Pastel colors swirl across Mars, revealing differences in the composition and nature of the surface in this false-color infrared image taken on May 22, 2009,by the Thermal Emission Imaging System (THEMIS) camera on NASA's Mars Odyssey orbiter.

The image shows an area 31.9 kilometers (19.8 miles) by 88.3 kilometers (54.9 miles) in the southern highlands of Mars. It is a result of altering the orbit of Odyssey so that the spacecraft passes over the day side of Mars earlier in the afternoon, when the ground is warmer and thus emits more strongly in the infrared frequencies detected by THEMIS. Prior to beginning the slow shift in orbit on Sept. 30, 2008, Odyssey was looking down at ground where the local solar time was about 5 p.m. When the shift was completed, on June 9, 2009, the orbiter and camera were looking down at ground where the local solar time is about 3:45 p.m.

In the image, dark areas mark exposures of relatively cold ground with abundant bare rock, while warmer basaltic sand covers the light blue-green regions. Reddish areas likely have a higher silica content, due either to a different volcanic composition or to weathering.

NASA's Jet Propulsion Laboratory manages Mars Odyssey for NASA's Science Mission Directorate, Washington, D.C. THEMIS was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Philip Christensen at Arizona State University. Lockheed Martin Space Sciences, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.