Goals: Voyager 1 and 2 were designed to take advantage of a rare planetary alignment to explore the outer solar system. Voyager 1 targeted Jupiter and Saturn before continuing on to chart the far edges of our solar system.
Voyager 1 was to become the second spacecraft to visit Saturn. Its mission there was to explore the planet and its rings, moons, and magnetic field in greater detail than was possible for its predecessor, Pioneer 11.
Accomplishments: Voyager 1 met all of its goals except for the experiments planned for its photopolarimeter, which failed to operate. The spacecraft found three new moons: Prometheus and Pandora, the "shepherding" moons that keep the F ring well-defined, and Atlas which similarly shepherds the A ring. Saturn's largest moon, Titan, was found to have a thick atmosphere which hides its surface from visible-light cameras and telescopes. Spacecraft instruments showed it to be mostly nitrogen, like Earth's atmosphere, but with a surface pressure 1.6 times as high as ours.
The spacecraft also imaged the moons Mimas, Enceladus, Tethys, Dione, and Rhea; revealed the fine structures of Saturn's complex and beautiful ring system; and added the G ring to the list of known rings.
Just as it used Jupiter's gravity to help it reach Saturn, Voyager 1 used a gravity assist at Saturn to alter its course and increase its speed, giving it a trajectory to take it out of the solar system. Voyager 1 entered interstellar space in August 2013.