Shining a light on space debris

May 30, 2017

Millions of bits of space junk are currently orbiting Earth, ranging in size from mere millimetres through to discarded, school bus-sized parts of multi-stage rockets.

Space debris

Featured image above: high-power lasers can gently nudge space debris out of the way of an operating satellite. Photo: Lyle Roberts

Each piece of debris in low earth orbit circles the planet around every 90 minutes, placing $1 trillion worth of space infrastructure at risk of collision and serious damage.

In May last year, a window on the International Space Station was chipped by a small piece of space debris believed to be a tiny flake of paint, which highlights the potential for more significant damage.

The idea of changing the orbit of debris using the photon pressure from lasers has been around for a while, but the Space Environment Research Centre (SERC) in Canberra is getting close to demonstrating proof of the concept. They plan to launch dummy satellites, each the size of a shoebox, into low orbit (around 570km) and fire at them with ground-based lasers to slow them down. The satellites will be equipped with sensors that can measure the amount of light hitting the target and the changes in orbit achieved with each pass.

In theory, this technique could be used to bring objects closer to Earth so that they eventually burn up in the atmosphere.

“These are very small forces; you need to know a long way in advance there’s going to be a collision. You can then use the photon pressure to change the orbit over time,” says Dr Steve Gower, general manager of SERC.

SERC plans to launch the first satellite in late 2018 and begin the demonstration phase the following year. The key industry participants on the project are EOS Space Systems and Lockheed Martin, and the project will use  all-Australian technology.

While this technique lacks the precision required to stop a speeding fleck of paint, it could be effective in manoeuvring objects with a high surface-area-to-mass ratio – think the size and weight of a computer monitor.

“We want a large surface area so we can use the maximum amount of particles of light, or photons, hitting the object,” says Gower.

This research program applies the knowledge gleaned from SERC’s other programs, which focused on tracking objects and predicting collisions. If successful, the potential for commercialisation includes offering conjunction analysis so satellite owners can move their assets out of the way of approaching debris or remove the offending space junk before a possible collision.

Find out more at serc.org.au

– Chloe Walker

For more CRC discovery, read KnowHow 2017.

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