After more than 12 years studying Saturn, its rings and moons, NASA’s Cassini spacecraft has entered the final year of its epic voyage. The conclusion of the historic scientific odyssey is planned for September 2017, but not before the spacecraft completes a daring two-part endgame.
Beginning on November 30, Cassini’s orbit will send the spacecraft just past the outer edge of the main rings. These orbits, a series of 20, are called the F-ring orbits. During these weekly orbits, Cassini will approach to within 4,850 miles (7,800 kilometers) of the center of the narrow F ring, with its peculiar kinked and braided structure.
“During the F-ring orbits we expect to see the rings, along with the small moons and other structures embedded in them, as never before,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California. “The last time we got this close to the rings was during arrival at Saturn in 2004, and we saw only their backlit side. Now we have dozens of opportunities to examine their structure at extremely high resolution on both sides.”
The Last Act: A Grand Finale
Cassini’s final phase — called the Grand Finale — begins in earnest in April 2017. A close flyby of Saturn’s giant moon Titan will reshape the spacecraft’s orbit so that it passes through the gap between Saturn and the rings – an unexplored space only about 1,500 miles (2,400 kilometers) wide. The spacecraft is expected to make 22 plunges through this gap, beginning with its first dive on April 27.