The Mars Express probe has discovered that the extensive layers of several kilometers beneath the soil of the equator of Mars are deeper than previously believed and suggest the presence of ice, so much so that it would be the largest amount of water found in this part of the planet. planet.
The Mars Express mission has been exploring the red planet for twenty years. A little over fifteen years ago, while studying the Medusae Fossae Formation (MFF), he found immense deposits up to 2.5 km deep but he could not clarify what they were.
“We have re-explored the MFF using more recent data from the Mars Express MARSIS radar, and we have discovered that the deposits are even thicker than we thought: up to 3.7 km thick,” details Thomas Watters of the Smithsonian Institution ( USA), lead author of both the new research and the initial 2007 study.
And the signals detected by MARSIS are “very similar” to those of the polar caps of Mars, “which we know are very rich in ice,” he points out. In fact, these deposits are so large that, if they melted, the buried ice would cover the entire planet with a layer of water between 1.5 and 2.7 meters deep, enough to fill Earth’s Red Sea.
The existence of this large mass of ice will help understand how the planet’s climate evolved but, above all, it will be essential to supply future manned missions, the authors emphasize.
The MFF is characterized by several wind-sculpted features, hundreds of kilometers in diameter and several kilometers high, that lie on the border between the high and low lands of Mars and are possibly the largest source of dust on Mars. .
The first observations from Mars Express revealed that the MFF was relatively transparent to radar and low density – typical characteristics of ice deposits – but at that time it could not be ruled out that they were giant accumulations of dust, volcanic ash or entrained sediments. by the wind.
And, although Mars is today an arid world, it once had abundant water, with dried river channels, ancient ocean and lake beds, and valleys excavated by water. Important reserves of ice have also been found, such as the enormous polar caps, buried glaciers near the equator, and near-surface ice that extends across the Martian soil.
But “how long ago did these ice deposits form and what was Mars like at that time?” If confirmed to be water ice, these massive deposits would change our understanding of Mars’ climate history. Any ancient water deposits would be a fascinating target for human or robotic exploration,” says Colin Wilson, ESA project scientist for Mars Express and the ExoMars Trace Gas Orbiter (TGO).
The extent and location of these icy MFF deposits would also make them potentially very valuable for our future exploration of Mars.
Missions to Mars will have to land near the planet’s equator, far from ice-rich polar caps or high-latitude glaciers, but they will need water as a resource, so finding ice in this region is almost a necessity for human missions. to the planet.
“Unfortunately, these MFF reservoirs are covered in hundreds of meters of dust, making them inaccessible for at least the next few decades. But every piece of ice we find will help us get a better idea of ??where the MFF water has flowed. Mars before, and where it may be today,” says Wilson.
