The threat represented for space missions by the increasing number of uncontrolled space objects has led to aninternational consensus regarding space debris mitigation guidelines. Given the naturally increasing debrispopulation, the congestion of some orbits and the risks related to cascading effects following accidental or intentionalbreakups, systems might be needed to actively remove debris. Concepts for active debris removal have beendiscussed in the scholarly literature. The present approach is based on a novel, expanding foam system, which servesas a drag augmentation device: the aim is to increase the area-to-mass ratio of debris such that atmospheric dragcauses natural reentry from low Earth orbits. The foam-based method realizes the drag augmentation by exploitingthe characteristics of foams. These can nucleate almost spherical envelopes around target debris with very limitedeffort of the spacecraft carrying and applying the foam. The approach offers the advantage over other methods of notrequiring any docking systems and the ability to deal with spinning and tumbling debris. The method can also beconceived as a preventive method embedded in future satellites. This paper presents the method and analyses itsperformance. Special emphasis is given to the key aspects of expanding foams, to the demonstration to specificdebris types, leading to sizing of the carrying spacecraft. It is equipped with an electric propulsion system thatenhances the performance of the complete mission scenario. With this approach, the specific foam ball radius can betailored to the debris. Its sizing considers the foam mass, the deorbiting time and the risks related to impactprobability of targeted objects. An upper threshold of 10 m radius assures the deorbiting of most of the selecteddebris within a reasonable time. The approach heavily relies on the foam characteristics, e.g. its density andexpansion factor. In this study a low order expanding model is introduced and several assumptions close to state-ofthe-art for ground-based foam models are considered. First results demonstrate the feasibility to deorbit up to 1 tondebris within 25 years from 900 km altitude with this method. A high power Hall effect thruster assures to deorbitabout 3 ton of cumulated space debris per year. All in all, the study demonstrates the feasibility of the method, evenas a relatively short-term application, since most key technology assumptions taken are based on state-of-the-artreferences.
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