All-Electric Spacecraft Precision Pointing Using Model Predictive Control

A new approach to ACS (attitude control system) design is presented for three-axis precision pointing of all-electric spacecraft. An model predictive Control (MPC) law is proposed, whose objective is to keep the spacecraft attitude and angular velocity within given bounds. The proposed methodology allows the designer to explicitly take into account both the fuel consumption and the number of firings of the thrusters, providing a suitable way to tradeoff these objectives by means of a scalar parameter. The approach is general enough to be applied to the three-axis attitude control problem, even in the presence of coupled dynamics. Simulation results show that the achievable accuracy is suitable for both communication and Earth observation GEO missions. Moreover, the fuel consumption and number of firing cycles make the proposed ACS a viable alternative to systems based on momentum wheels.