Apollo 17: Crew debriefing, TLI and translunar coast

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[edit] Apollo 17 Technical Debrief

Manned Spacecraft Center Document MSC-07631 -- 4 January 1973

[edit] 5.0 TLI THROUGH S-IVB CLOSEOUT

CERNAN

The TLI burn from the ground targeting point of view and targeting went just as written. We went down the checklist and cue card without any problems or any anomalies, without any changes except t o the manual. We had a change to all our manual angles to monitor the S-IVB burn because of the late lift-off. We wrote those down on our cue cards and were going to use those in case we had to take over during the burn. We had to change to the nominal and we rewrote both of those on our cue cards. That's the only basic change I think we had.

SCHMITT

The communications all through Earth orbit were excellent, as I recall. There was no difficulty getting the pads up. They came up expeditiously and well read. We actually gained a little time because we didn't have television. But we didn't need it. We could have configured it for use.If there's ever any attempt to do weather observing from Earth orbit , in the low orbit like that , you're going t o have to have a very clear plan of where you're looking at what time you're looking in order t o make reference as to where you are because you're moving so fast. You can't really keep track of where you are and specifically in terms of weather observation. Later on, once you get the whole globe in view, it's a relatively simple thing to pin down to within a few degrees of latitude and longitude where you are looking on the Earth.

CERNAN

On all these lunar missions, we've never really done much in Earth orbit except get prepared for the TLI burn. Future Earth-orbit flights need this continual map update, you're right. You have to do that . As I think back to 3 days in Earth orbit , unless you continually follow a map and a map update as to your rev as you progress around the world, what part of that world you're looking at is very difficult to follow except the precise piece of real estate you're flying over.

SCHMITT

The lunar orbital operation is somewhat different because you stay in the same groundtrack much longer I think.

CERNAN

The S-IVB performance was outstanding. She lit off on time and burned for 5 minutes and some odd seconds as I recall. And we had shutdown on time. The residuals and the EMS on the spacecraft are written down somewhere, but they were all very nominal, very excellent. We stayed in IU. As the S-IVB maneuvered, we flew through a sunrise during TLI, which in itself was also very interesting, very spectacular. We had nominal S-IVB performance after shutdown; and maneuvering to the sep attitude , we went through checkout load NOUN 17 and NOUN 22. There was again no noticeable pogo. The S-IVB sounded and performed just like it did on the insertion phase burn and I'll let the CMP pick up the separation and the transposition and docking.

SCHMITT

We all were very aware of PU shift.

CERNAN

I guess I could have called that or I was looking forward to seeing it. It is on my checklist. It' s on my cue card and I've looked for it and I've seen it in the simulator.

SCHMITT

It just didn't register in the simulators, I guess. And the other thing flying through that sunrise, it did to a small degree interfere with visibilit y in the cockpit.

CERNAN

It didn't bother me from the standpoint of monitoring on my side at all.

EVANS

As far as the separation from the SLA, it was nominal. There's a louder bang than I expected from pyros. This is the first time that I really noticed that in the plus-X translations, or in any translations as far as that goes, you get about c0.4 per second rates within the dead band. As opposed t o the simulator, it has about 0.1' per second on any of the translations maintaining attitude.Formation flight was great. The S-IVB by itself was as steady as a rock out there. No problems. I couldn't tell it was dead banding or moving at all. I came in relatively slow, about 0.1ft/sec, somewhere in that area.Docking was nominal. As soon as he got capture on the thing, there were no rates. Everything was steady. I didn't have to handle the translation controls or null rates at all. We went directly to hard dock. There's more spacecraft movement during that period because I feel that the COAS and the docking target were off a little bit. And I don't say misaligned, but it's a little bit off. But, of course, it was in limits and was no problem.

CERNAN

When we went t o retract, we got our big ripple fire - bang on the latches, so we had a relatively good hard dock. We only got one gray indication on the talkbacks. The other one was barber pole.

SCHMITT

There's a lot of descriptive material, I think, in the transcript on that. As I recall, we got two pulses in the ripple fire. It seemed like there was one or two latches and then the ripple fire.

CERNAN

I just recall a woomph!

SCHMITT

I think, if you look at the transcript, we said that there were two pulses t o it.

CERNAN

Subsequent inspection of the latches showed that there were three latches which were not made entirely. One of them, as I recall, had t o be recocked. Anyway, it turned out that once we got those three latches (which at that time looked like they were operating properly) reset, we got two barber poles on the talkbacks. Ultimately, latch 4 was found t o be unseated on the ring, although, at that time, it looked nominal. The attitudes given us were excellent; we were able t o watch the S-IVB maneuver. We were able to see the S-IVB vent and it all went well and nominal.

SCHMITT

It was very clean as far as any debris or anything coming out during the docking phase, and I could see a few little things that were bouncing around inside around the LM, particles of some kind. It was nothing like previous flights where they had a lot of debris. It was very clean.

CERNAN

As I recall, we undocked and separated just a little earlier than had tentatively been planned, but that was no problem because we were ready to do it.

