Since NASA’s Curiosity rover reached the surface of the planet Mars in August 2012, it has been sending a large amount of data that has shown us, among other things, the presence of nitrogen fixed in sediments (an essential element for the existence life as we know it) . Now, a team of scientists led by the Spanish Javier Martín-Torres from the Andalusian Institute of Earth Sciences, has just demonstrated that liquid (salty) water can continue to exist on the red planet. The work has been published in the journal Nature Geoscience .
The study, based on data from the REMS environmental station, shows that the environmental conditions measured in the Gale crater are favorable for the formation of transient liquid water in the form of brines (salt water), especially in the first 5 centimeters of the ground and especially during winter nights on Mars.
This phenomenon is possible thanks to perchlorates , salts that are found throughout the Martian surface and that absorb environmental water vapor to form brines or aqueous saline solutions (deliquescence). Curiosity has managed to record relative humidity near the surface and reveal that Gale Crater (which measures 154 kilometers in diameter) was a lake between 3.5 and 2.7 billion years ago and that it produces a daily cycle of water exchange. between the atmosphere and the ground, conditions that make the formation of this salty liquid water possible .
“ MSL – the mission that Curiosity is a part of – is not designed for the direct detection of liquid brines, nor is it designed to detect life, but rather to assess habitability conditions. The transition of soil salts from the hydrated or frozen states to small liquid droplets could only be directly measured by changes in electrical conductivity or colorimetric changes of those salty droplets within the soil. This type of contact science requires a subsurface probe and instruments that the MSL platform does not have, ”explains Martín-Torres.
Another piece of evidence that could justify the presence of these brines is that the rover’s wheels are suffering rapid deterioration , precisely because they have been in daily contact with corrosive perchlorate solutions in water since it landed on the red planet.
