Harpoon concept for removing space junk tested in orbit

A harpoon, the second of three engineering experiments for capturing space junk, was successfully fired last week.

A British satellite released from the International Space Station last year has successfully demonstrated a harpoon that could be used on future missions to clean up space debris, officials announced Friday.

The harpoon fired out of the RemoveDebris spacecraft Feb. 8, striking a target plate extended from the satellite on a 4.9-foot (1.5-meter) boom. The experiment was one of the main objectives of the $17 million (15.2-million-euro) RemoveDebris mission, conceived as a testbed for technologies engineers hope will allow future satellites to tidy up busy orbital traffic lanes by collecting dead satellites and rockets and driving them back into Earth’s atmosphere to burn up.

In a dramatic video released by Surrey Satellite Technology Ltd., the harpoon is seen catapulting out of the RemoveDebris spacecraft at a velocity of about 45 mph — 20 meters per second — and spearing its target. A cable attached to the harpoon kept the device from flying off and becoming its own piece of space junk.

The first experiment was a test of a net, tested successfully in September. The last of the three experiments, scheduled in a month, will test a sail designed to slow the satellite’s speed so that it gets de-orbited quickly.

I have embedded the video of the harpoon test below the fold.
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British test satellite uses net to capture target

A British test satellite has successfully used a net to capture a cubesat target, demonstrating the technology that someday could be used to clean space junk from Earth orbit.

“It worked just as we hoped it would,” said Prof Guglielmo Aglietti, director of the Surrey Space Centre. “The target was spinning like you would expect an uncooperative piece of junk to behave, but you can see clearly that the net captures it, and we’re very happy with the way the experiment went.”

If this were a real capture, the net would be tethered to the deploying satellite, which would then tug the junk out of the sky. As this was just a demonstration, the net and the box (which was actually pushed out from RemoveDebris to act as a target) will be allowed to fall to Earth on their own. Their low altitude means it should take only a couple of months before they burn up in the atmosphere.

I have embedded below the fold a video showing the net capture. It is quite spectacular. This was one of three different experiments on RemoveDebris that are testing space junk removal methods. The next is the use of a harpoon.
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European satellite designed to test space junk removal released from ISS

Europe’s RemoveDEBRIS satellite was released from ISS yesterday in preparation for its testing a variety of technologies for removing and deorbiting space junk.

The article at the link does a terrible job trying to describe this mission. Better to return to a news story from 2016, when Europe first announced this project. The video from that story, embedded below the fold, does an excellent job detailing the four experiments, which are mostly aimed at testing technologies that could be added to satellites that would make either their capture or deorbit easier.

Maybe the most interesting aspect of this mission however is how it got into space. It was launched as part of a SpaceX Dragon cargo mission. It was deployed by NanoRacks, using its privately developed deployment system attached to Japan’s Kibo module.

Launch from ISS means that the satellite’s deployment and orbit were far more controllable than if it had been launched directly into space as a secondary payload during a rocket launch. NanoRacks is selling this approach commercially, and this satellite is the largest deployed by them to date.
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NASA delays launch of space-junk removal test satellite

In order to do additional safety reviews NASA has ordered a six-month delay, at the minimum, in the launch of test space junk removal satellite.

“Nothing of this size has ever been launched from the ISS before,” said Jason Forshaw, RemoveDebris project manager at the University of Surrey’s Surrey Space Centre, which leads the consortium [that built the satellite]. “Most of the things they are launching from there are cubesats, much smaller objects, 10 [kilograms] or so,” Forshaw said. “As you can imagine, we are progressing through the safety reviews and we are just going through those at the moment.”

The article also includes some discussion of the legal limitations of salvage in space, once again due to the limits in the Outer Space Treaty.

European experimental space junk removal mission to launch

The competition heats up: A European Space Agency mission to test technologies for removing space junk will launch sometime next year.

Presented at the Royal Society’s summer science exhibition this week, and led by the Surrey Space Centre, the systems included a net, harpoon and drag sail, which scientists have incorporated into a test platform for launch into space. The platform will also carry “artificial junk” in the form of small satellites known as CubeSats.

Once the platform is launched into space, a CubeSat will be released. “The CubeSat will be ejected from the platform and then we’ll fire the net at it,” said Forshaw. The CubeSat, hopefully encased in the net, will then fall back towards Earth and burn up. In the case of the harpoon, the researchers have attached a target made of spacecraft material to a carbon-fibre boom that extends from the platform. “When the harpoon impacts it, it is actually going to simulate a real spacecraft being hit,” said Forshaw.

At the end of the mission the third system, a drag sail will be deployed. Attached to the platform, the sail will speed up its return to Earth where it will burn up in the atmosphere. Similar systems have been proposed for future satellites to allow them to be disposed of without leaving space junk.

With the Chinese, NASA, and private companies all developing robotic missions to either clean up space junk or repair satellites, the competition to do this work is going to get very intense in the next decade.