It weighed barely 570 pounds, ran on plutonium, and carried 1970s electronics — and in September 1979, after six years and billions of miles, Pioneer 11 became the first spacecraft in history to reach Saturn, slinging off Jupiter’s gravity along the way and finding a ring no telescope had ever revealed.

It weighed barely 570 pounds, ran on plutonium, and carried 1970s electronics — and in September 1979, after six years and billions of miles, Pioneer 11 became the first spacecraft in history to reach Saturn, slinging off Jupiter’s gravity along the way and finding a ring no telescope had ever revealed.

In September 1979 Pioneer 11, a 570-pound nuclear-powered probe built with 1970s technology, became the first spacecraft ever to reach Saturn — using Jupiter's gravity to slingshot itself there and discovering a previously unknown ring around the planet.