Tether-dragging maneuver strategy and tether control method

Tether-dragging maneuver is an effective on-orbit operation for transfer of retired satellite from one orbit to another. It makes explicit demands on maintenance and service on orbit. In recent years, most of the researches in tethered satellite field have focused on the deployment and retrieval of tethered sub-satellite or the momentum transfer of the satellites, but none of the studies has intensively delved into the tether-dragging maneuver strategy and tether control method. Control strategy of flexible united satellites is very important to ensure that the united objects transfer perfectly, and avoid collision and tether twine at the same time. In this paper, an orbit transfer algorithm for the united satellites is investigated based on finite thrust model in the earth-centered inertial coordinate, and a feed-forward control method of retired satellite on the basis of tension in the tether is presented in the transfer process. Finally, the transfer dynamic equation of retired satellite is established, meanwhile cases of the tether-dragging maneuver and tether control for GEO retired satellite are simulated. The result shows that the orbit transfer of the united satellites is successfully fulfilled by finite thrust and the oscillation of retired satellite is inhibited effectively by tether tension control.