[FPSPACE] The latest news on the Mars Rovers from Jim Bell
ljk4 at msn.com
Thu Oct 7 10:24:07 EDT 2004
Mars rovers receive go-ahead to keep roving, imaging the Red Planet
By Larry Klaes
The Mars Exploration Rovers (MER), Spirit and Opportunity, still exploring the Red Planet long after their 90-day warranties had expired, were given a six-month extension on their missions by the National Aeronautics and Space Administration (NASA). The rovers could continue working on Mars through next summer.
Utilizing scientific instruments designed by Cornell researchers and returning streams of data and images to Earth being processed by university students, these wheeled geologists have produced strong evidence that not only did water flow on Mars long ago, it may have covered that world with vast seas and even salty oceans.
To bring the community up to speed on these latest developments, the Cornell Campus Club invited Jim Bell, associate professor of astronomy and the lead scientist for the rovers' Pancam color imaging system, to present its first lecture of the 2004-05 season Sept. 30 at the Boyce Thompson Institute Auditorium.
The presentation, titled "Roving on Mars," gave the packed audience an illustrated and animated overview of "the excitement of the last nine months of roving around on Mars," said Bell.
Bell began by showing the landing sites of the rovers and explained why these places were chosen over many other regions on a world with a surface area equivalent to all the dry land on Earth.
Gusev crater was designated for exploration by Spirit due to a dry river bed running into the impact region. Scientists theorized that Gusev may have been a lake bed once filled with water by the river channel.
Meridiani Planum, on the other side of Mars from Gusev, was chosen for Opportunity not only because it seemed like a safe place to land the $400 million rover -- Bell said it was the "flattest place in the solar system" -- but because it contained a large amount of an iron oxide called hematite. On Earth, the presence of this mineral usually indicates that water is also present; perhaps Mars is the same.
The Boyce Thompson audience got a sneak preview when Bell showed a panoramic image from Spirit at the foot of the Columbia Hills, to which the rover spent months traveling from its landing site three kilometers away. The impressive color image had not yet been officially presented to the public; Bell said it would likely be the "signature picture of the mission."
Spirit also aimed its Pancam at the sky. The rover team captured such images as the sun slowly sinking behind a distant hill and witnessed solar eclipses by Mars' two small moons, Phobos and Deimos. These were the first solar eclipses ever seen from the surface of another planet; Bell described Phobos as a "potato traveling in front of the sun."
The rovers' world of origin also was imaged by them from Mars. Earth appeared as a "faint little dot" in the surprisingly bright twilight of the Martian dawn.
Spirit was targeted for the Columbia Hills after it had found no evidence for water in Gusev crater, only layers of volcanic minerals. Any signs that Gusev may once have been a lake bed would probably be buried "deep under the landing area," said Bell.
Meanwhile, the twin rover Opportunity had landed in a place unlike any that had ever been seen by all previous lander missions. The second rover had managed to touch down in a small crater (later named Eagle) "only a bit larger than this room," explained Bell, in a region that was primarily a sea of flat, rockless regolith.
Opportunity spent two months exploring Eagle crater, and for good reason. The tiny impact depression held great numbers of small, round mineral deposits the team named "blueberries" for their appearance. On Earth, such formations appear when large amounts of water course through rock layers, leaching out the iron into balls. The rovers also detected large amounts of sulfur and salt deposits.
With such strong data, the team announced that, at least where Opportunity was now roaming, at one time a large body of flowing liquid water existed, though for how long and how deep it penetrated have yet to be determined.
After exploring Eagle crater, Opportunity took a long trip eastward to the nearest large crater, named Endurance. This impact zone was described by Bell as the "size of the Rose Bowl stadium." Endurance, too, was filled with blueberries. Its greater depth also showed that the water in the area existed way back in the Martian past. There even appeared to be mud cracks in certain places.
The Cornell astronomer ended his lecture with speculative artwork depicting the ultimate goal of the exploration of Mars: The placing of humans on the planet's surface. Bell said that Spirit and Opportunity have "paved the way for humans on Mars," where "trained geologists can do even more wonderful things" on the Red Planet.
October 7, 2004
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