Prediction of Hyper-X Stage Separation Aerodynamics Using CFD

The NASA X-43 "Hyper-X" hypersonic research vehicle will be boosted to a Mach 7 flight test condition mounted on the nose of an Orbital Sciences Pegasus launch vehicle. The separation of the research vehicle from the Pegasus presents some unique aerodynamic problems, for which computational fluid dynamics has played a role in the analysis. This paper describes the use of several CFD methods for investigating the aerodynamics of the research and launch vehicles in close proximity. Specifically addressed are unsteady effects, aerodynamic database extrapolation, and differences between wind tunnel and flight environments. Introduction The Hyper-X research program was initiated in 1996 to demonstrate in-flight hypersonic scramjet propulsion. To get to the flight test conditions, the 12 ft long research vehicle (HXRV) is mounted on the nose of the first stage of an Orbital Sciences Corporation Pegasus booster. Given the non-axisymmetric shape of the HXRV, it is mounted onto an adapter tha..