One of a pair of planetary probes launched by the USA in 1977. It was virtually identical to Voyager 1, except that its power source was designed to last for much longer in order to survive the extended journey to Uranus and Neptune. Voyager 2 was launched on 20 August 1977. Its first encounter was with Jupiter on 9 July 1979, passing within 71,400 kilometres 44,000 miles of the planet. It passed close to Europa and Ganymede, complementing the coverage of the Galilean satellites obtained by Voyager 1. Saturn was reached in August 1981. Closest approach was on 25 August, at a distance of 101,000 kilometres 63,000 miles. The trajectory took the probe near the saturnian satellites Tethys and Enceladus. On 24 January 1986 Voyager 2 reached Uranus, which it passed at a distance of 107,000 kilometres 67,000 miles and the mission was completed with the Neptune and Triton encounter of 24 August 1989, when the craft passed within 48,000 kilometres 30,000 miles of the surface of Neptune. See also: Voyager Interstellar Mission.