Program interlocks – fairwell

See listJAN 30 196767-FM1-15FM/Deputy Chief, Mission Planning and Analysis DivisionProgram interlocks – fairwell

Ever since I've been involved with these spacecraft computer programs there has been an awful lot of flak regarding the program interlocks. Specifically, in the AS-204 program, there is a “Verb 37 Table” which prohibits the astronaut from calling up certain programs out of sequence. Constraints of this nature have been labeled intolerable, not only by the flight crew but by many other influential people. As a result of this, and partly due to the greatly increased complexity of the AS-258 programs, MIT has decided to include no interlocks whatsoever in them. Therefore, in the future it will be the crew's responsibility to see to it that they don't call programs in an improper sequence. The result of doing so may be no trivial as getting a bunch of garbage for answers, or in some cases could scramble the programs to the extent that it is necessary to initiate the sequence over again – perhaps at the cost of a considerable amount of time and effort. Apparently, there is no known circumstance whereby improper crew inputs could foul up the programs irrecoverably.

Since crew procedures will take the place of the “Verb 37 Table” in the AS-258 programs, MIT has prepared a preliminary program-matrix defining the sequences it is necessary to follow as the crew moves from one pro- gram to another. Copies of this preliminary matrix are available from Rick Nobles and Paul Stull for use in the development of crew procedures.

I am sure this will make all of you interlock critics happy.