NASA’s Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) is back in the business of tracking down near-Earth objects after a two-year sabbatical.

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The NEOWISE mission, which uncovered 34,000 new asteroids and characterized 158,000 more between 2010 and 2011, was switched off in February 2011 for 31 months. The spacecraft has now been switched back on to re-start its quest to track lumps of space rock that stray into Earth’s interplanetary neighborhood.

Before it was renamed to NEOWISE, the cryogenically-cooled spacecraft was known as the Wide-field Infrared Survey Explorer (WISE). WISE cataloged the entire infrared sky, discovering cool celestial objects like brown dwarfs, distant galaxies, interstellar dust, comets and asteroids. Now, during its “warm” phase (the cryogenic coolant has run out, leaving two of its four infrared instruments operational), the spacecraft has been renamed and devoted solely to the asteroid hunt.

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“NEOWISE not only gives us a better understanding of the asteroids and comets we study directly, but it will help us refine our concepts and mission operation plans for future, space-based near-Earth object cataloging missions,” said Amy Mainzer, principal investigator for NEOWISE at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

“The spacecraft is in excellent health, and the new images look just as good as they were before hibernation. Over the next weeks and months we will be gearing up our ground-based data processing and expect to get back into the asteroid hunting business, and acquire our first previously undiscovered space rock, in the next few months.”

NEOWISE was powered up in September and today, the first test infrared observations of known asteroids have been released.

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Pictured top, the dotted line shows the trajectory of the 26 mile-wide main belt asteroid 872 Holda as it passed through the constellation Pisces (the thin streak is a man made satellite passing through the NEOWISE field of view). This is one of the first images retrieved from the new NEOWISE campaign and it appears to be functioning just fine.

NEOWISE is a critical observatory in the hunt for NEOs and the identification of future targets for NASA’s asteroid capture mission.