Hypersonic Low-Density Aerothermodynamics of Orion-Like Exploration Vehicle

In the framework of Research Task Group 043 of the NATOResearch and Technology Organization, an analysis of the capabilities in prediction of aerothermal loads acting on a crew exploration vehicle at the higher altitudes of its reentry trajectory has been performed. In particular, the focus of this investigation is to provide information where overlap between the continuum approach (i.e., computational fluid dynamics) and particle approach (i.e., direct simulation Monte Carlo) occurs and improves understanding of relevant physics in transitional regime. Computational fluid dynamics calculations with slip flow boundary conditions had shown good predicting capabilities of slip velocity, slip temperature, and pressure, but not the surface heat flux. The analysis of the contributions to the total surface heat flux had exhibited the lack of continuum model in evaluating the convective heat flux in the transitional zone of the Orion reentry trajectory and an underestimation of shock wave thickness.