Voyager 2 was launched on August 20, 1977. Its trajectory was designed to allow flybys of Jupiter, Saturn, Uranus, and Neptune.
Voyager 1 was launched first on a longer trajectory as it had to study the two outermost planets-Uranus and Neptune-in addition to Jupiter and Saturn. Voyager 1 was launched second in such a way that it could overtake Voyager 2, before reaching Jupiter.
Picture Credit : Google