Dunes cover the majority of this image of <a href="https://en.wikipedia.org/wiki/Rabe_Crater" class="extiw" title="w:Rabe Crater">Rabe Crater</a>. As the dunes are created by wind action the forms of the dunes record the wind direction. Dunes will have a long low angle component and a short high angle side. The steep side is called the slip face. The wind blows up the long side of the dune. In this VIS image the slip faces are illuminated more than the longer side. In this part of the crater the winds were generally moving from the lower right corner of the image towards the upper left.
<p>Rabe Crater is 108 km (67 miles) across. Craters of similar size often have flat floors. Rabe Crater has some areas of flat floor, but also has a large complex pit occupying a substantial part of the floor. The interior fill of the crater is thought to be layered sediments created by wind and or water action. The pit is eroded into this material. The eroded materials appear to have stayed within the crater forming a large sand sheet with surface dune forms as well as individual dunes where the crater floor is visible. The dunes also appear to be moving from the upper floor level into the pit.
</p><p>The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images!
</p><p>Orbit Number: 35105 Latitude: -43.8533 Longitude: 34.8802 Instrument: VIS Captured: 2009-11-12 19:59
</p><p>Please see the <a rel="nofollow" class="external text" href="http://themis.asu.edu/terms">THEMIS Data Citation Note</a> for details on crediting THEMIS images.
</p>
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Science Mission Directorate, 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.
NASA/JPL-Caltech/ASU
<b><a rel="nofollow" class="external text" href="https://photojournal.jpl.nasa.gov/catalog/PIA22141">Catalog page</a></b><span style="white-space:nowrap"> <b>·</b></span> Full-res (<a rel="nofollow" class="external text" href="https://photojournal.jpl.nasa.gov/jpeg/PIA22141.jpg">JPEG</a><span style="white-space:nowrap"> <b>·</b></span> <a rel="nofollow" class="external text" href="https://photojournal.jpl.nasa.gov/tiff/PIA22141.tif">TIFF</a>)