http://www.digitaljournal.com/tech-and-science/technology/removedebris-mission-to-test-different-ways-to-grab-space-junk/article/508788

'RemoveDEBRIS' mission to test different ways to grab space junk

Posted Nov 29, 2017 by Karen Graham
We track 18,000 objects orbiting the Earth, but only 1,100 are functioning spacecraft. Additionally, there are an estimated 750,000 more pieces of debris floating around, any of which could cause serious damage to a manned spacecraft.
It is estimated that there are about half a million pieces of man-made rubbish orbiting the Earth  r...
It is estimated that there are about half a million pieces of man-made rubbish orbiting the Earth, ranging from huge defunct satellites, to spent rocket boosters and nuts and bolts.
NASA
Earlier this year, an experimental Japanese mission to clear 'space junk' or rubbish from the Earth's orbit ended in failure after a 700-meter (2,300-foot) long tether made from thin wires of stainless steel and aluminum failed to release.
Now, the latest project to clean up space debris has been announced. Astroscale PTE Ltd (ASTROSCALE) and Surrey Satellite Technology Ltd (SSTL, part of the Airbus Group) have signed a Memorandum of Understanding (MoU) to test different methods of removing space junk. The RemoveDEBRIS spacecraft mission is set to launch in 2018.
The RemoveDEBRIS mission is being led by the Surrey Space Centre at the University of Surrey, while Astroscale is assembling the washing-machine-sized RemoveDebris spacecraft, called the ELSA-d chaser satellite, using avionics provided by SSTL. The satellite will be equipped with optical sensing instruments and a redundant capture mechanism.
Approximately 95% of the objects in this illustration are orbital debris  i.e.  not functional satel...
Approximately 95% of the objects in this illustration are orbital debris, i.e., not functional satellites. The dots represent the current location of each item. The orbital debris dots are scaled according to the image size of the graphic to optimize their visibility and are not scaled to Earth.
NASA/LEO-Low Earth Orbit image
The BBC is reporting that Dr. Jason Forshaw, the project manager on the RemoveDEBRIS team, said: "RemoveDEBRIS will be one of the world's first missions in this area.... We have technologies on here that have never been demonstrated in space before."
The SpaceDEBRIS spacecraft will be launched to the International Space Station (ISS) during a resupply mission and will be unpacked by the astronauts once onboard. It will then be launched from the ISS to begin the experiments.
RemoveDEBRIS platform
SSTL has designed and manufactured a satellite platform, based on the SSTL-50, that will release, capture and deorbit two space debris targets, called DebriSATs, in sequence using various rendezvous, capture and deorbiting technologies, demonstrating in orbit, key active debris removal (ADR) technologies for future missions.
RemoveDEBRIS platform
RemoveDEBRIS platform
SSTS
The “chaser” satellite and the "Target" satellite will demonstrate key technologies necessary for ADR, such as rendezvous and docking and proximity operations. ASTROSCALE is designing and manufacturing the Chaser at their R&D office in Tokyo, using avionics from SSTL.
During the experiment, the SpaceDEBRIS spacecraft will release a small "target" satellite into space and then will use a net to recapture it. It will also fire a small harpoon at a target plate to see if the technology can accurately work in the weightless environment.
Then, if all goes well, the SpaceDEBRIS craft will demonstrate future de-orbiting technology. As the SpaceDEBRIS descends to Earth, a 10 square meters (108 square feet) sail will be deployed. The sail will slow the orbiter enough to assure it burns up as it enters the atmosphere.
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ASTROSCALE and SSTL
"It will prevent the spacecraft from becoming space junk itself," explained Dr. Forshaw. "People are starting to realize the significance of space junk and the problem it presents."
Dr. Hugh Lewis, a senior lecturer in aerospace engineering at the University of Southampton, said: "For some people, space debris is one of these things that is out of sight, out of mind. But from my perspective, it is one of the worst environmental catastrophes that we have encountered."