An On-Board Processor for OAO-C

Abstract

This paper describes the design of a stored program computer for spacecraft use and its application on the fourth Orbiting Astronomical Observatory (OAO-C). The computer, referred to as OBP-2, is a medium scale, parallel machine and has a memory capacity of 16,384 words of 18 bits each. It possesses a comprehensive instruction repertoire and operates on 45 watts of power (including the DC to DC converter). The machine operates at a 667 KHz rate and executes an add instruction in 7.5 microseconds. The primary function of OBP-2 on OAO-C will be auxiliary command storage, spacecraft monitoring and malfunction reporting, data compression and status summary, and possible performance of emergency corrective action for certain anomalous situations.