Mars Global Surveyor Mars Orbiter Camera Release: MOC2-32A, -32B Mars Global Surveyor Mars Orbiter Camera Image ID: 562578095.3001 P030-01
CAPTIONThis portion of MOC image 3001 shows small sand dunes and a wind-eroded deposit on the floor of an impact crater located in western Arabia Terra at 4.2°N, 5.3°W. The unnamed crater, seen in the context frame (A) above, is about 33.5 kilometers (20.8 miles) across and it has a dark "splotch" of windblown material on its southwest side. This dark splotch grades into a dark streak that emanates from the crater and points toward the southwest (lower left of A). The context frame also shows a somewhat brighter deposit that occupies the northern portion of the crater floor. Similar deposits are found in other craters in this same region of Mars.
The MOC picture was taken on October 28, 1997, shortly after Mars Global Surveyor's 30th closest approach to Mars. The subframe covers an area of about 3.2 x 3.5 km (2.0 x 2.2 miles). The MOC image reveals that the deposit in the northern portion of this crater is indeed eroded and has long, straight troughs (running from lower left to upper right) with scattered small mounds or buttes among them. The floors of these troughs have small dunes or drifts of windblown material (ridges that have crests that run from upper left toward lower right) in them.
Because it has been eroded by wind, the deposit on this crater floor must either consist of fine-grained sediment such as sand and silt, or a rock easily broken down into sand-sized particles. This erosion probably provided the source for the dark material that makes up the splotch and wind streak at the crater's southwestern side. These features together indicate that the strongest winds which blow through this region come consistently from the northeast. The origin of the material that comprises the eroded deposit is unknown.
The context frame (A; Viking Orbiter 1 #369S33) is the highest-resolution image obtained of this crater prior to the Mars Global Surveyor mission. At a resolution of 224 meters/pixel, it is about 45 times lower resolution than the MOC image.
The MOC subframe of #3001 was featured as Figure 3a in Malin et al., "Early Views of the Martian Surface from the Mars Orbiter Camera of Mars Global Surveyor," Science, v. 279, no. 5357, pp. 1681-1685; wherein it was erroneously stated that this image is of the floor of Crommelin Crater.
Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.
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