This image shows part of a low mountain belt that rings the Argyre impact
basin in Mars' southern hemisphere. The mountains or hills seen here are
located in the northwestern part of the Charitum Montes. Taken just
minutes after the sun had risen over the horizon, only the sun-facing
slopes are well illuminated and much of the scene is in shadow, but the
camera has nevertheless captured many details of the surface that are only
dimly illuminated. There are terrains that are both smooth and rough at
this scale (2.94 meters or 9.65 feet per pixel). The rough terrain is
littered with blocks roughly 10 meters (30 feet) across, and the smooth
material has a uniform appearance broken by subtle, undulating ridges. The
rough terrains usually occur at relatively high elevations, and smooth
material occupies the lowest areas. In some locations it is evident that
boulders from the rough terrain have tumbled downhill onto the smooth
material. The smooth material is younger than the rough terrain, and some
of it may have formed when water-rich or ice-rich debris flooded low-lying
areas. In other areas the smooth material mantles the topography like
deposits of airborne dust. Further upslope, the mountain flanks have a
variety of rough textures. In places the terrain has been eroded into
streamlined forms and striations, suggestive of glacial erosion. Gullies
formed in one spot near bottom center. Perhaps the most striking aspect of
this image is the dearth of fresh impact craters. The Argyre basin is
thought to be billions of years old, but much more recent processes have
greatly modified the surface.
This image was taken by the High Resolution Imaging Science
Experiment (HiRISE) camera onboard NASA's Mars Reconnaissance Orbiter
spacecraft on March 24, 2006. The image is centered at 52.20 degrees south
latitude, 300.75 degrees east longitude. It is oriented such that north is
7 degrees to the left of up. The range to the target was 1,470 kilometers
(913 miles). With 2x2 pixel binning, the scale of the image is 2.94 meters
(9.65 feet) per pixel, so objects as small as 8.82 meters (28.94 feet) are
resolved. In total this image is 29.47 kilometers (18.31 miles) or 10,040
pixels wide and 76.44 kilometers (47.50 miles) or 26,011 pixels long. The
image was taken at a local Mars time of 07:24 and the scene is illuminated
from the upper right with a solar incidence angle of 87.1 degrees, thus
the sun was about 2.9 degrees above the horizon. At an Ls of 29 degrees
(with Ls an indicator of Mars' position in its orbit around the sun), the
season on Mars is southern autumn.
Images from the High Resolution Imaging Science Experiment and additional
information about the Mars Reconnaissance Orbiter are available online at:
http://www.nasa.gov/mro or http://HiRISE.lpl.arizona.edu. For information
about NASA and agency programs on the Web, visit: http://www.nasa.gov.
JPL, a division of the California Institute of Technology in Pasadena,
manages the Mars Reconnaissance Orbiter for NASA's Science Mission
Directorate, Washington. Lockheed Martin Space Systems is the prime
contractor for the project and built the spacecraft. The HiRISE camera
was built by Ball Aerospace and Technology Corporation and is operated by
the University of Arizona.