SCOTT DETROW, HOST:
A piece of space debris weighing more than 1,000 pounds crash-landed in Kenya last week. The Kenya Space Agency says the metallic ring is about 8 feet in diameter, and they believe it's a separation ring from a rocket launch. Objects like this are usually designed to disintegrate upon reentering the Earth, and the agency says the investigation is ongoing. But the incident raises broader questions about the safety of space junk, especially as more countries and private companies venture into space. John Crassidis is somebody who thinks a lot about space junk. He is a professor of mechanical and aerospace engineering at the University of Buffalo, New York. Welcome.
JOHN CRASSIDIS: Thanks for having me.
DETROW: So on one hand, like I mentioned, a lot of these items are designed to disintegrate. On the other hand, more and more launches are taking place. There's more and more satellites circling the Earth. So is a headline like this surprising to you?
CRASSIDIS: No, not at all, actually. We've had many incidents, and you can actually point as early as this past year when a piece of metal from the International Space Station - or actually batteries - that crashed through the atmosphere and landed in somebody's roof in Florida. So that obviously isn't good, and there's been others (ph) too. So as you said, as we get more launches, this is going to happen more.
DETROW: I want to talk mostly more broadly about what to do about all of this, but let's take this incident from this past week in Kenya. Like I mentioned, it was likely from a launch. It was supposed to disintegrate - any sense what you think might have happened?
CRASSIDIS: The research that I've done into this, it may be an Atlas-Centaur rocket that was supposed to come back on December 30, but the flight path took it over Africa. And I'm not exactly sure if that's the real piece. So there still has to be a lot of research that needs to be done. Frankly, we just really don't know at this point.
DETROW: How much thought and preparation goes into minimizing this at this point?
CRASSIDIS: Well, we do a lot. Unfortunately, other countries do not, and the biggest offenders are China and Russia. So we have rules that we have to follow. For example, if a satellite has thrust on it, it has to do a controlled deorbit over the Pacific Ocean. So if anything does get through, it will go into an unpopulated area. Satellites that do not have thrust - and we're building a satellite, a small satellite here at the university - you have to show that drag is going to bring it back down within five years. And the other thing is, I would love to build a satellite out of titanium, but we can't because that generally does not burn up in the atmosphere. So we build it out of materials like aluminum that gives it more of a guarantee that it's going to burn up.
DETROW: Is there - I mean, because, like, space is an area where there is a lot of universal global agreements and compacts in place, is there anything on the books when it comes to space junk or are there things on the books that are being ignored?
CRASSIDIS: We have some very early 380s (ph). Like, we had one with the old Soviet Union in 1967 that could have been covered on this. Unfortunately, there are no modern treaties right now. And that is a shame, to be honest with you. The closest you can get to is United Nations put a document out in 2010, and they're just guidelines. Guideline four, don't make more space junk if you can avoid it. And we're not even following that. Go back to China, what they did in 2007, blew up one of those satellites with a missile. So we can't even follow the simple guidelines, and that's troublesome to me. So I think we need to, yeah, have countries talk together and making sure because they're putting their own people in harm's way too.
DETROW: Can you tell me more about that 2007 incident that jumped to mind for you?
CRASSIDIS: So in 2007, China blew up one of its own satellites with a missile just to show that they could, and that caused over 2,000 pieces of space debris. And it's estimated that most of that stuff is going to be up there for 100 years. Within six months, the NASA Terra satellite had to do a maneuver away from that debris. So we calculate a probability of collision - there's a lot of math in there. But if there's a chance that's bigger than 1 in 10,000, we will call up on the (ph) manufacturers and say, you probably should move away. That Terra satellite had a 6% chance at colliding with that Chinese debris. So it moved away to ensure it wouldn't hit with it. And that's happening a lot more often.
DETROW: Do you think there's any point when this is going to come to a head and there're going to be international agreements on what to do? - because you're talking about more and more instances of stuff interacting with people here on Earth and more and more chances of incredibly dangerous or expensive collisions in space.
CRASSIDIS: Well, unfortunately, nobody's taking it as seriously as they should. And I understand there's bigger problems to solve, but honestly, I hate to say it this way, I think if an astronaut gets hurt is the only way that we're going to wake up to this - is somebody dying from this.
DETROW: Is there any way to track this from home? Like, if somebody is like, well, I'm a little concerned something might fall in my house - reasonably or not or is just curious, is there any way to track the path?
CRASSIDIS: So we track everything a softball size and bigger. And the problem is that we can't see the objects all the time, so we have to rely on Newton's equations, the same equations he's done for gravity, to predict where they're going to go. And those predictions are off because there are small disturbances that can greatly affect the path. So sometimes these objects aren't exactly what we think they are. And in 2009, two large satellites, Iridium and Cosmos, collided and caused about 500 pieces of space debris. Those are very large objects, and they did not even meet that 1 in 10,000 threshold probability. So that told us that we're not tracking the satellites as well as we should be.
DETROW: That is John Crassidis, professor of mechanical and aerospace engineering at the University of Buffalo. Thanks a lot.
CRASSIDIS: Thank you.
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