Inertially pointing satellites which use reaction wheels as main actuators for attitude control are subject to the problem of wheel saturation. This problem can be partially obviated by means of suitable compensation strategies for the external disturbances acting on the spacecraft. In this paper, the problem of momentum control by means ofmagnetic actuators is analysed and the classical, usually adopted solution, is compared with an approach based on periodic LQ and H ∞ control. Simulation results are used to demonstrate the advantages of the periodic approach.