Control methods for geostationary debris removal using solar sailing: A hybrid low-thrust analysis of repeatable debris removal trajectories

Thousands of space debris objects remain in space after decades of spaceflight without sustainability regulations. Some of these objects de-orbit naturally, but not objects in the geostationary region for which active debris removal is needed. This thesis presents the case of geostationary debris removal using solar sailing, a propulsion method where no propellant is consumed, which allows for repeatable debris removal. A focus is given to find minimum-time trajectories between the geostationary region and a so-called ‘graveyard orbit’ and back. Optimisation using numerical methods is time-consuming, as these trajectories include hundreds of orbit revolutions. This work utilises analytical control methods instead to determine solar-sail control, specifically the ’Accessibility-and-deficit blending method’ based on locally optimal steering laws. Resulting mission times are compared with literature for validation, and a catalogue of mission time is found for a wide range of mission parameters, including additional thrust from a solar-electric propulsion engine.Aerospace Engineerin