Kepler Space Telescope

The Kepler Space Telescope was a NASA spacecraft designed to search for Earth-sized planets orbiting stars outside the Solar System. Launched in 2009, it operated for nine years and discovered thousands of exoplanet candidates. The mission's primary goal was to determine the frequency of small, rocky planets with conditions suitable for life. Kepler used the transit method to detect exoplanets by measuring the decrease in a star's brightness as a planet passed in front of it.