See list belowMAR 4 196868-PA-T-48APA/Chief, Apollo Data Priority CoordinationAscent Phase Mission Techniques meeting – February 27, 1968
1. In the absence of Charley Parker, our beloved leader, I inherited the job of chairing this meeting which probably accounts for why we didn't really get an awful lot done. However, there are a couple of things that are probably worth reporting.
2. We discussed the importance of the “stage verify” discrete to the spacecraft computer. Apparently, its sole purpose is to initialize the DAP such that it may perform properly. For example, it stops sending steering commands to the DPS trim gimbals. It also changes the spacecraft mass used in DAP operations from the ascent stage, plus whatever remains of the descent stage, to ascent mass only. Based on this information it computes jet firing duration for attitude control differently, of course. I had been concerned that failure to get this signal during Ascent would cause poor attitude control and we are initiating a program change request to back up “stage verify” with the “lunar surface flag” since whenever that event occurs use of the ascent stage only is a certainty. Jack Craven (FCD) pointed out that due to the design of the system the much more probable failure is to get a “stage verify” signal prematurely. If that happened, when we are still operating on the DPS, it would stop DPS steering and would make the RCS attitude control extremely sluggish. That would be bad news! All that is required to do this is for either of two relays to inadvertently open.
3. As you know, we are planning to devote a short period of time immediately after landing on the lunar surface to checkout of critical systems. This would be done both onboard and in the MCC leading to a GO/NO GO for one CSM revolution (about 2 hours). This is exactly the same sort of thing as the GO/NO GO for one revolution following earth launch. Jack Craven accepted the action item, which I had previously discussed with Gene Kranz, to establish how long it should take to do this system check in order that we may make all other mission planning and crew procedures consistent. It is expected to be in the order of 3 minutes, unless it takes a long time to really detect an APS pressure leak. Until the GO/NO GO we intend to remain in a state from which we can instantly “abort stage” and go. After that it will take much longer.
4. Almost all the rest of our discussion dealt with what the command module should be doing during and immediately following LM ascent from the lunar surface. One unresolved question was whether or not the command module should attempt to observe the LM ascent with the sextant. It was not clear what purpose would be served other than more rapid acquisition for rendezvous navigation tracking after insertion. It seemed to us the most important thing, of course, was for the command module to take whatever steps are necessary to assure getting a good LM state vector in its computer for rendezvous maneuver targeting as soon as possible. It seems almost certain that we should load the nominal LM insertion state vector in the CMC from the ground prior to LM ascent to guard against subsequent communication breakdown. It was also agreed that we should probably prepare the MCC to automatically take the LM post-insertion state vector from the LM telemetry and transmit it back to the command module. Whether we would actually do this or not depends on whether we lose more by forcing the command module to stay in the Uplink Command program (P-27) thereby preventing rendezvous tracking and onboard navigation for a substantial period of time. That is, analysis may show that with good VHF ranging and/or sextant tracking the command module may be able to converge on an acceptable LM state vector better without this ground participation, if it gets going more quickly.
5. I guess I am attacking the old “MIT me” in stating that we are seriously handicapped by having no reliable definition of the Luminary lunar surface and ascent programs (e.g. GSOP Chapters 4 and 5). I understand review copies of these should be available within 3 to 6 weeks and I am sure nothing more can be done to speed them up. We'll eat'em raw when they get here!