Outer-space rubbish removal

20 June 2014 - 02:42 By Reuters
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DUMPING GROUND: An artistic rendering of the thousands of satellites and other debris orbiting Earth
DUMPING GROUND: An artistic rendering of the thousands of satellites and other debris orbiting Earth
Image: ESA

Nobu Okada wants to save the planet from orbiting junk, which he says is in danger of cutting us off from the satellites we depend on and the outer space beyond.

"Debris affects our daily lives. What if you can't be prepared for storms, not watch the World Cup, if ships can't use GPS?" he told a conference recently.

"Our daily lives are totally dependent on satellite technology." Okada, 41, says his Singapore-based start-up Astroscale is just part of a dramatic shift in the "NewSpace" industry - the growth of private companies and new technologies challenging old, expensive government-driven programmes.

While small start-ups to giants like Google send ever more objects into space, Okada is tackling what Lux Research analyst Mark Bunger calls THE problem of NewSpace: clearing up what's already there.

Nasa estimates that more than 500000 bits of debris - from defunct satellites to marble-sized fragments like lens covers and copper wire - are orbiting Earth.

Millions more are too small to track. And because they're hurtling around at thousands of kilometres an hour, even small flecks of paint can be lethal when they collide - hitting the space shuttle, for example, smashing through a visor or tearing solar panels off satellites.

So far, this orbital mayhem has been largely the concern of space agencies. Okada says that's no longer enough.

"Somehow the amount of debris is still growing and there's no clear solution yet," he says.

Space junk hasn't just seeped into the popular consciousness because of the movie Gravity. Experts agree we've now hit the so-called Kessler Effect - when the number of objects in lower Earth orbit is dense enough that collisions could cause a cascade.

Some experts, though not all, agree with Okada's nightmare vision where it becomes harder to guarantee the safety of astronauts passing through these debris fields on the way to outer space.

"Suddenly you have a debris field acting as a real barrier to operations in the lower Earth orbit," says Jeff Forrest, Metropolitan State University of Denver chair of Aviation and Aerospace Science, "which would annihilate commerce in inner space, and make launching extremely risky."

There have been more than a dozen proposals, most either made or funded by major space agencies, to speed up the process or destroy the debris remotely. Australian researchers have proposed zapping debris with lasers. Others involve balloons, a solar sail, a wall of frozen water and harpoons.

Astroscale is developing a technology that Okada says is cheaper and better than these approaches. A mothership launches six smaller buoys which latch on to the 200 largest pieces of space junk and propel them into a lower orbit.

But there are problems. While the technological issues are not insurmountable, "the harder challenge is to make them economically feasible", says Sima Adhya, head of space at global speciality insurer Torus.

"I've yet to see a convincing business plan where a company could make money out of a service removing debris, or for a government to justify the expense."

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