"The combination of the ground-level and aerial view is much more powerful than
either alone," said Steve Squyres of Cornell University, Ithaca, N.Y. Squyres is
principal investigator for Opportunity and its twin, Spirit. "If you were a
geologist driving up to the edge of a crater in your jeep, the first thing you
would do would be to pick up the aerial photo you brought with you and use it to
understand what you're seeing from ground level. That's exactly what we're doing
here."
Images from NASA's Mars Global Surveyor, orbiting the red planet since 1997,
prompted the rover team to choose Victoria two years ago as the long-term
destination for Opportunity. The images show the one-half-mile-wide crater has
scalloped edges of alternating cliff-like high, jutting ledges and gentler
alcoves. The new image by the Mars Reconnaissance Orbiter adds significantly
more detail.
Exposed geological layers in the cliff-like portions of Victoria's inner wall
appear to record a longer span of Mars' environmental history than the rover has
studied in smaller craters. Victoria is five times larger than any crater
Opportunity has visited during its Martian trek.
High-resolution color images taken by Opportunity's panoramic camera since Sept.
28 reveal previously unseen patterns in the layers. "There are distinct
variations in the sedimentary layering as you look farther down in the stack,"
Squyres said. "That tells us environmental conditions were not constant."
Within two months after landing on Mars in early 2004, Opportunity found
geological evidence for a long-ago environment that was wet. Scientists hope the
layers in Victoria will provide new clues about whether that wet environment was
persistent, fleeting or cyclical.
The rovers have worked on Mars for more than 10 times their originally planned
three-month missions. "Opportunity shows a few signs of aging but is in good
shape for undertaking exploration of Victoria crater," said John Callas, project
manager for the rovers at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
|
An
image from NASA's Mars Reconnaissance
Orbiter shows the Mars Exploration Rover
Opportunity near the rim of "Victoria
Crater." Image credit: NASA/JPL/UA
Larger image
View related images
|
"What we see so far just adds to the excitement. The team has worked heroically
for nearly 21 months driving the rover here, and now we're all rewarded with
views of a spectacular landscape of nearly 50-foot-thick exposures of layered
rock," said Jim Bell of Cornell. Bell is lead scientist for the rovers'
panoramic cameras. NASA plans to drive Opportunity from crater ridge to ridge,
studying nearby cliffs across the intervening alcoves and looking for safe ways
to drive the rover down. "It's like going to the Grand Canyon and seeing what
you can from several different overlooks before you walk down," Bell said.
The orbiter images will help the team choose which way to send Opportunity
around the rim, and where to stop for the best views. Conversely, the rover's
ground-level observations of some of the same features will provide useful
information for interpreting orbital images.
"The ground-truth we get from the rover images and measurements enables us to
better interpret features we see elsewhere on Mars, including very rugged and
dramatic terrains that we can't currently study on the ground," said Alfred
McEwen of the University of Arizona, Tucson. He is principal investigator for
the orbiter's High Resolution Imaging Science Experiment camera.
JPL manages the rovers and orbiter for NASA's Science Mission Directorate. JPL
is a division of the California Institute of Technology in Pasadena.
Source:
http://mars.jpl.nasa.gov/mro/newsroom/pressreleases/20061006a.html
|
Distinctive perspectives on
news, technology & pop culture
While Opportunity spent its first week at the crater, NASA's newest eye in the
Martian sky photographed the rover and its surroundings from above. The level of
detail in the photo from the high-resolution camera on the Mars Reconnaissance
Orbiter will help guide the rover's exploration of Victoria. 