Mission Overview
Kepler, a NASA Discovery mission, is a space-borne telescope designed to search a nearby region of our galaxy for Earth-size planets orbiting in the habitable zone of stars like our sun. The habitable zone is the region around a star where the temperature permits water to be liquid on the surface of a planet. Liquid water is considered essential for the existence of life.
Kepler will hunt for planets using a specialized one-meter diameter telescope (3.3 feet) called a photometer. The photometer will continuously measure the precise brightness of more than 10,000 stars, waiting for the stars to “wink” when orbiting planets pass in front of them.
These events, called “transits” occur each time a planet crosses the line-of-sight between the planets parent star and the Kepler telescope. When this happens, the planet blocks some of the light from the star, resulting in the periodic dimming. This periodic signature is used to detect the planet and to determine its size and orbit.
By monitoring a large number of stars, Kepler will permit astronomers to estimate the total number of Earth-size planets orbiting in the habitable zone around stars in our galaxy. If Kepler does not discover any such planets, scientists will be able to conclude that we are likely alone in the galaxy.
Kepler launched from the Cape Canaveral Air Force Station in Florida in March 2009 on a Delta II launch vehicle. Following a 60-day commissioning phase, during which the photometer and spacecraft will be checked out and readied for the science mission, Kepler will spend three-and-a-half years conducting its search for planets orbiting other stars.
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