NASA Mars Picture of the Day: A Tale of 3 Craters

Mars Global Surveyor Mars Orbiter Camera

MGS MOC Release No. MOC2-907, 11 November 2004

NASA/JPL/Malin Space Science Systems

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)
image captures some of the complexity of the martian upper
crust. Mars does not simply have an impact-cratered surface,
it’s upper crust is a cratered volume. Over time, older
craters on Mars have been eroded, filled, buried, and in
some cases exhumed and re-exposed at the martian surface.
The crust of Mars is layered to depths of 10 or more kilometers,
and mixed in with the layered bedrock are a variety of ancient
craters with diameters ranging from a few tens of meters (a
few tens of yards) to several hundred kilometers
(more than one or two hundred miles).

The picture shown here captures some of the essence of the
layered, cratered volume of the upper crust of Mars in a
very simple form. The image shows three distinct circular
features. The smallest, in the lower right quarter of the
image, is a meteor crater surrounded by a mound of material.
This small crater formed within a layer of bedrock that
once covered the entire scene, but today is found only in
this small remnant adjacent to the crater.
The intermediate-sized crater, west (left) of the small one,
formed either in the next layer down–that is, below the
layer in which the small crater formed–or it formed in some
layers that are now removed, but was big enough to penetrate
deeply into the rock that is near the surface today.
The largest circular feature in the image, in the upper right
quarter of the image, is still largely buried. It formed in
layers of rock that are below the present surface. Erosion
has brought traces of its rim back to the surface of Mars.
This picture is located
near 50.0°S, 77.8°W, and
covers an area approximately 3 km (1.9 mi) across. Sunlight
illuminates this October 2004 image from the upper left.

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, California.
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,
California and Denver, Colorado.