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In 2020, the next NASA rover will be launched from Cape Canaveral Air Force Base in Florida and will sail to the Jezero crater on Mars. Jezero once housed an ancient system of lakes and deltas that scientists say would have captured and preserved information about the evolution of the red planet – and, if so, traces of ancient life .
The venue, announced last week by Associate Administrator of NASA's Science Mission Directorate, Thomas Zurbuchen, was chosen from 60 candidates for its rich geology dating from 3.6 to 3.9 billion years. The decision has been made for many years and, before the site was finally chosen, scientists from around the world gathered in Glendale, California, to bring their expertise to the last four landing sites candidates at the last of the four workshops on the landing sites of March 2020.
Tanja Bosak, badociate professor in the Department of Earth Sciences, Atmosphere and Planets of MIT, was one of those scientists. His work uses experimental geobiology to explore modern biogeochemical and sedimentological processes in microbial systems. For Bosak, the Jezero Crater is the ideal landing site to learn about the potential livability of early March.
"The geology of the crater of Jezero is very obvious [from orbit] and it is clear that the environment was habitable in the past," says Bosak. "It is older than any sedimentary environment preserved in the Earth's rock archives.The Jezero crater preserves some of the most ideal types of rocks we use to search for life on Earth."
In these rocks are clays and carbonates, minerals. known to facilitate the preservation of fossils on Earth. Bosak's work as an investigator in the Simons Collaboration on the Origins of Life (SCOL) contributed to a lecture at the October workshop titled "In Search of Prebiotic Signatures with the March 2020 rover ", given by David Catling. Catling is a professor of Earth Sciences and Space at the University of Washington and also a researcher at SCOL.
In his presentation, Catling claimed that even though life had never emerged on Mars, scientists could focus on the question of whether prebiotic precursors
Roger Summons, Schlumberger Professor of Geobiology at EAPS and SCOL researcher also contributed to the presentation. As the lead investigator of NASA's Astrophysics Institute's Complex Life Foundations team and a member of the Mars sample badyzer team using NASA's Curiosity robot, the work of Summons is about preserving organic matter in different environments on Earth and on Mars.
"We know, through our efforts to trace the oldest life on Earth, that the best chance of finding convincing and credible evidence will come from studies of well-preserved, fine-grained stratified rocks deposited at background of
Earlier in the year, Bosak and Summons collaborated on "A Practical Guide to Finding Fossils on Mars," a review article published in the Journal of Geophysical Research which summarized strategies behind the search for old biosignatures among the different potentially habitable Martian environments.The authors of the review mentioned the favorability of sedimentary environments very similar to those of the Jezero crater, because the badogues of these environments on Earth, like deltas and lakes, have the greatest potential for collecting and preserving molecular fossils and body microbes
In fact, organic matter has recently been detected in mudstones dating back 3 billion years ago at the site of an ancient lake at Gale Crater, the Mars Curiosity robot's research site. Rover. The results, published in Science sparked increased interest in the potential preservation of organic matter at other landing sites on Mars, including the Jezero crater. Indeed, unlike previous Mars missions, the Mars 2020 mission will not only perform measurements in the Martian environment, it will also collect and cache sediment nuclei from sites of interest that will then be returned. on Earth during a subsequent mission. Although much can be learned from imaging and spectroscopy tools that can be used remotely on spacecraft, nothing is comparable to the sensitivity and specificity of the chemical instrumentation that we can access in laboratories worldwide, "says Summons." This has been demonstrated time and time again by what has been learned in almost fifty years of studies on rocks that have been made on Earth during the d & rsquo; Exploration of the moon by Apollo. "
Bosak is particularly excited about the images and data that the rover will gather during his mission to Jezero Crater.The mission could shed light on the presence of carbonates on the edge of the crater "precipitated out of the lake, as do the limestones." On the Earth, "the limestones of the beginning of the Earth can have forms that record microbial interactions with sediments and mineral precipitation stimulated by microbes, "says Bosak.
Ben Weiss, professor of planetary sciences at EAPS, also attended the March 2020 landing site Workshop and presented with Anna Mittelholz, co-author, postgraduate student at the University of British Columbia, on potential studies of the Mars magnetic field.
"Jezero will also be an extremely interesting place to get samples to understand the history of the old Martian magnetic field," says Weiss. In the summer, Mittelholz and Weiss published an article in the journal Earth and Space Science titled "Mars 2020 Candidate Landing Sites: Magnetic Field Perspective", which details the results presented at the workshop.
On the occasion of the Martian planetary evolution, Mars lost its global magnetic field and much of its primitive atmosphere, which could have radically changed the Martian environment. Planetary magnetic fields are generated by the movement of metal fluids in planetary interiors during a process called dynamo. For example, the Earth's magnetic field is generated and maintained from its iron-rich molten core.
"The most important problem is to determine when the dynamo [Martian] is off.This would help determine if the transition of a heater, the loss of the dynamo field caused a start of more rain wet in early March on the current cold and dry condition, "said Weiss. "Jezero is a great place to test this hypothesis, as it contains rocks and minerals that are suspected to be dead."
In summary, the exploration of a rover and the collection of samples at the crater of Jezero could help refine the scientific knowledge. disciplines.
"The Jezero crater will provide a privileged place to understand the contribution of the dynamo to the protection of the first atmosphere and habitability of early March," Weiss said.
This information could also contribute to our understanding of why and how life has taken hold of our own planet.
"I think it's as good as possible," Bosak says.
Explore Further:
NASA chooses the old delta of the Martian River for the touch of the rover to 2020
More information:
Anna Mittelholz et al. Candidate Landing Sites of March 2020: Magnetic Field Perspective, Earth and Space Science (2018). DOI: 10.1029 / 2018EA000420
S. McMahon et al. Field guide to search for fossils on Mars, Journal of Geophysical Research: Planets (2018). DOI: 10.1029 / 2017JE005478
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