The Voyager 2spacecraft was launched in 1977, originally planned as Mariner 12 of the Mariner program. It is identical to its sister Voyager program craft, Voyager 1. Voyager 2 followed a somewhat different trajectory during its Saturn encounter, however, bypassing a close encounter with Titan in favour of taking advantage of a gravitational slingshot to travel on to Uranus and Neptune. It became the first and so far only probe to visit those two planets.
