MICROSATELLITE BUS FOR MULTIPLE

ABSTRACT: In recent years, new generations of relatively small satellites, the so called microsatellites, are emerging in many domain applications and are employing new technological solutions. The outcome is a reliable, high performance and inexpensive design of space systems. This paper underlines the key technological approaches adopted in SACI-1- Scientific Applications Satellite currently under development at INPE. The SACI-1 is the first of a series of Low Earth Orbit microsatellites. The spacecraft shall be launched in October 1997 in a piggyback configuration having the CBERS satellite (China-Brazil Earth Resources Satellite) as a co-passenger in the Chinese Long-March IV launcher. The payload of SACI-1 is composed of four scientific experiments namely: ORCAS, an investigation of the anomalous cosmic radiation fluxes; FOTSAT, an airglow photometer to measure the terrestrial airglow emissions; PLASMEX, a study of the plasma bubbles evolution and MAGNEX, a research of the geomagnetic field effect on charged particles. The SACI-1 bus is composed of six subsystems: a modular structure, a power conditioning unit, a S-Band communications, an active attitude control, an on-board transputer-based parallel computer and a passive thermal control. The driving factors being adopted throughout the design phases of SACI-1 are: development of a versatile bus supporting multiple missions, cost reduction with recurrent mission, design time acceleration