Pluto and its largest moon Charon
© NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research InstituteThis image of Pluto and its largest moon, Charon, was taken by the Ralph color imager aboard New Horizons on April 9, 2015, from a distance of about 71 million miles (115 million kilometers). It is the first color image ever made of the Pluto system by a spacecraft on approach.
Pluto, Charon and a growing number of smaller moons will offer an unprecedented scientific opportunity as our first robotic explorer to the Kuiper belt makes its historic flyby. But the mission will be far from over after July 14.
Pluto five moons
© ZME ScienceThe International Astronomical Union (IAU) is announcing that the names Kerberos and Styx have officially been recognised for the fourth and fifth moons of Pluto, which were discovered in 2011 and 2012.
NASA's New Horizons spacecraft is expected to make a historic flyby only 7,750 miles (12,500 kilometers) from the dwarf planet's surface. In the meantime, we've been gradually getting a sharper and sharper view of the dwarf planet and its system of moons. New Horizons - a compact, lightweight, powerfully equipped probe, packing the most advanced suite of cameras and spectrometers ever sent on a first reconnaissance mission.
New Horizon probe to Pluto
© NASA, ZME ScienceNew Horizon launched from Earth on January 19, 2006 and now is back online after 9 year journey to Pluto.

New Horizons will begin gathering science data in January and will not finish returning all of the data until late 2016. Because it will be traveling so fast, nearly all of the most important goals for the mission are met in the time from 2.5 hours before to 1 hour after closest approach.

The Pluto mission is divided into several phases:
  • Approach Phase 1: 180 to 100 days before closest approach (Jan 6-Apr 4; range to Pluto is 226-121 million km). SWAP and PEPSSI will measure plasma. LORRI will monitor motions of Pluto, Charon, and the smaller moons. Pluto is barely resolved.
  • Approach Phase 2: 100 to 21 days before closest approach (Apr 4-Jun 23; range to Pluto is 121-26 million km). Add in color observations, and search for satellites and rings. The start of this phase is chosen to roughly coincide with the time when LORRI has better resolution than Hubble, but Pluto will still be only a few pixels across.
  • Approach Phase 3: 21 to 1 days before closest approach (Jun 23-Jul 13; range to Pluto is 26-1.2 million km). Includes best, second-best, and third-best rotation coverage before closest approach, yielding the best global maps of Pluto and Charon. PEPSSI and SWAP may detect pickup ions and bow shock. LEISA and Alice can begin looking for variability in IR and UV. Search for clouds or hazes, tracking winds.
  • Near Encounter Phase: -1 to +1 days (Jul 13-15, within 1.2 million km) — sequenced in 2008 and 2009. Most of the highest-priority observations.
  • Departure Phase 1: 1 to 21 days after closest approach (Jul 15-Aug 4; range to Pluto is 1.2 to 24 million km). Remote sensing of Pluto and Charon is performed for only 1 rotation. SWAP and PEPSSI study magnetotail, pickup ions. REX studies nightside temperatures. Nix and Hydra high-phase observations. Search for rings.
  • Departure Phase 2: 21 to 100 days after closest approach (Aug 5-Oct 22; range to Pluto is 24 to 119 million km).
  • Departure Phase 3: 100 to 180 days after (Oct 22-Jan 1, 2016; range to Pluto is 119 to 203 million km). No remote sensing observations planned.
Once it's finished here, New Horizon will visit one or more Kuiper Belt Objects beyond Pluto. Here the probe will find objects believed to be representative of the material which condensed to form the other planets. Their growth into full sized planets was arrested early in the history of the solar system. Hence they hold clues about the distant past of the solar system and the chemical endowment of all the planets including our Earth. In the belt, there are billions of objects with a diameter greater than 10 km.