Project Voyager was a dual spacecraft long-range mission that conducted a "Grand Tour" of the Outer Planets. The huge distance between the planets was overcome by using gravity-assisted trajectories. The project, originally called "Mariner Jupiter/Saturn 1977" (MJS77) was approved by NASA and Congress in June 1972. MJS77 was renamed Voyager in 1977. Both Voyager spacecraft were launched using Titan III rockets with a Centaur upper stage. Voyager 2 was launched on August 20, 1977, two weeks before Voyager 1, which was launched on September 5, 1977. Voyager 1 followed a quicker trajectory to Jupiter, and arrived first. Voyager 1 made its closest encounter with Jupiter on March 5, 1979; Voyager 2 reached Jupiter on July 9, 1979. Voyager 1 reached Saturn on November 13, 1980. At the conclusion of the Voyager 1 Saturn encounter, it was determined that all its mission objectives were met, and Voyager 2 was reprogrammed to go on to Uranus after encountering Saturn. Voyager 2 encountered Saturn on August 26, 1981. Voyager 2 continued to Uranus, making its closest approach on January 24, 1986. With additional funding, Voyager 2 made its closest approach to Neptune on August 25, 1989.
From the description of Voyager Project Office Documents Collection, 1973 - 1990. (Jet Propulsion Laboratory Library and Archives). WorldCat record id: 733100004
