Use of External Torques for Desaturation of Reaction Wheels

Abstract

The problem of fuel-less desaturation of reaction wheels for a spacecraft in the sun-acquisition mode is considered. It is shown that there always exists angular motion in the vicinity of the required attitude when reaction wheels can be desaturated by either the solar-radiation-pressure torque or the gravity-gradient torque. Optimal desaturation attitude is obtained in a closed form. Additionally, the simplified expressions for desaturation attitude are presented.