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[ ambient drone ]

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[ music ]

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LRO is this amazing spacecraft that has seven science instruments on it,

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and it's been in orbit around the Moon since June of 2009.

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And it's collecting all sorts of data to help NASA make really good decisions in the future

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about where to send robotic spacecraft and humans, and to address fundamentally-important science questions

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not only about the Moon, but about the solar system in general.

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I'm Mark Robinson, and I'm the principal investigator of the Lunar Reconnaissance Orbiter Camera.

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Okay, what is LROC? That's a great question. Sounds like one camera, Lunar Reconnaissance Orbiter Camera, but it's not.

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It's actually three cameras. There are two identical narrow angle cameras that are very high resolution,

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they have pixels about this big, 50 centimeters, and it was designed so that you could look

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at a human scale on the surface to find safe and engaging landing sites.

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Then there's a third camera, wide angle camera, which is literally about this big.

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It maps the Moon in UV and visible wavelengths, and its key purpose is to

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look at compositional differences for both scientific and resource evaluation.

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It's not easy to find new impact craters because most of them are very small.

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The only way we can really do this is if we have a before image and an after image, and we've been in orbit for four years now.

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So what we're doing now is we're going back to images that were taken in the first year or two, put them on a computer screen, and blink them.

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And then it becomes really obvious, "Oh, look, there's a new crater there!"

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because it wasn't in the before, it's in the after, before after, and we call these temporal pairs.

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So now we have several thousand pairs, and to sit down and look at every single pixel in all those images

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would probably take one person, you know, ten or twenty or thirty years.

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So we started working on an algorithm, or a computer program, that searches the images by using a little template,

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the before and after pairs, and it automatically finds them. It gets like about a 90% success rate.

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So far we've found hundreds of changes on the surface.

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Many of them are too small to really know for sure if they're craters or if they're secondary craters,

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but we have found over 25 that are absolutely, positively confirmed craters,

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you can see the rim and the ejecta, and we've also made this amazing discovery that we find secondary craters related.

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There was a bright flash that was recorded by a video camera by a team at Marshall Space Flight Center,

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and it was the brightest flash they recorded so it must be therefore one of the biggest craters,

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and so they were really interested for us to take a picture, can you see the crater?

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Because they predicted how big it was going to be based on the energy but this is all a model,

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and so it's a great opportunity to actually calibrate their model.

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So we took a picture centered on their coordinates, and we didn't find a crater.

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We found these enigmatic little splotches, there was something...disturbance of the soil

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that wasn't in the original image, but we didn't know what it was.

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So we thought, okay, well their coordinates are off a little bit, because their pixels are really big from their camera,

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in fact their pixels are bigger than our image footprints.

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So we said, okay, no problem we'll move over to the west and we'll take a - you know, we're building up a mosaic.

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So the next month comes around, we take a picture and we do the same thing, look at the before, look at the after image: no crater.

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But more of these splotches...but also in that image we saw what looked like very faint rays,

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and we thought, "Boy, I wonder if those are actually rays from a crater?"

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So we just did this simple exercise of drawing lines and see where they converged,

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and then so the next month we came around, remember this is the third opportunity,

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we center the field of view of the camera right on that latitude-longitude, boom take another picture,

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comes down and there it is: beautiful 18-meter-diameter crater.

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And then we started looking and now we've got three of these, and there's hundreds of these little splotches that we're finding,

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these rays, and then we have the big picture: you could see that the splotches are actually lined up.

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These very small clods of ejecta were thrown out ten, twenty, thirty kilometers away,

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that's thirty-thousand meters compared to an 18-meter-diameter crater, so it's a very exciting discovery.

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[ music ]

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[ satellite beeping ]