See list attachedOctober 17, 196868-PA-T-227APA/Chief, Apollo Data Priority CoordinationD Rendezvous Open Items, Action Items or whatever you call them
I've reviewed my notes of the D Rendezvous meetings over the last couple of months and have found the following open/action items. I guess most, if not all, are being worked on. But time grows short and so I'm sending this list around to make sure of it. If you know of others, please give me a call.
1. (TRW) What are the expected ΔV residuals at the conclusion of the AGS controlled, DPS phasing burn? We want to null the x-axis to within 2 fps but must avoid excessive RCS jet impingement.
2. (MPAD) Shall the DPS be staged for rendezvous at TPI? It has been decided that the greatly improved vehicle maneuverability and resultant saving in RCS fuel makes this desirable, provided no recontact with the staged DPS is positively assured. Ed Lineberry is developing a technique to do this.
3. (MIT) Braking procedures are placing heavy weight on the rendezvous radar range and range rate, of course. If the tape meter fails, it is hoped that the crew can get raw radar data displayed on the PGNCS DSKY by use of the V62 RR self test routine. MIT is requested to verify this technique works and inform us of any constraints or idiosyncrasies involved in this procedure.
4. (MPAD/ASPO) What is the accuracy of the PGNCS rendezvous navigation when using an IMU aligned with the COAS rather than the AOT? ASPO should define the accuracy of a COAS which has not been calibrated inflight.
5. (MPAD/MIT) When computing the TPI₀ solution using the PGNCS Elevation angle option, what solution will be obtained? Note that the spacecraft will pass through 27.5° two times in the football trajectory.
6. What other problems or special procedures are needed for the TPI₀ maneuver, if any? For example, can dispersions make it more desirable to use the time option. It is interesting to note that the TPI₀ maneuver is applied more-or-less away from rather than toward the target spacecraft! This certainly affects the backup techniques involving boresighting along the LOS developed for a “standard” rendezvous TPI.
7. (TRW/AGS) How is the CSM state vector in the AGS updated if the PGNCS has failed and the CSM makes a maneuver? Note the AGS has no program equivalent to the PGNCS “Target ΔV” (R32).
8. (FCD) Assuming the LGC is powered down after the docked DPS burn (is this true or is it set to standby?), an E memory check is probably needed to commit to rendezvous. If required it must be added to the timeline and positive procedures developed to do it.
9. (MIT) Can the time required to make a GNCS PIPA bias test be reduced to less than 256 seconds?
10. (MPAD) Determine expected (3 sigma) shift in TPI time from nominal during the rendezvous to assist in selecting the TPI situation to aim for.
11. (FCSD) Define TPI window of acceptable lighting conditions and degree of constraint “hardness.”
12. (Data Priority) Based on 9 and 10 (above) establish the mission techniques regarding under what conditions, if any, the “Elevation Angle” option for TPI should be abandoned in favor of the “Time” option.
13. (GAEC/TRW/GCD) Shall an AGS gyro calibration be performed during the rendezvous period of activity? This depends on expected improvement in performance versus probability of screwing up the system.
14. How do we verify that the AGS is properly aligned from the PGNCS given the possibility of CDU transients?
15. Of course techniques for monitoring all of the main engine maneuvers are still undefined and must be developed.