Intercalibration Results. Charring Ablator Thermal Response Model (CAT) – A High-Fidelity Material Response Model

Low-density carbon/phenolic is a class of ablative materials that is attractive for blunt body space vehicles where weight and performance of the material are of primary importance, but shape preservation is not critical. Phenolic Impregnated Carbon Ablator (PICA) is of this family. PICA has gained heritage with the success of the Stardust mission. Its performance has been extensively tested in support of the Constellation program and the Mars Science Laboratory (MSL) aeroshell design. PICA-X, also of the same class, has been successfully used on Dragon, the commercial Space-X capsule. Most important for the engineering community, the MSL aeroshell has been instrumented, and extensive flight data for this material is expected in 2011 from the MEDLI project. Current material response models are inspired from the model of Kendall et al. published in 1968. This model has been able to reproduce within a reasonable accuracy, Arc Jet performance tests carried out on PICA in conditions relevant to NASA’s missions. Therefore, depending on the design layout and quantity of interest, current models are robust. In off design conditions, however, there is a strong need to improve current models. In the poster, a high-fidelity model, tailored for PICA family material architecture, is detailed and discussed. The model tracks the chemical composition of the gases produced during pyrolysis. As in the conventional model, it uses equilibrium chemistry to determine the recession rate. It also tracks the time evolution of the porosity of the material. Progress towards implementing this high-fidelity model in a code baptized, CAT, is outlined. Results for the workshop test case are presented as part of the verification process of the code development