Cassini’s Final Exploration Stage Sheds Light on Saturn’s Interaction with its Rings

Image credit: NASA/JPL-Caltech/Space Science Institute

Image credit: NASA/JPL-Caltech/Space Science Institute

Having spent 13 years orbiting Saturn, the Cassini spacecraft was sent to its Grand Finale phase, orbiting its last 22 times through the gap between Saturn and its rings. Cassini entered the planet’s upper atmosphere in September 2017, and there its mission ended. During its trajectory between the innermost D ring and the planet, the Cassini Ion Neutral Mass Spectrometer (INMS) provided in situ measurements of the chemical interactions between Saturn’s atmosphere and its rings. In addition to water, substantial amounts of methane, ammonia, molecular nitrogen and/or carbon monoxide, carbon dioxide, and impact fragments of organic-rich nanoparticles enter Saturn’s atmosphere from the D ring along the ring plane at influx rates between 4800 and 45,000 kg s-1. The significant mass of infalling material likely affects Saturn’s atmospheric chemistry and has implications for ring evolution. The data collected by Cassini will contribute to a better understanding of Saturn’s interactions with its rings, and  also contribute to our understanding of other ring-bearing planets that might exist around other stars. READ MORE