Upthread: “D” RENDEZVOUS MISSION TECHNIQUES ACTION ITEM LIST (Jun 25, 1968)
Downthread: “D” Rendezvous (Jul 25, 1968)
Massachusetts Institute of Technology Instrumentation Laboratory Cambridge,Massachusetts 02139 Attn: D. G. Hoag, Director Apollo Guidance & Navigation ProgramJUN 28 196868-PA-T-136AChief, Apollo Data Priority Coordinationnone
At the June 14 “D” Rendezvous Mission Techniques meeting, I unofficially (I guess) assigned at action item to your people who were there. Specifically, we asked for MIT's recommended procedure for adjusting the W-matrix during rendezvous navigation in both the LGC and CMC. As a matter of fact, I understand that your people intend to discuss this with the “D” flight crew while they are there the week of June 17. However, I would appreciate it if you could write down the procedure you recommend in one of your informal MIT memos for discussion and incorporation into the mission techniques at our next meeting.
Incidentally, I think there was substantial benefit from having your people at our last meeting and hope they can come down for the next one, which is currently scheduled for July 12.
“D” RENDEZVOUS MISSION TECHNIQUES OPEN ITEM LIST
(To be discussed at next meeting)
1. G&CD has recommended in their memo, EG21-M-59-68-376, that the AGS be used in the following manner on the “D” Rendezvous:
a. Align and initialize the AGS to the PGNCS after each PGNCS alignment.
b. Perform AGS targeting for all real and pseudo-burns using the on- board solution. Execute the burns with PGNCS, unless PGNCS has failed.
c. Perform an accelerometer calibration before each real and pseudo- burn.
d. Perform gyro calibrations in sufficient number (at least four times over a two-hour period) to verify the technique.
e. Perform at least one AOT or COAS alignment of the AGS, preferably AOT.
f. Update the AGS with the RR near the second TPI burn.
g. In the event of a PGNCS failure during the second rendezvous sequence, compute the AGS solutions with either charts or MSFN and execute the burns with the AGS if there is reasonable agree- ment. The AGS should be updated with the RR.
2. MPAD to present the pre-rendezvous ground rules and techniques to provide adequate lighting conditions and station coverage.
3. MPAD to report on analysis regarding modification to the RCS Separation burns to reduce probability of recontact due to small maneuver execution dispersions.
4. MPAD to report on which mirror image maneuvers need be biased as well as consequence of not doing so.
5. Crew will report results of simulator exercise regarding use of unstaged LM in terminal phase rendezvous.
6. FCD to report on techniques for checking the rendezvous radar during the mini-football and the football phase for purpose of go/no go.
7. MPAD to report consequences of using the MSFN uplinked PGNCS CSI/CDH targeting in the AGS for maneuver execution in the event of PGNCS failure. That is, are the errors thus incurred acceptable?
8. FCSD will define limits of acceptable TPI time slippage beyond which corrective action must be taken. Apparently, they will be based on CSM active rendezvous lighting constraints.
9. MPAD to establish acceptable difference limits for use in comparison of onboard vs MSFN rendezvous targeting (CSI, CDH, and TPI).
10. MIT to present recommended procedures for controlling the W-matrix by crew input to the LGC and CMC.
11. MPAD to report results of their survey into the onboard computation of CDH execution time which has been showing a tendency to be late. If this persists, it will result in TPI time slip, excess RCS ΔV costs, and difficulty in solution comparison.
12. FCD will report on acceptability of onboard PGNCS accelerometer bias determination while out of MSFN station coverage.
13. Rendezvous maneuver monitoring procedures will be reviewed for both critical and non-critical rendezvous phase burns. Attitude, attitude rate, and over and under speed limits will be established as well as the actions to be taken if they are exceeded. This, in effect, encom- passes the procedures to be followed in the event of a partial burn.
14. Review procedure and expected accuracy of the initial LM platform drift test made while docked to the CSM.
15. FCSD and MPAD will provide for review an up-to-date rendezvous navigation tracking schedule for both the LM and CSM.
16. Review Mission Control Center/crew pad message format.