It’s a rubbish start for the world’s first space clean-up experiment. A cable designed to drag space junk out of orbit has failed to deploy from a Japanese spacecraft.
More than half a million pieces of debris are currently whizzing around our planet, including abandoned satellites and fragments of old spacecraft. They pose a danger to working satellites and new space vehicles.
Scientists are working on a range of clean-up solutions, including cables, nets, harpoons, sails and robotic arms. All are designed to capture pieces of space junk and tug them down into Earth’s atmosphere where they will burn up and disintegrate.
On 28 January, the Japan Aerospace Exploration Agency (JAXA) started an inaugural in-space evaluation of their junk-removing cable technology.
A 700-metre-long metal cable was fitted to an unmanned spacecraft called Kounotori 6, which was on its way back to Earth after delivering supplies to the International Space Station.
The cable was meant to unfurl from the spacecraft, at which point an electric current would pass along its length. The idea was that the current would interact with the Earth’s magnetic field, creating a drag that pulled the spacecraft out of orbit. The spacecraft would then tumble into our atmosphere and become incinerated.
Proponents of such junk-removing cables say that special space vehicles could attach cables to existing pieces of space junk. In addition, each new satellite launched could go up with a cable that could be activated at the end of its working life.
However, Kounotori 6 was unable to release the cable to test its junk-removing potential, and JAXA could not fix the glitch before the spacecraft returned to Earth’s atmosphere this morning. “We could not extend the cable, but we think it is not because of the cable itself, but some other reasons,” a spokesperson for JAXA told New Scientist. “A detailed analysis is underway.”
“Releasing a cable may seem simple, but nothing in space is simple,” says Sean Tuttle at the University of New South Wales in Australia. “The tiniest thing can upset the whole system and you can’t just go up there and readjust things.”
The test’s failure should be seen as a setback rather than a nail in the coffin for junk-removing cables, Tuttle says. “There are several theoretically viable candidates for removing debris, but no one has actually shown one to work in space yet,” he says. “The sooner we get something to work the better.”
The Japanese cable test was the first in-space evaluation of debris-removing technology. The UK is planning to try nets, harpoons and sails in 2017, and the European Space Agency is proposing to test nets or robotic arms in 2023.
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