The detection of liquid water by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) at the base of the south polar layered deposits in Ultimi Scopuli has reinvigorated the debate about the origin and stability of liquid water under present-day Martian conditions. To establish the extent of subglacial water in this region, we acquired new data, achieving extended radar coverage over the study area. Here, we present and discuss the results obtained by a new method of analysis of the complete MARSIS dataset, based on signal processing procedures usually applied to terrestrial polar ice sheets. Our results strengthen the claim of the detection of a liquid water body at Ultimi Scopuli and indicate the presence of other wet areas nearby. We suggest that the waters are hypersaline perchlorate brines, known to form at Martian polar regions and thought to survive for an extended period of time on a geological scale at below-eutectic temperatures.
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Data reported in this paper are available through the Zenodo research data repository (https://zenodo.org/record/3948005).
The code used to produce the figures and numerical results stated in the text is available from the corresponding author on reasonable request.
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This work was supported by the Italian Space Agency (ASI) through contract ASI-INAF 2019–21-HH.0 and, in part, by EU H2020 agreement 776276 Planmap. MARSIS is operating onboard the European Space Agency spacecraft Mars Express. We would like to thank S. E. Beaubien for careful proofreading of the manuscript and improvement of the English.
The authors declare no competing interests.
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Lauro, S.E., Pettinelli, E., Caprarelli, G. et al. Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data. Nat Astron 5, 63–70 (2021). https://doi.org/10.1038/s41550-020-1200-6
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