The Hunt for Another Earth

NASA's new planet-hunting Kepler telescope launched into space late Friday, lighting up the night sky above Florida as it began an ambitious mission to seek out Earth-like planets around.

Kepler took off atop Delta 2 rocket from the Cape Canaveral Air Force Station in Florida at 9:49 (CST). The $600 million spacecraft will gaze at a single region of our Milky Way galaxy for at least three years in a planetary census that, scientists say, could fundamentally alter humanity's view of its role in the universe.

"At the end of those three years, we'll be able to answer, 'Are there other worlds out there or are we alone?'" said William Borucki, Kepler's principal investigator at NASA's Ames Research Center in Moffett Field, Calif., before launch.

Named after the 17th century German scientist Johannes Kepler, who discovered the laws of planetary motion, NASA's Kepler spacecraft will use those laws to seek out Earth-like worlds around distant stars.

The spacecraft will point its unblinking eye at a patch of sky near the constellations Cygnus and Lyra, where it will scan some 100,000 stars for the telltale dip in brightness that signals a planet crossing in front of its parent star as seen from Earth. The tiny "wink" in light that Kepler is designed to measure with 95 million-pixel camera is comparable to a person trying to watch a flea cross a car's headlight from miles away, NASA officials have said.

Since 1995, astronomers have discovered nearly 340 planets beyond our own Solar System, but the search has turned up mainly inhospitable worlds the size of Jupiter or larger that circle parent stars in orbits too extreme to sustain life as we know it.

Flight controllers plan to spend the next two months performing a series of tests to make sure Kepler is healthy and ready to work. If all goes well, the protective dust cover shielding Kepler's telescope eye will open about three weeks after liftoff.

Mission scientists hope to begin spotting larger Jupiter-like planets first, and then narrow the hunt down to Earth-like worlds as the mission wears on. While Kepler is designed to last about 3 1/2 years, it carries enough fuel to run for six years, they said.

But first, NASA has to get the spacecraft into its planet-hunting position.

"We have a lot of calibrations to do," Fanson said.

Below is a video animation of Kepler being launched and the sequences thereafter once out of Earth's atmosphere.