Voyager2 was launched on August 20, 1977. As did Voyager 1, it lifted off from Cape Canaveral, Florida, on a Titan 3E Centaur rocket. It reached its closest approach to Jupiter on July 9, 1979, at a distance of 350,000 miles (570,000 kilometers). It confirmed and observed volcanic activity on Jupiter’s moon Io, as well as crisscrossing lines on the surface of Europa; it also discovered several new rings and three new moons around Jupiter, and studied the Great Red Spot in detail.

Using the Jupiter flyby as a gravitational slingshot, Voyager 2 made it to Saturn; its closest approach was on August 25, 1981. It probed the upper atmosphere of Saturn with its radar system, and took pictures of Saturn, its rings, and its moons. It then used the Saturn flyby to slingshot it to Uranus, reaching its closest approach of 81,500 kilometers (50,600 miles) on January 24, 1986. It discovered ten previously unknown moons of Uranus, and studied the Uranian moons, atmosphere, magnetic field, and thin ring system.

Finally, using the flyby of Uranus as a gravitational slingshot, Voyager 2 made its closest approach to Neptune on August 25, 1989, only 3,000 miles (4,800 kilometers) above the planet’s north pole. Scientists expected it to find a planet very similar to Uranus. Instead, it found a dynamic, bluish-hued atmosphere covered with some of the strongest winds and storms in the solar system. Voyager 2 also found four partial ring arcs and six new moons around Neptune; measured the length of Neptune’s day and the strength of its magnetic field; and studied Neptune’s moon Triton in great detail, revealing a thin atmosphere, clouds, polar caps, and remarkable volcanic geysers of pressurized water.