Voyager 2 performed four gravity-assist maneuvers during its Grand Tour of the outer planets.
The spacecraft flew past Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. Each close planetary encounter bent Voyager 2’s path and changed its velocity relative to the Sun, allowing it to travel much farther than its launch vehicle alone could have managed.
This route depended on a rare alignment of the outer planets identified by JPL engineer Gary Flandro in 1964. The geometry allowed one spacecraft to use Jupiter, Saturn, Uranus, and Neptune in sequence. The alignment repeats only about every 175 years, making Voyager 2’s tour unusually difficult to reproduce.
A common mix-up is counting only the assists that sent Voyager 2 onward to another major target. In the standard Grand Tour count, Neptune’s final planetary flyby is included, giving four gravity assists in total.