In the summer of 1989, NASA's Voyager 2 became the first spacecraft to observe the planet Neptune, its final planetary target. Passing about 4,950 kilometers (3,000 miles) above Neptune's north pole, Voyager 2 made its closest approach to any planet since leaving Earth 12 years earlier. Five hours later, Voyager 2 passed about 40,000 kilometers (25,000 miles) from Neptune's largest moon, Triton, the last solid body the spacecraft will have an opportunity to study.
Voyager 2, launched August 20, 1977, visited Jupiter in 1979, Saturn in 1981 and Uranus in 1986 before making its closest approach to Neptune on August 25, 1989. Voyager 2 traveled 12 years at an average velocity of 19 kilometers per second (about 42,000 miles an hour) to reach Neptune, which is 30 times farther from the Sun than Earth. Voyager observed Neptune almost continuously from June to October 1989. Now Voyager 2 is also headed out of the solar system, diving below the ecliptic plane at an angle of about 48° and a rate of about 470 million kilometers a year.
