The Cassini spacecraft looks at Saturn's highly irregular moon Hyperion in this view from the spacecraft's flyby of the moon on Aug. 25, 2011.
Hyperion (168 miles, or 270 kilometers across) has an irregular shape, and it tumbles through its orbit: that is, it does not spin at a constant rate or in a constant orientation. (A standard reference latitude-longitude system has not yet been devised for this moon.) Images such as this one extend previous coverage and allow a better inventory of the surface features, the satellite's shape and changes in its spin.
The image was taken with the Cassini spacecraft narrow-angle camera using a combination of spectral filters sensitive to wavelengths of polarized green light centered at 617 and 568 nanometers. The view was obtained at a distance of approximately 36,000 miles (58,000 kilometers) from Hyperion and at a Sun-Hyperion-spacecraft, or phase, angle of 43 degrees. Image scale is 1,145 feet (349 meters) 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 mission for NASA's Science Mission Directorate in Washington. 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.
Credit: NASA/JPL-Caltech/Space Science Institute