Kepler Planet Hunter
Kepler is designed to survey our area of the Milky Way Galaxy to find and characterize Earth-sized and larger planets in or near the habitable zones of distant stars. A habitable zone encompasses the distances from a star where liquid water can exist on a planet's surface, a key component of life as we know it.
Kepler discovered the first planet in the habitable zone of a sun-like star in 2011.
Image Credit: NASA