Attitude determination and control for the deployment preparation phase of a space tether mission

A compact and low-cost architecture for the sensor and actuators of a deorbit device based on an electrodynamic tether, together with the corresponding attitude determination and control algorithms, is proposed and studied through numerical simulations. The solution, aimed at the tether deployment preparation phase, is based on four sensors (gyroscope, magnetometer, coarse sun sensors and GNSS), magnetorquers for the attitude control, a multiplicative Extended Kalman Filter, and the construction of two independent control laws for the detumbling of the deorbit device and the subsequent deployment pointing stabilization phase. The latter involves the alignment of the longitudinal axis of the deorbit device along a given direction different from nadir with an error below 10°. Monte Carlo analysis revealed the existence of an optimal gain for the control law in the detumbling phase that yields a detumbling time of around one orbit revolution only. The deployment pointing phase was also investigated through Monte Carlo analysis, for which initial conditions, errors in the attitude sensors, and uncertainties in the inertial properties of the device and the residual magnetic dipole were varied. The numerical results indicate that the proposed architecture and algorithms fit the requirements and are suitable for space tether missions in Low Earth Orbit.

Attitude determination and control for the deployment preparation phase of a space tether mission Articles