The twin Voyager 1 and 2 spacecraft continue exploring where
nothing from Earth has flown before. In the 25th year after
their 1977 launches, they each are much farther away from
Earth and the Sun than Pluto is and approaching the boundary
region -- the heliopause -- where the Sun's dominance of the
environment ends and interstellar space begins. Voyager 1,
more than twice as distant as Pluto, is farther from Earth
than any other human-made object and speeding outward at more
than 17 kilometers per second (38,000 miles per hour). Both
spacecraft are still sending scientific information about
their surroundings through the Deep Space Network (DSN).

Interstellar
Mission (Click on the image for a larger view)
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.