LaBoule, должен извиниться, слишком поторопился с ответом.
Работает это дело вот так:
The solar array and batteries also provide power to a mechanism which provides steering and pointing for the satellite. In the past, reaction wheels critically aligned with respect to three perpendicular axes have provided the steering and pointing functions. Rotating reaction wheels provide torques which depend in part on the speed and direction of rotation of the reaction wheel Known control laws are employed to adjust the reaction wheel speeds under the direction of, for example, a microprocessor, which is supplied power by the solar array and the batteries.
http://www.freepatentsonline.com/6234427.html
Только маховики не большие, а рассчитанные на большой крутящий момент, выходит.
The translation workplace 
