Status Report

NASA Mars Picture of the Day: A Dynamic Spirit Site

By SpaceRef Editor
January 5, 2004
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Mars Global Surveyor Mars Orbiter Camera

MGS MOC Release No. MOC2-596, 5 January 2004

NASA/JPL/Malin Space Science Systems

Two Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC)
images acquired before the spectacular January 2004 landing
of the Mars Exploration Rover (MER-A), Spirit, show the area
where the lander is currently believed to have touched down.
The identification of the area shown in the two pictures
above is based on
the pictures acquired by Spirit’s descent imaging system just before landing.
The lower picture was
obtained by MGS MOC on 22 July 2003, the upper picture
was acquired less than a month ago on 10 December 2003. What
is exciting about these two pictures is the differences in
the patterns of dark, squiggly streaks. These streaks are
believed to have been caused by the removal of bright dust by
large, passing dust devils. Comparison of the picture from
July 2003 with that of December 2003 show that a
different dark streak pattern developed over a period of
less than 5 months.

These two MOC images suggest that the landing site is a
dynamic, changing place on the time scale of several
months. MGS MOC has never seen a dust devil occur in
Gusev Crater, the location of the Spirit landing site.
MGS always flies over Gusev around 2 p.m. local time, so
this means that dust devils are not believed to be common
around 2 p.m. However, the changes in the dark streaks suggest
that dust devils definitely have occurred in Gusev Crater
over the past 5 to 6 months, and they most likely occur earlier
than 2 p.m. (perhaps closer to local 1 p.m. or noon).

These two MOC images are simple cylindrical map projections
(rotated somewhat; note the north arrow, N)
at a scale of about 3 meters per pixel (~10 ft/pixel); the
300 meter scale bar is about two-tenths of a mile long.
The images are located near 14.7°S, 184.6°W,
and are illuminated from the 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.

SpaceRef staff editor.