A comprehensive uncertainty analysis for high-fidelity flowfield simulations over a fixed aeroshell of Hypersonic Inflatable Aerodynamic Decelerator scale for Mars entry is presented for fully laminar and turbulent flows at peak stagnation-point heating conditions. This study implements a sparse-collocation approach for efficient and accurate uncertainty quantification in the high-fidelity numerical modeling of hypersonic reentry flow simulations, which may contain large numbers of aleatory and epistemic uncertainties.