Researchers from the Australian National University (ANU) and Japan’s Tohoku University have developed a new prototype satellite that fires plasma to de-orbit space debris.
Known as the ‘Sheppard’ system, it uses a bi-directional argon plasma thruster to both position itself in proximity to space junk and send the debris into a lower orbit to burn up. Research published in Scientific Reports shows how the team was able to control the plasma ejections precisely in both directions so that force can be imparted to the space junk while the satellite itself remains stationary.
“Our tests show you can push plasma out one end of a satellite to thrust it towards the junk, and then push it out the other end to send that junk in the right direction,” said Prof Rod Boswell from the ANU Research School of Physics and Engineering.
“If you can throw the gas out as a plasma, or charged gas, you can throw it out very quickly and make much better use of the fuel. You throw out less of it, because it’s thrown out very fast.”
So far, the concept has only been tested on the ground by Dr Kazunori Takahashi at his Tohoku University space simulation facility. The next phase of the research will see the team streamlining the design and working on a guidance system so that the satellite can not only de-orbit junk, but also track it down in the first place.
“Doing it up in space is going to require even more work. I call this the hunter killer satellite because it would have to hunt out the space junk,” said Boswell. “From the ground you can calculate the orbit trajectory, so you know within a certain number of kilometres – but then it would have to find the junk with its own radar.”
“We’re now trying to make this system much cheaper and much more effective, because at the moment it’s a laboratory instrument so it’s a big clunky thing. So we’re working with Dr Kazunori and universities in America and New Zealand to make these things applicable to actual spacecraft,