MADDIE SOFIA, HOST:
You're listening to SHORT WAVE from NPR. Hey, everybody. Maddie Sofia here with SHORT WAVE reporter Emily Kwong.
EMILY KWONG, HOST:
SOFIA: Hey, you. So today, we have a listener question episode.
SOFIA: This one is from Rachel Weiss (ph).
RACHEL WEISS: Hey there, SHORT WAVE. This is Rachel from Jacksonville, Fla. And I was curious about space junk. How much of a problem is it, if at all, and where is all this junk anyways?
SOFIA: Space. Oh, boy.
KWONG: The final frontier, Maddie, is not a pristine environment. Since the dawn of Sputnik, we've been filling it with satellites, man-made objects placed in orbit to collect data and send signals for military purposes, research, communication, navigation...
SOFIA: Our friend GPS.
KWONG: That's right. We are a satellite-dependent world. I want to introduce you to Moriba Jah. He enlisted in the U.S. military after high school and was stationed at Malmstrom Air Force Base in Montana when he noticed satellites for the very first time.
MORIBA JAH: You know, Montana is Big Sky Country, and not only do you see lots of stars in the Milky Way and all that, but I started noticing these dots going across the horizon.
KWONG: And he realized those dots were satellites.
JAH: I never imagined that, with my naked eye, I'd be able to see hardware, other satellites up there reflecting sunlight. And it was like, wow.
KWONG: Moriba now studies the movement of stuff in space, including space junk, at The University of Texas at Austin.
SOFIA: So what does he think of Rachel's question?
KWONG: Yeah, Moriba says space junk is absolutely a problem. We send this material up into space, and, for the most part, it never comes back. The U.S. Department of Defense is tracking on well over 20,000 artificial satellites - halos, rocket bodies, debris - and approximately 90% of that is non-operational.
KWONG: This is junk.
SOFIA: That's a lot of junk.
KWONG: Yeah. And the Department of Defense only tracks on objects that are, at minimum, 10 centimeters in diameter, so bigger than a softball.
SOFIA: So we don't actually even know the full extent of what's up there.
KWONG: Well, there's been a few statistical models trying to estimate it, but the important thing to know is that this aggregate of space junk is growing, most of it in low Earth orbit. NASA's own website describes this region as kind of an orbital space junkyard. And the population of space junk is likely to grow, which might be a problem for anyone who, you know...
SOFIA: Relies on satellites at all?
SOFIA: So today in the show, space junk - why it's a problem and how it's building up.
KWONG: In a final frontier with little regulation and a lot of trash, we'll tell you about the first planned mission to pick up space junk.
(SOUNDBITE OF MUSIC)
SOFIA: We are tackling a question from listener Rachel Weiss on space junk, this growing population of man-made objects cluttering up Earth's orbit. So how exactly does that happen?
KWONG: OK. First, let's consider what satellites are made out of - metal, plastic, glass, powered by batteries or solar panels. And when they're placed in specific orbital highways, they stay there, moving so quickly that they don't fall towards the Earth.
JAH: Kind of like, you know, if you had to put a boat in a body of water, you want to avoid fighting the current kind of thing.
KWONG: That's Moriba Jah, who we met earlier. He says that, from Sputnik onwards, our satellites have been creating debris, shedding spent rocket bodies, pieces becoming unglued - satellites have been known to explode when unspent fuel is on board.
KWONG: And, of course, they can cross flight paths and collide with one another.
JAH: And whenever satellites shed pieces, they tend to not shed one but many, many pieces, hundreds of thousands of pieces, depending on the type of collision.
KWONG: These collisions rarely destroy the satellites, but they can alter their operation and send pieces jettisoning off into space, affected not only by gravity but other physical forces.
JAH: Solar pressure, you know, thermal radiation, charged particle environment, interactions with, you know, magnetic fields...
KWONG: And all of this makes it very difficult to predict what space junk will do next. The little that falls back to Earth, which is one object a day on average, burns up or falls into the ocean. So space junk is probably not going to land on your head.
SOFIA: Have you calculated that probability? Because...
KWONG: Oh, I knew you were going to ask me this question. I haven't, but there is a scientist, Mark Matney at NASA's Orbital Debris Program, who has - it's one in several trillion.
SOFIA: Honestly, I still don't like it, but OK.
KWONG: Maddie, the people you should worry about more are astronauts, right? The International Space Station actually has a tracker to monitor for collision risk, and they will maneuver out of the way when the risk is too great.
SOFIA: Wow. But I feel like if there was a major collision, I would've heard about it, right?
KWONG: Yeah, there hasn't been a major collision. You know, the U.S. military, NASA and other agencies and groups around the world, they track debris and warn of potential collisions. But there's been a few scares in recent decades. So in 2015, for example, the crew on the International Space Station had to hide in their Soyuz capsules - basically, the station's lifeboat - when debris from an old Russian weather satellite came dangerously close.
SOFIA: I don't like that.
KWONG: No. Spacecraft and satellites will routinely maneuver out of harm's way but only if they have ample warning. So the whole spacefaring community was pretty rattled when, in 2007, the Chinese military destroyed one of their own weather satellites. They were testing out anti-satellite technology. Brian Weeden remembers tracking this big explosion for the U.S. Air Force.
BRIAN WEEDEN: I personally was sort of shocked. It was kind of like, wow.
KWONG: Brian was part of a squadron that counted the resulting debris.
