Impacts of tug and debris sizes on electrostatic tractor charging performance

Active debris removal techniques enable relocating noncooperative geosynchronous (GEO) debris objects into graveyard orbits. One proposed method is the electrostatic tractor concept. Here a tug vehicle approaches a target debris object and emits an electron beam onto the debris. The charging that results yields an attractive electrostatic force that is used to tow the debris object into a new orbit. In this study, the impacts of relative sizing between tug and debris on the efficacy of this charge transfer process are considered. By applying a charging model and incorporating nominal, quiet GEO space weather conditions, limitations on the size ratio that preclude charge transfer are identified for different levels of beam energy. The resulting electrostatic forces and impacts on reorbiting performance are studied. The results indicate that a larger tug vehicle will enable the tugging of a broader range of debris sizes, and that the tug size should be roughly as large as the expected debris size.