The space environment is unique. Natural decay of debris therein is much slower than pollutants in other environments, so that removal is difficult and expensive. Despites the voluntary implementation of mitigation guidelines, the amount of debris has surged in the last two decades due to increase and diversification of space actors, and the continuing militarization of space. Active Debris Removal has thus become a promising responsive scenario. This article examines key legal barriers to the implementation of removal, such as the lack of legal definition of space debris, ambiguities surrounding the jurisdiction and control over space debris, liability for possible damages caused in removal, and implications for space arms control. It further proposes that more comprehensive registration of space objects, an international catalogue of space debris and an international fund for removal should be promoted. Also, international cooperation should be enhanced to cope with space debris, while space arms control should be strengthened.

Due to the continuous space development by mankind, the number of space objects including space debris in orbits around the Earth has increased, and accordingly, difficulties of space development and activities are expected in the near future. In this study, among the stages for space debris removal, the implementation of a vision-based approach technique for approaching space debris from a far-range rendezvous state to a proximity state, and the ground test performance results were described. For the vision-based object tracking, the CAM-shift algorithm with high speed and strong performance, and the Kalman filter were combined and utilized. For measuring the distance to a tracking object, a stereo camera was used. For the construction of a low-cost space environment simulation test bed, a sun simulator was used, and in the case of the platform for approaching, a two-dimensional mobile robot was used. The tracking status was examined while changing the position of the sun simulator, and the results indicated that the CAM-shift showed a tracking rate of about 87% and the relative distance could be measured down to 0.9 m. In addition, considerations for future space environment simulation tests were proposed.