The twin Voyager 1 and 2 spacecraft are exploring where nothing from Earth has flown before. Continuing on their more-than-37-year journey since their 1977 launches, they each are much farther away from Earth and the sun than Pluto. In August 2012, Voyager 1 made the historic entry into interstellar space, the region between stars, filled with material ejected by the death of nearby stars millions of years ago. Scientists hope to learn more about this region when Voyager 2, in the “heliosheath" -- the outermost layer of the heliosphere where the solar wind is slowed by the pressure of interstellar medium -- also reaches interstellar space. Both spacecraft are still sending scientific information about their surroundings through the Deep Space Network, or DSN.
The primary mission was the exploration of Jupiter and Saturn. After making a string of discoveries there -- such as active volcanoes on Jupiter's moon Io and intricacies of Saturn's rings -- the mission was extended. Voyager 2 went on to explore Uranus and Neptune, and is still the only spacecraft to have visited those outer planets. The adventurers' current mission, the Voyager Interstellar Mission (VIM), will explore the outermost edge of the Sun's domain. And beyond.
Voyager 1 launched from Kennedy Space Flight Center. Voyager 1 returns first spacecraft photo of Earth and Moon.
Plume shapes are visible in overexposed images of the moon, lo, taken to provide a fix on guiding stars as Voyager 1 looked back over its shoulder on departure from Jupiter. When Voyager was launched, the only active volcanoes known were here on Earth, now here's a moon with ten times the volcanic activity of the Earth."
Voyager 1 enters Interstellar Space where it found a distinct change of neighborhood in interstellar space, where ashes from long-vanished stars float every three or so inches. It was an environment with more particles than the solar wind, the stream of charged particles forever racing off the sun's surface and into space.
Voyager 2 launched from Kennedy Space Flight Center. NASA decided to launch 2 before 1, calculating that Voyager 1 would arrive at Jupiter ahead of its twin.
Voyager 2 has the first-ever encounter with Uranus. The unexpected star of the Uranus encounter was the planet's smallest major moon, Miranda. Astronomers had expected the moon, discovered in 1948, to be a crater-strewn ice ball. The moon was heavily cratered, but it was also cut by deep cliffs and adorned with three grooved, racetrack-shaped plains that met in chevron shapes, as if giants had chiseled hundred-mile slabs of ice off its face. The spacecraft discovered 10 new moons, two new rings, and a strangely tilted magnetic field stronger than that of Saturn. A gravity assist at Uranus propelled the spacecraft toward its next destination, Neptune.
Voyager 2 returns first color images of Neptune. Voyager 2 is the only human-made object to have flown by Neptune. In the closest approach of its entire tour, the spacecraft passed less than 5,000 km above the planet's cloud tops. It discovered five moons, four rings, and a "Great Dark Spot" that vanished by the time the Hubble Space Telescope imaged Neptune five years later. Neptune's largest moon, Triton, was found to be the coldest known planetary body in the solar system, with a nitrogen ice "volcano" on its surface. A gravity assist at Neptune shot Voyager 2 below the plane in which the planets orbit the sun, on a course which will ultimately take the spacecraft out of our solar system.
Voyager 2 crosses Termination Shock.