Thu, Mar 30, 2017 - Page 9 News List

Space pollution could be humanity’s next big problem

While the world is slowly waking up to the threats posed by space debris, some have already started developing solutions to the problem

By Melissa Davey  /  The Guardian

Illustration: Mountain People

Jason Held rekindled his love for space while lying in a ditch in Bosnia in 1996, where he was one of 16,500 US troops deployed on a peacekeeping mission at the end of the Bosnian War.

Then a lieutenant, he said he had had “nothing to do but to watch the two armies put their guns away.” So he had signed up for a class in undergraduate biology through an army education program, taking the books to the ditch and passing the hours by studying.

“It wasn’t hard, but it was fun, and so then I did a physics class,” he said.

“Then I started buying some academic books on magnetics, and began thinking about energy distribution and how to create force and thrust for space objects,” he said.

In 2004, Held began his doctorate in robotics at the University of Sydney, and eventually founded the university’s space engineering laboratory, where he led a satellite project and worked on rocket engines.

Today, he leads the company Saber Astronautics in Sydney, where he has built technology he believes can be used to rid space of debris, one of the most pressing issues for space programs worldwide.

At least a couple of times every year, the International Space Station maneuvers to avoid a potentially catastrophic collision with space junk.

While estimations vary, there are about 4,000 active and inactive satellites in space. They are at risk of being hit by the approximately half a million bits of floating space debris, ranging in size from micro-millimeters to two double-decker buses.

“What everyone is realizing, is that this is a growing problem, though nobody gave a shit in the early days of space exploration,” Held said. “Why would they? There wasn’t a lot out there. If you think of the early days of aviation, you didn’t need air traffic control. It took a few plane accidents before air traffic control was put in place.”

“People are now starting to see congestion up in space, and if a satellite is up there and it deactivates for some reason while up there and you can’t move it, you have a giant bullet flying around at 8km per second,” he said.

Held hopes the device created by him and his team will be able to eliminate some of this junk and drag it back down into the atmosphere, where it will combust. Called the DragEN, the yo-yo like device weighs just under 100g and can be attached to spacecraft and satellites.

When activated, the DragEN unspools hundreds of meters of string made of a conductive material that gathers electric and magnetic forces as it travels through the earth’s magnetic field. This force drags the satellite back toward Earth and into the atmosphere.

Left to gravity alone, satellites can take decades to re-enter the atmosphere and combust. Held is not sure how long it will take for a satellite attached to the DragEN to do so. He hopes to find out soon: The Indian Space Research Organisation will trial the device in space for the first time on a satellite launch planned for later this year.

“The satellite mission is to take photos of the earth and downlink photos,” Held said. “At the end of its mission, the team will release the DragEN tether, which will start dragging the satellite back to Earth. We are all very interested to learn how DragEN unspools in space and how quickly or slowly it takes to come back down.”

Held is not alone in the race to tackle space junk. While Australia is not a big player in building spacecraft systems, it is an important collector of data and information from space. Australian researchers are using this information to monitor roughly 29,000 pieces of space junk and warn of collisions.

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