Realization of the spacecraft solar orientation mode without saturation of on board gyro system

We investigate the solar orientation mode of the spacecraft in a low Earth orbit. The normal to the plane of spacecraft solar arrays is constantly directed to the Sun in this mode, the longitudinal axis lies near the orbit plane, the absolute angular rate of the spacecraft is practically equal to zero. The mode is realized by gyro system. We consider two control laws for the gyro system. The first law provides only a stabilization of the spacecraft in the prescribed attitude. The second one provides additionally a decrease of the angular momentum of gyro system due to the special choice of the spacecraft turning about the normal to the solar arrays.