Ever since humans started sending satellites into space we've always neglected one very big issue - what happens when these man-made objects reach the end of their useful life? Some of the satellites will fall out of orbit, but many have remained in space for decades with no clear strategy of what to do with them. But as humans look to explore commercial space flight and populate other planets there's a growing concern that all of this space junk could pose a very real threat to our future space endeavours. So how do we actually go about cleaning up space?
Our guests in this episode:
- Francois Rigaut and James Gilbert from the Australian National University.
- Chris Blackerby from Astroscale.
- Mike Wall from Space.com. Check out his book: Out There - a Scientific guide to Alien Life, Antimatter, and Human Space Travel.
- Loren Grush from The Verge. Loren has a great video series called Spacecraft available at TheVerge.com.
Darknet Diaries: Check out the Darknet Diaries podcast to hear stories about hackers and those that have been hacked. For more information visit darknetdiaries.com.
Our theme music is by Breakmaster Cylinder.
And our cover artwork is by Andrew Millist.
News Report: “It’s a report from man’s farthest frontier, the radio signal transmitted from the soviet Sputnik, the first man-made satellite as it passed over New York earlier today.”
KRIS: It’s been over sixty years since the first satellite was launched into space, and it was only a matter of time before those satellites outlived their useful life, and turned into junk.
Joe Rogan: “Now how much of a risk is the space junk that we’ve left in the environment.”
Neil DeGrasse Tyson: “Oh, now don’t get me started”
ANDREW: Now not long ago, the game plan was to just leave those dead satellites floating around up there… and while that may not immediately sound dangerous in the largeness of space, all of this junk is starting to pile up, and it could pose a significant threat to the future of space exploration.
Newsreader: “Thousands of miles above our heads, hundreds of thousands of pieces of junk. Man-made rubbish travelling ten times the speed of a bullet.
KRIS: Welcome to Moonshot - the show exploring the world’s biggest ideas and the people making them happen. I’m Kristofor Lawson.
ANDREW: And I’m Andrew Moon.
KRIS: And in this episode of Moonshot we’re talking space junk, and those who after decades of ignorance, are now actually trying to clean it all up.
ANDREW: But before we start sweeping up our mess… it’s time for a word from our sponsors.
ANDREW: There are more than five hundred thousand pieces of space debris floating around the earth at this very moment… from old satellites to lost pieces of astronaut suits, rocket parts, paint chips, and a bunch of other stuff left behind.
KRIS: And like other man made waste down here on ground level, things are finally starting to catch up with us. We’re at this point now where people are realizing that all of junk that we’ve left up there in space could actually result in a significant problem for space exploration… and that’s because of a thing called the Kessler Syndrome. Here is Loren Grush, a senior science reporter for the Verge to explain.
Loren Grush: It’s this idea that as more and more space debris collides, fortunately that hasn't happened with much frequency but the more stuff we put up there, the more likely that they will collide and when these things do come into contact with each other, they create hundreds if not thousands of more pieces of space debris and then that becomes a risk too.
KRIS: The idea was named after Donald Kessler a NASA scientist who first described the phenomenon forty years ago. He stated that at one point we'll reach a critical density of debris in low orbit.
Francois Rigaut: Once you reach this point of the cascade then the low Earth orbit between 500 and 700 kilometer becomes totally unusable because then as soon as you ground something it's been destroyed.
KRIS: This is Francois Rigaut, an associate professor at the Australian National University Research School of Astronomy and Astrophysics.
Francois Rigaut: This cascade that we are talking about that has been illustrated by the movie Gravity, remember?
Gravity - Man's voice: “Debris from the missile strike has caused a chain reaction hitting other satellites and creating new debris. Travelling faster than a high-speed bullet up towards your altitude. Now copy”
ANDREW: And while right now the risk of anything that catastrophic happening is relatively low, Loren Grush says that risk may shift over time.
Loren Grush: It could eventually snowball out of control and then space and low Earth orbit would be unusable. And we wouldn't be able to send up anything up there it's just so congested.
Chris Blackerby: What we're trying to do is basically clean up low Earth orbit. It's an ambitious goal, but we want to create a long term, sustainable orbit for future generations.
