The Kepler Mission: Zeroing in on habitable Earths

NASA's Kepler Mission was launched on March 6, 2009 with the goal of determining the frequency of Earth-size planets in the habitable zone of solar-like stars using the transit photometry method. Kepler's driving design requirement was the ability to detect the 84-ppm change in brightness as an Earth-size planet transits its host star. As such, stability of the instrument and continuity of the data are keys for success. Kepler is beginning the third year of the planned 3.5 years of data collection and has already revolutionized the field of extrasolar planets, detecting over 2,300 planet candidates, the first Earth-size planets, the first circumbinary planets, and over 360 multiple-planet systems. The project has proposed an extension of the mission to NASA so that Kepler can continue collecting data and results for another four years.