In DepthAstronomy

Cassini embarks on twilight mission at Saturn

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Science  14 Apr 2017:
Vol. 356, Issue 6334, pp. 120-121
DOI: 10.1126/science.356.6334.120

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This month, NASA's Cassini spacecraft, which has spent the past 13 years exploring Saturn and its moons, will start the beginning of its end, threading the gap between the gas giant and its rings in the first of 22 week-long orbits that will culminate in September with a fiery and fatal plunge into the atmosphere. The Grand Finale, as NASA is calling the forays, should help answer questions about Saturn's atmosphere and interior. But most of all, it should end a debate about the mass of the water ice rings, which is a big clue to their age—whether they are 4.5 billion years old, nearly as old as the planet, or much younger.