we're interested in the out-of-plane part, so call it down to us, would you?
105:11:01 Young: Yes sir.
105:11:24 Young: Okay. My Noun 81 is minus 21.8, plus 4½, and plus 10.14,
Young is using the CSM AGC P34 to make his own calculations of the required Delta-V values, that the LM should burn at the TPI manoeuvre. The resulting values are; minus-X, 21.8; plus-Y, 4.5; plus-Z, 10.14; all in fps (minus-X, 6.6; plus-Y, 1.4; plus-Z, 3.1 m/s). The LM will adopt the out-of-plane plus-Y value.
105:11:34 Young: Plus 4½.
105:11:52 Young: Yes. For a change.
105:12:34 Young: Roger.
105:13:00 Cernan (in Snoopy): Houston, our new TPI time is 105:22:56.19.
105:13:06 Duke: Roger. Copy.
105:13:14 Cernan (in Snoopy): Why don't you give me an LOS time and an AOS while you've got it, while we got a chance.
105:13:19 Duke: Roger, Snoop. LOS is 105:32. AOS, 106:19. Over.
105:13:31 Cernan (in Snoopy): I got them. Thank you.
105:13:33 Duke: Roger. And Charlie Brown, Your LOS about the same.
105:13:36 Young: How my...
105:13:37 Duke: Your LOS about the same, Charlie Brown, and AOS also. Over.
105:13:44 Young: Roger. I missed those.
105:13:46 Duke: Okay, LOS...
105:13:47 Cernan (in Snoopy): 105:32 and 106:19.
105:13:57 Young: Okay. I'll get them [garble] for you later.
105:14:18 Stafford (in Snoopy): Okay. Charlie Brown, this is Snoop. I'm finally starting to see your flashing light, very faintly at 42 miles (77.8 km). Very faintly.
Young now prepares for an SPS backup burn, using P40, should the LM not be able to perform the TPI manoeuvre. He then manoeuvres to the desired attitude if the SPS burn is required.
105:15:55 Cernan (in Snoopy): Charlie Brown, this is Snoopy. We're burning your out-of-plane. Here's my Noun 81 for you that we're going to burn.
105:16:02 Young: Go.
105:16:03 Cernan (in Snoopy): Plus 21.7, minus 4.5, and minus 9.6.
The Noun 81 values from the PGNS for the TPI manoeuvre are; plus-X, 21.7; minus-Y, 4.5; minus-Z, 9.6; all in fps (plus-X, 6.6; minus-Y, 1.4; minus-Z, 2.9 m/s). This incorporates the minus-Y 4.5 fps (1.4 m/s) out-of-plane correction.
105:16:11 Young: Roger.
105:18:09 Stafford (in Snoopy): Okay. Charlie Brown, this is Snoopy. We're pitching down to put our X-axis towards you for the Auto maneuver from TPI.
105:18:17 Young: Roger.
Range is 39 miles (72 km).
105:19:28 Stafford (in Snoopy): Okay. We're at burn attitude, Charlie Brown.
105:19:32 Young: Roger. Almost me, too.
105:19:35 Stafford (in Snoopy): How about that?
This will be another Reaction Control System burn but the propellant will be fed from the Ascent Propulsion System tanks through the interconnect.
105:20:55 Stafford (in Snoopy): 2 minutes to the burn.
105:20:59 Young: Roger.
105:21:02 Cernan (in Snoopy): And Charlie Brown, our charts agree very closely, so we're Go.
105:21:07 Young: Roger. My numbers agree with your numbers.
105:21:10 Cernan (in Snoopy): Then, I guess were all in agreement, then. Let's go.
105:21:39 Cernan (in Snoopy): 1:19 to the burn.
105:21:42 Young: Roger.
105:21:57 Stafford (in Snoopy): Mark.
105:21:58 Stafford (in Snoopy): 1 minute to the burn.
105:22:00 Young: Roger.
105:22:24 Stafford (in Snoopy): 35 seconds. DSKY blank.
105:22:50 Cernan (in Snoopy): 7 seconds, John.
105:22:52 Stafford (in Snoopy): 5, 4, 3, 2, 1. Burning.
TPI burn is made using the LM RCS. Ignition at 105:22:55.58.
105:22:58 Cernan (in Snoopy): We're burning.
105:23:00 Young: Go to it.
105:23:02 Duke: We copy.
105:23:04 Cernan (in Snoopy): Got 15 to go.
105:23:05 Young: Roger.
105:23:06 Cernan (in Snoopy): 10 to go.
105:23:17 Stafford (in Snoopy): Burn's complete.
105:23:18 Young: Roger. Good show.
105:23:25 Duke: Snoop, Houston. We see you trimming. Good show.
105:23:44 Stafford (in Snoopy): Okay. 0, 1-1/10.
105:23:49 Duke: We copy, Snoop.
105:23:59 Stafford (in Snoopy): And Snoopy's pitching back up to acquire.
The LM is pointing the plus-Z axis towards the CSM to acquire it using the Rendezvous Radar. The LM crew are now focusing on Rendezvous Radar tracking to establish what trajectory errors exist following the TPI burn. P35 is used by the LM to compute the required Delta-V and other initial conditions required by the LGC for LM execution of the next midcourse correction of the transfer phase of an active LM rendezvous. Two opportunities are available for midcourse corrections if required, 15 and 30 minutes after TPI.
