Eleanor Hall reported this story on Tuesday, May 31, 2016 12:25:16

ELEANOR HALL: More than 170 million chunks of it are orbiting the earth, and could wipe out all our navigation and communication systems.



Space junk is more dangerous than it looks - a piece the size of a fleck of paint caused a crack in the International Space Station just this month.



Today, Australia's Space Environment Research Centre is hosting an international conference to discuss ways to deal with debris in space.



Dr Ben Greene is the centre's CEO and he also heads a private company that is working with a major aerospace firm to devise space tracking systems.



He joined me in our Canberra studio.



Dr Greene, to give us an idea of the seriousness of this space junk problem, if there were a major collision in space, just how much damage could that inflict on us here on Earth?



BEN GREENE: Well, the initial impact is economic. A satellite can cost anywhere between $20 million and $3 billion, so an individual collision would have an economic impact.



But what's more important is what the collective impact of these collisions is over a period of time because there is an immense amount of junk in space, and there are collisions every month, some of which are more serious than others.



The real concern we have here is that the collisions will reach an intensity and a frequency that there will be an avalanche of collisions and suddenly, instead of a collision a week, there'll be a collision a week this week, two next week, four the next week, and there will be a runaway process whereby the debris generation in space will become so fast that nothing will survive.



We call it the avalanche.



ELEANOR HALL: So you're talking about an avalanche of collisions. How likely is something like that, how soon could it happen?



BEN GREENE: Well, we can only go mathematically and different space agencies will differ in their forecasts but the most optimistic is about 25 years from now we will lose space and the most pessimistic is we're almost within the next five years we're at the 50/50 probability point.



ELEANOR HALL: And if that happened it would wipe out, what, all communications?



BEN GREENE: It would wipe out layers of satellites. So the most likely place it would happen is about 1,000 kilometres in space and that would wipe out about $300 billion worth of satellites.



And it would wipe out a whole level of technology to do with intense communications and responsive communications and Earth observation, crop maintenance, rapid response for bushfires, emergency services.



It's unbelievable how much we would lose.



If we lost the geoband through a different set of circumstances, but related to space debris, that would be also quite catastrophic and not fixable.



ELEANOR HALL: You say it's not fixable though, what do you mean by that?



BEN GREENE: Well, anything that gets to geostationary orbit is there permanently. The lower orbits actually will decay over time and fall down towards the Earth.



So if we had a relatively disastrous scenario in lower Earth orbit, say at 1,000 kilometres above the Earth, and it generated millions of pieces of debris, that would clean itself out, nature would clean that.



It has a cleansing process under gravitational and other forces that would pull that debris into the upper atmosphere and burn it up within the 1,000 years.



ELEANOR HALL: So what sort of junk is out there? Where does it come from?



BEN GREENE: We made it all. It's all man-made.



It's rocket bodies, exploded satellites, it's satellites that have died on orbit when they ran out of fuel, malfunctions.



There's 30,000 objects bigger than a football and they're the ones we’re most worried about because everything down to much smaller than a thumbnail will destroy a satellite, but the ones that are really big will destroy a satellite in ways which generate thousands of pieces of new debris and will contribute towards bringing forward the avalanche.



ELEANOR HALL: Yes, you say that something tiny will destroy a satellite, but because of the speed with which objects travel in space, even tiny specks can do damage. Tell us what happened with that cracked window in the International Space Station.



BEN GREENE: Well, the space station has armoured glass for its windows and the glass is literally five centimetres thick and very, very toughened and a paint fleck hitting that, even a speck of dust, they have quite a bit of damage on the surface of those windows already.



Many people don't know the space station has special armour plated survival quarters, where the crew have to retreat to every time there's a forecast of a near pass of space debris.



ELEANOR HALL: So the International Space Station has also had to shift orbit to avoid damage, what do unmanned satellites do if they're faced with a collision?



BEN GREENE: Well, the real problem for unmanned satellites is that the knowledge of the debris field - we know almost every individual piece of debris bigger than a football and so as I said, they're the ones that we are concerned with the most.



Australia, by the way, is the world leader in tracking and finding and maintaining knowledge about those pieces of debris. Very few people know that Australian technology and Australian infrastructure is in place that does a better job of monitoring that than anyone else in the world.



ELEANOR HALL: Why do we have that expertise?



BEN GREENE: It came out of Australian innovation, pure innovation. It was a research program started back in the '70s and it spiralled into a whole range of space information technologies, and in the '90s a decision was made to focus it on the space debris problem and within 10 years we had mastered the ability to find and track these objects very accurately.



Coming back to what unmanned satellites can do; if you knew where the debris was very accurately, you could manoeuvre the satellite around the debris.



Unfortunately, to manoeuvre satellite requires fuel and the lifetime of a satellite which means its commercial lifetime depends only on how much fuel it can carry.



So if you're manoeuvring the satellite all the time to miss debris collisions, you'll run out of fuel and your investment will last three years instead of 13 years.



So commercial operators are very reluctant to move their satellites unless they're really sure that the collision is going to happen - and really sure means that someone will tell them that the space debris is going to come within 100 metres of their satellite.



And right now, notwithstanding the Australian developments which are deploying very rapidly now to give more and more accurate information, the rest of the world is only providing that information at the five kilometres level.



So you can't manoeuvre a satellite to miss every five kilometre near miss because you'd be out of fuel in six months.



ELEANOR HALL: So what is the ultimate option for dealing with this debris? Is removing it the goal that you're really heading for?



BEN GREENE: Yeah, the Australian Government has funded the Space Environment Research Centre, which is a collaborative program between government and industry, so it's a three way participation - government, industry and universities.



And with the Commonwealth putting up a third of the funds, and the bulk of the funds coming from industry, and industry is developing through the seed technologies that have been made available to this new organisation - new technologies that within two years will rapidly reduce the risk of collisions and therefore buy us time to come up with the other solutions we need to mitigate the problem.



In other words if we can cut the number of collisions rapidly now, we'd slow down the growth of debris and we’d postpone the avalanche, and buying the time is important because there are other technologies, again pioneered in Australia, which are capable of reaching out and bringing that debris down, out of harm's way.



ELEANOR HALL: Well, one research team at your centre is working on, the sci-fi sounding notion of photon pressure. What's that?



BEN GREENE: Photon pressure is - this is one of the key programs we're working on. Photon pressure is where we generate using lasers, quite powerful laser beams and we very gently nudge, in other words it’s not using a laser to destroy the space debris or even damage it in any way, but use a surface effect of the light hitting the object to exert pressure on it and move it.



And we can move it in ways which are predictable into safer places initially and ultimately to move it into new orbits, where they will decay much more quickly and be burned up in the upper atmosphere.



ELEANOR HALL: Are there dangers of this technology falling into the wrong hands?



BEN GREENE: Well, every technology can be used in different ways and sometimes for less honourable purposes than others, but we really don't have a choice.



We have to go hard at this because it's not just the trillion dollars that's invested in the assets that are flying around in space, most people, if they think about it will understand that nobody would put a million dollars into space if it's not generating much more economic activity than a million dollars on the Earth.



This is where we live, this is where the business is run, this is where the crops grow, this is where the floods happen.



So a trillion dollars worth of investment in space is literally three to five trillion dollars worth of economic activity on Earth, which we have to keep going by sustaining the resource that it depends on which is the space information, the space assets.



ELEANOR HALL: Dr Greene, thanks so much for joining us.



BEN GREENE: Thank you.



ELEANOR HALL: That’s the chief executive of the Australia's Space Environment Research Centre, Dr Ben Greene, speaking to me from Canberra.