Pioneer 10
Pioneer 10 was the first spacecraft that explored the fifth planet from the Sun, Jupiter. Photography of Jupiter began November 6, 1973, at a range of 25,000,000 kilometers (16,000,000 mi), and about 500 images were transmitted. On December 4, 1973, Pioneer 10 made the closest approach with Jupiter at a range of 132 250 km (82 180 miles). During the mission, the on-board instruments were used to study the asteroid belt, the environment around Jupiter, the solar wind, cosmic rays, and eventually the far reaches of the Solar System and heliosphere. In 1976, Pioneer 10 passed Saturn's orbit, on February 11, 1979 it passed Uranus's orbit, on April 25, 1983 it passed Pluto, and on June 13, 1983, Pioneer 10 became the first spacecraft that passed Neptune's orbit.