LAUSR

Abstract Rigorous ground testing of spacecraft dynamics will significantly reduce various risks to a mission. A spherical-air-bearing-based testing platform provides nearly frictionless rotations about the three axes and can be used to simulate spacecraft attitude dynamics on Earth. However, gravity-induced unbalance torque causes undesirable disturbances on the platform during testing. This paper explores two techniques for estimating the inertia properties and center of mass offset values of a spacecraft simulator with three rotational degrees of freedom. Numerical simulation results of these two estimation techniques: a batch method using linear least squares, and an online method using recursive least squares, are reported. These techniques are then compared in terms of accuracy of the estimated parameters, noise sensitivity, and computational load.