A Twin-Wheel Momentum Bias/Reaction Jet Spacecraft Control System.

A spacecraft control system is presented that uses two identical speed-biased and speed-modulated reaction wheels with resultant momentum nominally oriented along the orbit normal. The wheels are in a vee configuration and the system is devised so that along with gas reaction jets, a horizon sensor, and electronics, it provides closed-loop continuous control about the pitch and roll axes with active nutation damping. Equations of motion, control system block diagrams, and dynamics and stability analyses are presented. The application of the system to a typical spacecraft indicates ease of design, good response, and simple, state-of-the-art implementation. Author