"The last MARSIS observations have been done on the South Pole," adds Giovanni Picardi, MARSIS Principal Investigator, from the University of Rome 'La Sapienza'. "The quality of the preliminary results of the advanced analysis we are still performing are really exciting and promising, with respect to the main scientific objectives of our experiment." The objectives include the detection of subsurface water.

The OMEGA Visible and Infrared Mineralogical Mapping Spectrometer has taken giant steps towards answering that question. OMEGA detects minerals on the surface of Mars. Three in particular reveal the history of Martian water. "We have demonstrated that water could have been stable on Mars's surface but not for very long," says Jean-Pierre Bibring, Institut d'Astrophysique Spatiale, Orsay, France, and OMEGA's Principal Investigator.

OMEGA detected clay-like minerals that form during long-term exposure to water, but only in the oldest regions of Mars. That suggested water flowed during the first few hundred million years of the planet's history only. When these bodies of water were lost, water then occasionally burst from inside the planet but quickly evaporated.

During the evaporation they made sulphates, the second mineral that OMEGA detected. When even this stopped and the remaining water on Mars became permanently frozen, then the atmosphere gradually turned the soil red by creating the third mineral OMEGA detected, ferric oxide.

Mars has been like this for thousands of millions of years. "It is remarkable that, for the first time, we have identified where and when liquid water might have been present on Mars. It is not where one thought of before," says Bibring.

The images from the High Resolution Stereo Camera (HRSC) point towards the same conclusions. They show the Martian surface in the most exquisite detail, revealing features just 10 metres across. They cle
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Contact: Agustin Chicarro
agustin.chicarro@esa.int
31-715-653-613
European Space Agency
16-Oct-2006