NASA moon mission captures fleeting view of sister craft
BY STEPHEN CLARK
Posted: 29 January 2014
Coupling a fortuitous orbital alignment with meticulous planning, a camera aboard NASA's Lunar Reconnaissance Orbiter caught a smeared glimpse of another moon probe in an image released Wednesday.
But scientists in charge of the Lunar Reconnaissance Orbiter Camera calculated how to record a view of LADEE on Jan. 14 as the two probes traveled at near-perpendicular angles more than 20 miles over the moon's tortured surface.
"Since LROC is a pushbroom imager, it builds up an image one line at a time, thus catching a target as small and fast as LADEE is tricky! Both spacecraft are orbiting the moon with velocities near 1600 meters per second (3600 mph), so timing and pointing of LRO needs to be nearly perfect to capture LADEE in an LROC image," wrote Mark Robinson, LROC's principal investigator at Arizona State University in Tempe.
During the Jan. 14 encounter, controllers commanded LRO to roll 34 degrees to the west to line up the spacecraft's narrow-angle camera with LADEE's expected position on its flight path. LRO's imager was designed to snap sharp pictures of the moon, not fast-moving nearby spacecraft, so the initial result showed LADEE as a smeared streak backdropped by a clear landscape of lunar craters.
"Despite the blur it is possible to find details of the spacecraft, which is about 1 meter wide and 2 meters long. You can see the engine nozzle, bright solar panel, and perhaps a star tracker camera (especially if you have a correctly oriented schematic diagram of LADEE for comparison)," Robinson wrote.
LRO launched in June 2009 to map the lunar surface and complete a geological survey of the moon, revealing new insights into how the moon formed and evolved, creating a global lunar atlas, and helping scientists find deposits of watery compounds.
Since arriving in lunar orbit in October, LADEE achieved the first high-speed laser communications link-up between the moon and Earth and is now collecting data on the moon's tenuous atmosphere.
LRO and LADEE were joined at the moon in December by China's Chang'e 3 lander, which deployed a small mobile rover. LRO's camera has already imaged the Chinese probe on the lunar surface.
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