Mars Orbiter Sees Rover Tracks Among Thousands of New Images
NASA's Mars Global Surveyor, starting its third mission
extension this week after seven years of orbiting Mars, is
using an innovative technique to capture pictures even
sharper than most of the more than 170,000 it has already
Image above: Wheel tracks left by NASA's Mars Exploration Rover Spirit, and even the rover itself, are visible in this image from NASA's Mars Global Surveyor orbiter. The tracks and rover are in the area south of a crater informally named "Bonneville," which is just southeast of the center of the image. Image courtesy: NASA/JPL/MSSS. + Full image
+ Click for animation of spacecraft imaging technique.
One dramatic example from the spacecraft's Mars Orbiter
Camera shows wheel tracks of NASA's Mars Exploration Rover
Spirit and the rover itself. Another tells scientists that
no boulders bigger than about 1 to 2 meters (3 to 7 feet) are
exposed in giant ripples created by a catastrophic flood.
Those examples are available online at
. In addition, about 24,000
newly catalogued images that Mars Global Surveyor took
between October 2003 and March 2004 have been added to the
Mars Orbiter Camera Image Gallery at
. These include additional
pictures of the Mars Exploration Rover sites seen from orbit.
"Over the past year and a half, the camera and spacecraft
teams for Mars Global Surveyor have worked together to
develop a technique that allows us to roll the entire
spacecraft so that the camera can be scanned in a way that
sees details at three times higher resolution than we
normally get," said Dr. Ken Edgett, staff scientist for Malin
Space Science Systems, San Diego, Calif., which built and
operates the Mars Orbiter Camera. The technique adjusts the
rotation rate of the spacecraft to match the ground speed
under the camera.
"The image motion compensation is tricky and the spacecraft
does not always hit its target. However, when it does, the
results can be spectacular," Edgett said.
Image above: Researchers' goal in taking this image was to
look for boulders in the large ripples formed by an ancient
catastrophic flood in Mars' Athabasca Vallis.
Image courtesy: NASA/JPL/MSSS. + Full image
The Mars Orbiter Camera acquires the highest resolution
images ever obtained from a Mars-orbiting spacecraft. During
normal operating conditions, the smallest objects that can be
resolved on the martian surface in these images are about 4
to 5 meters (13 to 16 feet) across. With the adjusted-
rotation technique, called "compensated pitch and roll
targeted observation," objects as small as 1.5 meters (4.9
feet) can be seen in images from the same camera. Resolution
capability of 1.4 meters (4.6 feet) per pixel is improved to
one-half meter (1.6 feet) per pixel. Because the maneuvers
are complex and the amount of data that can be acquired is
limited, most images from the camera are still taken without
using that technique.
Mars Global Surveyor began orbiting Mars on Sept. 12, 1997.
After gradually adjusting the shape of its orbit, it began
systematically mapping the planet in March 1999. The Mars
Orbiter Camera's narrow-angle camera has now examined nearly
4.5 percent of Mars' surface, including extensive imaging of
candidate and selected landing sites for surface missions.
The Mars Orbiter Camera also includes a wide-angle camera
that observes the entire planet daily.
"Mars Global Surveyor has been productive longer than any
other spacecraft ever sent to Mars, since it surpassed Viking
Lander 1's longevity earlier this year and has returned more
images than all past Mars missions combined," said Tom
Thorpe, project manager for Mars Global Surveyor at NASA's
Jet Propulsion Laboratory, Pasadena, Calif. The mission will
complete its 25,000th mapping orbit on Oct. 11.
Principal goals for the orbiter's latest mission extension,
beginning Oct. 1, include continued weather monitoring to
form a continuous set of observations with NASA's next Mars
mission, Mars Reconnaissance Orbiter, scheduled to reach the
red planet in 2006; imaging of possible landing sites for the
Phoenix 2007 Mars Scout lander and 2009 Mars Science
Laboratory rover; continued mapping and analysis of key
sedimentary-rock outcrop sites; and continued monitoring of
changes on the surface due to wind and ice. Because the
narrow-angle camera has imaged only a small fraction of the
surface, new discoveries about surface features are likely to
come at any time. The extension runs two years, through
September 2006, with a budget of $7.5 million per year.
Dr. James Garvin, NASA's chief scientist for Mars and the
Moon, said, "Mars Global Surveyor continues to catalyze new
science as it explores Mars at scales compatible with those
that our Mars Exploration Rovers negotiate every day, and its
extended mission will continue to set the stage for upcoming
observations by the Mars Reconnaissance Orbiter."
Additional information about Mars Global Surveyor is
available online at: http://mars.jpl.nasa.gov/mgs/
addition to semi-annual releases of large collections of
archived pictures, the Mars Orbiter Camera team posts a new
image daily and last year began soliciting public suggestions
for camera targets on Mars. These materials can be viewed
online at http://www.msss.com
. For more information about
NASA and other space science programs on the Internet, visit
Guy Webster (818) 354-6278
NASA's Jet Propulsion Laboratory
Don Savage (202) 358-1547
NASA Headquarters, Washington, D.C.