mirrored file at http://SaturnianCosmology.Org/ For complete access to all the files of this collection see http://SaturnianCosmology.org/search.php ========================================================== CNN.com /SPACE Global dust storm raging on Mars This Hubble Space Telescope image of Mars taken in September shows that dust has obscured all surface features on the red planet. This Hubble Space Telescope image of Mars taken in September shows that dust has obscured all surface features on the red planet. _________________________________________________________________ _________________________________________________________________ WASHINGTON (AP) -- A planetwide dust storm unlike anything known on Earth has raged across Mars for weeks and may cause NASA engineers to make slight changes in the flight path of a spacecraft set to arrive in less than two weeks. Photographs from the Hubble Space Telescope and from Mars Global Surveyor, now orbiting the planet, show that dust is obscuring virtually the whole surface of the red planet, the biggest Martian storm ever seen. Mars is covered with "a veil of hazy, reddish dust," Jim Garvin, head of NASA's Mars exploration program, said Thursday at a news conference. The planetwide storm sprang to life from a smaller duster that appeared in a southern plain called the Hellas basin in June. Sequential views show that dust from that basin spread north and east, and soon the whole planet was blotted from view by a reddish-orange cloud. "That storm spawned other storms, and by mid-August storms were raging across the planet," said Philip Christensen of Arizona State University. RESOURCES Message Board: Space exploration Christensen said the dust obscures the sun so much that the Martian surface has cooled by about 10 degrees. Dust thrown aloft, however, has absorbed sunlight and has warmed by some 80 degrees to about 4 degrees from its normal minus 76. The storm is settling some now, Christensen said, but he predicted other storms will occur in coming months as Mars makes its closest approach to the sun. NASA scientists said the storm is associated with Mars' southern spring. The planet is tilted on its axis, rather like Earth, and its closest approach to the sun comes when it is spring in the southern hemisphere. The Hellas basin is in the south. It is not clear to scientists why a local storm on Mars suddenly bloomed into a planetwide roar, said Richard Zurek of NASA's Jet Propulsion Laboratory in Pasadena, California. "We don't understand the details," he said. NASA's 2001 Mars Odyssey, the agency's latest probe to the red planet, enters Mars orbit October 23. Engineers plan to use the Martian atmosphere to slow the craft and settle it into orbit, a technique called aerobraking. Because of the storm and the warming of dust clouds around Mars, Zurek said it is expected that the upper atmosphere will rise slightly. This means the Mars Odyssey will encounter the atmosphere at a higher altitude than when there is no storm about the planet. Zurek said Odyssey has an atmospheric density sensor, and engineers will use data from that device to guide the spacecraft path and control the aerobraking. "We will toe-dip," he said, meaning the craft will gradually settle into the atmosphere until it reaches the targeted amount of drag needed to accomplish the aerobraking. NASA scientists said dust kicked up from the Martian surface now towers more than 40 miles. Winds at the surface are thought to be clipping along at more than 80 miles an hour, while high-altitude winds are even faster -- close to 260 miles an hour. Cloud patterns on Mars have been observed from Earth for more than a century, but a planetwide dust storm was first seen in 1956. Fifteen years later, the Mariner 9 spacecraft arrived in Martian orbit only to find the planet shrouded in dust. After that, dust storms were sighted every four to five years. "There seems to be an average of one storm every three Martian years," said Zurek. "Why there are storms in some years and not in others is not known." Mars is much farther from the sun than Earth and takes longer to orbit the sun. As a result, Mars' "year" is equal to about two Earth years. NASA's Mars Odyssey was launched April 7. It is scheduled to settle into a 250-mile circular orbit and use instruments to gather information about the planet's minerals, geologic history and radiation patterns. Agency officials are eager for Odyssey to succeed to recoup some of the momentum lost when two NASA probes, the Mars Climate Orbiter and Mars Polar Lander, failed in 1999. Copyright 2001 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.