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Spirit headed to Gusev FROM NASA PRESS KIT Posted: December 31, 2003 Selection of landing sites for the two Mars Exploration Rovers required more than two years of intensive study. More than 100 scientists and engineers participated in evaluating sites both on the basis of favorable criteria for safe landings and on the prospects for outstanding science opportunities after the rovers reach the ground. To qualify for consideration, candidate sites had to be near Mars' equator, not too rugged, not too rocky, not too dusty, and low enough in elevation so the spacecraft would pass through enough atmosphere to slow down sufficiently. In all, 155 potential sites met the initial safety constraints. Detailed observations by two active orbital spacecraft, Mars Global Surveyor and Mars Odyssey, provided an unprecedented amount of information for evaluating finalist candidate sites. The pair that made the final cut satisfied all the safety criteria; they also show powerful evidence of past liquid water, but in two very different ways.
An asteroid or comet impact perhaps as much as 4 billion years ago dug Gusev Crater. Many smaller, younger impact craters pock Gusev's 150-kilometer-diameter (95-mile) floor. One of the largest branching valleys on Mars, likely carved by flowing water more than 2 billion years ago, leads directly into Gusev Crater through a breach in the crater's southern rim. Gusev sits at 15 degrees latitude south of Mars' equator at longitude 184.7 degrees west, in a transition zone between the ancient highlands on the southern part of the planet and smoother plains to the north. The valley, called Ma'adim Vallis, snakes northward Nile-like about 900 kilometers (550 miles) from the highlands to Gusev. In places, it gapes more than 25 kilometers (16 miles) wide and 2 kilometers (1.2 miles) deep. Water flowing down the valley would have pooled in Gusev Crater, dropping sediments there before exiting through a gap in the crater's northern rim. Comparable crater lakes, such as Lake Bosumtwi in Ghana, exist on Earth. Gusev's lake, if indeed it did exist, is now gone. But the floor of Gusev Crater may hold water-laid sediments that preserve records of the lake environment, of the sediments' highlands origins and of the sediments' river trip. As a potential complication, sedimentary layers may lie buried under later deposits from volcanic eruptions or wind-blown dust. If so, the best chances for finding sedimentary rocks may be in material thrown outward when younger craters were excavated by impacts that punched through the covering layers. The targeted landing area for Spirit is an ellipse about 78 kilometers (48 miles) long and 10.4 kilometers (6.5 miles) wide near the center of Gusev Crater. Several small craters in and near the ellipse have likely stirred up rocks from underneath the top veneer of Gusev's flat floor. Whether they have dug deep enough to expose lake-related material if volcanic overburden is deep remains to be seen. A Mars Exploration Rover is well equipped to pursue clues to Gusev's past environment. The panoramic camera and miniature thermal emission spectrometer will scan the scene for an initial survey of the surroundings after landing. Decisions about where to drive Spirit and how to use its other tools will depend on what that survey shows, such as whether any sedimentary rocks appear to be accessible. As the rover drives to new locations during its planned three months of Mars surface operations, a succession of further panoramic surveys will multiply the number of candidate rocks to consider for up-close examination. If Spirit can find and approach sedimentary samples, several physical traits that the panoramic camera and the microscopic imager could reveal might testify about the long-ago environment. The rock abrasion tool could provide the cameras with fresh, unweathered surfaces to examine. The types of traits scientists may be checking for include:
Spirit's miniature thermal emission spectrometer, alpha particle X-ray spectrometer and Mossbauer spectrometer could provide a different set of clues about Gusev Crater's past. These three instruments analyze the composition of rocks and soils. Scientists may use them to look for evidence such as:
The geographical coordinates for the center of Spirit's landing ellipse target are 14.59 degrees south latitude and 175.3 degrees east longitude. Gusev Crater was named in 1976 for Russian astronomer Matvei Gusev, who lived
from 1826 to 1866. Ma'adim Vallis takes its name from the Hebrew word for Mars.