105:24:09 Stafford (in Snoopy): Houston, this is Snoop. You can't believe how noisy those thrusters are.
105:24:15 Duke: Roger, 10. Can't even imagine.
105:24:18 Stafford (in Snoopy): It sounds like being inside a big rain tub with about 2-inch (5-cm) hail beating all over you.
105:24:25 Cernan (in Snoopy): Hey, babe. Heres where the [garble] AGS [garble].
105:24:36 Young: Okay. Pitching up to give you radar target here.
Young pitches the CSM up to allow P20 rendezvous radar tracking and tracking of the LM optically through the sextant.
105:24:39 Cernan (in Snoopy): He's waiting to...
105:24:40 Stafford (in Snoopy): Yes.
105:24:41 Young: Okay, Snoop.
And Snoopy's now on an intercept trajectory to Charlie Brown. And he burned his own solution which agreed very closely within a few tenths with the ground solution. He burned Delta-V of 24.1 feet per second (7.3 m/sec) at 105 hours, 22 minutes, 56 seconds.
Young is running P35, CSM transfer phase midcourse targeting program.
105:27:18 Stafford (in Snoopy): Okay, Houston. This is Snoopy. We have solid lock, and first update appears real good.
105:27:26 Duke: Roger, Snoop, we copy. We got 4 minutes 50.
105:27:29 Duke: Mark.
105:27:30 Duke: To LOS for you. Over.
105:27:35 Stafford (in Snoopy): Roger.
Range 26 miles (48 km).
Range rate 125 feet per second (38 m/s).
105:28:33 Cernan (in Snoopy): Houston, Snoop. I'm taking you off of High Gain.
105:28:36 Duke: Okay. Roger. You're reading my mind.
105:29:15 Stafford (in Snoopy): ...20.4 miles [37.8 km]. Over.
105:29:24 Young: Roger. I concur. [Garble].
105:29:40 Cernan (in Snoopy): We're only 20 miles (37 km) [garble] way.
Current radar range, 20 miles (37 km).
105:29:49 Young: [Garble] VHF, I think. [Garble].
105:29:58 Young: [Garble] 5 minutes now.
105:30:11 Young: God damn! That one felt like it was coming inside.
105:30:50 Cernan (in Snoopy): I can barely see it.
105:30:51 Young: Can you?
105:30:52 Cernan (in Snoopy): Just barely.
105:30:54 Young: I can't see any flashing at all.
105:31:23 Stafford (in Snoopy): There he is.
105:31:25 Young: [Garble] with it.
105:31:28 Stafford (in Snoopy): Okay.
105:31:57 Young: Okay, any time.
105:31:59 Cernan (in Snoopy): Mark it.
105:32:00 Stafford (in Snoopy): It's right on them.
105:32:01 Cernan (in Snoopy): Right on them?
105:32:02 Stafford (in Snoopy): Yes.
And this is Apollo Control at 105 hours, 32 minutes. Both Charlie Brown and Snoopy have gone behind the Moon, and we have Loss Of Signal. When we next see them, they should be station keeping; getting ready to dock. We're showing the Command Module, Command Service Module Charlie Brown, in a 63.37-nautical-mile (117.36 km) orbit, and Snoopy is on an intercept trajectory. Snoopy performed two good burns during the time we had acquisition, the Constant Delta Height maneuver at which time we had a Constant Delta Height following that maneuver 14.94 nautical miles (27.67 km), and then the terminal phase itself completed just a short time ago. The - there are two midcourse corrections programmed if needed. The nominal Delta-V is zero in both of those, and Charlie Duke just remarked that just before Snoopy went around the corner, he heard Tom Stafford say they were just taking a mark, and they were right on. So they may or may not do either of those midcourses. And then the terminal phase is finalization. The braking maneuvers will be performed behind the Moon, and at acquisition time, they should be station keeping within a few feet of each other. Acquisition for the Charlie Brown; 106 hours, 18 minutes, 39 seconds; for Snoopy; 106 hours, 18 minutes, 55 seconds. This is Mission Control, Houston.
The LM DSEA voice and data recorder, stopped recording at 104:44:40. Therefore no transcript exists of the crew activity in both spacecraft during the final approach, mid-course corrections, braking and station keeping.
Terminal phase events.
The first midcourse correction was carried out at 105:37:56, using the RCS. Delta-V values; plus-X, 0.0; minus-Y, 0.4; plus-Z, 1.2; total 1.27 (all fps) (plus-X, 0.0; minus-Y, 0.12; plus-Z, 0.36; total 0.39 m/s).
The crews commented on the midcourse corrections in the post mission crew debrief.
Cernan, from the 1969 Technical debrief: "P35 and P20 worked like a gem. Our updates, which we looked at a number of times, were zero in range and zero in velocity. Our midcourse corrections came out very small. The first time they were minus 0.8, minus 0.4, and plus 0.8 (fps) (minus-X, 0.24; minus-Y, 0.12; plus-Z, 0.24 m/s). We were plotting right up the pike; range rate was nominal."
Stafford, from the 1969 Technical debrief: "We were debating whether to make the first midcourse or not, but we decided to go ahead and do it since we wanted to evaluate the system from a performance standpoint."
