Free-Space Dynamics and Control of the Rotary-Motion Extended Array Synthesis Spacecraft Concept

The Rotary-Motion Extended Array Synthesis spacecraft is a dual-spin spacecraft with long tethers held in tension by the spin. This paper derives the free-space (not considering orbital effects) dynamics of this spacecraft, and it compares two controllers in performance and the effort expended. In contrast to prior work, one of the controllers used takes account of the tether motion rather than just considering the hub motion. The spacecraft is simulated performing a challenging task including an acceleration and 90 deg slew with both controllers. The controller that accounts for the tether motion uses similar to 10% less fuel while providing similar errors.