NASA’s Lunar Orbiter Takes a Hit
A Moon-orbiting camera briefly shuddered — then got back to work — when it was hit by a tiny bit of space rock no bigger than a pinhead.
It's inescapable that, left in space long enough, anything and everything will be struck by bits of interplanetary debris. And so it was that at 21:18:48.404 Universal Time on October 14, 2014, during its 23,986th orbit of the Moon, NASA's Lunar Reconnaissance Orbiter got whacked.Fortunately, even though the attacking particle was moving very fast, perhaps 7 km per second, it wasn't large — just an estimated 0.8 mm across and maybe 6 billionths of a gram. In fact, LRO personnel back on Earth might never have known about the strike were it not for a swatch of zigzag jitter seen in one of its images — evidence that was only recently discovered once someone inspected the archived file. No other sensors recorded an anomaly at that moment, and the spacecraft wasn't moving its solar-cell panels or antenna.
Instead, it appears that the one of the craft's two telephoto cameras took a tiny hit on the big, scoop-shaped radiator that helps cool the camera's detector.
"The meteoroid was traveling much faster than a speeding bullet," says Mark Robinson (Arizona State University), who leads the Lunar Reconnaissance Orbiter Camera team. "In this case, LROC did not dodge a speeding bullet, but rather survived a speeding bullet!"
LROC's telephoto cameras build up images one line at a time as the spacecraft coasts high above the lunar surface. As shown here, the image scan started fine but then briefly recorded a zigzag pattern about 10 pixels wide. That corresponds to an angular jitter of roughly 1 arcsecond (1⁄3600°). At the time, LRO was recording a strip of lunar terrain on the Moon's farside, just to the northwest of Mare Orientale.
Read more about this barely-there impact in this ASU news release, and take some time to explore LRO's amazing photographic record using this interactive lunar map.
The post NASA’s Lunar Orbiter Takes a Hit appeared first on Sky & Telescope.
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PUBLISHED; June 02, 2017 at 04:54AM
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