November 23, 2021

Examine

Hello all, I’m Stuart Layt, welcome to Examine.

First things first - the more observant among you have likely already twigged that I am not your regular correspondent Liam Mannix. If you missed last week’s newsletter, Liam is heading off on leave to welcome his first child, and we wish him and his partner all the best as they start on an incredible journey.

While he’s away, I’ll be filling in on Examine, bringing you all the latest and most interesting science news from Australia and around the world. I am the science reporter for Brisbane Times and cover health, science and technology for BT as well as the broader group of Nine mastheads including The Sydney Morning Herald and The Age.

I’m going to be handing the reins back to Liam in the new year, but until then, I can’t wait to share some incredible science stories with you. Speaking of which ...

The danger of space junk

Imagine a piece of metal, travelling at an incredible speed, nearly 8km per second. Now imagine it slamming into another piece of metal, which slams into another, and another, until there is a deadly cloud of shrapnel whizzing through space, shredding anything in its path.

Now imagine it surrounds the Earth.

In such a scenario, launching things into space would be almost impossible, as anything trying to pass through the debris field would likely be struck and disintegrate itself, only adding to the problem.

This is the absolute worst-case scenario of the so-called Kessler Syndrome, named after NASA scientist Donald J. Kessler who first proposed the idea in 1978.

The idea sounds like the stuff of science fiction, so much so that it is - the movie Gravity starring Sandra Bullock and George Clooney features a Russian missile test destroying a satellite, causing a chain reaction which sends deadly debris spinning around the Earth.

So it was with more than a little dread that space watchers looked on in horror last week as almost that exact scenario played out - a Russian missile specifically designed to destroy satellites took out a decommissioned Russian satellite, causing a large and dangerous debris cloud.

Fortunately, the movie’s plot did not play out in real life, although the debris cloud briefly threatened astronauts on the International Space Station, who had to take shelter in case the station was hit.

Russia wanted to send a message that it, like a handful of other countries, including the USA and China, had the capability to shoot down a satellite if it wanted to.

Countries and private companies have condemned the move but the action also shone a fresh light on the growing issue of space junk.

Pictured above is NASA’s official tracking visualisation of all the objects just in low Earth orbit. It’s not quite as crowded as it looks, with the dots in the image quite a bit larger in scale to the actual objects they represent. But it does give an idea of the size of the cloud already in orbit around the Earth.

It is estimated that about 20,000 large artificial objects are in orbit around the Earth, only a little over 2200 of which are functional satellites, according to NASA’s US Space Surveillance Network.

The rest are decommissioned satellites and large pieces of debris left over from previous space missions.

However, that estimate only includes the objects large enough to be actively tracked - it’s thought that there is also more than 34,000 pieces of debris about 10cm in diameter, and up to 128 million pieces of debris smaller than 1cm.

More than 1500 trackable pieces have now been added to that cloud by the Russian satellite’s destruction, which space junk expert Alice Gorman from Flinders University said was a wake-up call that more needs to be done about the rubbish whizzing over our heads.

“Space junk is being created all the time, but this is the sudden addition of a lot of new material, which unfortunately accelerates us toward a Kessler Syndrome situation,” Professor Gorman said.

“There was absolutely no necessity for a test like this to be done, it was purely political demonstration, and it’s worrying that nations think it’s okay to still do this.”

The cloud of debris will now need to be taken into account every time a nation or company wants to launch something into that area of the sky.

Professor Gorman said the issue will only get worse, with more than 100,000 satellites of various sizes expected to be launched into low Earth orbit over the next decade, creating a bottleneck at the gateway to the cosmos.

“While it’s true that space is huge, it’s not infinite, and adding lots of material in the same place is going to eventually have an impact,” she said.

Much of Australia’s own contributions to the new space race is in the form of “microsatellites” - small, box-sized objects which can be used for a range of purposes from surveillance to tracking agricultural patterns.

Such items are useful, but also add to the growing cloud of objects which need to be observed and managed.

The nightmare scenario for us on Earth would be if communications satellites started to fall victim to a Kessler cascading event, which would affect everything from GPS to telecommunications, all of which rely on signals bounced off satellites to function.

Fortunately most of those are in geostationary orbit much higher up, but Professor Gorman said the risk wasn’t negligible.

There are efforts to clear at least some of the debris which humans have left behind on space missions. Australian company Neumann Space announced just this week that it is working with three other firms to turn space junk into fuel.

The companies want to set up a facility which would capture and process the debris in orbit, turning it into reusable metal rods.

Earlier this year, EOS Space Systems proposed a plan to use a ground-based laser, set to be installed in Canberra, to push larger pieces of debris out of orbit.

Professor Gorman said the efforts were encouraging, but more needed to be done both to clean up the debris that was there and to stop more of it being generated.

“It’s a rapidly changing situation, and if it does tip over into Kessler Syndrome, there’s really no going back,” she said.

Examine is a space for exploring the most important and interesting evidence and ideas – but it’s also a conversation. I want to hear what you think, or why you think I’m wrong.

Email me your thoughts, tweet me, or forward this email to anyone else who might be interested, so they can get involved in the conversation.

Stuart Layt Reporter