NASA Mars Odyssey THEMIS Image: Candor Chasma 05-13-2005

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Context image credit: NASA/Mars Orbiter Laser Altimeter (MOLA) Team
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The THEMIS VIS camera is capable of capturing color images of the

Martian surface using five different color filters. In this mode of

operation, the spatial resolution and coverage of the image must

be reduced to accommodate the additional data volume produced from

using multiple filters. To make a color image, three of the five

filter images (each in grayscale) are selected. Each is contrast

enhanced and then converted to a red, green, or blue intensity image.

These three images are then combined to produce a full color, single

image. Because the THEMIS color filters don’t span the full range

of colors seen by the human eye, a color THEMIS image does not

represent true color. Also, because each single-filter image is

contrast enhanced before inclusion in the three-color image, the

apparent color variation of the scene is exaggerated. Nevertheless,

the color variation that does appear is representative of some change

in color, however subtle, in the actual scene. Note that the long

edges of THEMIS color images typically contain color artifacts

that do not represent surface variation.

This false color image shows part of the floor of

Candor Chasma in central Valles Marineris. This

image was collected during Southern Fall.

[Source: ASU THEMIS Science Team]

NASA’s Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA’s Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, 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.

Image Credit: NASA/JPL/Arizona State University