Modeling of dynamics and control for Gravity Probe B

For current and future scientific space missions the challenge lies in very demanding requirements on the disturbance reduction and rejection which is done by the attitude and/or translation control system. Drag-free control is one of the key technologies for many scientific. space missions. Its application eliminates or diminishes non-gravitational accelerations on a satellite to a level which allows the execution of highly sensitive experiments like on Gravity Probe B, STEP and LISA. A high-fidelity spacecraft dynamics and control simulator has been developed to aid in design, test and verification for missions with a very high level of performance. The simulator is firstly adapted to Gravity Probe B. The post-mission analysis of Gravity Probe B has dual purpose: On one side verification of simulator modules is achieved by comparison to flight data but also the science data processing benefits from system identification of disturbances previously not modeled.