Statistical variance in radiative properties of porous materials

In the quest for planetary exploration, space vehicles play a significant role in the transportation of payloads. A crucial component of the space vehicle is the thermal protection system, which protects the vehicle from overheating while entering a planetary atmosphere. The entry is a high-speed process which can result in significant radiative heat loads on space capsules. To understand the material response of heat shields, an integrated simulation framework is required which couples computational fluid dynamics with material response solvers. The mechanism behind transport of radiative signatures is fundamentally different from the conductive mode of energy transport, and penetration of radiative signatures depends on the radiative coefficients of the thermal protection system (TPS) material that protects the space capsule. Radiative coefficients depend on material architecture and vary based on micro scale features and manufacturing defects that result in inconsistency across billets of the heat shield. Combining with other microscale properties like permeability, stress, and thermal conductivity, variability in radiative properties will lead to variations in the response of heat shields. In this study, a statistical approach is used to generate radiative coefficients of Fiber Form microstructures, and these coefficients are correlated to micro scale features such as porosity.