The Space Shuttle general purpose computers rely on complex, error-free software to assure accurate response and perfect synchronization of key Shuttle systems. Shuttle flight software engineers develop, test and verify the Primary Avionics Software System (PASS), which is loaded into the Shuttle computers to manage flight control systems, engines, data networks, communications, power and environmental systems aboard the Orbiter throughout all phases of flight.
For crew safety and vehicle loss prevention, the Backup Flight System (BFS) was also created to provide basic Guidance, Navigation, and Control (GN&c