ANDREW: That’s Chris Blackerby from Astroscale - a company that is now actively trying to clean up the mess mankind has left in space. Chris has worked in the space sector for over fifteen years, mainly with NASA, but is now Astroscale’s COO
Chris Blackerby: It is an incredibly complex issue, not just from a technology standpoint, but from this whole issue of international norms, and standards, and pressures from outside regulatory agencies and various business case scenarios as well. So it's a really exciting topic to be working on.
KRIS: So, What you're building is essentially the garbage truck of space?
Chris Blackerby: Yeah. Yeah. Exactly. I mean, we like to make it sound a little cooler than that, but yeah. Basically, it is. Yeah. We're the tow service at this point, like going up and making sure that the orbits are maintained. That's our first step.
KRIS: Astroscale essentially wants to send rockets to orbit that carry satellites specifically designed to retrieve and remove the big pieces of debris that are already floating around, to help limit the risk of future accidents.
Chris Blackerby: Obviously larger pieces of debris have a higher potential to hit more things. So, if we can pull down a couple of those a year, we can really reduce the risk.
KRIS: The business more generally has two main areas of focus, the first is active debris removal - that is, the cleaning up of all the junk that is already up there in space. The second part is called end of life services, which aims to remove satellites from orbit once they’ve been decommissioned.
Chris Blackerby: You know, the reason that we have a hitch on the back of our car is so when it breaks down on the highway ... In America, we use AAA. They come over, and they hook up to the car, and they can tow it away.
ANDREW: Astroscale’s idea is this. Whenever you want to launch satellite - you would need to install a hitch that will make it easier for the satellite to be returned back to earth.
Chris Blackerby: Our proposal is having a circular plate that attaches to the satellite, lightweight, really minimally intrusive, doesn't impact the activity of the satellite itself. On the surface of the plate would be a ferromagnetic material. We're talking about having a nickel surface on the plate. It is not magnetic in itself, but it can be attached to by a magnet, so that when that satellite fails, when its end of life is reached. What we’re proposing first is when it fails before it reaches end of life. We would then send up our chaser satellite to go and attach to it and bring it down.
KRIS: While the initial plan will see each satellite dive into the atmosphere and burn up, the long-term view is to make all of this technology reusable.
Chris Blackerby: The cost of that from a delta v, a change in orbit perspective, and the fuel costs are really cost prohibitive at this point, so we're right now as a company looking at tech roadmaps and how we can develop the technology to make that a viable business case.
ANDREW: And part of that business case is making sure that companies that go through the effort of sending a satellite to orbit - actually have a plan to remove the debris when they’re done.
Chris Blackerby: We think that companies would start to see this as a necessity, the same way we would, again, pay for towing a broken down car, that they would want to remove those risks from their orbit.
KRIS: But while the business prospect of getting companies to have a plan to remove future debris is all pretty clear - the issue remains - what do we do about all of the junk that’s already up there. Many of the initial satellites were sent up by governments - who may not be as keen to go spending the money to remove a problem that they can’t actually see.
Chris Blackerby: The governments look at this and say, "Well, the benefit of bringing it down is this, and the cost is this. The cost far outweighs the benefit, so we're not gonna look at that right now.”
ANDREW: But just because you can’t see it - doesn’t mean it’s not a problem. And Chris says that governments and businesses actually need to take some responsibility for what they send into orbit. Because, as we mentioned at the top, when things go wrong - they can make the problem worse.
Chris Blackerby: There have been accidents, the most significant of which was almost 10 years ago now. There was a collision between a defunct Russian satellite and a US communications satellite from a company named Iridium. They collided in low Earth orbit and created tens of thousands of pieces of debris. So, that's the kind of thing that could happen.
ANDREW: And with so much debris actually up in space - how do we even keep track of it all?
Loren Grush: There are many different US agencies that monitor this so anytime someone wants to launch a rocket, the FAA has to give them a launch licence. The FCC also is responsible for giving licences for radio communication. And so whenever you want to talk with your satellite in space, the FCC has to give you like a narrow band of the radio spectrum that you can use to communicate. And through that licencing process, the FCC can also approve or deny you based on how small you are. And then once your in space, the defence department is the one that tracks everything that we know of and see in orbit. So they use this thing called the Space Surveillance Network which a bunch of antennas down here on Earth and they track everything that's, I believe, bigger than a softball and that’s thousands and thousands of objects.
