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Close Views Show Saturn's Rings in Unprecedented Detail
Jet Propulsion Laboratory
January 30, 2017

Newly released images showcase the incredible closeness with which NASA's Cassini spacecraft, now in its "Ring-Grazing" orbits phase, is observing Saturn's dazzling rings of icy debris.

The views are some of the closest-ever images of the outer parts of the
main rings, giving scientists an eagerly awaited opportunity to observe features with names like "straw" and "propellers." Although Cassini saw
these features earlier in the mission, the spacecraft's current, special orbits are now providing opportunities to see them in greater detail.
The new images resolve details as small as 0.3 miles (550 meters), which
is on the scale of Earth's tallest buildings.

Cassini is now about halfway through its penultimate mission phase --
20 orbits that dive past the outer edge of the main ring system. The ring-grazing
orbits began last November, and will continue until late April, when Cassini begins its grand finale. During the 22 finale orbits, Cassini will repeatedly plunge through the gap between the rings and Saturn. The first finale
plunge is scheduled for April 26.

For now, the veteran spacecraft is shooting past the outer edges of the
rings every week, gathering some of its best images of the rings and moons. Already Cassini has sent back the closest-ever views of small moons Daphnis and Pandora.

Some of the structures seen in recent Cassini images have not been visible
at this level of detail since the spacecraft arrived at Saturn in mid-2004.
At that time, fine details like straw and propellers -- which are caused
by clumping ring particles and small, embedded moonlets, respectively
-- had never been seen before. (Although propellers were present in Cassini's arrival images, they were actually discovered in later analysis, the following year.)

Cassini came a bit closer to the rings during its arrival at Saturn, but
the quality of those arrival images (examples: 1, 2, 3) was not as high
as in the new views. Those precious few observations only looked out on
the backlit side of the rings, and the team chose short exposure times
to minimize smearing due to Cassini's fast motion as it vaulted over the
ring plane. This resulted in images that were scientifically stunning,
but somewhat dark and noisy.

In contrast, the close views Cassini has begun capturing in its ring-grazing orbits (and soon will capture in its Grand Finale phase) are taking in
both the backlit and sunlit side of the rings. Instead of just one brief
pass lasting a few hours, Cassini is making several dozen passes during
these final months.

"As the person who planned those initial orbit-insertion ring images --
which remained our most detailed views of the rings for the past 13 years
-- I am taken aback by how vastly improved are the details in this new collection," said Cassini Imaging Team Lead Carolyn Porco, of Space Science Institute, Boulder, Colorado. "How fitting it is that we should go out
with the best views of Saturn's rings we've ever collected."

After nearly 13 years studying Saturn's rings from orbit, the Cassini
team has a deeper, richer understanding of what they're seeing, but they
still anticipate new surprises.

"These close views represent the opening of an entirely new window onto Saturn's rings, and over the next few months we look forward to even more exciting data as we train our cameras on other parts of the rings closer
to the planet," said Matthew Tiscareno, a Cassini scientist who studies Saturn's rings at the SETI Institute, Mountain View, California. Tiscareno planned the new images for the camera team.

Launched in 1997, Cassini has been touring the Saturn system since arriving
in 2004 for an up-close study of the planet, its rings and moons, and
its vast magnetosphere. Cassini has made numerous dramatic discoveries, including a global ocean with indications of hydrothermal activity within
the moon Enceladus, and liquid methane seas on another moon, Titan.

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the mission for the agency's Science
Mission Directorate in Washington. JPL is a division of Caltech in Pasadena. The Cassini imaging operations center is based at Space Science Institute
in Boulder, Colorado.

For more information about Cassini, visit:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

News Media Contact
Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov

Steve Mullins
CICLOPS/Space Science Institute, Boulder, Colo.
720-974-5859
media@ciclops.org

2017-019

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