Aeroshape design of reusable re-entry vehicles by multidisciplinary optimization and computational fluid dynamics

This paper deals with the development of a multidisciplinary design framework for reusable space vehicles, able to provide a round-trip crew transport capability to low Earth orbit, and especially for the support and supply services of the International Space Station. Design activities rely on a shape optimization procedure adopted as a-priori knowledge to find concept aeroshapes able to satisfy specific mission objectives and requirements. Optimization results are obtained with a floating point version of a Multi-Objective Genetic Algorithm. A detailed engineering-based aerodynamic analysis of a promising design candidate is provided throughout descent flight regimes considering the range of Mach numbers from 25 to 0.3. Aerodynamic computations in high speed range of re-entry corridor are performed with an hypersonic panel code which relies on Surface Impact Methods. Additionally, a subsonic panel code based on potential flow theory is adopted to evaluate low speed coefficients. Trade-off candidate eligible for a phase-A design is then validated creating a CFD test matrix in a set of forty specified way-points along with the re-entry trajectory. Finally, preliminary considerations about viability of the configuration are given with reference to longitudinal stability margin.