Associated Press - May 13, 2009 4:24 PM ET

PASADENA, Calif. (AP) - A newly launched NASA telescope has begun scanning the cosmos for Earth-like planets.

NASA said Wednesday the Kepler spacecraft will spend the next 3 1/2 years staring nonstop at 100,000 stars in a remote patch of the Milky Way for potentially habitable planets.

The start of Kepler's science mission comes two months after it rocketed from Cape Canaveral, Fla. Engineers have been busy calibrating the craft for its job.

The mission costs $600 million.

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