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Mission facts Mission preview - Our story examining the Mars Exploration Rover project. Getting to Mars - Our story previewing the rovers' descent and landing to the Martian surface. Illustration - A graphic showing the entry, descent and landing timeline. Gusev Crater - The landing site for the Mars Exploration Rover Spirit. MER spacecraft - A technical look at the parts and pieces of the Mars Exploration Rover spacecraft. Mission science - A look at the science instruments and objectives for the Mars rovers. Future exploration - Our story looking at NASA's plans for Mars missions through the decade. Soviet Space For the first time ever available in the West. Rocket & Space Corporation Energia: a complete pictorial history of the Soviet/Russian Space Program from 1946 to the present day all in full color. Available from our store.U.S. - U.K. - E.U. - Worldwide Viking patch This embroidered mission patch celebrates NASA's Viking Project which reached the Red Planet in 1976.U.S. - U.K. - E.U. - Worldwide Apollo 7 DVD For 11 days the crew of Apollo 7 fought colds while they put the Apollo spacecraft through a workout, establishing confidence in the machine what would lead directly to the bold decision to send Apollo 8 to the moon just 2 months later.U.S. - U.K. - E.U. - Worldwide Gemini 12 Gemini 12: The NASA Mission Reports covers the voyage of James Lovell and Buzz Aldrin that capped the Gemini program's efforts to prove the technologies and techniques that would be needed for the Apollo Moon landings. Includes CD-ROM.U.S. - U.K. - E.U. - Worldwide Soviet Space For the first time ever available in the West. Rocket & Space Corporation Energia: a complete pictorial history of the Soviet/Russian Space Program from 1946 to the present day all in full color. Available from our store.U.S. - U.K. - E.U. - Worldwide Viking patch This embroidered mission patch celebrates NASA's Viking Project which reached the Red Planet in 1976.U.S. - U.K. - E.U. - Worldwide Apollo 7 DVD For 11 days the crew of Apollo 7 fought colds while they put the Apollo spacecraft through a workout, establishing confidence in the machine what would lead directly to the bold decision to send Apollo 8 to the moon just 2 months later.U.S. - U.K. - E.U. - Worldwide Gemini 12 Gemini 12: The NASA Mission Reports covers the voyage of James Lovell and Buzz Aldrin that capped the Gemini program's efforts to prove the technologies and techniques that would be needed for the Apollo Moon landings. Includes CD-ROM.U.S. - U.K. - E.U. - Worldwide Apollo Collage This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.STS-127 Patch The official embroidered patch for shuttle Endeavour's flight to finish building Japanese section of the space station.![]() Hubble Patch The official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase.Project Orion The Orion crew exploration vehicle is NASA's first new human spacecraft developed since the space shuttle a quarter-century earlier. The capsule is one of the key elements of returning astronauts to the Moon.Fallen Heroes Patch Collection The official patches from Apollo 1, the shuttle Challenger and Columbia crews are available in the store.Columbia Report A reproduction of the official accident investigation report into the loss of the space shuttle Columbia and its crew of seven. U.S. - U.K. - E.U. - Worldwide Mars Panorama DISCOUNTED! This 360 degree image was taken by the Mars Pathfinder, which landed on the Red Planet in July 1997. The Sojourner Rover is visible in the image. U.S. Apollo 11 Mission Report Apollo 11 - The NASA Mission Reports Vol. 3 is the first comprehensive study of man's first mission to another world is revealed in all of its startling complexity. Includes DVD!U.S. - U.K. - E.U. - Worldwide Rocket DVD If you've ever watched a launch from Kennedy Space Center, Cape Canaveral, Vandenberg Air Force Base or even Kodiak Island Alaska, there's no better way to describe what you witnessed than with this DVD.U.S. - U.K. - E.U. - Worldwide Apollo 11 special patch Special collectors' patch marking the 35th anniversary of the historic Apollo 11 moon landing is now available.U.S. - U.K. Get e-mail updates Sign up for our NewsAlert service and have the latest news in astronomy and space e-mailed direct to your desktop (privacy note: your e-mail address will not be used for any other purpose). |
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