Destination: Jupiter and Saturn. Launched: Aug. 20 (Voyager 2) and Sept. 5 (Voyager 1), 1977. Mission: To explore Jupiter and the other outer planets. Launched in 1977, Voyager 1 and Voyager 2 passed Jupiter in 1979 and sent back surprising color TV images of that planet and its moons. Voyager 1 passed Saturn in Nov. 1980. Voyager 2 passed Saturn in Aug. 1981 and Uranus in Jan. 1986. Voyager 2 encountered Neptune in 1989 and discovered four rings around the planet, six new moons, a giant spot, and evidence of volcanic-like activity on its largest moon, Triton. The spacecraft sent back over 9,000 pictures of the planet and its system. Voyager 2 remains the only spacecraft ever to have visited the worlds of Neptune and Uranus. On Feb. 13, 1990, at a distance of 3.7 billion miles, Voyager 1 took its final pictures of the Sun and six of its planets as seen from deep space. NASA released the extraordinary images to the public on June 6, 1990. Only Mercury, Mars, and Pluto were not seen.
In its quarter-century of exploration, the Voyager project has returned immense amounts of information. Voyager 1, at 9.2 billion miles from the Sun, is currently the most distant human-made object in the universe, and Voyager 2 is 7.4 billion miles from the Sun. Both spacecraft currently constitute the Voyager Interstellar Mission (VIM) and continue to relay news of their surroundings through the Deep Space Network (DSN). The craft and mission could last until 2020.