Tethered System Attitude Control After Attachment Point Blocking

A three-axis attitudecontrolsystem based on the integration of a reaction wheel and a mobile tether attachmentpoint on board each platform of a two-mass tetheredsystem is analysed. An abrupt stop of the mobile attachmentpoint of one platform is simulated, and a control law to limit the two-platform angular differences is derived considering the other platform mobile attachmentpoint. The control laws are derived by making use of analytical attitude models, and are then implemented in a three-dimensional numerical code, which simultaneously integrates the system orbital and attitude dynamics. Final results show that the proposed control laws allow to limit the angular differences between the two platforms within values adequate for microwave remote sensing applications (10−3 deg); moreover the attitude high frequency oscillations are effectively damped.