Observation of an Ablating Surface in Expansion Tunnel Flow

Hydrocarbon-based ablators, such as carbon phenolic, have a complex role, as the resultant carbon-based compounds are both strong absorbers and emitters of radiation, thereby greatly altering the radiative heat flux to the vehicle. Thermal and chemical conditions in a shock layer can be highly nonequilibrium. As a result of the high temperatures encountered, chemical species dissociate, ionize, and recombine, often forming new species. At sufficient enthalpies, species reradiate significant heat fluxes in all directions, including to the body itself.