Multidisciplinary design optimization of a re-entry vehicle shape and trajectory

Abstract

In this paper, the preliminary design of a re-entry vehicle is presented as the result of the simultaneous optimization of its shape and trajectory. This large-scale, non-linear programming problem has been decomposed into disciplinary subsystems describing flight dynamics, aerodynamics and weight sizing analyses. Whereas these are solved independently for computational and organizational reasons, the couplings between the subsytems require a continuous information exchange. This is provided by means of a multidisciplinary design optimization technique at the optimizer level. The basic shape considered is a lifting body consisting of two cones and a spherical nose cap. In the optimization, maximum crossrange and minimum total heat load are considered alternatively as the objectives. Constraints are imposed on the stagnation heating rate at the vehicle's nose, on the vehicle's weight and longitudinal stability. From a quantitative point of view, the results largely improved the objectives compared to the starting baseline/trajectory. Qualitatively, they offered interesting insights on the nature of this highly coupled problem.