Development of hardware for a drag-free control system

Space-borne gravitational wave missions like LISA require Drag-Free Contorl (DFC) systems to control the motion of a constellation of spaceraft to high positional accuracy so that Michelson interferometers of vast scales can be implemented and used to detect gravitational waves. The spacecraft will continually experience forces and torques due to external disturbances, resulting in positional perturbations. Therefore the development of a DFC system is essential to stabilize the spacecraft to a specified tolerance. Prior to such space-borne gravitational wave missions, a technology demonstrator mission, such as the proposed ODIE, ELITE or SMART-2, is needed to test the feasibility of drag-free spacecraft technology. This paper discusses the requirements of the hardware needed to implement a DFC system. Contorl-loop models ahve been develoepd to model the DFC system's dynamic behavior, which enabled quantification of its performance. Results show that if an accelerometer noise level of 1×10-12 m Hz-0.5 and thruster noise level of 1×10-8 N Hz-0.5 can be realized then the ODIE acceleration budget can easily be met.