Posted: Sat, Mar 20, 2004, 9:47 AM ET (1447 GMT)
ESA's Mars Express spacecraft has detected large quantities of water ice in the south polar regions of Mars, concluding that there may be far more ice there than previously thought. The spacecraft, in orbit around Mars for nearly three months, used an imaging spectrometer to map the deposits of water and carbon dioxide ice around the south pole, allowing scientists to divide the polar region into three parts. One is the bright ice cap itself, which is 85% carbon dioxide and 15% water. The second area are steep scarps at the edge of the ice cap, made almost entirely of water ice. The third area is a region of permafrost that extends for tens of kilometers away from the scarps: the area contains water ice mixed into the soil. The presence of permafrost was inferred from data provided by NASA's Mars Odyssey spacecraft two years ago, which carried a neutron spectrometer that detected hydrogen concentrations in those regions thought to be consistent with water ice deposits. Scientists plan to use another instrument on Mars Express, a radar, later this year to look for subsurface water deposits.
