THE AMSAT PHASE IIIB SPACECRAFT

Abstract

The AMSAT Phase IIIB spacecraft is the second in the third generation of communications satellites in the (Radio) Amateur Satellite Service. It is designed to provide worldwide communications to the global radio amateur community, for hours at a time each day, using a single spacecraft. The spacecraft is designed to require a minimal amount of ground control and incorporates a single RCA 1802 based microcomputer that performs all the altitude control, command, decoding, and telemetry processing functions. This flight computer operates in a multitasking environment and incorporates a number of unique hardware and software features, including the absence of ROM (it is totally RAM based) and the incorporation of a high-level software language developed in Germany, known as IPS, which belongs to the FORTH family of languages.