ESA Technology image of the week November 23, 2023 An ESA project with the Astronomical Institute of the University of Bern (AIUB) investigated the tumbling behaviour of derelict satellites. The study was supported through ESA’s General Support Technology Programme, developing promising technologies for space. The project combined optical, laser ranging and radar observations to refine an existing ‘In-Orbit Tumbling Analysis’ computer model, aiming to identify, understand and predict the attitude motion of a fully defunct satellite within a few passes. More than 20 objects were observed during a two-year campaign. Among the study results, it was found that rocket bodies and satellites in lower orbits are mostly influenced by gravity gradients and magnetic-induced eddy currents, while up at geostationary altitudes, satellites with large solar panels are sensitive to solar radiation pressure.