Author: Brad Plumer

Date: 26/10/2013

Source: AGE

Cleaning up the flying trash is possible but nobody wants to pay for it, Brad Plumer reports.

Space is getting awfully messy.

The amount of debris in Earth’s orbit keeps multiplying each year, damaging satellites and putting astronauts in harm’s way. If the problem gets severe enough, it could eventually make low-earth orbit unusable.

Scientists have known about the space trash problem since the 1970s. It even features in the recent Hollywood blockbuster Gravity.

Yet the world’s nations have never quite been able to agree how to solve the problem. The technology to clean up debris exists but no one can decide how to pay for it.

In a recent paper, three economists argue that a user fee should be placed on all orbital launches to pay for the clean-up.

“User fees are a solution straight out of the Reagan era to deal with these environmental issues,” co-author Peter Alexander says.

Satellites are used for everything from communications to television to Earth monitoring and military surveillance. Roughly 49 per cent of satellites are in low-earth orbit, which is also where astronauts work. Another 41 per cent are higher up, in geosynchronous orbit.

And those routes are getting clogged.

The US Strategic Command is aware of more than 21,000 man-made objects in orbit larger than 10 centimetres, but hundreds of thousands of even smaller pieces can’t be tracked.

Many move at extremely high speeds, up to 35,000 km/h.

Astronauts working on the International Space Station occasionally have to scramble into their Soyuz escape capsule when metal shards fly near, just in case a piece hits the station.

“A 10-centimetre sphere of aluminium would be like seven kilograms of TNT,” one NASA scientist says.

The nightmare scenario is a cascade of collisions that becomes unstoppable. This is known as the “Kessler syndrome”, after NASA astrophysicist Donald Kessler, who first predicted the possibility in 1978.

So far his initial prediction of an apocalypse by 2000 has turned out to be premature. But in 2009, we saw the first major collision between two intact satellites – a US Iridium and an ageing Russian Cosmos. The end result: 2000 additional chunks of metal flying around Earth.

A major report by the National Research Council in 2011 warned that we might be 10 or 20 years away from severe problems.

Recently, aerospace engineers at the University of Colorado outlined a plan to haul away debris using static electricity.

But a user fee for orbital launches would create its own headaches. Most of the debris, after all, was put there by the US and Russia/the Soviet Union, with China a close third. (In 2007, China blew up one of its own satellites to show off its weapons capabilities, creating an additional 3000 bits of debris.)

Should a launch tax apply retroactively? Should the US and Russia pay most of it?

“Good questions,” says Mr Alexander. “The bargaining environment here has become incredibly complex. So we looked at the simplest solution, imposing a launch fee.

“The amount of debris will continue to grow over the next 200 years. Until now, we’ve had voluntary guidelines … and the physics community is saying this is not sustainable.”