WEEDEN: And in the end, we ended up cataloguing more than 3,000 objects. So that one satellite got turned into 3,000 things, and that's just the things we can track.
SOFIA: Wasn't space junk a big part of the movie "Gravity"?
KWONG: You are remembering correctly.
(SOUNDBITE OF FILM, "GRAVITY")
ED HARRIS: (As Mission Control) Debris from the missile strike has caused a chain reaction, hitting other satellites and creating new debris...
KWONG: This 2013 Hollywood movie, it begins with a chatty George Clooney and Sandra Bullock servicing the Hubble Space Telescope, gazing contentedly back at Earth, when this huge cloud of debris from a missile strike rips through...
(SOUNDBITE OF FILM, "GRAVITY")
HARRIS: (As Mission Control) Expect a communications blackout at any moment.
KWONG: ...And it's a bad situation.
(SOUNDBITE OF FILM, "GRAVITY")
GEORGE CLOONEY: (As Matt Kowalski) Half of North America just lost their Facebook.
KWONG: This dramatic portrayal definitely raised the profile of space junk, even if the portrayal wasn't very accurate.
WEEDEN: I think maybe, on the whole, it has been a good thing for the issue, even if I might grumble a little bit.
SOFIA: Scientists love to grumble.
KWONG: (Laughter) That's Brian Weeden again. He's now the director of program planning for the Secure World Foundation - thinks a lot about sustainability in space - and he says that opening scene in "Gravity" doesn't capture the true problem.
WEEDEN: All the debris that catches them is portrayed as sort of a nuclear chain reaction, right? There's one event that sets off this series of things that all happen very fast. The reality is sort of the opposite, where it's like climate change.
KWONG: The problem with space junk is it's a long, relatively slow accumulation over decades, with a big negative impact down the road.
SOFIA: Got it.
KWONG: Yeah. So Brian says mitigating the risk of space junk involves convincing people launching satellites, governments and companies, to change their behavior now, mindful of the future.
WEEDEN: And maybe have a little inconvenience or a little more cost now to forestall bad things in the future. And that's a really difficult argument to make because we humans just aren't engineered to kind of think like that.
KWONG: Especially when nothing truly catastrophic has happened yet. But space junk is already proving to be problematic in the short term. It's translating into real-world costs as satellite operators field alerts about potential collisions.
WEEDEN: Do I change my satellite's orbit? Because that costs fuel, and that will shorten the lifetime of your satellite.
KWONG: Which isn't good for the commercial space economy, which is kind of booming right now.
SOFIA: Yeah, we did that episode all about how SpaceX is going to put a bunch of satellites up there.
KWONG: Right. You know, in the long term, space junk has the potential to not only collide with manned spacecraft like the International Space Station but threaten satellites at all levels of orbit, like those used for imaging and weather data collection.
WEEDEN: Which then could mean our climate models are less accurate, or we don't have a good way to track emitters, and that could have negative impacts down the road.
SOFIA: Yeah, we're going to need that data.
KWONG: We are. But here's the thing - there's no international regulation for how satellites should operate. There's only guidelines.
KWONG: Yes. Guidelines from the Inter-Agency Space Debris Coordination Committee for mitigating the risk of debris - things like deorbit your satellite after 25 years by burning it up or bringing it down, passivate the upper rocket stage - meaning vent all the remaining fuel or draining the batteries.
SOFIA: So it's not as explode-y (ph).
KWONG: Yes. So there's less risk for debris. Countries do this, but it's totally voluntary. It's up to each individual nation to implement. So until there's greater accountability, space junk will continue to be a problem.
SOFIA: OK. We've talked about the problem. Give me a solution, Kwong. Like, what is being done to clean up this junk?
KWONG: Well, we're not seeing much in the skies. There's been demonstrations of different cleanup technologies on Earth that could be used in space - magnets, deployable nets, harpoons...
SOFIA: A little space fishing.
KWONG: Yeah, in the orbital sea. Most of this cleanup technology is being developed in Europe and Japan. But here's the thing - we don't know what's the best way to yank this swiftly moving debris out of orbit to a place where it can safely burn up. You would need a high level of precision to remove that junk without creating more of it.
SOFIA: And I feel like that would take a lot of money to pull that off.
KWONG: Yes. So it was a pretty big deal when, last December, the European Space Agency greenlit the first-ever cleanup mission, called ClearSpace-1, which is estimated to cost over $100 million. In 2025, the European Space Agency plans to send a cleanup robot to scoop up a chunk of old European rocket.
SOFIA: A chunk. So they're spending over $100 million to clean up one piece of space junk?
KWONG: It's a big piece.
KWONG: It is. More significantly, this hasn't been done before, right? Can we agree?
KWONG: This is kind of progress. It could be a game changer in the void of space, which Moriba considers an ecosystem that we need to actually try to protect.
JAH: So if these natural pathways become too polluted, too congested, if we can't use these orbital highways anymore, then you can say goodbye to these services and capabilities. So this is my concern - a tragedy of the commons, as it were, in near-Earth space because of this lack of holistic management of this finite resource.
KWONG: For me, it's so easy to see space as infinite.
KWONG: But the space we use most, that houses our satellites, is actually pretty finite.
SOFIA: Emily Kwong, thank you for taking on this enormous listener question. And thank you, Rachel Weiss, for sending it in.
KWONG: Thanks, Rachel.
SOFIA: This episode was produced by Brit Hanson, edited by Viet Le and fact-checked by Berly McCoy.
KWONG: Thanks for listening to SHORT WAVE from NPR.
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