A new rope module for LM-1 computer

See list belowAUG 18 196767-FM-T-62FM/Deputy ChiefA new rope module for LM-1 computer

1. On August 16 General Bolender approved remanufacture of Module III of the LM-1 spacecraft computer program ropes. This was done based on the recommendation of both MIT and MSC technical personnel in order to correct two deficiencies.

2. The first, and most serious, is associated with the Descent Propul- sion System (DPS) trim gimbal control by the Digital Autopilot which, under certain circumstances, could result in an attitude instability during the DPS burn. MIT has estimated that the probability of this instability occurring might be as high as 20 percent. If it happened the ground controllers would be forced to prematurely shut down the engine, seriously jeopardizing the remainder of the mission.

3. The second improvement was to provide restart protection for the fire-in-the-hole sequence. Without this change a computer restart occurring at a critical time would have resulted in staging without igniting the ascent engine, also demanding difficult ground controller action.

4. The current schedule calls for MIT to release the revised version of this program by August 31 to Raytheon for rope manufacture. The final decision as whether or not to use this flight rope module has not been made at this time, as I understand it, but will depend on such things as the results of a series of tests to which the system must be subjected, and the flight schedule itself. I sure will be glad to see that bird fly before it drives us all over the brink.