The Voyager Mission
This mission was meant to be more than potentially discovering aliens. The two spacecrafts were sent into space to investigate Saturn’s and Jupiter’s planetary systems. Upon completion of these primary goals, the crafts managed to travel further.
Voyager 2’s Journey
Once Voyager 2 had analyzed Jupiter and Saturn, the spacecraft moved onto Neptune and Uranus. It visited Neptune’s and Uranus’ planetary systems. Voyager 2 remains the only probe to have explored both Uranus and Neptune.