Computers in Spaceflight: The NASA
Experience
Part One: Manned Spacecraft
Computers
Introduction
- [7] In the first 25
years of its existence, NASA conducted five manned spaceflight
programs: Mercury, Gemini, Apollo, Skylab, and Shuttle. The latter
four programs produced spacecraft that had on-board digital
computers. The Gemini computer was a single unit dedicated to
guidance and navigation functions. Apollo used computers in the
command module and lunar excursion module, again primarily for
guidance and navigation. Skylab had a dual computer system for
attitude control of the laboratory and pointing of the solar
telescope. NASA's Space Shuttle is the most computerized
spacecraft built to date, with five general-purpose computers as
the heart of the avionics system and twin computers on each of the
main engines. The Shuttle computers dominate all checkout,
guidance, navigation, systems management, payload, and powered
flight functions.
-
- NASA's manned spacecraft computers are
characterized by increasing power and complexity. Without them,
the rendezvous techniques developed in the Gemini program, the
complex mission profiles followed in Apollo, the survival of the
damaged Skylab, and the reliability of the Shuttle avionics system
would not have been possible.
-
- When NASA began to develop systems for
manned spacecraft, general-purpose computers small and powerful
enough to meet the requirements did not exist. Their development
involved both commercial and academic organizations in repackaging
computer technology for spaceflight.
