The Cassini visual and infrared mapping spectrometer analyzed the surface
composition of Saturn's moon Iapetus as Cassini flew over the polar
region on Dec. 31, 2004. The image at left shows the reflectance at
4-microns, which is dominated by the minerals on Iapetus' surface. Two
large craters are seen in this image. The polar water ice is relatively
dark at this wavelength, so the ice cap is not seen. The next frame shows
carbon dioxide on the surface. The carbon dioxide peaks at mid latitudes
and shows less strength at the pole and along the equator (the dark band
curving near the left edge of the image). The third frame shows the
strength of water absorption on Iapetus. The brightest regions are due
to water ice near the pole. The grayer areas indicate water bound to
minerals on the surface. The color composite shows water as blue, carbon
dioxide as green, and non-ice minerals as red.
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 visible and infrared
mapping spectrometer team is based at the University of Arizona, Tucson.
For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov.
For more information about the visual and infrared mapping spectrometer
visit http://wwwvims.lpl.arizona.edu/.
