A new study based on data provided in recent years by the Exomars mission advances the theory that water is hidden in canyons on Mars. The Europe-Russia space partnership seems to be beginning to bear fruit as we await the second part of the mission. Water on Mars at low latitudes could change the objectives of future missions. But how was it possible to achieve this result?
Exomars: exploring Mars through traces of water
The first part of the Exomars mission started in 2016 from the Bajkonur cosmodrome with the TGO (Trace Gas Orbiter) and the Schiapparelli lander on board. As is widely known, not everything went right: the lander was destroyed due to control system failure resulting from the IMU. The second act will most likely take place in 2022, when the protagonists will be the Kazachok lander and the Rosalind Franklin rover.
Until then, ESA and ROSMOCOS rely on the Trace Gas Orbiter TGO. As its name suggests, the primary purpose of the probe is to study trace gases: in particular, attention is focused on hydrogen, an element present in water. The object of the study was the most superficial layers, up to one metre, of the Martian surface. All this was made possible by a special instrument: the FREND – Fine Resolution Epithermal Neutron Detector – neutron telescope.
With the new data from Exomars, it has been possible to literally dig into the soil of the Red Planet: it has long been known that there is water on Mars, particularly relegated to the poles of the plate, where temperature and pressure conditions allow the presence of water in a solid state. Mars Express had already detected traces of water at low latitudes, but its instruments were unable to go ‘below the dust’.
Neutron hunting provides clues to the presence of water
The lead author of the study is Igor Mitrofanov of the Space Research Institute of the Russian Academy of Sciences in Moscow. The team used data in the time frame from May 2018 to February 2021, the subject of the study was neutron emission from Martian soil. When galactic cosmic rays hit wet soil they emit fewer neutrons than they do for dry soil. FREND achieved an unprecedented feat thanks to the sensitivity of the instrument.
“FREND has revealed an area with an unusually large amount of hydrogen in the colossal canyon system of the Valles Marineris: assuming that the hydrogen we see is bound in water molecules, as much as 40% of the near-surface material in this region appears to be water.”Igor Mitrofanov – Institute of Space Research, Russian Academy of Sciences, Moscow
The Valles Marines are very extensive geological formations up to 10 km deep near the planet’s equator, certainly not easy to explore. The area presumably containing the water is about the size of Holland, but it is not clear whether the water is chemically bound to the minerals or present in the form of ice. The mineral data allow a bias towards the second hypothesis, although the scientists admit that the mix of conditions for which the results of the study would be possible is not perfectly clear.
What might the discovery of water on Mars at low latitudes entail?
The future encounter between man and Mars is likely to take place at low latitudes, where conditions are probably more favourable for human survival. The new discovery implies important considerations for the design of future missions. Having water available on a planet like Mars could make it easier for the next The Martians. Not only that, it represents a place where traces of past life on the Red Planet are likely to be found.
“This result truly demonstrates the success of the joint ESA-Roscosmos ExoMars programme.”Colin Wilson, scientist on ESA’s ExoMars Trace Gas Orbiter project.
Valles Marines is 4000 km long, 200 km wide and is the deepest canyon system in the Solar System, five times deeper than Earth’s Grand Canyon. Studies are continuing in an attempt to fully unravel the mystery of water on Mars. From 2022, reinforcements from the Exomars mission will arrive: with all three contributions, there will certainly be a clearer and more complete picture.