Open-Loop Minimum-Energy Maneuver of a Solar-Sail Using Magnetic Torques and Reaction Wheels

This paper presents an open-loop, minimum-energy control law for attitude maneuver of a solar-sail. The proposed control law utilizes the magnetic torques and reaction wheels to reorient the solar-sail for near-earth missions. Using the calculus of variations and Pontryagin’s minimum principle, the necessary and sufficient conditions were derived for the nonlinear model of the solar-sail. Then the optimal control problem was formulated as a two-point boundary-value problem and solved via the Shooting method. The computed control law can be utilized in a flight-computer and in a sampled-data feedback closed-loop system which can compensate for disturbance torques.