Creating new lasers to move space objects

30 August 2018

One of the University's two academics to receive 2018 ANU Translational Fellowships recently says the funding will help advance her project to a prototype phase.

Associate Professor Celine D'Orgeville, who is based at the Advanced Instrumentation and Technology Centre (AITC) at Mount Stromlo, received funding to help advance her research into the area of adaptive optics and what she calls 'guide star lasers'.

Professor D'Orgeville says the technique is about compensating for atmospheric distortion to improve the tracking of space debris, and ultimately to be able to modify their trajectory.

"With adaptive optics, you're going to be able to correct for that distortion in real time. In order to make that correction, you first need to measure what's the atmospheric turbulence and in order to make that measurement you're going to need the light source that you're going to use to probe the atmospheric turbulence," she said.

"To do that I use what is called a guide star laser."

The laser interacts with sodium atoms in the atmosphere, making them glow, which then allows scientists to probe atmospheric turbulence.

Professor D'Orgeville says this atmospheric interference, or 'turbulence' means it is more difficult to see objects in space from the Earth's surface.

Guide star laser technology first involved the use of liquid dyes to create laser light. But this technique was messy and involved chemicals that are flammable and not safe. Later versions have used solid-state crystals to create lasers. The current technology involves fibre optics, but this technology is produced by just one commercial vendor.

"My aim is to develop a competing technology based on semiconductor chips. The beauty of it is we're talking semiconductor technology so we are talking miniaturisation - a smaller system, less components, therefore less expensive, easier to operate, easier to maintain.

"So the aim of the Translational Fellowship is to bring this semiconductor guide star laser technology to market."

Professor D'Orgeville says the project, which is centred around doing a better job tracking space debris so that debris can be shifted by other, more powerful lasers, is in a prototype phase and the next phase will be to test the technology on the 1.8-metre telescope up at Mount Stromlo.

"The Space Environment Research Centre uses that technology when tracking space objects, and its particular focus is space debris.

Professor D'Orgeville says guide star lasers will be used in some of the world's biggest telescope projects, including the ANU-backed Giant Magellan Telescope project.

"They all use adaptive optics and they all use guide star lasers because there's no point in building these giant telescopes if you don't correct for atmospheric turbulence. And astronomers are still interested in doing it from the ground because it's way cheaper than doing it from space. It's a bit more complicated, but it costs much less."

Adaptive optics are used for other purposes including astronomy and laser communications as well.

But Professor D'Orgeville says space junk is something she is particularly focused on helping to alleviate.

"With more debris in space, there's a high risk of collisions with existing space assets such as satellites we use for communication, monitoring earth, banking, GPS positioning, you name it.

"My technology will work alongside technology that's designed to mitigate the threat of space debris collisions further into the future until hopefully by then we'll have found a way to clean up space."