Because it looked like Earth in its early days, Mars is the only place in the universe where humans are likely to find traces of ancient alien life. And never before has the exploration of the Red Planet been so promising. Three missions (United Arab Emirates, China, United States) will take advantage this summer of a favorable celestial positioning to send a new flight of robots, in orbit or on the ground of our close neighbor, the most coveted of the solar system.
“Mars is the priority of space exploration because we know that billions of years ago, it was habitable”, explained during a press conference Jean-Yves Le Gall, the president of CNES, the French space agency that designed one of the main instruments of the NASA “Mars 2020” mission.
While the Moon is “desperately empty of life”, Mars seemed “promising in terms of habitability from the 17th century”, the first observations showing the possibility of the presence of frozen water at the South Pole, traces the astrophysicist Francis Rocard in his book “Latest news from Mars”.
In 1976, two American landers from the Viking program provided, for the first time, in situ data on the atmosphere, the ground … showing that there was no life present on the surface of this large frozen desert. “It was a blow to the bamboo”, which slowed down Martian exploration for 20 years, said this specialist in the solar system, interviewed by AFP. “We had to change the strategy, with a new doctrine, which has become + follow water, follow carbon, follow light +” – the presuppositions for the formation of the living, he continues.
In the early 2000s, the proof that liquid water had flowed in quantity rekindled passions, and since then, each mission brings “more and more evidence that Mars is not as dead as it is believes “, explains Michel Viso, exobiologist.
“History of water”
The work of NASA’s Perseverance rover, scheduled to land in February 2021, is eagerly awaited. Complementing the Curiosity robot, working in a Martian crater since 2012, Perseverance will take up residence in an as yet unexplored environment: the Jezero crater, from which it must take samples to bring them back to Earth in the long term – it will be a first. This 45 km diameter basin is an ideal candidate for having been able to preserve traces of a past life on its surface. It is rich in sedimentary rocks (clays and carbonates, life traps), and, above all, its delta relief is attributed to the mouth of an ancient river. By studying the geology of Jezero, the rover will be able to characterize the geochemical environment which saw the birth of the lake, making it possible to understand “the history of water”, hopes Francis Rocard. “Because yes, water has flowed on Mars, but the question that tarnishes us is: for how long? The longer will be the best for the living to be able to form,” said the astrophysicist.