Aerothermodynamic Optimization of Reentry Heat Shield Shapes for a Crew Exploration Vehicle

Gradient -based optimization of the aerodynamic perfor mance, static stability, and stagnation -point heat transfer has been performed to obtain optimal heat shield geometries for blunt -body planetary entry vehicles. Cross -sections considered include oblate and prolate ellipses, rounded -edge polygons, and round ed -edge concave polygons. Axial profiles consist of the spherical -segment, spherically -blunted cone, and power law. Aerodynamic models are based on modified Newtonian impact theory with semi -empirical shock -standoff distance and heat transfer correlations. Methods have been verified against wind tunnel and flight data of the Apollo Command Module and the Fire II experiment; they are within 12% for aerodynamic coefficients and stagnation -point heat fluxes. The selected design point corresponds to the setting in which the Apollo 4 Command Module generated its maximum heat flux, at an altitude of 61 km and a velocity of 10.3 km/s. Results indicate that oblate parallelogram configurations provide optimal sets of aerothermodynamic characteristics.

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