¹S.A.Connell et al. (>10)
Journal of Geophysical Research (Planets)(in Press) Open Access Link to Article [https://doi.org/10.1029/2025JE009243]
¹Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
Published by arrangement with John Wiley & Sons

Investigating the stability of hydrated minerals is integral for examining the preservation ofrocks for potential Mars Sample Return and has major implications for models that use rover‐basedobservations to quantify Mars’ global water budget. The Mars 2020 Perseverance rover produces abrasionpatches to investigate fresh rock surfaces at Jezero crater, Mars. However, due to operational constraints, thefull analysis process typically takes several martian days (sols), and freshly exposed hydrated minerals maydehydrate upon atmospheric exposure between abrasion patch creation and their analyses. To assess thepotential for short‐term dehydration, the SuperCam instrument conducted the first in situ rover‐based dehydration experiment on rock exposures of the “Bright Angel formation.” The SuperCam andSHERLOC rover instruments indicated that the primary mineral hydration phases were Fe‐hydroxides, Ca‐sulfates such as bassanite (mixed with anhydrite), with possible minor contributions from non‐interlayer‐waterphyllosilicates (e.g., hydroxyl‐bearing only). The experiment involved a four‐sol sequence of observations onthe Steamboat Mountain abrasion patch, beginning just 22 min after abrasion. Dehydration was assessed bytracking changes in the 1.93 μm H2O absorption feature, which is sensitive to structural, absorbed, andadsorbed water. No significant changes in hydration were observed over the 93 hr, suggesting that the exposedminerals were already in a low hydration state and/or exhibit high stability under current martian surfaceconditions. These findings imply bulk rocks with low hydration and high stability minerals may not dehydrateupon exposure to the modern martian atmosphere on short time scales, consistent with predictions fromlaboratory simulations of Mars‐like environments.