Impact of Retro Rocket Plumes on Upper Stage Aerodynamics during Stage Separation

Kurzfassung

In this paper we report on an extensive investigation of the separation process of the first two stages of a carrier rocket corresponding to VEGA, which employs solid rocket motors. The effect of the plume of first stage retro rockets on upper stage aerodynamics and aerothermal loads is analysed mostly by means of windtunnel testing in the hypersonic windtunnel H2K of DLR Cologne. Aerodynamic coefficients are determined by force measurements. In addition pressure distributions on the upper stage surface and Schlieren images for flow visualization are recorded. Infrared thermography measurements are conducted to determine the effect on aerothermal loads. Different flow conditions are achieved by variation of Reynolds number, retro rocket injection pressure ratio and angle of attack.