Mars Global Surveyor
Mars Orbiter Camera

Mars Orbiter Camera (MOC) High Resolution Images:
Eroded Crater Floor Deposit in Western Arabia Terra


Mars Global Surveyor Mars Orbiter Camera Release:          MOC2-32A, -32B
Mars Global Surveyor Mars Orbiter Camera Image ID:         562578095.3001

(A) Portion of Viking Orbiter 1 image 369S33, at a scale of 224 meters (732 feet) per pixel. The outline of the MOC subframe (B) is shown as a white box in this figure. North is up, sun illumination is from the upper right.


(B) Subframe of MOC image 3001 reproduced at full resolution, a scale of about 5.0 meters/pixel (16 feet/pixel). Sun illumination is from the lower left.

You may need to adjust the images for the gamma of your monitor to insure proper viewing.

Note: This MOC image is made available in order to share with the public the excitement of new discoveries being made via the Mars Global Surveyor spacecraft. The image may be reproduced only if the image is credited to "Malin Space Science Systems/NASA". Release of this image does not constitute a release of scientific data. The image and its caption should not be referenced in the scientific literature. Full data releases to the scientific community are scheduled by the Mars Global Surveyor Project and NASA Planetary Data System. Typically, data will be released after a 6 month calibration and validation period.

Click Here for more information on MGS data release and archiving plans.


This 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.

To MSSS Home Page