Magnetic and Momentum Bias Attitude Control Design for the HETE Small Satellite

A design study of the attitude control system for the High Energy Transient Experiment (RETE) small satellite is presented. The satellite is 3-axis stabilized and sun pointing, with stringent pointing stability requirements. For actuation, magnetic torquers and a momentum wheel are chosen for their technological maturity and lack of consumables. One science instrument (CCD UV camera) and sun sensors provide attitude measurement. Two complimentary control strategies are implemented to maximize controllability given the expected wide variation in Earth field direction. As this actuator complement is particularly suitable for a variety of small satellite missions, the design guidelines presented here should be of use to many designers.