Measurements of target compressive and tensile strength for application to impact cratering on ice‐silicate mixtures

Small icy bodies in the outer solar system have been shown to consist of ice‐silicate mixtures. The results of previous impact cratering experiments on ice‐silicate mixture targets showed that a crater volume decreases with increasing silicate content. Surface strength controls craterings in laboratory experiments and on small bodies with a certain degree of strength. In this study we measured the uniaxial compressive and tensile strength of the targets used in previous impact cratering experiments by uniaxial compression and Brazilian tests, respectively, at 263 K and calculated the shear strength from the measured values. We found the uniaxial compressive and tensile strength increased with silicate content, which explains why the crater volume decreases with increasing silicate content. Since the gradient of increase of the uniaxial compressive and the tensile strength was different, the difference between the tensile strength and the uniaxial compressive strength becomes smaller with the increase of silicate content up to 50 wt %. We show that the crater spall diameter is better scaled by the tensile strength to compensate the difference of the silicate content than by the uniaxial compressive strength.