Immense ice deposits found at south pole of Mars

By Will Dunham

WASHINGTON (Reuters) - A spacecraft orbiting Mars has scanned huge deposits of water ice at its south pole so plentiful they would blanket the planet in 36 feet of water if they were liquid, scientists said on Thursday.

The scientists used a joint NASA-Italian Space Agency radar instrument on the European Space Agency Mars Express spacecraft to gauge the thickness and volume of ice deposits at the Martian south pole covering an area larger than Texas.

The deposits, up to 2.3 miles thick, are under a polar cap of white frozen carbon dioxide and water, and appear to be composed of at least 90 percent frozen water, with dust mixed in, according to findings published in the journal Science.

Scientists have known that water exists in frozen form at the Martian poles, but this research produced the most accurate measurements of just how much there is.

They are eager to learn about the history of water on Mars because water is fundamental to the question of whether the planet has ever harbored microbial or some other life. Liquid water is a necessity for life as we know it.

Characteristics like channels on the Martian surface strongly suggest the planet once was very wet, a contrast to its present arid, dusty condition.

Jeffrey Plaut of NASA's Jet Propulsion Laboratory in Pasadena, California, who led the study, said the same techniques are being used to examine similar ice deposits at the Martian north pole.

Radar observations made in late 2005 and early 2006 provided the data on the south pole, and similar observations were taken of the north pole in the past several months, Plaut said.