Hardness And Yield Strength Of Co2 Ice Under Martian Temperature Conditions

Although ice fracturing and deformation is key to understanding some of the landforms encountered in the high-latitude regions on Mars and on other icy bodies in the solar system, little is known about the mechanical characteristics of CO2 ice. We have measured the hardness of solid CO2 ice directly in the laboratory with a Leeb hardness tester and calculated the corresponding yield strength. We have also measured the hardness of water ice by the same method, confirming previous work. Our results indicate that CO2 ice is slightly weaker, ranging between Leeb similar to 200 and 400 (similar to 10 and 30 MPa yield strength, assuming only plastic deformation and no strain hardening during the experiment), for typical Martian temperatures. Our results can be used for models of CO2 ice rupture (depending on the deformation timescales) explaining surface processes on Mars and solar system icy bodies.Plain Language Summary We have measured the hardness and calculated the strength of dry (carbon dioxide) ice. It is slightly weaker than water ice in the temperature range that can be found on Mars. Our results can be used in models of how surface features on Mars and on other icy surfaces in the solar system are formed.