AYESHA RASCOE, HOST:
NASA is about to make history tomorrow by ramming a spacecraft into an asteroid for real. The goal is to change how the asteroid moves through space. NASA says it's the first test of a technology for defending the planet in case there's ever a dangerous space rock on a collision course with Earth. NPR science correspondent Nell Greenfieldboyce has been following this mission. Hi, Nell.
NELL GREENFIELDBOYCE, BYLINE: Hey.
RASCOE: So I want to make one thing clear. This asteroid is not actually threatening our planet right now, right?
GREENFIELDBOYCE: It is no threat to us. It is no threat at all. It's about 7 million miles away, and it's not on a path that would bring it to us. This whole thing is just practice, like a drill. The mission is called DART, or Double Asteroid Redirection Test, and the folks working on it are aware that the whole thing sounds far out. Here's program scientist at NASA, Tom Statler.
TOM STATLER: We are moving an asteroid. And this is stuff of science fiction books and really corny episodes of "Star Trek" from when I was a kid. And now it's real.
GREENFIELDBOYCE: So just for a sense of scale, the researchers say the spacecraft is, like, the size of a golf cart, and it'll be ramming into an asteroid the size of, like, the Great Pyramid in Egypt at 14,000 miles per hour.
RASCOE: Could that send the asteroid in our direction if they hit it in the wrong angle?
GREENFIELDBOYCE: Zero chance.
RASCOE: OK.
GREENFIELDBOYCE: Zero chance of that. NASA officials have emphasized that over and over. You can imagine people worry about that. They say this is just not scientifically possible. The asteroid, which is named Dimorphos, is actually orbiting an even bigger asteroid. That's why it's called the Double Asteroid Redirection Test. And hitting the smaller asteroid should alter its course so that it moves even closer in to its big asteroid buddy.
RASCOE: I would imagine that a test like this is pretty expensive.
GREENFIELDBOYCE: Three-hundred million dollars - more than that. Yes.
RASCOE: That is a lot of Beyonce concert tickets. So does that mean that a killer asteroid is something that the government is worried about 'cause that's a lot of money?
GREENFIELDBOYCE: I wouldn't say worried, necessarily, but, like, aware. Scientists think there's a lot more out there that we haven't found and tracked yet. If one of those did take aim at our planet, something that size could, like, wipe out a city or a small country.
RASCOE: What will NASA learn from this test that would help them deal with that?
GREENFIELDBOYCE: So researchers think they know how the asteroid should respond to this little push. But until you try it, you don't really know. Telescopes on seven continents and space telescopes like James Webb will all be watching. And in the days and weeks after the collision, scientists will calculate exactly how the asteroid's movements changed. And all of that will go into their computer models of the stuff to help them get ready for the future.
RASCOE: Will we be able to watch the asteroid getting hit from where we are on planet Earth?
GREENFIELDBOYCE: Well, the spacecraft does have a camera on it that'll be beaming back pictures. The impact will happen at 7:14 p.m. Eastern time Monday. And in the last hour before that happens, NASA's website will broadcast images showing the asteroid getting closer and closer and closer until the spacecraft goes splat and the pictures suddenly stop.
RASCOE: OK. I mean, that doesn't sound as dramatic as what we saw in Hollywood with Bruce Willis, like, on asteroids, setting off nukes and all this stuff.
GREENFIELDBOYCE: That is definitely the Hollywood portrayal.
RASCOE: Yes.
GREENFIELDBOYCE: Nukes are the go-to solution for movies, but planetary defense experts in the real world don't like them because they could just cause a lot more problems than they solve, really. And, you know, the idea is that if you can spot the asteroids out there, you could have years of advance warning - you know, plenty of time to come up with a plan that would be something more subtle, like giving an asteroid just a little nudge to send it off, like, on a different course. And that's exactly what they're going to be testing out.
RASCOE: NPR science correspondent Nell Greenfieldboyce, thank you so much for joining us.
GREENFIELDBOYCE: Thank you. Transcript provided by NPR, Copyright NPR.