KRIS: Last year Astroscale launched IDEA-OSG-1 to try and monitor micro-debris in low earth orbit but the rocket failed and the satellite was ultimately destroyed. So what kind of impact does losing something as important as a satellite have on a startup company?
Chris Blackerby: It was tough initially, obviously, because the team had put a couple of years into building this satellite. It was hard, but space is tough. This is what happens in this business. Everybody knew that. We have a team of experienced engineers and a team of passionate people who were ready to go back and solve it. So, you know, after a day of licking our wounds we were ready to get right back at it.
KRIS: Now Astroscale’s goal isn’t to remove all of the debris from around the Earth - Chris says that just wouldn’t be at all realistic.
Chris Blackerby: To say reducing all of the debris, it's like saying, "Are we ever going to be able to remove every piece of trash from the ocean?" That's not likely. What we would like to do on that latter example is remove as much as possible, to make sure that wildlife is sustained and we maintain clean aquatic environments as much as possible. That's kind of what we're aiming for. So I think that's probably the more realistic goal.
KRIS: And unlike cleaning up garbage here on Earth, it seems like people are going to need to come up with more out of the box ideas to have any hope of removing all the junk in space. And Chris says we’re only just scraping the surface of how we deal with this big looming problem.
Chris Blackerby: We're at the front end of this issue, and Astroscale is not just developing the technology. We're trying to help be a thought leader, to think about how we can solve these problems, and a lot of that is in this issue of, "Okay. Let's think of a creative way to fund this stuff." We're getting a lot of interest from a lot of different areas.
KRIS: And we’ll be exploring more of these creative ideas for dealing with space junk - right after this break.
KRIS: Welcome back to Moonshot - I’m Kristofor Lawson. And when it comes to removing all of that debris that’s floating around in space Astroscale aren’t actually the only ones for dealing with the problem.
Mike Wall: People have proposed a sort of giant shrimp trawler in the sky, basically, with a net.
KRIS: This is Mike Wall, a senior writer at Space.com
Mike Wall: Not the same size as a sea going vessel on earth, obviously, but a satellite up there with a net that it uses to snag stuff and drag it down. That's a real idea that people are taking seriously, and there are a bunch of other ones too. Some of them are really space age, like using a laser on earth to blast things out of the sky. That would pose a bunch of other problems obviously.
James Gilbert: Eventually, we want to be able to perturb space junk out of orbit with these lasers using photon pressure.
ANDREW: This is James Gilbert. He’s a project engineer at the Australian National University. His idea is that everytime a small piece of space debris passes overhead, a laser could be focused on it.
James Gilbert: Eventually, due to the force that photons actually exert on an object, which is very small, but it's there. Like, you don't feel it from the sun or anything, but it's there. If you do that many times, eventually you can just destabilize it and it goes away.
KRIS: Is that a little bit like the laser from the Death Star, but you're just focusing it on space junk?
James Gilbert: Yeah, yeah. We only focus it on space junk. Honest. Yes. That's the reason we're developing this.
ANDREW: And it may or may not surprise you that shooting a laser beam at this space junk from earth is actually not that easy. See it turns out that the atmosphere creates a significant problem when you’re trying to point your laser at space.
KRIS: And while you may have this picture of the death-star laser beam destroying a planet… in reality a powerful laser beam on the earth’s surface actually loses its power the closer it gets to space.
Francois Rigaut: The characteristic of the atmospheric turbulence is that most of the turbulence is in the first 100 meter above ground but you have about 40-50% that is distributed between 100 meter and typically 12 to 15 kilometer. So you may still have turbulence very high like 10 kilometers..
KRIS: All of this means your laser beam is actually quite spread out as it approaches space, making it almost useless for removing space junk. But if you can pre-scramble the transmission of the laser on Earth and work out the atmospheric conditions, it’s possible to use the Earth's atmosphere kind of like a magnifying glass - so that as the scrambled laser passes through the atmosphere it concentrates on a point in space, allowing you to remove the debris.
