First flyby of an object beyond Neptune

On 14/07/2015, NASA’s New Horizons spacecraft completed the first close flyby of Pluto, becoming the first mission to explore a trans-Neptunian object at close range. The spacecraft passed within approximately 12,500 kilometers of Pluto’s surface during closest approach after a journey of more than nine years since its launch on 19/01/2006. Operating autonomously during the encounter, New Horizons collected high resolution images and scientific measurements while traveling at about 14 kilometers per second. Because of the extreme distance from Earth, about 4.8 billion kilometers, confirmation of the successful flyby was received several hours later. Data returned from the encounter revealed Pluto as an active and complex world. Images showed vast plains of nitrogen ice, including the bright region later named Tombaugh Regio, along with mountains composed largely of water ice rising several kilometers high. Scientists identified evidence of glacial movement, varied terrain, and a layered atmosphere dominated by nitrogen with multiple haze layers extending to high altitudes. The observations indicated that Pluto’s surface is geologically diverse rather than uniformly cratered. New Horizons also observed Pluto’s largest moon, Charon, during the flyby. The images revealed deep canyons, smooth plains, and surface fractures suggesting past internal activity. The spacecraft further collected data on Pluto’s smaller moons and measured the environment around the dwarf planet. The flyby marked the first detailed exploration of the Kuiper Belt region and extended spacecraft reconnaissance to the outermost known major bodies of the solar system.