The Cassini probe ends its epic mission to the Saturn system after an almost 20-year voyage with a plunge into the upper atmosphere of the gas giant, where it will burn up like a meteor.
It was launched Oct 15, 1997, as a joint mission of NASA, the European Space Agency and Italian Space Agency.
Pioneer 11 and Voyagers 1 and 2 conducted flybys of Saturn decades ago, offering glancing views of the planet. Cassini reached the system in 2004, and began returning the first-ever clear and close views of the giant and its moons. During mission extensions the spacecraft made 60 additional orbits of Saturn, 26 flybys of Titan, seven of Enceladus, and one each of Dione, Rhea and Helene. It discovered "that Titan has Earth-like processes," according to NASA, "and that the small moon Enceladus has a hot-spot at its southern pole, plus jets on the surface that spew out ice crystals, and liquid water beneath its surface."
Cassini settled into Saturn's orbit in Nov 2016, and began successive penetrations of the rings. The so-named Grand Finale of Apr 2017 describes a series of dives between the planet and the inner edge of the rings. They culminate with the spacecraft's deadly encounter with the Saturnian atmosphere.
The cameras will be snapping as Cassini makes its final plunge, providing a last close view of the planet until the next probe.
Date written/update: 2017-01-04