NASA Space Probe Reaches Comet NASA scientists confirm that a space probe has hit its comet target. They hope the collision will reveal clues about how the solar system formed.
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NASA Space Probe Reaches Comet

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NASA Space Probe Reaches Comet

NASA Space Probe Reaches Comet

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The Fourth of July fireworks started early.

(Soundbite of control-room announcement)

Unidentified Man #1: Team, we got a confirmation...

Unidentified Man #2: OK, we got a confirmation. All right!

(Soundbite of laughter and applause)

MONTAGNE: Scientists wearing red and blue shirts jumped up and down at the Jet Propulsion Laboratory here in California upon receiving word from 83 million miles away that a comet had smashed into a NASA probe. The first pictures of the impact show a giant explosion throwing debris over a mile into space. Scientists hope data from the experiment will shed some light on how the planets in our solar system formed billions of years ago. NPR's science correspondent David Kestenbaum joins me now. Good morning.


Good morning.

MONTAGNE: So pretty big excitement in the control room there.

KESTENBAUM: It was really dramatic because they had pictures going all the way up till the final seconds before the probe was destroyed. So the probe has this camera on it and you see the comet getting bigger and bigger and bigger and when it's really close, you can actually see--it look almost like a stone that you might pick up off the beach, sort of partially weathered but not entirely smooth. And that's the last picture because the craft gets vaporized. But they had a second spacecraft nearby that was watching the whole thing and that sent back a picture that was just--the whole room erupted in applause. It looked like an artist's drawing or a painting. You could see the comet and the bottom third of it or so is completely obscured by a giant explosion.

MONTAGNE: Now I've seen this described--this event described as a speeding bullet managing to hit another speeding bullet. Was it really that hard?

KESTENBAUM: The hard part was that the comet--it doesn't really just go straight. It has these little outbursts where some gas will burst off in one direction. One scientist called them sneezes. And that causes the comet to wander around a bit, sort of like a knuckle ball pitch. So the probe that--its job was to get run over, to stay in the path of the comet, had to actually do some course corrections to make sure it stayed in the right place.

MONTAGNE: Now scientists had predicted that this would create a crater, some said as small as a house or as big as a football field. What did it turn out to be?

KESTENBAUM: It was clearly a really big explosion. I think they don't quite know the size of the crater at this point, but that's the sort of thing they want to look at. The idea here is that comets have inside them material that hasn't literally seen the sun for four and a half billion years. The comets were put together the same time the planets were, but the comets have been really unchanged over all these years. And so by looking at the shape of the crater and by studying the debris that comes out, they hope to understand what that early material was like. One scientist said, `We've got a wealth of data here that's going to take me into my retirement.'

MONTAGNE: Well, did the collision change the course of the comet?

KESTENBAUM: The head of JPL said this morning that there's a comet up there in the sky wondering what in the heck hit it, but really it's the probe that got run over and got vaporized. The probe weighed something like 800 pounds and the comet is much bigger. It's 10 miles across. So in the scheme of things, we're pretty small. And if a comet were heading toward the Earth, you'd have to do something pretty dramatic to deflect it. Although one scientist was saying that the Impactor created what they call a jet, so a small bursting of material out to one side. And that over the long, long period, that would actually deflect the comet slightly, so in a sense, this is a sort of thing that you could do if you had a comet and you caught it early enough and realized that it was eventually was, in many orbits, hit the Earth. You could deflect it slightly by something like this.

MONTAGNE: NPR science correspondent David Kestenbaum. Thanks very much.

KESTENBAUM: You're welcome.

MONTAGNE: And you can see pictures of the comet's collision with the space probe at

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