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February
20, 2009: Are there other worlds like ours? Are we
alone?
NASA's
Kepler spacecraft is about to begin an unprecedented journey
that could answer these ancient questions.
Kepler
is scheduled to blast into space from Cape Canaveral Air Force
Station, Fla., aboard a Delta II rocket on March 5 at 10:48
p.m. EST. It is the first mission with the ability to find
planets like Earth -- rocky planets that orbit sun-like stars
in a warm zone where liquid water could be maintained on the
surface.
Above:
An artist's concept of an Earth-like planet orbiting a distant
star. Credit: Dana Berry/NASA. [video]
[more]
"Kepler
is a critical component in NASA's efforts to find and study
planets where Earth-like conditions may be present,"
said Jon Morse, the Astrophysics Division director at NASA
Headquarters in Washington.
The
mission will spend three and a half years surveying more than
100,000 sun-like stars in the Cygnus-Lyra region of our Milky
Way galaxy. It is expected to find hundreds of planets the size
of Earth and larger orbiting at various distances from their
stars. If Earth-size planets are common in the habitable zone
(where conditions favor liquid water), Kepler could find dozens
of worlds like ours. On the other hand, if those planets are
rare, Kepler might find none.
The
Kepler telescope is specially designed to detect the periodic
dimming of stars caused by transiting planets. Some star systems
are oriented in such a way that their planets cross in front
of their stars, as seen from our Earthly point of view. As
the planets transit, they cause their stars' light to slightly
dim, or wink: 1
MB video. The telescope can register changes in brightness
of only 20 parts per million.
"If
Kepler were to look down at a small town on Earth at night
from space, it would be able to detect the dimming of a porch
light as somebody passed in front," said James Fanson,
Kepler project manager at NASA's Jet Propulsion Laboratory
in Pasadena, Calif.
 To
accomplish this feat, Kepler will use the largest camera ever
launched into space, a 95-megapixel array of charged couple
devices or "CCDs."
Right:
Kepler's completed flight focal plane array with the 42 science
CCDs and four fine guidance CCDs in the corners. [Larger
image]
By
staring at one large patch of sky for the duration of its
lifetime, Kepler will be able to watch planets periodically
transit their stars over multiple cycles. This will allow
astronomers to confirm the presence of planets. Earth-size
planets in habitable zones would theoretically take about
a year to complete one orbit, so Kepler will monitor those
stars for at least three years to confirm their presence.
Ground-based telescopes and NASA's Hubble and Spitzer space
telescopes will perform follow-up studies on the larger planets
that they can see.
"Kepler
is a critical cornerstone in understanding what types of planets
are formed around other stars," said exoplanet hunter
Debra Fischer of San Francisco State University. "The
discoveries that emerge will be used immediately to study
the atmospheres of large, gas exoplanets with Spitzer. And
the statistics that are compiled will help us chart a course
toward one day imaging a pale blue dot like our planet, orbiting
another star in our galaxy."
For
more information about the Kepler mission, visit: http://www.nasa.gov/kepler
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Editor: Dr.
Tony Phillips | Credit: Science@NASA
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Nomenclature:
The science team chose to name the mission
for Johannes
Kepler (1571-1630) for his fundamental contributions
to the fields of celestial mechanics and optics. It
was Kepler who championed the Copernican idea of a heliocentric
solar system, in which the planets all orbit the sun.
Kepler discovered the laws
of planetary motion—three basic mathematical expressions
that describe the motions of planets.
Credits:
Kepler is a NASA Discovery mission. Ames is the home
organization of the science principal investigator,
and is responsible for the ground system development,
mission operations and science data analysis. JPL manages
the Kepler mission development. Ball Aerospace &
Technologies Corp. of Boulder, Colo., is responsible
for developing the Kepler flight system and supporting
mission operations. NASA's Marshall Space Flight Center,
Huntsville, Ala., manages NASA's Discovery program.
NASA's
Future: US
Space Exploration Policy |
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