BEIJING, March 16 (Xinhuanet) -- Entrepenuers have been speculating about vacation resorts on or under the surface of the moon for years featuring swimming pools, hotels, tennis courts, even golf courses. So, what about beachfront bungalows on Mars?

    A new radar technique aboard the Mars Express orbiter has proven Mars has enough water ice at its south pole to cover the entire planet in more than 30 feet of water if it ever melted, according to a NASA spokesman.

    NASA astronomers have penetrated for the first time about 2.5 miles (nearly four kilometers) beneath the south pole's frozen surface. The data showed nearly pure water ice lies beneath.

    Layered deposits of ice and dust that cap the North and South Poles of Mars were first found in the early 1970s. Until now, the deposits have been difficult to study closely with existing telescopes and satellites.

    "This is the first time that a ground-penetrating system has ever been used on Mars," said the new radar study's lead author, Jeffrey Plaut of NASA's Jet Propulsion Laboratory. "All the other instruments used to study the surface of Mars in the past really have only been sensitive to what occurs at the very surface."

    Plaut and his colleagues probed the deposits with radar echo sounding, typically used on Earth to study the interiors of glaciers. The instrument, called the Mars Advanced Radar for Subsurface and Ionospheric Sounding, or MARSIS, beams radio waves that penetrate the planet's surface and bounce off features having different electrical properties.

    The reflected beams revealed 90 percent or more of the frozen polar material is pure water ice, sprinkled with dust particles. The scientists calculated the water would form a 36-foot-deep ocean if spread over the Martian globe.

    "It's the best evidence that's been obtained to date for that thickness," said Ken Herkenhoff, a planetary geologist at the U.S. Geological Survey in Flagstaff, Ariz., who studies the Martian polar regions. He was not involved in the current study.

    Scientists have long known that Mars¡¯north polar cap is a massive storehouse of water ice, and the current research team says they will use their radar technique to refine past estimates of its thickness and make-up.

    "These polar ice deposits are by far the largest reservoir of water or water ice that we know of on Mars," Plaut said. "There¡¯s evidence that about 10 times or maybe even 100 times that much water has flowed across the surface of Mars to carve the various channels, the outflow valleys and other features we see in the images and topography data."

    Scientists think variations in Mars¡¯orbit and tilt drive the planet's climate over time, though a few astronomers have speculated about how the sun's activity could be warming the Red Planet and several others.

    In addition to warming from the atmosphere, ice-thawing heat could come from the core of Mars, similar to the plumes of heat that cause volcanic eruptions on Earth. But evidence from the new radar study suggests the Martian crust is icy cold and rigid.

    (Agencies)