A nine-year journey to Pluto
New Horizons launched in 2006 and used a Jupiter gravity assist in 2007 on its way to Pluto. Before arrival, distant observations supplied limited surface detail. Cameras, spectrometers and particle instruments prepared to examine the dwarf planet and its moons.
The distance prevented real-time ground handling of every encounter action. Teams planned pointing and observation sequences in advance for onboard execution and data storage.
The flyby of July 14, 2015
On July 14, 2015, New Horizons passed Pluto, coming roughly 12,500 kilometres above its surface. Multiple instruments measured shape, terrain, composition and atmosphere across Pluto and its satellite system.
The spacecraft concentrated on observations during the encounter, then sent a status signal and gradually transmitted its stored data. A brief passage supplied material for a much longer period of transmission and analysis.
Icy plains, mountains and young terrain
Images revealed broad plains, mountains and varied terrain. Nitrogen ice covered parts of the plains, while harder water ice formed elevated terrain. Differences in crater populations indicated differing histories of surface modification.
Charon also displayed canyons and varied surfaces. Spectra and atmospheric observations connected image patterns with composition, building geological and environmental descriptions of the system.
From a point of light to a studied world
Stern and the mission team published initial results in 2015, combining terrain, ice composition, atmosphere and satellite observations. Young surface regions and evidence of geological activity changed expectations about such distant bodies.
The encounter linked telescopic measurements with close-range exploration. Maps, spectra and atmospheric data supplied material for continuing studies of surface change and exchanges between ice and atmosphere.