Francois Rigaut: You can actually analyse using a guide star and most of the time it’s going to be a laser guide star. So it’s an artificial guide star that you create at about a 100 kilometre height. So if you point this giant star in the direction of the debris that you want to push, you can actually, by analyzing the line that's coming back from this laser guide star, know the aberration in your atmosphere. And if you know the aberration and you deform your deformable mirror to exactly counteract the aberration, your laser beam will start all scrambled but when it will have crossed all the atmosphere it will be restored and flat.
KRIS: But ultimately will that be a feasible way of getting rid of all the junk? Here’s Mike Wall again.
Mike Wall: Like, it would definitely work. But anytime you have one group saying, "We have this space laser that we're going to shoot satellites with. But you can trust us, we'll only use it for good." There's going to be some people who would say, "Wait a second. How can we believe you?" Yeah, that's a scary prospect.
ANDREW: When we think about all of the space activity that’s about to happen in the next decade and beyond the need to remove all the debris becomes even more urgent. If humans actually start flying into space commercially, which there are all signs that we will, we need to make sure we don’t end up in a Gravity-type situation, so that we can secure the safety of those first space tourists.
Chris Blackerby: We don't want to have to go through, play the game of Frogger, you know, the old video game. Remember that? Hopping around different trash highways to get out to the moon, or to get out to Mars. We want to avoid that issue.
ANDREW: Astroscale is focused on trying to act quickly - to reduce the potential for a catastrophic event as it becomes easier, and cheaper to launch satellites.
Chris Blackerby: It doesn't take a rocket scientist to figure out that the more you add to a certain orbit, the more likelihood that something could happen. And so there's a lot of companies now that are talking about and are actually doing launching small satellites into low Earth orbit. A certain small percentage of those will likely fail, and if they fail at a certain height, they're gonna be stuck in that orbit for centuries. So it will be this constant threat orbiting the globe that could at any time hit an asset, a company asset, or a government asset.
KRIS: And while we know that space junk is a growing problem there is still a lot of debate surrounding who is ultimately responsible for cleaning up all the mess that we’ve already created.
Chris Blackerby: In Japan, where we're I'm based and where the majority of Astroscale’s work takes place, the Japanese government has been very interested in this, and they're talking about how to make some kind of missions in the future work, where we can actually remove some old, defunct, Japanese rocket bodies. They're actively talking about it, you know, arguably one of the leaders globally in talking about finding solutions to do this.
KRIS: The US recently introduced Space Policy Directive 3 - which encourages the Defense and Commerce Departments to boost their ability to both manage and track the objects that exist in space to provide safe transportation for future commercial activities.
Chris Blackerby: It's basically put out there to say, "Hey. Let's figure this out." The steps being taken right now by governments are farther than I've ever seen. In talking to people in DC, in London, in Tokyo, people are saying, "Oh, yeah. This is becoming a critical issue," and governments are starting to take notice. They're starting to sit up, and pay attention to this, and think about how they can solve this problem.
Chris Blackerby: The commercial companies are recognising that it's not just a nice to do, environmental, sustainability issue. Which on its own is positive, right? We tell our kids to clean up after themselves and pick up trash. It's just a good thing to do, from the environmental perspective. They’re also recognising that it’s a business sustainability issue. That if they wanted to make sure that they’re able to maintain their business service that they should be doing this. So, to that end, we see different commercial groups, organisations, getting together to say ‘Hey, people are starting to take notice of this, the public is starting to take notice, governments are starting to take notice, let’s get ahead of the curve and put in place norms and standards that we all say will follow.’
ANDREW: Like all great space moonshots this mission to clean up our solar system, could seem a bit overwhelming and perhaps a little far out of reach. But Chris says it’s these big futuristic goals that make space such an exciting industry to work in.
Chris Blackerby: It's not just Star Trek, Star Wars, things that we can't relate to. It's stuff that we can relate to on an everyday basis, and it really does change the world, the work that people do in space. All of the passion and excitement and possibility that starts at a young age and doesn't really leave the people who are connected in the space industry, it makes it just an exciting place to work.