[edit] 6.0 TRANSLUNAR COAST

EVANS

The IMU realignment and optics calibration - We've mentioned the visibility of the stars in talking about the systems in the section on systems. Systems anomalies - We already hit that one. Heat flow demonstration - it worked great. There were no real problems on it. It was a real time operation with ground. Everything is recorded on the down-link.

SCHMITT

There was some problem with the orientation of the experiment. As I recall, you reoriented it between the two experiments. I never quite understood why there was that problem. It was a checklist problem or something.

EVANS

The problem was something about the orientation of the radial experiment with respect to the X-axis. I pointed the radial experiment along the X-axis. It was supposed t o be perpendicular to the X-axis, but it shouldn't have made any difference in the results anyhow.PTC - We got it started and had no problem.Cislunar navigation or navigational sightings - It's already mentioned in the systems part.

SCHMITT

You mentioned apparently you had a very good Delta-H determination - horizon determination.

EVANS

The P23s worked out great. The vehicle is heavy enough that you can control it quite easily with minimum impulse. I used the EMP on P23 so that once you had the star in the field of view and all lined up you could recycle through the program without getting all the maneuver data on the thing. While it was recycling, I could just watch the spacecraft and not let it drift too far out of field of view. When it came back in, I would maintain the star in the middle of the crosshairs of the sextant and maneuver the spacecraft so I could get the substellar point and maintain the substellar point. As it turns out, I guess the resulting Delta-H is within the limits that are recorded in the E-memory.Midcourse correction - I think that's all recorded on the down-link. There should be nothing anomalous about that .Photography - Jack, I guess you've taken most of the pictures on the translunar coast.

SCHMITT

Most of the photography came to GET within a few minutes. It was almost a continuous effort at the beginning of the day and maybe in the middle and at the end with some irregularities - getting a continuous record of a very nice view of the Earth and the weather patterns. We had about three-quarters to two-thirds Earth through most of the translunar coast period. And that should be in the photographic logs on the ground.

SCHMITT

High gain antenna performance - Through the whole mission, not just translunar coast when I was using it, it was perfectly nominal. The ground did most o f the calling on it. Between omis and high gain when they didn't call, it was easy enough to get the high gain t o peak up. Usually in MANUAL and WIDE and either AUTO or REACQ depending on the occasion, it seemed to work very well. I wasn't aware of any high gain anomalies.

EVANS

Daylight IMU realign and star check - Again you can't see the stars through the telescope. Most of the time you can't see the stars through the telescope. However, if you have a good alignment and it shows up in the sextant, there's no problem.ALFMED experiment - I think that's all recorded on the downlink. The one thing that I might add to that is that prior to this time I hadn't seen a light flash. So I put it on anyhow and sure enough the light flashes are there. And that's all recorded.

SCHMITT

In the experiments notebook, where the LMP was taking notes on the ALFMED experiment comments, it was necessary in this translunar coast period because we were on omnis and PTC. It is very difficult,with two guys observing t o take notes if they both start seeing marks at the same time. Interestingly enough maybe even for the experiment the marks seem t o come in batches. There'd be periods of quiescence, then both of us would start seeing marks. So the notes are relatively incomplete and, hopefully, the DSE plus the down-link will fill in all the gaps. It's feasible to take notes but they will be incomplete compared to the verbal description.

EVANS

CM/LM Delta-P - Nominal.Orbital science photos - We really didn't have any on translunar coast.

AS17-154-23598: View of LM, Earth from moon. Perspective seems correct for hatch window - perhaps window was partially covered?

SCHMITT

Nothing was called out. We used about a half a mag on the Earth, maybe more.

EVANS

More than that. We used a full mag before we got to the Moon.LM and tunnel pressure was okay, no problems.Removal of the probe and drogue - Went as advertised. Worked great.Odors - Every time I got up in the tunnel after docking or anytime, there was always a musty burned odor or something. It's hard t o describe.

SCHMITT

Like a powder burn.

EVANS

Kind of like a powder burn, I guess. This was there both in lunar orbit docking and transearth docking. This was the second day we were out when we finally went up in the tunnel. Every time I opened up the tunnel, that' s what it smelled like.

We didn't mention the SIM door jett. I guess I never did see the door. You guys wouldn't let me up to the window.

SCHMITT

Yes, we saw the door. I didn't get it right away. I was supposed t o be taking pictures out of the window.

CERNAN

I saw it right away out of the hatch window. You should have been taking pictures out of the hatch because it wasn't immediately obvious out the window. It came off just as clean as a whistle, with almost no tumbling until it got 20 or 30 feet away from the spacecraft. Then you could see that there was just a little roll and a little pitch as it drifted on away, but very very little. Not a great deal of debris and garbage as I recall came off with it either. You could probably sum up all the pyro operations by saying there are absolutely no questions. They're just good, solid, hard thuds, including SIM door jett . Just a big solid bang, really not that much different than some of the other big bangs when you separate the spacecraft. They're just all big, hard, solid clunks.

SCHMITT

I don't remember what Apollo 16 said about it. Apollo 15 was suited, and they commented they didn't even know it went.

CERNAN

I'm surprised at that, even suited. It was a very definite jolt to the spacecraft when the door was jettisoned.

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