Cassini's Grand Finale: Discoveries and Highlights One Year Later
Abstract
The Cassini-Huygens mission ended in a science-rich blaze of glory on September 15, 2017. Covering a period of roughly ten months, the Grand Finale and Ring Grazing orbits marked the final phases of Cassini's 13-year mission, ending with the first time in-situ exploration of the region between the rings and planet. On its final orbit, Cassini plunged into Saturn's atmosphere at 126,000 km/hr (35 km/sec), vaporizing and satisfying planetary protection requirements, while sending back its final bits of unique science data for as long as possible.
On November 29, 2016, a single Titan flyby sent Cassini into a series of 20 highly inclined, elliptical Ring Grazing orbits with peripases just outside Saturn's main rings at distances within 10,000 km of Saturn's F ring. These orbits provided high-resolution views of Saturn's F and A rings, providing prime viewing conditions of fine scale ring structures such as propellers, and included the closest flybys of tiny ring moons. A final close flyby of Titan on April 22, 2017 propelled Cassini across Saturn's main rings. In its 22 Grand Finale orbits, the spacecraft repeatedly dove between Saturn's innermost rings and upper atmosphere to answer fundamental questions that were unattainable earlier in the mission. The Grand Finale explored a region of the Saturn system that was unexplored by any previous outer planet spacecraft. Saturn's gravitational and magnetic fields were measured to unprecedented accuracy, providing information from which constraints on the interior structure of the planet, mass distribution in the rings, and the structure of the internal magnetic field could be obtained. The Grand Finale orbits provided the highest resolution observations ever of both Saturn's C and D rings and Saturn's atmospheric weather layer. Direct in-situ sampling of the ring particle composition, upper atmosphere and the innermost radiation belts was also achieved. This talk will present key science findings and new mysteries gleaned from the Ring Grazing and Grand Finale orbits. The research described in this paper was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2018 California Institute of Technology. Government sponsorship is acknowledged.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.U21A..01S
- Keywords:
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- 5737 Magnetospheres;
- PLANETARY SCIENCES: FLUID PLANETSDE: 6265 Planetary rings;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 6275 Saturn;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 6280 Saturnian satellites;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS