The New Horizons Mission to Pluto (Invited Presentation)

After decades of planning and a 9-year journey, the New Horizons spacecraft reached Pluto on July 14, 2015, providing our first close-up view of the Kuiper Belt Object and its five moons. Pluto's surface is found to be remarkably diverse with a wide range of terrain ages, geomorphology color, composition, and photometric properties. Images of Pluto show strong evidence for both an H2O-ice crust and a geologically young surface. Although Pluto's atmosphere has a surprisingly low base pressure (7-10 microbars), the gas extends to higher altitudes than anticipated from Earth, contains trace hydrocarbons and exhibits an extensive global haze layer. . Pluto's varied surface and current activity questions how processes on small planets can be powered so long after formation. Charon's surface geology is surprisingly diverse with the satellite's north pole being unexpectedly dark. We find no evidence for and atmosphere on Charon. Pluto's small satellites Hydra and Nix are relatively small, elongated, icy objects with albedos intermediate between Charon and Pluto. The New Horizons spacecraft carries two instruments, SWAP and PEPSSI, that measure low and high energy particles respectively. These particle instruments have been measuring the conditions in the solar wind for most of the trajectory from Earth to Pluto. The Venetia Burney Student Dust Counter measured impacts from micron-sixed dust particles. These particle instruments also made observations during the flyby of Pluto on July 14, 2015. We report on New Horizons measurements of the interaction of the solar wind interaction with Pluto's extended atmosphere and discuss comparisons with theoretical expectations.