Voyager 1 and 2 launched in 1977 on a Grand Tour that comes once every 176 years. How they mapped Jupiter, Saturn, Uranus and Neptune — and carried the Golden Record.
Voyager 2 flew past Uranus in 1986 and Neptune in 1989 — and that's still our only close look. Why the Decadal Survey ranks an ice giant orbiter a top priority.
