On July 9, 1979, NASA's Voyager 2 spacecraft made its closest approach to Jupiter.

It came within 354,000 miles (570,000 kilometers) of the planet's cloud tops. Voyager 2 was one of two space probes launched by NASA in 1977 to study the outer planets. It discovered a few rings around Jupiter. Also, both Voyager 1 and 2 probes spotted volcanoes erupting on the Jupiter's moon, Io. Voyager 2 took longer to reach Jupiter than its sister spacecraft, Voyager 1, but also got to visit Uranus and Neptune. This made it the only spacecraft to visit either of the ice giants.