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NASA officials say its asteroid defense test was a success

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NASA says its mission to knock an asteroid off course — a test of planetary defense — succeeded beyond its expectations.

A MARTINEZ, HOST:

NASA's mission to move an asteroid has apparently been an earth-shattering success.

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LORI GLAZE: For the first time ever, humanity has changed the orbit of a planetary body.

MARTINEZ: That's the space agency's Lori Glaze. As NPR's Geoff Brumfiel reports, the test proves there's at least one way to defend Earth from an incoming space rock.

GEOFF BRUMFIEL, BYLINE: This was NASA's plan to save the world. Take a spaceship the size of a golf cart and smack it into an asteroid the size of an Egyptian pyramid at 14,000 miles an hour. Step one, steer the golf cart into the asteroid - not exactly easy. Both are moving really fast, and space is really big. But they did it.

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ELENA ADAMS: We have impact.

UNIDENTIFIED PERSON #1: And we have impact.

UNIDENTIFIED PERSON #2: And we did it.

BRUMFIEL: In late September, the little spacecraft known as DART splatted like a bug on the windshield of its target asteroid called Dimorphos. Dimorphos actually orbits a bigger asteroid called Didymos, which brings us to step two. Researchers had to figure out if the splat did anything, or in technical terms, did DART change the time it takes Dimorphos to go around Didymos? At yesterday's press conference, NASA scientists announced that they'd measured the change at around 32 minutes, which is good?

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NANCY CHABOT: So a period change of 32 minutes is spectacular and exciting.

BRUMFIEL: Nancy Chabot is a planetary scientist at the Johns Hopkins Applied Physics Laboratory, where the mission is based. She says the change in time means the path of Dimorphos around Didymos also changed.

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CHABOT: Dimorphos just now orbits ever so slightly closer to Didymos than it used to previously.

BRUMFIEL: So job done; asteroid moved. Not that it really matters this time. Neither of these asteroids are on a collision course with Earth. But NASA's Lori Glaze says the space agency now wants to step up its search for asteroids that are because the sooner humanity finds them, the easier it will be to move them out of the way.

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GLAZE: The more time we have for that little nudge, the better off we are.

BRUMFIEL: That's why NASA now wants to build a new space telescope just for asteroid hunting.

Geoff Brumfiel, NPR News.

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