AYESHA RASCOE, HOST:
The big crash was hidden from telescopes, but astronomers were able to confirm a derelict SpaceX rocket plowed into the moon last week. And that has once again ignited the debate around all the stuff we're firing off into space and sometimes into the moon. Thousands of defunct satellites, discarded rocket stages and the pieces that used to belong to them are orbiting the Earth. So when does all this space junk pose a problem? Is it already a problem? To get some answers, we called John Crassidis. He's a professor at the Department of Mechanical and Aerospace Engineering at the University at Buffalo. Welcome to the program.
JOHN CRASSIDIS: Thanks for having me on.
RASCOE: Can you give us a sense of the scale of this problem, and what are the issues that come out of having all of this junk in space?
CRASSIDIS: As far as a scale, a lot of people like to say that space is very big, and I keep saying it's getting smaller every day. So right now, we currently track about 54,000 objects that are greater than about a softball size. And we haven't had that many instances of collisions, but the big one we'd had was in 2009 when two big satellites, Iridium and Cosmos, collided even though we thought we had tracked them well. So we're getting to a point that we have to start to think seriously and not getting into what's known as Kessler syndrome, where we have so many collisions that the probability of colliding is going to be so great that we can't put stuff into space.
RASCOE: For the listeners who may be listening to this and looking up to the sky trying to see if, you know, something's about to fall on their head, does any of this debris pose a threat for us down here?
CRASSIDIS: I wouldn't worry about it at all. We - yeah...
RASCOE: (Laughter) OK.
CRASSIDIS: The chances of getting hit by lightning are orders of magnitude bigger. But there have been cases where humans have been hit, but nobody's been killed. But very rare. So don't change your day plans.
RASCOE: OK (laughter). With all of that up there, though, anyone with a working satellite, along with any mission that involves leaving Earth, has to deal with it. So right now, how are people making adjustments?
CRASSIDIS: So what happens is - there's a lot of math behind this, but we can compute a probability of collision, anything greater than a 1 in 10,000 chance. So we don't want take any chances here. The Air Force will call one of the manufacturers and say, you probably should move. You don't necessarily have to move it, but you probably should. But we can only do this for so long 'cause we're putting up more stuff than is coming down. And like I said, in 50 years, I think we'll probably be in trouble.
RASCOE: What can be done about it? Are there plans to clean it up?
CRASSIDIS: That's the other really big problem. There are no advanced technologies that we have that can clean this up right now. So we need to buy time. There's also a political aspect. There's no modern-day treaties. So we have some rules to reduce the amount of debris that we do with our sister nations, but not everybody follows them.
If you look up U.N. guidelines, in 2010, they put up some guidelines. Guideline No. 4 said don't try to create space debris. Well, China, in 2007, blew up one of its own satellites with a missile - caused about 2,000 pieces of space debris. Russia did it. India did a little - much more controlled experiment, but we can't even follow the simple guidelines, and that's disheartening to me.
RASCOE: Right now, everybody is not playing according to the rules. What will that mean for us on Earth? Like, how will it directly impact us, especially if we get to that point where we're not able to send things up into space?
CRASSIDIS: So we rely on satellites for everything in our everyday lives today. So it'll definitely impact our everyday lives. We're not going to go back to the Stone Age, but we probably go back to the '50s where we don't have satellites, right? So obviously not good. We don't want that to happen.
RASCOE: And you're talking about, like, GPS and all that stuff that we rely on. What are some other things that we rely on satellites for?
CRASSIDIS: Well, the internet, Starlink. Now we're doing all the great science that we do to study the universe and study the Earth. We're not going to be able to do. So it impacts our lives. And there's communications, right? We do a lot of communications now with satellites. We're not going to be able to do that anymore. So it's going to be a problem. Yeah.
RASCOE: That's John Crassidis from the University at Buffalo. Thank you so much for joining us.
CRASSIDIS: Thank you. Transcript provided by NPR, Copyright NPR.
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