Unraveling the true nature of Martian "LH-kieserite"

The exploration of our Solar system currently ranks among humanitys most exciting endeavors. The various strategies aiming to accomplish this feat include the reconnaissance of other planets and their moons, not only to investigate their surface topography, but also to assess the distribution and nature of local rocks and minerals, which in turn tells us more about the history of their formation and the processes having taken place on the particular celestial body. In this respect, the proven presence of various hydrated sulfate minerals is highly important. Not only do they contain significant amounts of chemically bound water, they also form part of its distribution cycle and even allow it to remain liquid below its usual freezing point, thus potentially enabling it to host primitive extraterrestrial life forms. For example, on the icy moons of Jupiter and Saturn the presence of sulfates often assists in maintaining a liquid ocean beneath their icy surface. On Mars, these minerals serve as storage of vast quantities of water and constitute part of the planetary water cycle. It is therefore of utmost relevance to unravel the true nature of the sulfates present on a given celestial body and to assess, in the laboratory, their chemical behavior. In course of a recently finished research project we now uncovered important hints about the potential presence of a hitherto overlooked group of magnesium sulfate minerals, summarily abbreviated MHSH, including the mysterious LH-kieserite, in our solar system. Their properties vary based on their water content as well as on chemical elements partially replacing magnesium, in turn leading to changes in their spectra and overall chemical behavior. If we could prepare MHSH and analyze these changes in detail here on Earth, such lab results would greatly assist the evaluation of measurements on other planets, currently attainable only in two ways by scanning of reflected spectra with orbiters or via direct measurements at the surface by current and upcoming rover missions, as is the case for Mars. Hence, the declared mission of our research project can be summarized as follows: 1) to refine the preliminary synthesis process for MHSH and fine-tune it for variations of the chemical composition as expected for planets and moons; 2) to investigate and document in detail the spectroscopic and crystallographic properties as a function of chemical composition, using infrared and Raman spectroscopy as well as X-ray diffraction; and 3) to perform these experiments also at low-temperature and high-pressure conditions relevant to the surface and interior of celestial bodies of our solar system. The obtained results will serve as a benchmark for comparison with data sent from Mars or the icy moons, enabling us to infer even the chemical composition of the material on the planets surface from infrared or Raman spectra.