Spacecraft computer program status report

Tom Gibson and I went to MIT on May 25 and 26 with one of our primary objectives to determine exactly what the program schedule situation was for the AS-504 (AS-207/208) spacecraft computer programs. Although we had a number of very fruitful discussions with MIT people, such as Ed Copps, Dick Battin, John Dahlen, and Bob Mallard, on this subject, we really did not find out what we wanted to know. However, I am very encouraged to see the enthusiasm and vigor with which Ed Copps is attacking this problem.

Ed has set June 3, 1966, as a target for getting out the first cut at a Program Development Plan, which he is anxious to talk to us about during the following week. In fact, he intends to come down then not only to talk over the program as he has put it together but also to discuss its preliminary output regarding the AS-207/208, 503, and 504 schedule situation. Tom and I concluded that it would be better to accept this delay than for us to attempt to do the job ourselves, which is for all practical purposes the same thing he is trying to do. Our main objective, of course, is to find out what the pacing items are so that maximum attention can be given to these items in an attempt to bring what is expected to be an unacceptable schedule more into line. Possible lines of attack are as follows:

  1. Review and, if possible, reduce or simplify our requirements involving the pacing programs.

  2. Give top priority to programmers working on those routines for computer access.

  3. Authorize somewhat inefficient use of computer storage by those programmers to speed up the coding process, even at the sacrifice of deletion of other routines.

  4. Reassignment of personnel to the critical areas even though inefficient.

  5. Reassignment of certain tasks from people working on the critical systems to other groups, such as AC Electronics, MSC, or other internal MIT units, etc.

It is not our intention to dispute MIT estimates of time required to carry out specific tasks, shortening the time to anticipate delivery, by telling them to do a job in two months which they feel requires three; although, of course, these estimates must be carefully examined to assure ourselves we are getting the correct picture.

It is to be emphasized that we must look at the overall schedule situation and not just the program for a specific flight. There are obvious interactions end trade-offs that could be made between the programs for AS-207/208 and those for AS-503 and AS-504. If all efforts to remain within the flight schedule fail and the programs do become pacing for these flights–as they very well could be–we must be in a position to understand the trade-off of flight schedule delays of one mission as compared to another.

A couple of items which Ed Copps did tentatively identify as problem areas which might be influencing the schedule are the following:

  1. Special guidance programs are required to enable yaw steering during the lunar orbit insertion maneuver, providing for plane change in excess of 6°. Ed says the Design Reference Mission calls for a 12° capability, although he doubts that other spacecraft systems constraints would permit such great plane changes. Accordingly, he asked us to re-examine this specification to determine if we could live with a 6° plane change capability, thereby avoiding the necessity of formulating and including these special guidance programs.

  2. Everyone at MIT seems to feel that the preparation of the Guidance System Operations Plan (GSOP) is the most critical of all items since so much of the work must be delayed until this final definition of program requirements is finished. Accordingly, we will attempt to take all possible steps to assist MIT in this work, including having MSC people stationed at MIT to assist in the development of the GSOP and, almost simultaneously, giving MSC approval of it. Also, it is intended to work on the more critical pacing items first as ones are identified and initiate procedures whereby official MSC approval can be obtained on these parts as they are completed rather than waiting for delivery of the entire package.

I’d like to make one final observation regarding the overall situation. It’s probably terrible; I really don’t know yet. But it’s my feeling that everything that can be done to help has been done. We are reacting to the problem areas as fast as possible; MIT has reorganized in what seems to be the best possible way, and they appear to be getting things on a businesslike basis, which up to now has probably been our worst problem.

Terms & Abbreviations


see AS-503


see AS-504

AC Sparkplug

AC Sparkplug was the principal contractor for the construction of Apollo guidance systems.


see AC Sparkplug


AS-207/208 (also known as AS-278) was to have been the first test of the LM in Earth orbit. It was also to have be a dual mission with the command and lunar modules launched on separate Saturn 1Bs. The mission was cancelled after the Apollo 1 fire and the Saturn 1Bs were used to launch Skylab 3 (AS-207) on July 28, 1973 and Skylab 4 (AS-208) on November 16, 1978. The LM was first tested by Apollo 5 in January 1968.


Before the Apollo 1 fire, the mission referred to as AS-503 was an unmanned Earth orbit test flight of the LM and CM scheduled for October 1967. The launch vehicle, SA-503 was used for Apollo 8, December 23 1968.


Before the Apollo 1 fire, the mission referred to as AS-504 was originally scheduled for December 1967. AS-504 eventually launched as Apollo 9, March 3 1969.

Battin, Richard

Member of the MIT Instrumentation Lab. You can take his MIT Astrodynamics class online

Copps, Ed

Member of the MIT Instrumentation Lab

Dahlen, J. M.

Member of the MIT Instrumentation Lab. Director, Systems Engineering Division, Apollo Guidance and Navigation Program.

Dick Battin

see Battin, Richard

E. Copps

see Copps, Ed


see Guidance System Operations Plan

Guidance System Operations Plan

The GSOP was essentially the specification for how the guidance computer and its software where required to work for a specific mission. Many of GSOP’s are available online including the GSOP for the cancelled AS-207/208 mission

John Dahlen

see Dahlen, J. M.


Massachussets Institute of Technology. In these memos, MIT is shorthand for the MIT Instrumentation Laboratory, created and led by avionics pioneer Charles Stark Draper. It is now known as the Charles Stark Draper Laboratory and became independent of MIT in 1973.


Manned Spacecraft Center. Now known as Johnson Space Center.