Estimating Jezero Crater Rock Density and Strength Using Perseverance Drill Data: Implications for Future Mars Missions and Analog Mars Studies

Abstract Although no rovers are currently capable of directly measuring rock density and strength, these properties are highly valuable to better understand the types of rocks that are being investigated by a rover, as well as the conditions on Mars during and after rock formation. Here, we use engineering data collected by the corer on the Perseverance rover to infer rock density and strength (unconfined compressive strength, or UCS) by comparing drill data for martian rocks to drill data for well‐characterized analog materials that were cored using the same equipment on Earth. We calculate the energy expended by the drill to core each rock and find discrete correlations between both energy and measured rock density, as well as energy and strength of the analog materials. These correlations are then used to calculate likely values for density and strength of the rocks cored on Mars. Potential homogeneity of the martian samples is also indicated by changes in the drill response during coring. Overall, we find a wide range of UCS and density for the martian rocks. Endmembers are consistent with rover team interpretation as igneous (high strength and density) and sedimentary (low strength and density) lithologies. The extraordinarily low strength and density of the sedimentary materials are further consistent with greater porosity resulting from generally sparse cementation on Mars. The majority of rocks interpreted as igneous by team members, however, were also substantially weaker and less dense than expected based on their composition and texture, suggesting that interpretations may need refinement.