Launch of Kepler Space Telescope

Kepler was a NASA space observatory launched from Cape Canaveral on a Delta II rocket, designed to search for Earth-sized planets orbiting other stars. It stared continuously at a patch of sky in the constellations Cygnus and Lyra containing about 150,000 stars, looking for the tiny dips in light that occur when a planet passes in front of its star. The mission, led by principal investigator William Borucki, discovered thousands of exoplanet candidates and well over two thousand confirmed planets, showing that planets are common in the galaxy. After the failure of two reaction wheels it continued as the K2 mission, and it was retired in 2018 when it ran out of fuel.

Open on the timeline