Spirit hits a home run, Opportunity examines 'Roosevelt'
Sat Feb 18, 2006 at 20:42 UTC
This week, Spirit arrived at "Home Plate," a feature that, when seen from orbit, looks like the home plate of a baseball diamond. Home Plate is a roughly circular feature about 80 meters (260 feet) in diameter that might be an old impact crater or volcanic feature.
The Spirit team has been eager to get to Home Plate and has been enjoying distant views of the feature and a curious "bathtub ring" of light-colored materials along its edges. The team has pushed the rover hard to get here before the deep Martian winter sets in.
After scientists had identified Home Plate from orbit, they had many theories about what it could be and what they might see. But when Spirit's panoramic camera (Pancam) took this and other images, the science team was stunned. This Pancam image is of an outcrop nicknamed "Barnhill" and surrounding rocks on the north side of Home Plate, showing the most spectacular layering that Spirit has seen.
Pancam and microscopic imager views of the layers in the rocks reveal a range of grain sizes and textures that change from the lower to the upper part of the outcrop. This may help scientists figure out how the material was emplaced. Spirit is also conducting work with its arm instruments to figure out the chemistry and mineralogy of the rocks. Scientists have several hypotheses about what Home Plate could be, including features made by volcanoes and impact craters, and ways that water could have played a role. They are busy trying to figure out what the data from Spirit is really telling us.
Image Credit: NASA/JPL-Caltech/Cornell/UNM
Spirit took this mosaic of images using the panoramic camera on the rover's 746th day, or sol (Feb. 7, 2006), of exploring Mars. Scientists are acquiring and processing image data for more views of the same terrain in approximate true color. Full-resolution image.
As Spirit works at Home Plate during February, the science team is choosing informal names for rocks from the great players and managers of the Negro Leagues of baseball. This outcrop, "Barnhill," is informally named for David Barnhill, the ace of the New York Cubans' pitching staff during the early 1940s. He compiled an 18-3 record in 1941 and defeated Satchel Paige in the 1942 East-West all-star game. Other rocks in the area are informally named for Josh Gibson, "Bullet Joe" Rogan, and Cumberland Posey. Stay tuned this month, as the Baseball Hall of Fame elects more players from the Negro Leagues and Spirit continues to examine these spectacular rocks.
Image Credit: NASA/JPL/Cornell/USGS
This image mosaic from the microscopic imager aboard NASA's Mars Exploration Rover Opportunity shows detailed structure of a small fin-like structure dubbed "Roosevelt," which sticks out from the outcrop pavement at the edge of "Erebus Crater."
Roosevelt lines a fracture in the local pavement and scientists hypothesize that it is a fracture fill, formed by water that percolated through the fracture. This would mean the feature is younger than surrounding rocks and, therefore, might provide evidence of water that was present some time after the formation of Meridiani Planum sedimentary rocks.
The image shows fine laminations (layers about 1 millimeter or .04 inch thick) that run parallel to the axis of the fin. Some of the textures visible in the image likely indicate that minerals precipitated from the outcrop rocks, but sediment grains are also apparent.
The three frames combined into this mosaic were taken during Opportunity's 727th Martian day, or sol (Feb. 8, 2006). In subsequent days, the rover completed textural and chemical inspection of Roosevelt to help the science team understand this structure's significance for Martian history. Full-resolution image.
JPL Image Releases
