Experiments with the spacecraft Progress uncontrolled attitude motion

We describe the results of flight tests of two modes of the spacecraft Progress uncontrolled attitude motion, which are offered for carrying out experiments in microgravity science. They are triaxial gravitational orientation and spacecraft rotation in the orbital plane around the axis of the maximal moments of inertia. The tests were carried out from 27.02 to 07.03.2005 on the spacecraft Progress M-51. The spacecraft attitude motion in those modes was reconstructed by processing telemetry information about electric current from spacecraft solar batteries. The measurements of the current, collected on a time interval about a few hours, were processed simultaneously by means of the least squares method and integration of the spacecraft attitude motion equations. The estimations of the mathematical model parameters and initial conditions of an attitude motion were obtained as a result of such processing. The real quasi-steady acceleration component was calculated for found motions and the point on board the spacecraft where experimental equipment can be placed.