Assessment of Mars 2020 Forebody Heating Predictions with Coupled Material Response

The objective of this work was to assess the impact of flowfield–material response coupling on reproducing near-surface temperatures within the Mars 2020 forebody thermal protection system. Both equilibrium and nonequilibrium coupled material response approaches were considered. Turbulent transition estimates were included in the flowfield modeling based on transition times inferred from flight measurements. A coupled equilibrium ablation model was found to overpredict the in-depth temperatures near the surface by over 100 K in the stagnation region and by about 200 K near the leeside shoulder, which was subject to turbulent heating augmentation. For nonequilibrium surface chemistry, two finite rate models were used to model the chemical process on the vehicle surface. The first was a model consisting of N 2 catalysis and CO 2 recombination, and the second was a model consisting of only N 2 and O 2 catalysis. Near the stagnation point, the N 2 and CO 2 model was found to be within about 3% of the peak temperature near the surface; however, overprediction of the in-depth temperatures was observed early in the trajectory, similar to the equilibrium surface chemistry model. The N 2 and O 2 catalysis model was found to significantly underpredict near-surface in-depth temperatures.