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Mars Global Surveyor
Mars Orbiter Camera

Evidence for Recent Liquid Water on Mars:
Channels and Aprons in East Gorgonum Crater

MGS MOC Release No. MOC2-241, 22 June 2000


(A) 3 MOC Image View


25%-size Color 890 KBytes
50%-size Color 3.4 MBytes

(B) Context in Viking Image


50%-size Context 70 KBytes
Full Resolution Context 225 KBytes

(C) Close-up of Apron Deposit


25%-size B&W 160 KBytes
50%-size B&W 600 KBytes

This suite of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) pictures provides a vista of martian gullies on the northern wall of a 12 kilometer-(7.4 mile)-wide meteor impact crater east of the Gorgonum Chaos region on the red planet.

The first picture (A, left) is a composite of three different high resolution MOC views obtained in 1999 and 2000. The second picture (B, middle) shows the location of the high resolution views relative to the whole crater as it appeared in the highest resolution image previously acquired of the area, taken by the Viking 1 orbiter in 1978. The third picture (C, right) shows a close-up of one of the channels and debris aprons found in the northwestern quarter of the impact crater.

Some of the channels in this crater are deeply-entrenched and cut into lighter-toned deposits. The numerous channels and apron deposits indicate that many tens to hundreds of individual events involving the flow of water and debris have occurred here. The channels and aprons have very crisp, sharp relief and there are no small meteor impact craters on them, suggesting that these features are extremely young relative to the 4.5 billion year history of Mars. It is possible that these landforms are still being created by water seeping from the layered rock in the crater wall today.

The crater has no name and it is located near 37.4°S, 168.0°W. The composite view in (A) includes a picture taken by MOC on September 10, 1999, a picture obtained April 26, 2000, and another on May 22, 2000. The scene from left to right (including the dark gap between photos) covers an area approximately 7.6 kilometers (4.7 miles) wide by 18 km (11.1 mi) long. Sunlight illuminates the scene from the upper left. MOC high resolution images are taken black-and-white (grayscale); the color seen here has been synthesized from the colors of Mars observed by the MOC wide angle cameras and by the Viking Orbiters in the late 1970s.

Images Credit: NASA/JPL/Malin Space Science Systems

For Media/Print purposes:

Here are full-resolution views of the large color mosaic and the apron figure. The color image is too long for some web browsers (in this case, you must save the link to your desktop and view with other software):

A brief description of how the color was generated:

The MOC narrow angle camera only takes grayscale (black and white) pictures. To create the color versions seen here, we have taken much lower resolution red and blue images acquired by the MOC's wide angle cameras, and by the Viking Orbiter cameras in the 1970s, synthesized a green image by averaging red and blue, and created a pallete of colors that represent the range of colors on Mars. We then use a relationship that correlates color and brightness to assign a color to each gray level. This is only a crude approximation of martian color and should only be considered representative of Mars. It is likely Mars would not look like this to a human observer at Mars.

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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