Probe unearths likely water supply on Mars

CAPE CANAVERAL, Fla., May 28 (UPI) -- A NASA probe has discovered vast quantities of what is likely frozen water beneath the dry, dusty soils of Mars, scientists announced Tuesday.

"What we have found is much more ice than we ever expected," said University of Arizona's William Boynton, the principal investigator for one of the science instruments on the Mars Odyssey spacecraft, which made the finding.

Since February, the satellite has been mapping Mars and using a suite of spectrometers to hunt for key elements, including hydrogen, in the planet's soils. In a series of papers to be published in this week's journal Science, the researchers unveil their startling and early results.

A large region around the planet's south pole shows huge quantities of hydrogen buried as far as the spectrometers can see -- about one meter below the surface. Although the hydrogen could exist in rocks and clays, the amount is so great -- 20 percent to 50 percent of the total mass -- scientists are convinced it is more likely that the hydrogen is bound with oxygen in the form of water. Because of the temperature at the poles, the water would be frozen and mixed with the soil to form dirty ice.

The teams of researchers also found the concentration of the suspect ice increases with depth, hinting of even greater reservoirs buried deeper underground.

"This may really be just the tip of the iceberg," said Boynton.

The finding is based on the detection and intensity of gamma rays emitted by hydrogen and by the intensity of neutrons, one of the three major sub-atomic particles, that are affected by hydrogen atoms.

The hydrogen-rich region extends from the planet's poles to within about 50 degrees of its equator, researchers said. Hydrogen in lesser concentrations also was detected in the equatorial regions.

Mars Odyssey is just three months into a planned two-and-a-half-year mission to map the planet and probe its subsurface elements.

"This result has come very early in the mission," said Cornell University and Mars researcher James Bell.

Although the finding may fuel efforts to land humans on Mars and make use of local water supplies, Bell is more intrigued by what it may mean for understanding the red planet's mysterious past. Scientists suspect Mars was once a warmer, wetter world, with a thicker, nurturing atmosphere that may have been in place long enough to sustain a surface environment suitable for simple biological life.

"We don't know how much water is there," said Bell. "It could be a very extensive inventory of what were once lakes, ponds and even oceans. "

With more detailed information arriving daily from Mars Odyssey and surface rovers scheduled to be dispatched to the planet throughout the decade, the secrets of Mars may soon unravel.

(UPI photos WAX2002052801, WAX2002052802, WAX2002052803 available)