Abstract: The new wind tunnel AT-303 was commissioned in the Institute of Theoretical and Applied Mechanics in 1999. Owing to the high level of stagnation pressure, AT-303 is able to duplicate realistic flight Reynolds number values of re-entry vehicles, within the Mach number range of 8 to 20. In the frame of an ISTC project conducted by ITAM in collaboration with ESTEC and EADS-ST, aerodynamic investigations of different aerospace vehicles have been performed in the AT-303 wind tunnel. The flow quality and performance of instrumentation of the AT-303 wind tunnel have been checked by testing the HB-2 (AGARD) reference model with force measurements and comparing the results obtained with available experimental and numerical data. Typical aerospace hypersonic vehicles (flight test bed EXPERT supported by ESTEC and potential re-entry demonstrator ARES-H proposed by EADS-ST) have been tested in the Mach and Reynolds number ranges corresponding to realistic flight conditions. Measurements of aerodynamic forces and moments were performed to determine the main aerodynamic characteristics of these vehicles. The paper presents the results of these investigations. An analysis of the experimental data has been conducted, including the comparisons with theoretical data. The lessons learned from these studies are drawn, and recommendations for future studies are proposed.