Can we plan nominally to burn the APS to fuel depletion?

FC4/Chief, GNC SectionFEB 5 196868-PA-T-22APA/Chief, Apollo Data Priority CoordinationCan we plan nominally to burn the APS to fuel depletion?

1. During our Ascent Mission Techniques meeting on January 31, something rather important came up. It was thought by several of the people there that it is now considered acceptable to burn the APS engine to fuel depletion. If this is the case, I am sure we would change the way we intend to perform the nominal lunar rendezvous mission. As you know, the present plan calls for making all maneuvers after insertion into orbit with RCS and, of course, since there is a chance of running out of APS fuel we would not open the interconnect.

2. On the other hand, if it is possible to run the APS to fuel depletion I am sure we would attempt to make the maneuvers using that engine, recognizing that if fuel depletion occurs during the maneuver we would have to finish it up with RCS. But, obviously whatever delta V we acquired with the APS gives that much saving from our critical RCS. Would you please have your people look into this and let me know if this is a reasonable way to operate the APS in a nominal mission. I think Jerry Elliott picked up this action item. I am writing this note just to make sure you hear about it.

3. Incidentally, it might also influence how we use the APS on the “D” and “E” mission, too. I'm not sure how.