Gravitational Orientation of Progress MS-07 and Progress MS-08 Transport Cargo Spacecraft

The uncontrolled rotational motion of Progress MS-07 and Progress MS-08 transport cargo spacecraft in the mode of gravitational orientation of a rotating satellite was reconstructed. Modes were implemented in April and August 2018. The reconstruction was conducted using an integral statistical method according to measurements of spacecraft angular velocity. Measurement data obtained at a certain time interval were processed together with the least squares method by integrating the equations of spacecraft motion relative to the center of mass. As a result of processing, the initial conditions of motion and parameters of the used mathematical model were estimated. The correctness of the reconstruction was checked by measuring the current taken from the solar panels. In the mode of gravitational orientation, the spacecraft rotated around its longitudinal axis with an angular velocity of 0.1–0.2 deg/s oscillating relative to the local vertical.