A team led by Western University is preparing for an international mission of the ExoMars rover in 2028 that aims, in part, to better discover how clays formed on Mars and to what extent water may or may not have been involved.
Planetary geologists Livio Tornabene and Gordon Osinski, supported by a three-year flight program from the Canadian Space Agency (CSA) and Fieldwork Grant for the Advancement of Science and Technology (FAST)They are part of a large international team for ExoMars of the European Space Agency Rover Rosalind Franklin mission.
The rover was delayed in its launch opportunities in 2018, 2020 and 2022: the first two times due to technical problems (and in 2020, the pandemic) and then in 2022 due to the outbreak of Russia's unauthorized war in Ukraine. Most international partnerships with Russia were severed two years ago and ESA has since pivoted the design of ExoMars to eliminate Russian involvement.
Tornabene and Osinski are co-investigators on the PanCam camera, which obtains visual and color information in the environment, and the new Enfys spectrometer that examines the surface for minerals. (Enfys – “rainbow” in Welsh – is led by Matt Gunn of Aberystwyth University in Wales and Peter Grindrod of the Natural History Museum in London, and is funded by the UK Space Agency.)
Three years of field tests are planned with these instruments along with laboratory analysis to examine the samples that are collected. The first site, likely an impact crater known as Nördlinger Ries in Germany, will be surveyed in late 2024 or sometime in early 2025. The other planned locations are still being evaluated.
These tests will provide “ground truth” that is not available to scientists on Mars, since ExoMars is not involved in sample return and will work from afar. The team will evaluate the instruments' work at three different clay field sites on Earth: one formed by a meteorite impact, another formed in a volcanic area, and another by surface sedimentary erosion.
“The main scientific goal is to try to better understand clays in different environments here on Earth, so that maybe we can better understand the origins of clays on Mars, because it is not as simple as some scientists believe,” Tornabene told SpaceQ in an interview. . This will be important for ExoMars Rosalind Franklin: the mission's work will include evaluating clays in Mars' equatorial Oxia Planum, an area that is about four billion years old, almost as old as the 4.5 thousand-year-old solar system. millions of years.
“Clays form very easily and abundantly on Earth because there is water that interacts with rocks, and one of the byproducts of that interaction of water with rocks is that it alters the minerals in clays,” Tornabene said. “That may not be the way it's done on Mars. “That is still a very open question.”
While Earth is used as a reference point for understanding much of planetary science, each world has its own set of environments, formation conditions, and more. Tornabene notes that asteroids, which certainly don't have running water like Earth, have also hosted clay, such as Ryugu, which was visited by the Japanese Hayabusa2 mission. Rather, the clay formed because hydrogen and oxygen molecules, ingredients of water, are abundant in the solar system and were incorporated into some asteroids during their formation.
“So all you really need to do is add heat to the system,” he continued. “One of the ways to do this, especially in the early history of the solar system, is through impacts. You provide heat through impacts…you may have heard of this term “hydrothermalism” or “hydrothermal system.” So that they can begin to circulate the fluids, through heat.”
The most important implication could be how much water existed on early Mars. There is ample evidence of canals, ancient lakes, water-forming rocks, and perhaps even groundwater on the planet through observations from various spacecraft and rover missions. But how long the water flowed and how much water flowed have implications for the formation of clay and (for many scientists) the preference of that now-desert planet for ancient life.
What adds complexity is if a lot of water stopped flowing, how it happened; For example, it may have been through a thinning atmosphere that, not being protected by a magnetic field, was stripped away when charged particles from the sun hit atmospheric molecules. Several missions have been investigating the history of water on Mars for the last generation, and a sample return effort by NASA and ESA (which face funding and design challenges) may return fragments of Mars for analysis in the 2030s to learn more as well.
But if Mars were not a wet world, asteroids would provide a path for clay formation: “There is no way these bodies would have ever hosted oceans, rivers and lakes. “This emphasizes that clays can form under different conditions that do not require a warm, humid period on Mars,” Tornabene said.
CSA's FAST grant is not only beneficial for the return of science, he added, but also for the training of students, which will allow approximately six people to participate. “Not only are we training as members of the current team, but we will also train the next generation and give them the type of experiences that will hopefully lead to their own mission experiences.”
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