Another AGC program development report

See listOCT 17 196666-FM1-137FM/Deputy Chief, Mission Planning and Analysis DivisionAnother AGC program development report

Just got back from the northlands and couldn't resist sending out another note, although I really don't have much to report. The program develop- ment planning at MIT seems to be progressing nicely. We did pick up a couple of items that require attention; e.g.,

a) It is necessary that NASA provide specifications on the charac- teristics of the command signals from the AGC to the SIVB for the trans- lunar injection simulation maneuver in the AS-278/503 computer program. Rick Nobles (FSB) has the action on this.

It was re-emphasized by MIT that they were not developing the capability of confirming stability of the over-all system. Their model of the SIVB is strictly rigid body and is not adequate for that purpose. It is my understanding that MSFC will perform whatever studies are necessary to confirm adequate stability for this maneuver mode. This will be discussed at the MSC/MSFC Flight Mechanics Panel meeting next week.

b) Studies continue at MIT on the formulation of the offset targeting to support the stable orbit rendezvous technique. This simulation work is required to prepare the framework of an MDRB [program change request). This work should be completed within about two weeks, at which time they will prepare the MDRB. MIT is proceeding on the assumption that this capa- bility shall be provided on both the LM and command module with an option available for each to compute the maneuvers necessary if the other vehicle is active.

c) An investigation is currently underway at MSC to determine the advisability of starting the LM descent propulsion system at 10% thrust rather than 30% thrust. It will simplify the LGC program, but since the formulation and coding must be completed very soon, we will derive very little benefit from this change if a decision is not made very soon. In fact, there will come a time where the change will make our job more difficult.

d) Since so much concern has been expressed, both at MSC and MIT, with regard to the need for star/landmark and/or star/horizon navigation on the AS-503 mission, I have requested MIT to prepare an MDRB for in- cluding that capability in the AS-278/503 program. Since the formulation of these programs has been pretty well completed, I expect the major impact will be in having to finish all the coding in time for initiation of program systems integration which is scheduled to begin early in December.

MIT reported that their work on the action items assigned them at the AS-204 CAR are essentially complete.

a) Procedures for manual computer re-start will be available October 14th. [Incidentally, MIT feels this action should never be carried out and certainly don't guarantee it; however, in accordance with our request they have laid out the best procedures they could for manually forcing the computer to re-start from a known location).

b) On October 14th they will provide a list of parameters which must be input into the erasable memory if a complete loss of erasable memory occurs. Procedures for carrying out this process will be ready by October 21st.

c) A complete description of the Flag Word will be available October 14th.

d) A description of how to correct the PIPA bias, etc., will be available on October 14th. Documentation of detailed crew procedures will be completed by October 21st.