During the STS-119 flight of Space Shuttle Discovery, two sets of surface temperature measurements were made. Under the HYTHIRM project1 quantitative thermal images were taken with a telescopic infrared camera system mounted in a Navy P-3 Orion aircraft. In addition, the Boundary Layer Transition Flight Experiment2 made thermocouple measurements at discrete locations on the Orbiter wind side. Most of these measurements were made downstream of a surface protuberance designed to trip the boundary layer to turbulent flow. In this paper, we use the US3D computational fluid dynamics code to simulate the Orbiter flow field at conditions corresponding to the STS-119 re-entry. We employ a standard two-temperature, five-species finite-rate model for high-temperature air, and the surface catalysis model of Stewart. 3 This work is similar to the analysis of Wood et al.4 except that we use a different approach for modeling turbulent flow. We use the one-equation Spalart-Allmaras turbulence model5 with compressibility corrections6 and an approach for tripping the boundary layer at discrete locations. In general, the comparison between the simulations and flight data is remarkably good.