The New Horizons probe will be the first spacecraft to study Pluto, the most well-known of the Kuiper Belt objects, which orbit in the frozen outskirts of the solar system.
New Horizons will not stop at Pluto, but will slingshot past it to encounter an object called PT1 in January, 2019 before heading out of the solar system.
New Horizons got a speed boost from Jupiter’s gravity in 2007. Without it, the probe would not have reached Pluto until the year 2036.
About the size of a grand piano, New Horizons is powered by a radioisotope thermoelectric generator (RTG). This nuclear battery releases energy though the decay of 24 lbs. (11 kilograms) of radioactive plutonium. Similar generators were used by the Voyager space probes and on the moon by Apollo astronauts.
New Horizons’ onboard scientific instruments include cameras, spectrometers, a dust particle detector and radio wave experiments.
Source SPACE.com: All about our solar system, outer space and exploration.
Source: http://www.space.com/27989-new-horizons-pluto-mission-explained-infographic.html