Shock tube radiation modeling and sensitivity analysis: Radiation modeling of H2/He entry flows within an uncertainty quantification framework

Future missions such as the Uranus Orbiter and Probe will require robust modeling tools to predict the extreme thermal environments encountered during atmospheric entry at velocities approaching 25 km/s. Under these conditions, radiative heating can contribute significantly to the total heat flux, making accurate radiation modeling essential for thermal protection system design. This work focuses on developing a predictive framework for the radiative output of H2 /He entry flows and on identifying the chemical processes that most strongly influence radiative heating. Radiance predictions are computed by a one-way coupling of a flow model with detailed chemistry to NASA’s NEQAIR radiation software. A variance-based sensitivity analysis was performed to quantify the contribution of reaction rate uncertainties to variations in radiative output. Model results show the model’s ability to reproduce East experimental data, and a preliminary sensitivity analysis identifies H2 dissociation and electron-impact excitation as the groups of reactions with the most significant influence on radiative intensity, establishing the foundation for future calibration of reaction rates using shock tube experiments.