Abstract:  A power optimization strategy utilizing the null space of the control momentum gyroscopes (CMGs) set is developed for a spacecraft attitude control using CMGs. A 4-CMGs set is used as the attitude control actuator for the spacecraft. For a N-CMGs set with N ≥ 4, there exists a one degree of freedom non trivial null motion unless the CMG configuration reaches a singular configuration. Based on the degree of freedom, the optimal solution is solved analytically by using a properly de ned power cost function. The power optimization algorithm is applied to attitude tracking task and attitude stabilization task respectively. Simulations show that this power optimal strategy works better for attitude stabilization than for attitude tracking control.

Key words: control momentum gyro scopes (CMGs), power optimal, spacecraft attitude control