Cassini Shows Grandeur of Two Saturn Moons

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Carolina Martinez (818) 354-9382
Jet Propulsion Laboratory, Pasadena, Calif.

Heidi Finn (720) 974-5859
Cassini Imaging Central Laboratory for Operations
Space Science Institute, Boulder, Colo.

Image Advisory: 2004-278 November 23, 2004

Cassini Shows Grandeur of Two Saturn Moons

New views of two of Saturn's moons, Titan and Tethys,
represent the most detailed look at these moons to date and
show a sharp contrast between them -- one is foggy and one is
cratered.

The Cassini spacecraft captured the puzzle pieces for the full-disc
view of the mysterious Titan during its first close encounter on
Oct. 26, 2004. The mosaic comprises nine images taken at distances
ranging from 650,000 kilometers (400,000 miles) to 300,000
kilometers (200,000 miles).

The pictures are available at http://saturn.jpl.nasa.gov ,
http://www.nasa.gov/cassini and http://ciclops.org .

The images that make up the mosaic were processed to reduce
effects of the atmosphere and to sharpen surface features. The
mosaic of images has been trimmed to show only the illuminated
surface and not the atmosphere around the edge of the moon.
The Sun was behind Cassini, so nearly the full disc was
illuminated. South polar clouds are seen at the bottom.

Surface features are best seen near the center of the moon.
The surface features become fuzzier toward the outside of the
image, where the spacecraft is peering through more haze. The
brighter region on the right side near the equator is named
Xanadu Regio. Scientists are debating what processes may have
created the bizarre surface brightness patterns seen there.
Titan's lack of obvious craters is a hint of a young surface.
However, the exact nature of that activity, whether tectonic,
wind-blown, river-related, marine or volcanic, is still
unknown.

Two days after the close encounter with icy Titan, Cassini
captured the images used in the mosaic of the battered and
cratered moon Tethys. The result is the best-ever natural
color view of Titan.

As seen here, the surface of Tethys has a neutral hue. Three
images form this natural color composite. The mosaic reveals
a world nearly saturated with craters -- many small craters
lie on top of older, larger ones, suggesting an ancient
surface. Grooves can be seen at the top and along the boundary
between day and night.

Tethys is known to have a density very close to that of water,
indicating that it is likely composed mainly of water ice.
Its frozen mysteries await Cassini's planned close flyby in
September 2005.

The images to create this mosaic were taken on Oct. 28, 2004,
at a distance of about 256,000 kilometers (159,000 miles) from
Tethys. This view shows the trailing hemisphere of Tethys,
which is the side opposite the moon's direction of motion in
its orbit.

Both images were taken with the narrow angle camera onboard
the Cassini spacecraft. The Cassini-Huygens mission is a
cooperative project of NASA, the European Space Agency and the
Italian Space Agency. The Jet Propulsion Laboratory, a
division of the California Institute of Technology in
Pasadena, manages the Cassini-Huygens mission for NASA's
Science Mission Directorate, Washington, D.C. The Cassini
orbiter and its two onboard cameras were designed, developed
and assembled at JPL. The imaging team is based at the Space
Science Institute, Boulder, Colo.

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