Uncertainty quantification applied to the analysis and design of a hypersonic inflatable aerodynamic decelerator for spacecraft reentry

The primary objective of this research is to investigate the uncertainty in the multidisciplinary analysis of a Hypersonic Inflatable Aerodynamic Decelerator configuration for Mars entry, subject to uncertainty sources in the high-fidelity computational models and the operating conditions. Efficient uncertainty quantification methods based on stochastic expansions are applied to the analysis of the hypersonic flowfield, fluid-structure interaction, and flexible thermal protection system response of a deformable inflatable decelerator. Uncertainty analysis is first applied to the hypersonic flowfield simulations to quantify the uncertainty in the surface convective and radiative heat flux, pressure, and shear stress of a fixed inflatable decelerator, subject to uncertainties in the binary collision integrals of the transport properties, chemical kinetics, non-Boltzmann radiation modeling, and the freestream conditions. The uncertainty analysis for fluid-structure interaction modeling is conducted to quantify the uncertainty in the deflection and resulting surface heat flux, shear stress, and pressure of a deformable inflatable decelerator, subject to uncertainties in material structural properties, inflation pressure, and important flowfield uncertain variables identified in the initial study. The deflection uncertainty is shown to be primarily driven by the structural modeling uncertain variables and found to be insignificant in contributing to the resulting surface condition uncertainties. Uncertainty analysis is finally applied to the flexible thermal protection system bondline temperature for a ballistic Mars entry trajectory, subject to uncertainties in the material thermal properties and important flowfield variables from the initial study. The uncertainty in the bondline temperature is compared to its allowable temperature limit and shown to be primarily driven by the material thermal properties of the outer fabric and insulator layers, and the freestream density --Abstract, page iv