The Voyager programme consisted of a pair of unmanned scientific probes, Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favourable planetary alignment. Although they were officially designated to study just Jupiter and Saturn, the two probes were able to continue their mission into the outer Solar System. These probes were built at JPL (Jet Propulsion Lab) and were funded by NASA.
The Voyager probes were originally conceived as part of the Mariner program, and designated Mariner 11 and Mariner 12, respectively. They were then moved into a separate programme named Mariner Jupiter-Saturn, later retitled Voyager because it was more appealing and romantic. Voyager is a scaled-back version of the Grand Tour programme of the late 1960s and early 1970s. The Grand Tour's plan was to send a pair of probes to fly by all the outer planets; scaled back because of budget cuts. However, in the end, Voyager fulfilled all the Grand Tour flyby objectives except for Pluto, which at the time was considered a planet by the IAU.
In the 1990s, Voyager 1 overtook the slower travelling Pioneer 10 to become the most distant human made artifact in space. Voyager 1 and Pioneer 10 are also the most widely-separated man made objects in the Universe because they are travelling in roughly opposite directions from the Sun.
Credit: NASA/JPL, nemonequam
Music: Chorale Prelude in F Minor: J.S. Bach (arr. Busoni)