Aerothermal analysis of nominal and off-design first stage separation in a launch vehicle with retrorockets

This paper reports some preliminary results of an aerothermal analysis of the first stage separation in a space launch vehicle based on retrorockets. Stage separation is a critical phase of the ascent launcher, especially the separation of the first stage inside the atmosphere can involve significant risks of stage collision and of high aerothermal loads. A simulation of the dynamics of the first stage with active retrorockets w.r.t. the remaining part was analyzed and discussed. The first stage motion takes into account the effect of the thrust produced by retrorockets and of the aerodynamic forces which are evaluated through 3D viscous numerical simulations computed by the commercial solver CFD++. The present analysis considers both the nominal case, where all retrorockets work normally, and an off-design scenario where some retrorockets fail.