Rank 27 documents Kepler — the 1,052 kg Ames Discovery mission that stared at 115 square degrees of Cygnus for four years and confirmed more than 2,700 exoplanets through transit photometry. William Borucki's team launched aboard Delta II on 6 March 2009, measuring starlight dips as planets crossed their hosts and statistically proving that worlds are common throughout the galaxy. Reaction-wheel failures in 2013 ended the primary pointing mission, but the K2 extended campaign repurposed solar-pressure balance to survey the ecliptic plane until fuel depletion in October 2018. Kepler-452b and thousands of Earth-size candidates reframed humanity's place in a crowded cosmos. Heritage Collector renders the telescope hero, Cygnus field, transit curve, and habitable-zone diagram exactly as the master PNG dictates.