Saturn's rings arc above the Cassini spacecraft while storms in the planet's atmosphere pass below it in this artist's concept of the final phase of the Cassini mission. The craft will fly close to Titan, Saturn's largest moon, on April 21, reshaping Cassini's orbit. Beginning the following week, it will make 22 passes between Saturn and the inner edge of its rings, flying just a few thousand miles above the planet itself. Cassini will end its mission in September by diving into Saturn's clouds, which will destroy the long-operating craft. [NASA/JPL/Caltech]