See list attachedOctober 25, 196868-PA-T-235APA/Chief, Apollo Data Priority CoordinationSome more C’ Lunar Orbit Mission Techniques
At our October 14 C' Lunar Orbit Mission Techniques meeting we settled on a few things I would like to tell you about. Along with the TEI block data to be sent up each revolution in lunar orbit, we are also going to update the spacecraft state vector in the CMC every revolution. This will be done after tracking the pseudo-landing site and before the P52 fine alignment. Some consideration was also given to including a TEI external ΔV targeting load on the uplink each revolution but this will not be done since the block data should be adequate. Incidentally, the block data will be for a TEI maneuver for the revolution following the present one – that is, about three hours after its transmission.
We discussed the use of the tape recorder if the high-gain antenna does not work. In this event, you recall, it is not possible to dump the tape at lunar distances. The question to be answered is: What data should be recorded on the tape to be brought back by the spacecraft out of lunar orbit? Surely high-bit recording of the SPS burns – LOI and TEI – must be included and will use about half of the tape (15 minutes at high-bit rate). Recording of landmark tracking on the back side of the moon should have a high priority to be included and will take very little tape. The technique will be for the crew to obtain all of the sightings on a given landmark, which the CMC will temporarily store in memory. After completion of taking that set of observations the recorder is turned on for approximately 20 seconds at low-bit rate to collect and save that data. Since we are making eight sets of observa- tions on the back of the moon, we are only using 160 seconds worth of tape, that is, about 2½ minutes out of the remaining one-half hour at low-bit rate.
What else should be recorded is an open question and people with require- ments should come forward soon and identify themselves so the procedures can be worked out for the “no high-gain antenna” situation. Of course, if the high gain is working, continuous recording on the back side of the moon should be standard practice.