Design of mass saving configurations for winged reentry vehicles

This paper reports the strategy adopted and the methodologies implemented to investigate the problem of the most performing shape for a Winged Re-entry Vehicle (RV-W). The RV-W mission considered is a gliding flight into the descent plane starting from an altitude of 120 km. During the descent both thermal and dynamic quantities are accounted for crew livability and structural integrity. The touchdown velocity, the TPS temperature at wall and the normal load factor and asymptotic dynamic pressure peaks are taken into account as parameters for structural integrity while the TPS inner surface temperature is considered for crew livability. The shape is modeled by a parametric model based on Coons surfaces and a five-parameters law rules the insulating material thickness distribution. The Thermal Protection System (TPS) material considered is Li-900. The three-degree of freedom model for the re-entry trajectory is integrated until the touchdown occurs and a subsonic drag parachute system is foreseen. The thermal state of the surface is calculated under the radiative equilibrium hypothesis and the heat flux at the surface is determined via hypersonic boundary layer relations. The temperature through the TPS thickness is integrated locally with the nonstationary one-dimensional model. Results for a minimum weight configuration optimization performed by a Genetic Algorithm (GA) method are presented.