Solar Pressure Attitude Stabilization of Earth-Pointing Spacecraft

The development of a solar pressure control system for three-axis attitude control of Earth-oriented spacecraft is presented. A controller configuration consisting of two rotatable mirrorlike surfaces, representing the minimum hardware implementation, is considered. Optimal control theory is applied to synthesize a feedback control law directly governing the differential rotation of the control surfaces. The system performance is evaluated through the response analysis of a satellite subject to destabilizing gravity gradient torques as well as external disturbances. Even under such adverse conditions, the results indicate a moderately sized controller to be quite effective in maintaining the desired Earth-pointing spacecraft orientation. The validity of the optimal control law is established for all times of the year, and the feasibility of implementing suboptimal control policies is also examined.