Experiences with the goddard computing system during manned spaceflight missions

The computer field today is expanding spectacularly on many fronts. One of the important application areas is the use of the computers as the heart of large information processing systems. These applications require the design and implementation of large automatic realtime computer systems. Since these systems require the expenditure of extensive programming and hardware design efforts, it is important that we study existing systems with a view toward establishing guidelines for the development of future systems of even larger scope. The system we will discuss in this paper is the Goddard Realtime Computing System which was used to support all the National Aeronautics and Space Administration manned missions to date. It is currently being augmented to support the forthcoming Gemini Non-Rendezvous flights, and has been used to provide prime computing support for the Saturn SA-5 and SA-6 flights, the first Gemini GT-1 flight, the orbital Centaur flights to mention a few. It is the purpose of this paper to briefly summarize some of the experiences, difficulties, techniques developed, and lessons learned during the design, implementation, and operation of this system.