by Staff Writers
Pasadena CA (JPL) Sep 19, 2016
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
During the Grand Finale, Cassini will make the closest-ever observations of Saturn, mapping the planet's magnetic and gravity fields with exquisite precision and returning ultra-close views of the atmosphere.
Scientists also hope to gain new insights into Saturn's interior structure, the precise length of a Saturn day, and the total mass of the rings - which may finally help settle the question of their age. The spacecraft will also directly analyze dust-sized particles in the main rings and sample the outer reaches of Saturn's atmosphere - both first-time measurements for the mission.
"It's like getting a whole new mission," said Spilker. "The scientific value of the F ring and Grand Finale orbits is so compelling that you could imagine a whole mission to Saturn designed around what we're about to do."
Getting Into Saturn, Literally
This particular orientation enables the spacecraft to leap over the rings with a single (and final) Titan flyby in April, to begin the Grand Finale.
"We've used Titan's gravity throughout the mission to sling Cassini around the Saturn system," said Earl Maize, Cassini project manager at JPL. "Now Titan is coming through for us once again, providing a way for Cassini to get into these completely unexplored regions so close to the planet."
The Grand Finale will come to a dramatic end on Sept. 15, 2017, as Cassini dives into Saturn's atmosphere, returning data about the planet's chemical composition until its signal is lost. Friction with the atmosphere will cause the spacecraft to burn up like a meteor soon afterward.
To celebrate the beginning of the final year and the adventure ahead, the Cassini team is releasing a new movie of the rotating planet, along with a color mosaic, both taken from high above Saturn's northern hemisphere. The movie covers 44 hours, or just over four Saturn rotations.
'A Truly Thrilling Ride'
And so, although the mission's end is approaching - with a "Cassini Final Plunge" clock already counting down in JPL mission control - an extremely important phase of the mission is still to come.
"We may be counting down, but no one should count Cassini out yet," said Curt Niebur, Cassini program scientist at NASA Headquarters in Washington. "The journey ahead is going to be a truly thrilling ride."
Saturn at JPL
Explore The Ring World of Saturn and her moons
Jupiter and its Moons
The million outer planets of a star called Sol
News Flash at Mercury
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|