Having now passed closer to Tethys than the Voyager 2 spacecraft, Cassini has returned the best-ever natural color view of this icy Saturnian moon.
As seen here, the battered surface of Tethys (1,062 kilometers, 660 miles across) has a rather neutral hue. The image here is a mosaic of two footprints at which three (red, green and blue) images were taken to form a natural color composite. It reveals a world nearly saturated with craters – many small craters lie on top of older, larger ones, suggesting an ancient surface. At the top and along the boundary between day and night, the moon’s terrain has a grooved appearance.
This moon is known to have a density very close to that of water, meaning that it is likely composed mainly of water ice. Its frozen mysteries await Cassini’s planned close flyby in September 2005.
The view shows primarily the trailing hemisphere of Tethys, which is the side opposite the moon’s direction of motion in its orbit. The image has been rotated so that north on Tethys is up.
The images comprising this color view were taken with the narrow angle camera on October 28, 2004, from a distance of about 256,000 kilometers (159,000 miles) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 50 degrees. The image scale is 1.5 kilometers (0.9 miles) per pixel.
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 imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.