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MAGE ADVISORY

October 12, 1998

MARS GLOBAL SURVEYOR CAPTURES DETAILED VIEWS OF OLYMPUS MONS, KASEI VALLIS RIVER CHANNEL

       NASA's Mars Global Surveyor has captured some spectacular new views of Olympus Mons, the largest volcano in the solar system, and a system of giant channels on the red planet known as Kasei Vallis.

       The new images are available on the Internet at http://www.jpl.nasa.gov, http://mars.jpl.nasa.gov, http://photojournal.jpl.nasa.gov/ and at http://www.msss.com.

       Taken on April 25, 1998, from a distance of about 900 kilometers (560 miles) above the surface, this wide-angle image of Olympus Mons captures the west side of the volcano on a cool, crisp winter morning. Olympus Mons is by far the tallest volcano in the solar system, rising higher than three Mount Everests and spanning the width of the entire Hawaiian island chain.

       The images of Kasei Vallis, a system of giant channels thought to have been carved by catastrophic floods more than a billion years ago, illustrate the complexity of the planet's geologic history. These images were acquired on June 4, 1998, and reveal details of the 6-kilometer-diameter (4-mile) crater as it pokes out from beneath an "island" in the valley. The mesa was created in part by the flood and by its subsequent retreat, which caused small landslides of the scarp that encircles it. A "mote" or trench partly encircles the crater to the west and south. This moat formed were the turbulence of the floodwaters interacting with the crater rim eroded material in front of and alongside the crater.

       When Mars Global Surveyor reaches its final mapping orbit in March 1999, the spacecraft's camera will be used to make daily global maps of Martian clouds and weather systems. The wide-angle images will resemble weather satellite pictures of Earth and will help the Mars Global Surveyor science teams plan their observations and test computer-driven prediction models of Martian weather.