NASA | JPL-Caltech | AGU | 2018 Oct 04
New research emerging from the final orbits of NASA's Cassini spacecraft represents a huge leap forward in our understanding of the Saturn system -- especially the mysterious, never-before-explored region between the planet and its rings. Some preconceived ideas are turning out to be wrong while new questions are being raised.
- A few of the findings from Cassini's direct sampling: complex organics rain down from Saturn's rings; inner-ring particles take on electric charges and travel along magnetic-field lines; newly revealed electric-current system and radiation belt; and up-close measurement of Saturn's near-zero magnetic-field tilt. Credits: NASA/JPL-Caltech
Six teams of researchers are publishing their work Oct. 5 in the journal Science, based on findings from Cassini's Grand Finale. That's when, as the spacecraft was running out of fuel, the mission team steered Cassini spectacularly close to Saturn in 22 orbits before deliberately vaporizing it in a final plunge into the atmosphere in September 2017.
Knowing Cassini's days were numbered, its mission team went for gold. The spacecraft flew where it was never designed to fly. For the first time, it probed Saturn's magnetized environment, flew through icy, rocky ring particles and sniffed the atmosphere in the 1,200-mile-wide (2,000-kilometer-wide) gap between the rings and the cloud tops. Not only did the flight path push the spacecraft to its limits, the new findings illustrate how powerful and agile the instruments were. ...
New Radiation Belt Discovered at Saturn
Max Planck Institute for Solar System Research | 2018 Oct 04
Approximately one year ago a spectacular dive into Saturn ended NASA’s Cassini mission - and with it a unique, 13-year research expedition to the Saturnian system. In the mission’s last five months, the probe entered uncharted territory again: 22 times it plunged into the hitherto almost unexplored region between the planet Saturn and its innermost ring, the D-ring. On Friday, 5 October 2018, the journal Science is releasing a total of six articles describing first results from this mission phase. In one of these papers a research team led by the Max Planck Institute for Solar System Research in Germany and the Applied Physics Laboratory of the Johns Hopkins University in the USA for the first time reports on the unique proton radiation belts formed in close proximity to the planet. Due to presence of the dense A-, B-, and C-rings, this area is almost completely decoupled from the main radiation belt and the rest of the magnetosphere, which extend farther outward. ...
- This image shows the proton radiation belts of Saturn. The radiation in the area between the planet and the D-ring can be seen enlarged in the inset and was first observed in the last mission phase of the Cassini mission. It is created by the incidence of galactic cosmic radiation on the planet’s rings. The protons generated in this way subsequently interact with the atmosphere of Saturn, its thin D-ring and its ringlets. (© MPS/JHUAPL)
Scientists Study Saturn’s Rings to Discover Downpour
Southwest Research Institute | 2018 Oct 04
INMS Instrument Detects Large Influx of Materials Raining into Saturn's Atmosphere from Rings
Using some of the Cassini spacecraft’s final measurements, Southwest Research Institute scientists have discovered that complex organics rain down from Saturn’s rings into its upper atmosphere. Cassini’s final orbits allowed instruments to sample particles in the ring environment, discovering that the inflow of water and other material is much heavier than expected. ...
Cassini's Final Year: Science Highlights and Discoveries
Geophysical Research Letters | Special Collection
Closing with Saturn -- Special Edition
Science 362(6410) | 2018 Oct 05