November 12 marks the 35th anniversary of when NASA's Voyager 1 spacecraft zoomed past Saturn. Between its flyby in 1980 and sister craft Voyager 2 the next year, these were the last close-up views of the planet for more than 20 years. What did we learn from Voyager 1?
All told, there have been five missions to Saturn over the years. Pioneer 11 did a quick zoom past the planet and moons in 1979, quickly followed by Voyager 1 and Voyager 2 in 1980 and 1981, respectively. The Voyagers were taking advantage of a rare alignment of the outer planets that allowed them to explore Jupiter, Saturn, Uranus and Neptune by using "gravity assists" to get from one to the next.
Then there was a long hiatus until Cassini went forth into the darkness in 1997, arriving at the planet in 2004. It can't be overstated how valuable a long-term mission to Saturn and its moons is, compared to a flyby. The people working on the Cassini mission have been observing changes in Saturn's atmosphere and its moons as the planet moves around the sun, getting different amounts of heating in the northern and southern hemispheres. Voyager 1's journey, by contrast, just gave close-ups of the planet and system for a few days.
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