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NASA’s Mars Rovers Continue to Explore and Amaze

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This view from the panoramic camera on NASA’s Mars Exploration Rover Opportunity shows an outcrop called "Olympia" along the northwestern margin of "Erebus" crater. The view spans about 120 degrees from side to side, generally looking southward. The outcrop exposes a broad expanse of sulfate-rich sedimentary rocks. The rocks were formed predominantly from windblown sediments, but some also formed in environmental conditions from damp to under shallow surface water. After taking the images that were combined into this view, Opportunity drove along along a path between sand dunes to the upper left side of the image, where a cliff in the background can be seen. This is a cliff is known as the "Mogollon Rim." Researchers expect it to expose more than 1 meter (3 feet) of new strata. These strata may represent the highest level observed yet by Opportunity. The image is an approximately true-color rendering generated using the panoramic camera’s 750-nanometer, 530-nanometer and 430-nanometer filters. Image Credit: NASA/JPL-Caltech/Cornell


The panoramic camera on NASA’s Mars Exploration Rover Spirit took the hundreds of images combined into this 360-degree view, the "Husband Hill Summit" panorama. The images were acquired on Spirit’s sols 583 to 586 (Aug. 24 to 27, 2005), shortly after the rover reached the crest of "Husband Hill" inside Mars’ Gusev Crater. This is the largest panorama yet acquired from either Spirit or Opportunity. The panoramic camera shot 653 separate images in 6 different filters, encompassing the rover’s deck and the full 360 degrees of surface rocks and soils visible to the camera from this position. This is the first time the camera has been used to image the entire rover deck and visible surface from the same position. Stitching together of all the images took significant effort because of the large changes in resolution and parallax across the scene. The image is an approximately true-color rendering using the 750-nanometer, 530-nanometer and 480-nanometer filters for the surface, and the 600-nanometer and 480-nanometer filters for the rover deck. Image-to-image seams have been eliminated from the sky portion of the mosaic to better simulate the vista a person standing on Mars would see. This panorama provided the team’s first view of the "Inner Basin" region (center of the image), including the enigmatic "Home Plate" feature seen from orbital data. After investigating the summit area, Spirit drove downhill to get to the Inner Basin region. Spirit arrived at the summit from the west, along the direction of the rover tracks seen in the middle right of the panorama. The peaks of "McCool Hill" and "Ramon Hill" can be seen on the horizon near the center of the panorama. The summit region itself is a broad, windswept plateau. Spirit spent more than a month exploring the summit region, measuring the chemistry and mineralogy of soils and rocky outcrops at the peak of Husband Hill for comparison with similar measurements obtained during the ascent. Image Credit: NASA/JPL-Caltech/Cornell

NASA’s durable twin Mars rovers have successfully explored the surface of the mysterious red planet for a full Martian year (687 Earth days). Opportunity starts its second Martian year Dec. 11; Spirit started its new year three weeks ago. The rovers’ original mission was scheduled for only three months.

"The rovers went through all of the Martian seasons and are back to late summer," said Dr. John Callas of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. He is deputy rover project manager. "We’re preparing for the challenge of surviving another Martian winter."

Both rovers keep finding new variations of bedrock in areas they are exploring on opposite sides of Mars. The geological information they collect increases evidence about ancient Martian environments including periods of wet, possibly habitable conditions.

Spirit is descending from the top of "Husband Hill" to examine a platform-like structure seen from the summit. It will then hurry south to another hill in time to position itself for maximum solar-cell output during the winter.

"Our speed of travel is driven as much by survival as by discovery, though the geology of Husband Hill continues to fascinate, surprise, puzzle and delight us," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rover’s science instruments. "We’ve got this dramatic topography covered with sand and loose boulders, then, every so often, a little window into the bedrock underneath."

From the composition and texture of more than six different types of rock inspected, scientists deduced what this part of Mars was like long ago. "It was a hot, violent place with volcanic explosions and impacts," Squyres said. "Water was around, perhaps localized hot springs in some cases and trace amounts of water in other cases.

Aided by a good power supply from Spirit’s solar cells, researchers have been using the rover at night for astronomical observations. One experiment watched the sky during a meteor shower as Mars passed through the debris trail left by a passage of Halley’s comet. "We’re taking advantage of a unique opportunity to do some bonus science we never anticipated we would be able to do," said Cornell’s Dr. Jim Bell, lead scientist for the rovers’ panoramic cameras

Opportunity is examining bedrock exposures along a route between Endurance and Victoria craters. It recently reached what appears to be a younger layer of bedrock than examined inside Endurance. In Endurance, the lowest layers of bedrock were deposited as windblown dunes. Some of the upper layers were deposited as underwater sediments, indicating a change from drier to wetter conditions over time.

The bedrock Opportunity began seeing about two-thirds of the way to Victoria appears to lie higher than the upper layers at Endurance, but its texture is more like the lowest layer, petrified sand dunes. This suggests the change from drier to wetter environmental conditions may have been cyclical.

Iron-rich granules are abundant in all the layers at Endurance but are much smaller in the younger bedrock. These granules were formed by effects of water soaking the rocks. One possibility for why they are smaller is these layers might have spent less time wet. Another is the material in these layers might have had a different chemistry to begin with.

Rover researchers are presenting their latest data today during the American Geophysical Union meeting in San Francisco. Images and information about the rovers and their discoveries are available on the Web at: http://www.nasa.gov/vision/universe/solarsystem/mer_main.html. For more information about NASA and agency programs on the Web, visit: http://www.nasa.gov/home .

Guy Webster | Quelle: EurekAlert!
Weitere Informationen: www.nasa.gov/vision/universe/solarsystem/mer_main.html
www.nasa.gov/home
www.nasa.gov/vision/universe/solarsystem/mer-20051205.html

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