HETE Satellite Processing System

The HETE (High Energy Transient Experiment) satellite is a joint project between MIT's Center for Space Research and AeroAstro. The primary goal of the High Energy Transient Experiment is to determine the origin and nature of cosmic gamma-ray bursts. The objectives include the simultaneous broad band observation of energetic, transient astrophysical sources in the UV, x-ray and gamma-ray energy ranges, and the precise location and identification of cosmic gamma-ray burst sources. A continuous slow data rate down link of major events is to be broadcast to 20 receive-only ground stations, allowing other astrophysical assets to observe events detected by HETE. AeroAstro is building the HETE spacecraft bus for MIT and is responsible for the development, manufacture test, and integration of the spacecraft bus. and spacecraft bus hardware / payload hardware integration. AeroAstro will also provide the complete ground segment consisting of 2 full duplex ground stations and approximately 20 receive-only ground stations. This paper presents a summary of the HETE satellite data processing system designed and manufactured by AeroAstro. The data handling system which is built around a combination of the INMOS Transputer and a Motorola DSP56001 processor which is also used to manage most of the other spacecraft functions such as attitude control and power management. Payload processors, memory system and spacecraft processor are integrated in the spacecraft central electronics box, and share a common back plane.