HEIDI FINN (720) 974-5859 MEDIA RELATIONS OFFICE CASSINI IMAGING CENTRAL LABORATORY FOR OPERATIONS SPACE SCIENCE INSTITUTE, BOULDER, COLO. http://www.ciclops.org
UNVEILING NEW SURFACE FEATURES ON TITAN AND DIONE December 16, 2004
Cassini's dance among Saturn's entourage, Titan and Dione, on Monday revealed new details on the moon's surfaces. Cassini swept within (1,200 kilometers) 750 miles of Titan's surface, and orbital mechanics permitted Cassini to get a close look at Dione, Saturn's fourth largest moon. This was the last pass by Titan before Cassini releases the European Space Agency's Huygens probe on Dec. 24 (U.S. Times Zones) on a course to plunge into the moon's murky atmosphere on Jan. 14.
Images of Titan released today show regions of the body that had not been clearly seen before, as well as fine details in Titan's intermittent clouds. A bright 560-kilometer wide (345 mile) semi-circle within the region called Xanadu, and a 330-kilometer wide (205-mile) multi-ringed feature to the northeast of Xanadu are also visible. These may be impact related, but without information on the height of these features, this interpretation cannot be confirmed. A mottled texture is seen within Xanadu, including dark, crisscrossing lines, suggestive of tectonic activity.
No definitive craters have been found in these images, though several bright rings or circular features are seen in the dark terrain. However, without topographic shading, their identification as impact structures can not be confirmed.
Cassini also found Titan's upper atmosphere to consist of a surprising number of haze layers as shown in the ultraviolet image of Titan's night side limb. The many fine haze layers extend several hundred kilometers above the surface. Although this is a night side view, with only a thin crescent receiving direct sunlight, the haze layers are bright from light scattered through the atmosphere.
Cassini imaging scientists are intrigued by the complex braided structure of surface fractures on Saturn's icy moon Dione. Very detailed images taken during Cassini's closest approach to Dione on Dec. 14, 2004, centered on the wispy terrain for which Dione is known. To the surprise of Cassini imaging scientists, the wispy terrain does not consist of thick ice deposits, but rather the bright ice cliffs created by tectonic fractures.
"This is one of the most surprising results so far. It just wasn't what I expected," said Carolyn Porco, Cassini Imaging Team Leader.
As Cassini closed in on Dione for a close flyby, the spacecraft captured a set of images of the icy moon which have been put together to make a mosaic, showing a stunning detailed global view.
The highest resolution images and interpretations will be discussed today during a press conference at the American Geophysical Union fall meeting in San Francisco.
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 European Space Agency built and managed the development of the Huygens probe and is in charge of the probe operations. The Italian Space Agency provided the high-gain antenna, much of the radio system and elements of several of Cassini's science instruments. The imaging team is based at the Space Science Institute, Boulder, Colo.