"Digital Autopilot For Apollo: A Radical Change"

Cline Frasier
NASA Johnson Space Center


Putting the primary flight control into the AGC/LGC guidance and navigation computers involved conflict and controversy. It was radical technological change under pressure. Today, digital control of everything is “the way things are.” In 1962, when Apollo was being designed, we were in the dark ages, and pilots had never flown planes relying on a general purpose digital computer for flight control. At the time, reliability for the best aircraft inertial navigation systems was about 15 hours MTBF. Astronauts believed that anyone who would trust their lives to a digital computer was crazy. The digital autopilot for Apollo was a radical departure from the analog systems everyone knew, understood and loved. Why would anyone even consider the unknowns of digital flight control for Apollo? This is an insider’s story of how it happened.


Presented in Session G: "Digital Engineering and Computer Design: A Retrospective and Lessons Learned for Today's Engineers"

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