“D” Rendezvous

See list attachedJUL 25 196868-PA-T-168APA/Chief, Apollo Data Priority Coordination“D” Rendezvous

1. A great many things were discussed and resolved at the July 22 “D” Rendezvous Mission Techniques meeting. They will all be fully recorded in the minutes. There were three items, however, I would like to call particular attention to at this time by this memo.

2. In order to avoid any chance of recontact as a result of maneuver dispersions in the CSM RCS separation maneuver which starts off the “D” mission rendezvous, it was decided to increase its magnitude from 1.0 to 2.5 fps. It will still be performed in a radial direction. This was brought about when it was recognized that an error of about 0.4 fps in the horizontal retrograde direction would result in recontact after the big phasing burn. Dispersions of that magnitude could easily occur due to imperfect velocity nulling during station keeping, G&N maneuver dispersions, spacecraft venting, etc.

3. It has been established that the elevation angle to be used by both spacecraft in determining all TPI times – nominal and contingency – will be 27.5°.

4. The out-of-plane component of the TPI maneuvers shall be targeting to force a node at TPF rather than at the second midcourse correction maneuver. This will also apply to the lunar rendezvous mission, which the “D” was attempting to simulate in this respect. The change is being made to simplify the crew timeline and procedures; it is felt to be entirely adequate based on the recently adopted plans for handling out-of-plane on the lunar rendezvous.

5. The above decisions are considered firm and should be immediately incorporated in all aspects of the Apollo Program to which they apply. They will only be changed if there is a darned good reason – not just to make things a little better!