Saturn's Rings Alter Its Ionosphere

In April of this year, NASA nudged the Cassini spacecraft into an orbit that took it through a narrow gap between Saturn’s innermost ring (the D-ring) and the gas giant itself.Over the next few months, Cassini skimmed the upper atmosphere of the ringed planet nearly two dozen times. During 11 of those orbits, Cassini’s Radio and Plasma Wave Science (RPWS) instrument took unprecedented measurements of Saturn’s ionosphere — a shell of charged particles that surrounds the pl