The twin Voyager 1 and 2 spacecraft are exploring where nothing from Earth has flown before. As they continue their more-than-40-year journey since being launched in 1977, they each are much farther away from Earth and the sun than Pluto.
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.
To accomplish their two-planet mission, the spacecraft were built to last five years. But as the mission went on, and with the successful achievement of all its objectives, the additional flybys of the two outermost giant planets, Uranus and Neptune, proved possible -- and irresistible to mission scientists and engineers at the Voyagers' home at the Jet Propulsion Laboratory in Pasadena, California. As the spacecraft flew across the solar system, remote-control reprogramming was used to endow the Voyagers with greater capabilities than they possessed when they left the Earth. Their two-planet mission became four. Their five-year lifetimes stretched to 12 and is now near forty-three years. Eventually, between them, Voyager 1 and 2 would explore all the giant outer planets of our solar system, 48 of their moons, and the unique systems of rings and magnetic fields those planets possess.
As of May 2021, Voyager 1 is at 22.3 billion kilometers (152.7 AU) from the Sun. Voyager 2 was at a distance of 18.5 billion kilometers (126.9 AU). Voyager 1 is escaping the solar system at a speed of about 3.6 AU per year. Voyager 2 is escaping the solar system at a speed of about 3.3 AU per year. Traveling at the speed of light, it would take approximately 21 hours to transverse the distance between Earth and Voyager 2.