The Voyager mission was designed to take advantage of a rare geometric arrangement of the outer planets in the late 1970s and the 1980s which allowed for a four-planet tour for a minimum of propellant and trip time.
The Voyager mission was designed to take advantage of a rare geometric arrangement of the outer planets in the late 1970s and the 1980s which allowed for a four-planet tour with a minimum of propellant and trip time. This layout of Jupiter, Saturn, Uranus and Neptune, which occurs about every 175 years, allows a spacecraft on a particular flight path to swing from one planet to the next without the need for large onboard propulsion systems.
NASA’s Voyager 1 spacecraft launched after Voyager 2, on a faster, shorter trajectory. This image captures that moment in Cape Canaveral, Florida on Sept. 5, 1977.
Image credit: NASA/JPL-Caltech/KSC