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UCT SpaceLab student presents novel debris removal concept at European Space Debris conference.

1 Jun 2017 - 09:15

Since the beginning of the Space Age, over 6600 satellites have been launched into space. Today there are over one thousand operational satellites in space that provide useful services to millions of people all over the world.  However, these satellites face a growing risk of collision with man-made space debris. There are currently some 23,000 objects in space that are large enough to be tracked from the ground, and hundreds of thousands of other objects that are too small to be tracked, but also pose a threat to operational satellites and human spaceflight.  If future generations are to benefit from the use of satellites as we do, urgent action must be taken to address the space debris problem. Members of UCT SpaceLab have been addressing this problem from several different technical, diplomatic and regulatory perspectives.

Some technical solutions aim at capturing defunct satellites for disposal by burning up in the atmosphere. A number of concepts have been proposed for capturing satellites. These include the use of nets, harpoons and mechanical arms, among others.  These methods all rely on impulsive contact with the target object, which is generally tumbling in space. This has an attendant risk of pushing the target away if the capturing action does not work properly first time.   UCT SpaceLab masters student Louis Feng has developed a novel non-impulsive method of capturing debris that essentially comprises a series of arms that envelopes an object within a capture volume.

Feng presented this concept at the annual European Space Debris conference held in Darmstadt, Germany, in late April 2017, where it attracted attention from a number of experts in the field.  The concept, called MEDUSA, which stands for Mechanism for Entrapment of Debris Using Shape-memory Alloys, is based on the use of the shape-memory alloy Nitinol  to create the capturing volume around the target object. Feng built a prototype of the MEDUSA device and demonstrated the proof-of-concept in a series of experiments carried out at UCT SpaceLab and at the Institute for Space Systems in Stuttgart University. Feng’s conference presentation was based on the results of these experiments. He is already considering ways to improve the performance and efficiency of the MEDUSA device.