Launch: January 19, 2006
Launch Vehicle: Atlas V 551 first stage; Centaur second stage; STAR 48B solid rocket third stage
Location: Cape Canaveral Air Force Station, Florida
Trajectory: To Pluto via Jupiter Gravity Assist
Early Cruise: The first 13 months included spacecraft and instrument checkouts, instrument calibrations, small trajectory correction maneuvers and rehearsals for the Jupiter encounter. New Horizons passed the orbit of Mars on April 7, 2006; it also tracked a small asteroid, later named "APL", in June 2006.
Jupiter Encounter: Closest approach occurred February 28, 2007. Moving about 51,000 miles per hour (about 23 kilometers per second), New Horizons flew about 3 to 4 times closer to Jupiter than the Cassini spacecraft, coming within 1.4 million miles (2.3 million kilometers) of the large planet.
Interplanetary Cruise: Activities during the approximately 8-year cruise to Pluto included annual spacecraft and instrument checkouts, trajectory corrections, instrument calibrations and Pluto encounter rehearsals.
In January 2015, New Horizons entered the first of several approach phases that will culminate with the first close-up flyby of the Pluto on July 14, 2015. At closest approach, the spacecraft comes about 7,750 miles (12,500 kilometers) from Pluto system and about 17,900 miles (28,800 kilometers) from Charon.
New Horizons has the capability to fly beyond the Pluto system and explore additional Kuiper Belt Objects. New Horizons carries extra hydrazine fuel for a KBO flyby; its communications system is designed to work from far beyond Pluto and its scientific instruments can work in light levels even lower than the dim sunlight at Pluto.
So the New Horizons team had to undertake a dedicated search for small KBOs the spacecraft could reach. In the early 2000s, no such KBOs had even been discovered. The National Academy of Sciences directed New Horizons to fly by small KBOs about 20 to 50 kilometers (about 12 to 30 miles) across, which are more likely to be primitive bodies, less well-formed than planets like Pluto.
In 2014, using the Hubble Space Telescope, New Horizons science team members discovered three KBOs – all in the range of 20-55 kilometers across, and all with possible flyby dates in late 2018 or in 2019 — a billion miles beyond Pluto.
In summer 2015, after the Pluto flyby, the New Horizons team will work with NASA to choose the best candidate among the three. In fall 2015, operators will fire the engines aboard New Horizons – at the optimal time to minimize the fuel required to reach the selected target – to begin the journey.
All NASA missions that seek to do more exploration beyond their primary objectives submit a proposal to NASA to fund an extended mission. The proposal to explore additional KBOs will be due in 2016; it will be evaluated by an independent team of experts to gauge its merit: the team will evaluate the health of the spacecraft and its instrument payload, the value of the science New Horizons can do at a KBO, the cost of the flight to and the exploration of the target KBO, and more. If it recommends funding and NASA approves, the New Horizons Extended Mission would begin in 2017, allowing the team to plan and test the encounter (which would take place one-two years later) and to continue to operate New Horizons.