Attitude control by inertia wheels of a tethered interferometric SAR for topographic mapping

Various attitude control laws of a two masses tethered space system by using inertia wheels are analysed in this paper. The authors propose a zero-momentum system, consisting of the integration of three independent reaction wheels on board each platform. The control laws are derived by using a simplified attitude model and are then implemented in a three-dimensional numerical simulator, which simultaneously integrates the orbital and attitude equations. Final results show that pitch and yaw angular differences between the two platforms can be kept within values adequate for microwave remote sensing applications (10^–3 deg); in addition roll high frequency oscillations are damped.Based on a paper presented at the 11th National Congress of the Italian Association of Aeronanties and Astronautics, October 1991.