MOFFETT FIELD, Calif. - Sensitive detectors that may help find habitable planets orbiting distant stars as part of NASA's Kepler Mission are undergoing tests at Ames Research Center, Moffett Field, Calif.

Scheduled to launch in February 2009, the Kepler Mission will measure tiny variations in the brightness of stars to find planets that pass in front of them during their orbits. During these passes or "transits" the planets will slightly decrease the star's brightness. The detectors are similar to the image detectors found in a digital camera, but much more sensitive.

"This is a major milestone for the Kepler mission," said David Koch, deputy principal investigator for the Kepler Mission. "We will use hardware identical to what we will be flying on Kepler in the test bed at Ames. We will have the ability to create transits of a star so that we can see the change in the star's brightness. By simulating transits, we will be able to demonstrate that the flight hardware will work," Koch explained.

Kepler mission scientists will determine the frequency of Earth-size and larger planets in or near the habitable zone around other stars. Although hundreds of larger, Jupiter-like planets composed of gas already have been detected, Kepler mission scientists are seeking smaller planets where water, and perhaps, life, could exist.

"We expect to find dozens of planets in the habitable zone of solar-like stars that are terrestrial size, rocky planets, similar to Earth," said William Borucki, Kepler's science principal investigator. "We will learn whether Earths are common or rare in our galaxy."

There will be 42 charge coupled devices (CCDs) used in the focal plane of the telescope during the actual mission. Together, the 42 CCDs make up a large array measuring about a foot square in Kepler's telescope. This is the largest array of CCD detectors ever flown in space, Koch said.

In this month's Single String Transit Verification Test at Ames, scientists will be testing only one CCD, measuring approximately one-inch by two inches. Scientists will use a Kepler Technology Demonstration test bed to generate a star field, a pattern of stars, to represent that part of the sky where mission scientists will search for transits. The tests will verify the detectors' ability to measure the tiny light intensity variations.

In space, the array of detectors will be covered with sapphire field-flattener lenses and use a telescope, which Borucki said will search a region of sky 30,000 times larger that the Hubble Space Telescope is able to observe.

Kepler is a NASA Discovery mission. NASA Ames is the home organization of the science principal investigator and is responsible for the ground system development, mission operations and science data analysis. Kepler mission development is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Ball Aerospace & Technologies Corp., Boulder, Colo., is responsible for developing the Kepler flight system.

For more information about the Kepler mission, visit:

http://kepler.nasa.gov/

For more information on NASA programs, visit:

http://www.nasa.gov