[meteorite-list] Cassini to Make Last Close Flyby of Saturn Moon Dione
From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 13 Aug 2015 17:45:03 -0700 (PDT)
Cassini to Make Last Close Flyby of Saturn Moon Dione
Jet Propulsion Laboratory
August 13, 2015
NASA's Cassini spacecraft will zip past Saturn's moon Dione on Monday,
Aug. 17 -- the final close flyby of this icy satellite during the spacecraft's
Cassini's closest approach, within 295 miles (474 kilometers) of Dione's
surface, will occur at 11:33 a.m. PDT (2:33 p.m. EDT). Mission controllers
expect fresh images to begin arriving on Earth within a couple of days
following the encounter.
Cassini scientists have a bevy of investigations planned for Dione. Gravity-science
data from the flyby will improve scientists' knowledge of the moon's internal
structure and allow comparisons to Saturn's other moons. Cassini has performed
this sort of gravity science investigation with only a handful of Saturn's
62 known moons.
During the flyby, Cassini's cameras and spectrometers will get a high-resolution
peek at Dione's north pole at a resolution of only a few feet (or meters).
In addition, Cassini's Composite Infrared Spectrometer instrument will
map areas on the icy moon that have unusual thermal anomalies -- those
regions are especially good at trapping heat. Meanwhile, the mission's
Cosmic Dust Analyzer continues its search for dust particles emitted from
This flyby will be the fifth targeted encounter with Dione of Cassini's
tour at Saturn. Targeted encounters require maneuvers to precisely steer
the spacecraft toward a desired path above a moon. The spacecraft executed
a 12-second burn using its thrusters on Aug. 9, which fine-tuned the trajectory
to enable the upcoming encounter.
Cassini's closest-ever flyby of Dione was in Dec. 2011, at a distance
of 60 miles (100 kilometers). Those previous close Cassini flybys yielded
high-resolution views of the bright, wispy terrain on Dione first seen
during the Voyager mission. Cassini's sharp views revealed the bright
features to be a system of braided canyons with bright walls. Scientists
also have been eager to find out if Dione has geologic activity, like
Saturn's geyser-spouting moon Enceladus, but at a much lower level.
"Dione has been an enigma, giving hints of active geologic processes,
including a transient atmosphere and evidence of ice volcanoes. But we've
never found the smoking gun. The fifth flyby of Dione will be our last
chance," said Bonnie Buratti, a Cassini science team member at NASA's
Jet Propulsion Laboratory in Pasadena, California.
Cassini has been orbiting Saturn since 2004. After a series of close moon
flybys in late 2015, the spacecraft will depart Saturn's equatorial plane
-- where moon flybys occur most frequently -- to begin a year-long setup
of the mission's daring final year. For its grand finale, Cassini will
repeatedly dive through the space between Saturn and its rings.
"This will be our last chance to see Dione up close for many years to
come," said Scott Edgington, Cassini mission deputy project scientist
at JPL. "Cassini has provided insights into this icy moon's mysteries,
along with a rich data set and a host of new questions for scientists
The Cassini-Huygens mission is a cooperative project of NASA, ESA (European
Space Agency) and the Italian Space Agency. JPL, a division of the California
Institute of Technology, manages the mission for NASA's Science Mission
Directorate in Washington.
For more information about Cassini, visit:
Jet Propulsion Laboratory, Pasadena, Calif.
preston.dyches at jpl.nasa.gov
Received on Thu 13 Aug 2015 08:45:03 PM PDT