Seventh “D” Mission Rendezvous Mission Techniques meeting

See list belowMAR 13 196868-PA-T-61APA/Chief, Apollo Data Priority CoordinationSeventh “D” Mission Rendezvous Mission Techniques meeting

1. The “D” Rendezvous Mission Techniques meeting of March 10 was probably one of the least productive so far, and I sincerely apologize for it. I must have been tired or something. Even so, with all that talent present, there must be something worthwhile reporting.

2. At one of our earlier meetings we tentatively established that platform alignments would be performed by both vehicles during each period of darkness throughout the rendezvous exercise. Paul Pixley (MPAD) presented some data at this meeting which showed that, from a rendezvous navigation standpoint, loss of observational data—rendezvous radar in the LM and sextant in the CSM—during platform alignment hurts us more than a little platform drift. Accordingly, it is their proposal that platform alignments only be performed prior to the separation burn which initiates the football rendezvous in the beginning and in the darkness period shared by the pseudo-TPI when the LM is above the command module. This applies to both the LM and CSM. Unless someone has reason for disagreeing with this, their recommendation is accepted and all further work should be based upon it.

3. In response to an action item from the very first meeting, the Orbital Mission Analysis Branch (formerly the Rendezvous Analysis Branch) reported their progress on developing techniques for insuring proper station coverage and lighting conditions during the rendezvous exercise in spite of trajectory perturbations earlier in the mission. The most significant of these perturbations, of course, is failure to launch on time. As a result of their work, it is anticipated they will recommend selection of an earlier nominal launch time and change in direction of the SPS engine tests early in the mission so that the spacecraft will nominally fly in a higher orbit, during the period between them. In addition, it will probably be recommended that these big SPS burns be separated in time by approximately a day instead of occurring within the same period of activity. If these things are done it will be possible to compensate for lift off time delays by decreasing the horizontal, in-plane component of these SPS burns in real time such that the spacecraft does not go to such a high altitude, thereby shortening the orbital period during that period. The implementation to carry out targeting of these maneuvers in real time may utilize the rendezvous mission planning tools in the RTCC that are already available. Their proposed approach would be to modify the SPS burns using the Gemini Agena maneuver logic to cause the spacecraft to rendezvous with a phantom target. The phantom target being where the spacecraft would have been if it had been launched on time and followed the nominal maneuver sequence. If this technique proves to be as resonable as it seems to be now, changes to the nominal mission plan noted above will be processed through the FOP by Morris Jenkins.

4. I just reread that last paragraph and it sounds like I'm still asleep. Does it make sense to you?