iTWire - First probe beneath Mars surface finds water ice

First probe beneath Mars surface finds water ice

By William Atkins
Sunday, 18 March 2007 19:43

Using a ground-penetrating instrument for the first time, Mars Express scientists conclude nearly pure water ice, laced with dust particles, exist almost 4 kilometers under the frozen surface of Mars' South Pole.

The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument, aboard the European Space Agency’s (ESA’s) Mars Express spacecraft, produces a low frequency, pulse-limited wave through the use of a radar sounder and altimeter. Waves are able to penetrate beneath the Martian surface, which are then reflected back up to a receiving antenna. Over 300 slices were created by MARSIS of the icy Martian subsurface. Water ice, at a percentage of about 90%, was found to a depth of about 3.7 kilometers (2.3 miles).

This is the first time that this water ice has been accurately measured. In the past, scientists were only able to make an educated guess to its amount. MARSIS scientist Giovanni Picardi, of the University of Rome (Italy), declares, “MARSIS is showing to be a very powerful tool to probe underneath the Martian surface, and it's showing how our team’s goals—such as probing the polar layered deposits—are being successfully achieved. Not only MARSIS is providing us with the first ever views of Mars’ subsurface at those depths, but the details we are seeing are truly amazing. We are expecting even greater results when we will have concluded an on-going, sophisticated fine-tuning of our data processing methods. These should enable us to understand even better the surface and subsurface composition.”

Mars Express scientists conclude that if this water ice is (hypothetically) thawed out, the resulting liquid ice would cover the planet’s surface to a depth of about 11 meters (36 feet).

MARSIS is also taking images of the northern polar region of Mars, which contains similarly looking layered deposits under the surface.

It is important to learn more about the history of water on Mars because it may lead scientists to a conclusion as to whether life ever existed on Mars. Such findings help us on the Earth learn more about our past, present, and future.

The results found by these Mars Express scientists appear in the article “Subsurface Radar Sounding of the South Polar Layered Deposits of Mars”, which appears in the March 15, 2007 issue of Science magazine.

For more information on the ESA Mars Express mission, go to: http://www.esa.int/SPECIALS/Mars_Express/index.html.