Abstract: The computer system for missile guidance comprises five parallel processors interconnected by a global bus; with each processor having its own CPU, program memory, temporary memory, and two critical variable memories, interconnected by a local bus. The program memory and critical variable memory are hard MNOS to survive nuclear radiation. Each processor has its own cycle time, synchronized by a master clock. In each processor, the cycle has three phases for intercommunication, task processing, and critical variable storage. Thus the critical variables are stored only after task processing is completed.