The REX – Free Flyer is a DLR R&D concept for a returnable and reusable orbital experiment facility. A sharp edged re-entry vehicle design based on flat panels offers certain economic advantages and substantial aerodynamic benefits in the hypersonic speed regime. The aerodynamic design of the REX – Free Flyer vehicle is based on the pre-design tool SOSE. This tool is developed by the DLR and uses the shock-expansion-method in order to calculate the pressure distribution on the vehicle shape. Thus all important coefficients and moments are known and an adequate configuration can be designed. For the design process there are different criteria which have to be fulfilled. The vehicle has to accommodate the payload (payload: 0.4x0.4x0.7 m³). The maximum volume of the launcher (e.g. Vega) may not be exceeded. The vehicle should be stable, trimmable, and of simple shape with a lift-to-drag ratio larger than 1.2. After the pre-design of the vehicle shape, the next task is to compute the aerothermodynamic loads acting on the vehicle by performing Navier-Stokes-Calculations.
Results of the pre-design study with SOSE: Lift/Drag-ratio and pitching moment coefficient