This
story was updated at 12:10 a.m. EST on March 7.
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 alien stars.
Kepler blasted
off atop a Delta 2 rocket from the Cape Canaveral Air Force Station in Florida
at 10:49 p.m. EST (0349 March 7 GMT). 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.
Kepler separated
from its booster about an hour after liftoff and headed toward an
Earth-trailing orbit that will circle the sun once every 371 days. The
successful liftoff came on the heels of NASA's Feb. 24 failure of a landmark
climate-monitoring satellite, which crashed into the ocean just after launch.
A planet
like ours "out there"
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 its
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.
Astronomer
Geoff Marcy, a Kepler co-investigator at the University of California at
Berkeley, called Kepler a "mission for the ages."
"Kepler is
the first telescope ever conceived by humanity that can actually detect planets
like Earth," Marcy said just before launch.
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.
NASA hopes
to use Kepler to sift through those planetary behemoths for the smaller, rocky
worlds - like our own Earth - that happen to orbit their parent stars in a
region just right for liquid water to exist at the surface.
"What
exists is an incredibly random, chaotic, you know, wild range of planets,"
said Debra Fischer, an astronomer at the San Francisco State University who is
not directly involved with the Kepler mission, in a recent briefing. "Kepler is
really going to probe the habitable zones of planets."
The range
of the so-called habitable zone, or Goldilocks zone, around a star varies
depending on the star's size, but is generally considered to be the region in
which liquid water - an essential ingredient of life on Earth - can exist at
the surface. Too close to a star and a planet is too hot, while too far
out will yield icy, frozen worlds, researchers said.
"What we
want is a temperature that's just right," said Borucki. "The so-called
Goldilocks zone."
More
work ahead
With Kepler
now in space, the work to outfit the telescope for its planet-hunting mission
will begin in earnest.
Jim Fanson,
NASA's Kepler project manager at the Jet Propulsion Laboratory in Pasadena,
Calif., said Thursday that 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.
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