No special spacecraft computer programs are to be developed for AS-208B and AS-503

See listJAN 10 196767-FM1-4FM/Deputy Chief, Mission Planning and Analysis DivisionNo special spacecraft computer programs are to be developed for AS-208B and AS-503

The decision has bean made by the Apollo Program Manager that unique computer programs need not be developed for missions AS-208B (LM) and AS-503 (CM). This decision was brought about due to concern that effort on these programs would affect development of the main line programs. It is certainly consistent with numerous other actions taken recently in support of this activity such as augmenting the MIT staff and providing additional facilities for this work.

AS-208B LM:

As you recall, MIT had been directed to develop a LM program in support of the AS-258B alternate mission to be flown if some failure on AS-206 precluded flying the AS-256 mission as planned. It was to provide the capability for the crew to initialize the system such that it could carry out an unmanned maneuver sequence basically equivalent to that planned for AS-206. The only addition to the AS-206 program for AS-208B was the capability of performing an inflight alignment of the platform by the crew. Although MIT has been directed to cease work on a unique AS-208B program, they have been requested to investigate the use of the AS-206 program without change for the AS-258B mission. I feel there is a good chance that by a combination of special crew procedures and assistance from the ground, techniques could be developed for carrying out this backup mission with that program.

AS-503 CM:

It had been felt desirable to add three capabilities listed below to the AS-205 CM program specifically for the AS-503 mission. Since the schedule impact was unacceptable for the AS-258 mission, direction had been given to MIT to develop a unique AS-503 command module program consisting of the basic AS-205 program with the following added: (a) astronaut steering of the booster into earth orbit, (b) star/landmark and star/horizon naviga- tion, and (c) TLI steering of the SIVB. Now, based on a review by the Apollo Program Manager, it has been concluded that the over-all Apollo project will benefit more by using the AS-205 program as is. MIT has been directed in accordance with this decision.

For the sake of completeness, I might point out the rationale behind the decisions for these deletions.

a) It has been concluded that astronaut steering of the booster is not required for main line Apollo. At some later time, when schedule and storage permit, it may be desirable to reconsider this addition. Agree- ment has been reached by all responsible management personnel, both here at MSC and at Headquarters, on this subject.

b) It is felt that adequate experience and confidence may be ob- tained in the spacecraft navigation mode utilizing star/landmark and star/ horizon observations on AS-503 by merely making the observations as pre- viously planned, but not processing them onboard except to include them on the downlink for post-flight analysis.

c) Although some elements of MSC have been proposing that command module guidance steering of the SIVB would be prime for the translunar injection (TLI) maneuver, the Program Manager emphasized that this is not MSC's position, and as a result the only purpose this program could provide on AS-503 is a backup in the event of a failure of the Saturn guidance prior to the maneuver. Adequate alternate procedures are avail- able for post-flight analysis of the spacecraft guidance systems to deter- mine if it could have handled this task properly in the absence of the actual TLI guidance program.

I should point out that it is currently planned to include the capabili- ties discussed in both (b) and (c) in the AS-504 command module program.