NASA Mars Picture of the Day: MOC View of Spirit’s Trek to the Columbia Hills

Mars Global Surveyor Mars Orbiter Camera

MGS MOC Release No. MOC2-960, 3 January 2005

MOC2-960a: Spirit track from lander to Columbia Hills Composite of MOC images R15-02643 and R20-01024

MOC2-960b: Annotated, segmented view of Spirit track Composite of MOC images R15-02643 and R20-01024

MOC2-960c: Faded rover track and new dust devil streak MOC images R15-02643, R20-01024; MER-A Navcam Images (courtesy NASA/JPL)

NASA/JPL/Malin Space Science Systems

The Mars Exploration Rover, Spirit, landed in Gusev Crater
a year ago. Over the course of its mission, the Mars Global Surveyor (MGS)
Mars Orbiter Camera (MOC) has been tracking Spirit’s progress from
orbit. During the rover’s 90 sol primary mission, it drove from the
lander to nearby Bonneville Crater. When the extended mission began,
the rover was already making progress down toward the Columbia Hills,
several kilometers to the southeast.

The first picture shown here, MOC2-960a, is a composite of MOC
images R15-02643 and R20-01024, showing the complete rover track
from the lander to the Columbia Hills. Spirit’s rover track shows
up nicely from orbit, because the surfaces disrupted and churned
by the wheels are darker than the surrounding, dust-coated plain.

The second picture, MOC2-960b, is a segmented view of the first.
In this case, the location of the lander, parachute, and backshell
are indicated in frame A, and the rover track down toward the
Columbia Hills can be traced through A, B, and C. In frame A,
Bonneville Crater is the largest crater in the upper right quarter
of the image. Spirit drove up to Bonneville’s rim, before driving
away from it, toward the southeast. The base of the Columbia Hills
is seen in the lower right quarter of frame C. In frame B, notice
that the rover track followed along the edge of a lighter-toned and
wider dark streak, believed to have been formed by a dust devil
sometime before Spirit landed. The proximity of the rover to this
streak was not recognized in rover images.

The third picture, MOC2-960c, includes additional annotations
that can be used in reference to the previous pictures, indicating
the location of the rover track and lander. This third picture
illustrates the occurrence of a new dark streak thought to have
formed by a dust devil that was bigger and wider than the Spirit
rover. This dust devil was not observed by the rover. The first
picture in the upper left is MOC image R15-02643, acquired on
30 March 2004 (Spirit’s sol 85). The second picture, upper right,
is MOC image R20-01024, obtained on 18 August 2004 (Spirit’s sol 223).
A dark streak occurs in the larger crater in the lower right quarter
of the August 2004 image. This streak was not present when the March
image was obtained. Inspection of Spirit’s navigation camera images
obtained on 20 April 2004 (Spirit’s sol 106), when the rover was
at the rim of this crater, revealed that the streak was present
on 20 April 2004. Thus, the dust devil must have occurred some time
between 30 March 2004 and 20 April 2004.

In addition to the formation of a new dust devil streak in the
30 March to 20 April 2004 period, another change seems to
have occurred at the landing site. The rover track between
the lander and the rim of Bonneville Crater (the largest crater in
MOC2-960c) seems to have faded between 30 March and 18 August.
This could be an artifact of the different sunlight illumination
conditions between the two images, or it may indicate that fine
dust settled on the older portions of the track, obscuring it
from view. Assuming the MGS MOC mission will continue for several
more years, the MOC team plans to re-visit the Spirit lander
site from time to time, to see what other changes may occur.

Previous MGS MOC Images of the Spirit landing site:

• MOC image of Spirit Rover and its Tracks 27 September 2004
• Apollinaris, Gusev, and Spirit 3 September 2004
• MGS MOC image of Mars Exploration Rover, Spirit, on Mars 23 January 2004
• MOC Wide Angle View of Gusev Crater at the Moment of Spirit’s Landing 7 January 2004
• MOC images of Spirit Landing Site, changes in dust devil/wind streaks 5 January 2004
• MOC Image Mosaic of Mars Exploration Rover (MER-A) Spirit Landing Site 3 January 2004
• MOC Wide Angle View of Gusev Crater, Spirit Landing Site 2 January 2004

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.