Modelling the Oscillating Pattern of the Apparent Spin Period of Inactive GLONASS Satellites

The spin period of a space debris is a key design parameter for Active Debris Removal missions. This parameter can be extracted from photometric data, in the form of light curves. The Astronomical Institute of the University of Bern has performed optical observations of inactive GLONASS satellites for more than eight years. The estimated spin period of a subset of these target satellites has shown two characteristics features: an oscillating pattern and a secular trend. This paper describes a simulation environment that allows modelling the long-term evolution of the spin period of a spacecraft, to understand which parameters affect the aforementioned features. Two simulated test cases are presented, demonstrating the capability of the model to capture these features, provided an ad-hoc set of initial parameters.