Key Technological Solutions towards the SACI-1 Microsatellite Design

The advantages of a small scale space program over its bulky and complex space counterparts have been extensively documented in the technical literature. These systems are carrying on affordable solutions to telecommunications, earth observation, small-scale space science besides their direct effects in improving general education and training. Cost-effectiveness with reciprocity of mission needs is the utmost driving factor brought up in the process design. Hence the emphasis of this paper is on the key technical solutions adopted in the SACI microsatellite program currently under development by INPE, in Brazil. SACI-1, which stands for Scientific Applications Satellite, is a 60 kg Low Earth Orbit microsatellite spinstabilized on a modular architecture carrying four scientific payloads. SACI-1 is scheduled to be launched in October 1997 using a Long March 4 as a piggyback of CBERS (China Brazil Earth Resources Satellite). SACI-1 payloads were chosen from an open opportunity announcement which resulted in the following experiments: ORCAS, an investigation of the anomalous cosmic radiation fluxes; AIRGLOW PHOTOMETER, a monitoring of the terrestrial airglow emissions; PLASMEX, a study of the plasma bubbles life cycle which interferes particularly in low frequency bands in the equatorial region; and MAGNEX, a research on the geomagnetic field and its effects over charged particles. Space hardware for some subsystem equipment was conveniently selected in an off-the-shelf inventory which in turn may accelerate development and test time. The microsatellite program is being cooperatively conducted among research institutions, universities and small industries. A dedicated and compact team with short lines of communications and succinct and essential documentation were adopted to minimize bureaucracy. Two receiving stations in Brazil will cover the ground segment employing a LAN PC-based approach. Moreover, as a trend, Principal Investigators can have interactive direct access to their scientific payloads from their own institutions. A computer network as the INTERNET will greatly enhances the efficiency of data dissemination and payload configuration.