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.
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.
Some of the new information even hints at the possible existence of a thin layer of liquid water at the base of the deposits.
But while images taken by NASA's Mars Global Surveyor spacecraft made public in December suggested the presence of a small amount of liquid water on the surface, researchers are baffled about the fate of most of the water. The polar deposits contain most of the known water on Mars.
Plaut said it appears perhaps 10 percent of the water that once existed on Mars is now trapped in these polar deposits. Other water may exist below the planet's surface or perhaps some was lost into space through the atmosphere, Plaut said.
