Active Local Vibration Isolation Applied to a Flexible Space Telescope

Two problems in the design of large space telescopes are the effects of vibrating equipment on optical alignments and the instabilities that may result from flexible coupling between the attitude sensors and actuators. This paper explores a design concept where the spacecraft is divided into two modules: a quiet optics module containing the attitude sensors and a vibrating equipment module containing the attitude actuators. The modules are connected by active isolation devices that transmit low-frequency attitude control forces but attenuate higher-frequency disturbances. Performance analyses were based on a fifty-degree-of-freedom spacecraft model with nine active control loops.