Back in April we reported on the successful launch of the SpaceX Falcon 9 rocket to the International Space Station which carried, along with supplies and experiments for the orbiting outpost, the RemoveDEBRIS spacecraft. Developed by the University of Surrey, RemoveDEBRIS was designed as the world’s first practical demonstration of what’s known as Active Debris Removal (ADR) technology. It included not only a number of different technologies for ensnaring nearby objects, it even brought along deployable targets to use them on.
Orbital debris (often referred to simply as “space junk”) is a serious threat to all space-faring nations, and has become even more pressing of a concern as the cost of orbital launches have dropped precipitously over the last few years, accelerating number and frequency of new objects entering orbit. The results of these first of their kind tests have therefore been hotly anticipated, as the technology to actively remove debris from Low Earth orbit (LEO) is seen by many in the industry to be a key element of expanding access to space for commercial purposes.
Six months after its arrival in space we’ve now starting to see the first results of the groundbreaking tests performed by the RemoveDEBRIS spacecraft, and so far it’s very promising.
Everything’s Harder in Space
To test debris removal technology, you need some “debris” to target. To that end, RemoveDEBRIS deployed a CubeSat target and allowed it to drift approximately seven meters away. Once the target had moved to the prescribed distance, a net developed by Airbus was fired at it. When the center of the net struck the CubeSat, weights along its edges wrapped around the target, completely ensnaring it.
While arguably an ancient technology, even the simple act of throwing a net becomes infinitely more difficult when you’re 300 km above the Earth’s surface. Director of the Surrey Space Center, Professor Guglielmo Aglietti, said: “While it might sound like a simple idea, the complexity of using a net in space to capture a piece of debris took many years of planning, engineering and coordination between the Surrey Space Centre, Airbus and our partners – but there is more work to be done. These are very exciting times for us all.”
One Small Step of a Longer Journey
Capturing a free-flying object with a net launched from a spacecraft is a neat trick to be sure, and like the upcoming Japanese demonstration of space elevator technology, is a historic first. But it’s only one part of addressing the space junk epidemic in LEO. What do you do with the target once you’ve caught it?
Soon RemoveDEBRIS will demonstrate technologies for pulling an ensnared object out of orbit, such as a drag sail. This lightweight expandable structure can be attached to the captured object, greatly increasing the atmospheric drag acting on it. As the additional drag lowers the object’s speed, its orbit will decay much more rapidly than it would normally in the thin upper atmosphere.
The University of Surrey hasn’t solved the problem of space junk just yet, but this early success is still something to be excited about. Especially for those who’ve had first hand experience with the danger it poses our spacecraft and astronauts.
“It’s great to see the net deployed and trying out various ways to triage the situation” says NASA’s Michael Interbartolo, former member of the Space Shuttle’s Guidance, Navigation, and Control (GNC) Flight Control team. “Anything we can do to remove that debris, from tools lost during a space walk or bolts from a separation stage or a breakup of a long dead satellite, the safer things will be for the Space Station, astronauts or other spacecraft.”