Spallation on Carbon Ablators

A comprehensive analysis of publicly available research statements on spallation processes of ablative heat shield materials is presented. Based on the published data and numerical simulations thereof, a definition of spallation with respect to its fundamental parameters is given. Results from ablation and spallation experiments as well as analytical and numerical models are compared and discussed with respect to the conditions and mechanisms that lead to spallation. The driving mechanisms are oxidation, pyrolysis gas outflow, shear forces, and thermal stress. Based on the summary of the current state-of-knowledge of spallation, propositions are made for future experimental and numerical investigations.