Strength of comet material and Hertzian contact-mechanics applied to the landing of Philae on comet Churyumov-Gerasimenko

Abstract

We estimate the strength of cometary material using fracture mechanics and regarding the comet material as a green "ceramic" body. The breakage strength Y is estimated using the fracture strength of ceramic slurries, so-called green bodies, and is compared to other approaches to estimate Y, and he results are applied to the break-up of comet nuclei. In a second part, we apply Hertzian contact mechanics to model the impact stress or impact force per area p0 during the landing operation of Philae. If the yield strength Y of the comet material is much less then p0, breakage will occur below the comet surface.