Dynamics analysis of a two-body gravitationally oriented satellite

The rigid body motion of a two-body satellite under the action of gravitational torques is analyzed. The satellite consists of two rigid bodies connected by a universal joint where damping is provided in the two journals. The motion of the satellite relative to the mass center thus has five degrees of freedom, two of which are provided with energy dissipation. It appears that the rigid body motion of such a composite satellite will automatically converge upon a motion in which a given axis of the satellite is earth-pointing. The equations of motion are derived directly from those of Euler. Necessary stability criteria are established. Numerical solutions for a practical scheme are presented