SpaceX Cargo Ship Will Carry First Test of Space Debris Cleanup
Which is better for snagging dead satellites, a harpoon or a net? We’ll soon find out.
/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/filer/52/19/5219cff1-b6fd-4efa-b8ad-5e65b6759f38/debris_net.png)
Finally, somebody’s doing something about Earth’s orbital trash problem.
A European satellite designed to test different methods of “active debris removal” is scheduled to launch to the space station on a SpaceX Dragon cargo ship on April 2. It will be the first in-space test of technologies to collect and remove large pieces of orbital junk, a growing threat that has long concerned the world’s space agencies. A Japanese experiment in space trash removal, called KITE, had to be scrapped last year when the spacecraft’s tether failed to deploy.
The $18.5 million RemoveDEBRIS satellite due to launch on Monday was funded half by the European Commission, and half by a consortium of 10 companies, including the spacecraft’s builder, Surrey Satellite Technology in England, and Airbus, which contributed the net and harpoon mechanisms to be evaluated in the tests.
If the schedule holds, the 220-pound RemoveDEBRIS satellite will be pushed out of the station’s Japanese module airlock in late May to begin a series of experiments. About the size of a dorm room refrigerator, it will be the largest satellite ever launched from the station.
In the first test, a CubeSat released from the main spacecraft will maneuver to a distance of more than 20 feet, where it will unfurl a balloon (to provide a bigger target). A net similar to the kind used in commercial fishing will then be deployed from the main spacecraft to capture the CubeSat. Atmospheric drag should cause the netted CubeSat to burn up in the atmosphere in a matter of weeks, according to Guglielmo Aglietti, Director of the Surrey Space Centre at the University of Surrey, and the principal investigator for RemoveDEBRIS.
For the second test, another CubeSat will be released to fly at a distance from the main spacecraft, where a camera and LIDAR will observe it to assess how well future trash-collecting satellites could judge the position and speed of a piece of debris.
Then, to test a different method of snaring space trash, a standoff target—made of representative satellite materials—will be shot with a harpoon connected to a tether. Finally, a large sail will be unfurled from the main satellite to increase its atmospheric drag and cause it to burn up during re-entry, about a year and a half later. The project investigators expect to have all their tests wrapped up by the end of this year, says Aglietti.
If everything works as hoped, the technologies tested on RemoveDEBRIS will be incorporated into planning for the e.deborbit mission planned for launch around 2024. That project, expected to cost some $400 million, aims to capture and de-orbit the eight-ton Envisat spacecraft. RemoveDEBRIS is just a first step toward the much more ambitious goal of removing the largest dead satellites from orbit. Those are the biggest threats, since a hit from some other bit of speeding space junk could turn any of them into thousands of new pieces of debris. And with 7,500 tons of garbage already circling the Earth, that’s an accident global space managers would dearly like to prevent.