HiRISE camera details dynamic wind action on Mars

February 8, 2008, Tucson, AZ--Mars has an ethereal, tenuous atmosphere at less than 1% percent the surface pressure of Earth, so scientists working on The University of Arizona's (U of A's) High Resolution Imaging Experiment, or HiRISE, are challenged to explain the complex, wind-sculpted landforms they're now seeing in unprecedented detail. Ball Aerospace and Technologies of Boulder, CO, built the HiRISE camera operated by the U of A.

Feb 8th, 2008

February 8, 2008, Tucson, AZ--Mars has an ethereal, tenuous atmosphere at less than 1% percent the surface pressure of Earth, so scientists working on The University of Arizona's (U of A's) High Resolution Imaging Experiment, or HiRISE, are challenged to explain the complex, wind-sculpted landforms they're now seeing in unprecedented detail. Ball Aerospace and Technologies of Boulder, CO, built the HiRISE camera operated by the U of A.

The HiRISE camera on NASA's Mars Reconnaissance Orbiter, the most powerful camera to orbit another planet, can see 20-inch-diameter features while flying at about 7,500 mph between 155 and 196 miles above the Martian surface. One of the main questions has been if winds on present-day Mars are strong enough to form and change geological features, or if wind-constructed formations were made in the past, perhaps when wind speeds and atmospheric pressures were higher.

Scientists since the 1970s Viking missions have puzzled over what appears to be dust covering Mars' 6-to-13-mile-high volcanoes. Near the volcanic summits, the air is about one one-thousandth of Earth's atmospheric pressure. "HiRISE keeps showing interesting things about terrains that I expected to be uninteresting," said HiRISE principal investigator Alfred McEwen of the U of A's Lunar and Planetary Laboratory. "I was surprised by the diversity of morphology of the thick dust mantles. Instead of a uniform blanket of smooth dust, there are often intricate patterns due to the action of the wind and perhaps light cementation from atmospheric volatiles."

HiRISE images show that what covers the slopes of the high Martian volcanoes are definitely dunes or ripples that appear to have an organized reticulate structure possibly formed by winds blowing from multiple directions. But how this material can be blown around at this low pressure is still a mystery.

For more information, visit www.ballaerospace.com.

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