AILSA CHANG, HOST:
Well, I guess we can say mission accomplished. NASA sent Osiris-REx into space to land on an asteroid and return with a sample of it. A container full of asteroid stuff landed in Utah yesterday. And here to tell us more about it is Jessica Barnes, a co-investigator on the Osiris-REx mission and a research team lead. Welcome.
JESSICA BARNES: Thank you so much. It's a pleasure to be here.
CHANG: It's a pleasure to have you. OK. So how did it feel to see Osiris-REx land?
BARNES: Oh, relief, excitement. I'm still on cloud nine. I can't quite believe that it's happened, that we're here and keep having to pinch myself. It's very exciting for the whole team.
CHANG: All right. So were there any concerns on reentry?
BARNES: I mean, there are always concerns, things that - certain marks that we have to hit on point to get us from space to Earth's surface. For me, the terrifying moment - well, there were two. One was...
CHANG: Yeah.
BARNES: ...Coming through the atmosphere. It gets very hot. There's a lot of friction. And so, you know, the sample return capsule has to withstand that for it to reach the surface. And it did. So that was great. And then the final, for me, kind of relief moment was not it actually landing on the surface, it was the parachute opening 'cause once that main parachute opened, we knew that the capsule was going to land safely.
CHANG: Wow. So explain to us why this particular asteroid is so special scientifically.
BARNES: Well, there are many reasons. So Bennu is one of millions of asteroids that we know of. It's the right size to be orbited by a spacecraft like Osiris-REx and large enough, but not too big, that we could touch the surface and back away safely. But I think it's also important to know that Bennu has a nonzero chance of impacting Earth. It's one of these near-Earth asteroids that we term a hazardous asteroid because someday in the future it could impact Earth. Not when any of us will be around to see it. If it happens, it would be in a couple of hundred years' time.
CHANG: Oh. That's not that long from now, actually.
BARNES: But that's why we want to go out and study these near-Earth asteroids, so that we can enhance our planetary defense capabilities.
CHANG: Yeah, planetary defense.
BARNES: (Laughter) Yeah.
CHANG: You say that nonironically. This is a real thing. Yeah.
BARNES: No, exactly. NASA's - NASA and other space agencies are very interested in planetary defense.
CHANG: OK. What is the most burning question that I guess we all have that our planet has looking at those contents?
BARNES: Oh, I think that answer might vary depending on which science team member you're talking to. But since you're talking to me...
CHANG: Yeah.
BARNES: ...The one I'm most interested in is - a lot of my research focuses on understanding where water in our solar system came from, how it was distributed early on, how Earth became habitable. And so for me, it'll be looking at what its water content and isotopic composition is and how that compares to what we know about meteorites. Were objects like Bennu delivering water to the inner solar system and possibly Earth when Earth was forming and evolving very early on?
CHANG: So cool. That is Jessica Barnes, an assistant professor at the University of Arizona and co-investigator of NASA's Osiris-REx mission. Thank you so much for joining us today.
BARNES: Thank you very much for having me. Transcript provided by NPR, Copyright NPR.
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