Method and apparatus for compensating for solar torque transients on a satellite during a solar eclipse

A system compensating for solar pressure disturbance on an orbiting satellite comprises sensor means (34) for measuring the satellites attitude ( theta ) relative to a predetermined satellite axis and providing an attitude measurement signal ( theta ) in the predetermined axis. Further provided are control means (36) for receiving the attitude measurement signal ( theta ) and calculating satellite attitude compensation control signals (Tc) in the predetermined axis. An eclipse transient compensation device (40) provides an eclipse signal to the control means (36) indicating the satellite is being eclipsed from the sun. Said control means (36) removes signals (Ti) being applied to the actuation means (38) from the control means (36) for compensating solar pressure on the satellite. Further are provided actuation means (38) for actuating the satellite in a predetermined axis in response to the compensation control signals (Tc) from the control means (36) (Fig. 2). Further is disclosed a respective method of maintaining a orbiting satellite in a predetermined satellite attitude against the disturbance of solar pressure on the satellite.