Reconstruction of attitude motion of the small spacecraft by measurements of the current from solar arrays

We reconstruct the attitude motion of the small spacecraft, which was located in a geostationary orbit. This motion was controlled by reaction wheels. The Spacecraft passed in uncontrolled rotation, and the direct telemetry information about its attitude motion was absent. There was a problem to determine the real spacecraft attitude motion by available indirect information. We used the telemetry data of a current generated by solar arrays. This data, obtained on the time intervals about few hours, were processed jointly by the least squares method with integration of the spacecraft attitude motion equations. We quote the processing results for 10 data segments, which allowed to reconstruct the spacecraft real attitude motion and to estimate a total momentum of reaction wheels.