Annotated version
This sweeping mosaic of Saturn's moon Enceladus provides broad regional
context for the ultra-sharp, close-up views NASA's Cassini spacecraft
acquired minutes earlier, during its flyby on Aug. 11, 2008. See PIA11114
and PIA11113 for the higher resolution views.
This false-color mosaic combines Imaging Science Subsystem (ISS)
narrow-angle camera images obtained through ultraviolet, green, and
near-infrared camera filters. Areas that are greenish in appearance are
believed to represent deposits of coarser grained ice and solid boulders
that are too small to be seen at this scale, but which are visible in the
higher resolution views, while whitish deposits represent finer grained
ice. The mosaic shows that coarse-grained and solid ice are concentrated
along valley floors and walls, as well as along the upraised flanks of the
"tiger stripe" fractures, which may be covered with plume fallout that
landed not far from the sources. Elsewhere on Enceladus, this coarse water
ice is concentrated within outcrops along cliff faces and at the top of
ridges. The sinuous boundary of scarps and ridges that encircles the south
polar terrain at about 55 degrees south latitude is conspicuous. Much of
the coarse-grained or solid ice along this boundary may be blocky rubble
that has crumbled off of cliff faces as a result of ongoing seismic
activity. This mosaic complements the imaging coverage acquired during
Cassini's July 2005 flyby of Enceladus by showing portions of the moon's
south polar region and tiger stripes, or sulci, that were in darkness
during that flyby (PIA06247).
The reversed lighting conditions over the polar region (compared to the
July 2005 images) highlight features, such as fractures and ridges, that
are barely visible in the July 2005 views, and vice versa. The four most
prominent sulci (from top to bottom: Damascus, Baghdad, Alexandria and
Cairo) appear as generally horizontal fractures near lower right, and they
extend into the moon's night side. The mosaic is an orthographic
projection centered at 63.0 degrees south latitude, 281.3 degrees west
longitude, and has an image scale of 60 meters (196 feet) per pixel. The
original images ranged in resolution from 28 to 154 meters (92 to 505
feet) per pixel and were taken at distances ranging from 5,064 to 25,949
kilometers (3,140 to 15,468 miles) from Enceladus.
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 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 operations center is based at the Space
Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/. The Cassini imaging team
homepage is at http://ciclops.org.