Smart and lightweight robotic capture system of space debris

The capture and removal of space debris is an important and increasing area of research since debris can put at serious risk operational satellites and space missions. The main challenging areas of research are related to the minimization of the impact force and its effect on the capture system and the motion damping of the tumbling target in the post-capture phase. In literature many different capture systems have been presented, and among them net capturing is one of the most promising since it is a flexible solution, low weight and low cost, and moreover close rendezvous and docking are not mandatory. Nevertheless, the reliability of net deployment and of the wrapping up of the target should be increased and the tumbling compatibility still needs to be developed. In this paper, an innovative capture system is presented based on a net operated by means of a robotic system, which overcomes the above mentioned limitations of the net systems and still has the same advantages. The net is safely wrapped over the debris by the robotic arms, which then close the net and entrap the debris with a highly enhanced reliability with respect to a simple net system. In addition, this system addresses the problem of de-spinning of the debris and of damping the vibrations due to capture mainly thanks to a flexible ring on which the robotic arms are mounted and a cable system which puts the net in tension after the debris capture thus helping in the de-spinning. Another strength of the proposed system is that, even if it can be deorbited with a change in velocity of the combined system, other operation modes are possible: the debris can be captured, de-spinned, and then relaunched to a lower or graveyard orbit eventually harvesting and reusing part of the kinetic energy of the debris or, even more efficiently, bounce on the system towards a lower or graveyard orbit. These modes of operations, which are discussed in the paper, are particularly interesting since they increase the energy efficiency of the system and allow the system to be reusable for the capture and removal of many debris