Status Report

Mars Odyssey THEMIS Image: Galle Crater

By SpaceRef Editor

June 19, 2002

Filed under Daily Themis Pictures, Mars Odyssey THEMIS, US

Image Context:

Context image credit: NASA/Mars Orbiter Laser Altimeter (MOLA) Team

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The Science

The Story

This image is of part of Galle Crater, located at 51.9S, 29.5W. This image was
taken far enough south and late enough into the southern hemisphere fall to
catch observe water ice clouds partially obscuring the surface. The most
striking aspect of the surface is the dissected layered unit to the left in the
image. Other areas also appear to have layering, but they are either more
obscured by clouds or are less well defined on the surface. The layers appear
to be mostly flat lying and layer boundaries appear as topographic lines would
on a map, but there are a few areas where it appears that these layers have
been deformed to some level. Other areas of the image contain rugged,
mountainous terrain as well as a separate pitted terrain where the surface
appears to be a separate unit from the mountains and the layered terrain.

[Source: ASU THEMIS Science Team]

Galle Crater is officially named after a German astronomer who, in 1846, was the first to observe the planet Neptune. It is better known, however, as the “Happy Face Crater.” The image above focuses on too small an area of the crater to see its beguiling grin, but you can catch the rocky line of a “half-smile” in the context image to the right (to the left of the red box).

While water ice clouds make some of the surface harder to see, nothing detracts from the fabulous layering at the center left-hand edge of the image. If you click on the above image, the scalloped layers almost look as if a giant knife has swirled through a landscape of cake frosting.

These layers, the rugged, mountains near them, and pits on the surface (upper to middle section of the image on the right-hand side) all create varying textures on the crater floor. With such different features in the same place, geologists have a lot to study to figure out what has happened in the crater since it formed.

[Questions? Email marsoutreach@jpl.nasa.gov]

[Source: NASA/JPL Mars Outreach]

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

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