Odyssey's Homer: Hints of Water near Both Poles of Mars (Science News This Week)

Article excerpt

Sensors on board the Mars Odyssey spacecraft have spied strong signs of ice buffed near both poles of the Red Planet, exactly the regions where scientists previously had said that frozen water deposits could exist.

If confirmed, the large permafrost-like reservoirs could contain a large part of Mars' suspected water resources. Finding substantial amounts of readily accessible water would be the space-faring equivalent of a grand slam home run because the water could be used by people during future Mars explorations. The water also raises scientists' hopes of finding life on Mars.

Even though the Odyssey probe has been taking data for just a few months and hasn't yet deployed its most sensitive instruments, data from three devices--one that measures gamma rays and two that detect neutrons--suggest there are copious amounts of hydrogen buffed 1 meter or so beneath the soil in the polar regions of Mars. Gamma rays and neutrons are emitted from hydrogen-rich soil when cosmic rays strike Mars' surface, says William V. Boynton of the University of Arizona in Tucson.

Hydrogen could exist on Mars in materials, such as hydrated minerals, other than ice, says Boynton. However, none of those substances can account for the large amount of hydrogen Odyssey has detected. From the concentrations of hydrogen measured, scientists estimate that in some spots up to 50 percent of the subsurface material by weight could be ice.

Within those areas for which Boynton's team measured average concentrations, some sites will be less hydrogen-rich and others will have more than their share, notes William C. Feldman of the Los Alamos (N.M.) National Laboratory. "There's got to be places where there's [pure] ice" he notes.

Boynton, Feldman, and their colleagues discussed their results at a meeting of the American Geophysical Union in Washington, D. …