The Kepler mission was a NASA space observatory that operated between 2009 and 2018 with the goal of discovering Earth-size exoplanets orbiting other stars. It achieved this by monitoring the brightness of over 150,000 stars in a specific region of space for signs of periodic dips in brightness, which could indicate the presence of a planet passing in front of the star. Kepler discovered thousands of exoplanets during its mission, revolutionizing our understanding of the prevalence and diversity of planets in our galaxy. The mission provided valuable data for studying the potential habitability of exoplanets and the formation and evolution of planetary systems.