How do you clean up junk in outer space? Try a harpoon

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A harpoon flung from a satellite has successfully captured a piece of pretend junk in an experiment that could have major implications for how we clean up the huge mess people have made in outer space.

The harpoon — no bigger than a writing pen — pierced an aluminum panel the size of a table tennis racket attached to the end of a satellite boom. 

A video shows the harpoon slamming into the target and knocking it off its perch before the cable becomes entangled around the boom.

The distance was just 1.5 metres and researchers were delighted.

"The idea is that you can shoot an old satellite and then you pull it down until it burns into the atmosphere," Guglielmo Aglietti, director of the Surrey Space Centre at the University of Surrey in the U.K., told As It Happens host Carol Off.

"In the future, [it] can be used to go and capture real pieces of debris."

And there is plenty of debris to capture.

Humans have been exploring space for about 60 years, and we've left tons of so-called "space junk" in our wake.

This debris includes old satellite and rocket parts that no longer work and pose a threat of collision with new satellites and spaceships, as well as the International Space Station (ISS)

"In space at this moment, we think there are about 8,000 tonnes of debris,"Aglietti said.

Aglietti is principal investigator of the RemoveDebris satellite mission, which is experimenting with ways to clean up debris in orbit, hundreds kilometres above the Earth.

He said the next step for the consortium, which includes the aeronautics company Airbus, would be to offer this as a service to go after real space debris.

He said a much bigger harpoon will be needed in order to snare a real dead satellite "Moby Dick-style." 

"It just has to be scaled up so that in future our partners can ... start clean-up operations of the space environment," he said.

Earlier successes

The same team used a net to capture a piece of space junk in a test last September. And in December, they tracked a tiny satellite ejected from the mother ship, using lasers.

All that remains is for the 400-kilometre-high satellite to re-enter the atmosphere and burn up.

If all goes according to plan, a sail will inflate in March and eventually drag the satellite down, its mission accomplished.

The experiment was launched to the ISS last April and released from the station last June.

"We are very happy because so far we have done three experiments and all three have been working," Aglietti said.

Written by Alison Broverman, with files from Associated Press. Interview produced by Sarah Cooper.