scope:

Description of Driving Event:

The space shuttle computer system faces a continuing evolution in flight requirements and increased equipment obsolescence accompanied by greater and more expensive maintenance problems. There is a large list of waiting software change requirements covering such things as the extended duration orbiter missions, crew requested changes, mission-specific changes, and general improvements. Due to the rapid evolution of computer technology, it is difficult to keep any given generation of computer equipment in use for more than a few years. After that, it becomes increasingly difficult to obtain replacement parts. There is also the opportunity to incorporate new capabilities. In the projected 30-year horizon for the space shuttle, it will be necessary to upgrade the system several times.

There now are a number of arguments that favor starting a study for long-term space shuttle avionics computer evolution. They are based on the events that can be expected in 8 to 10 years. The hardware in the "new" general purpose computer will become obsolete and require replacement in about that time period. Also within that time period, the limit on available memory in the space shuttle computers will have been reached. Expansion with the "new" general purpose computer will not be possible without major software changes that would require massive reverification.