AbstractThis paper presents a new multidisciplinary design optimization (MDO) methodology for preliminary design of an aeroassisted orbital transfer vehicle (AOTV) performing a two-way transfer between a low-Earth “parking” orbit and a high-energy orbit. This work has been performed in the frame of Onera's CENTOR [N. Bérend, C. Jolly, F. Jouhaud, D. Lazaro, Y. Mauriot, C. Monjaret, J.M. Moschetta, M. Parlier, J.L. Pastre, Y. Servouze, J.L. Vérant, Project CENTOR: Preparing the design of future orbital transfer vehicles; IAC-07-D.2.3.07, in: 58th International Astronautical Congress, 24–28/09/2007, Hyderabad, India] project whose objective is to prepare tools and methodology for studying and designing future space transportation systems for new kinds of missions such as on-orbit servicing (OOS), payload ferrying, or in-situ observation of space-debris. Using simplified models and an appropriate low-dimension formulation for the optimization problem the method makes possible to obtain rapidly and easily a global view of the trade-off between the payload mass and the total mass. It also makes possible to discuss the feasibility of the vehicle with regard to different multidisciplinary constraints and technology hypotheses for the heat shield. This approach is illustrated by eight different AOTV design studies, considering two different missions (LEO–MEO and LEO–GEO), two different propulsion technologies (LOX-LH2 and LOX-CH4) and two different thermal protection system (TPS) characteristics. In each case, we discuss the feasibility and characteristics of the lightest vehicle carrying a prescribed 100kg payload, and, conversely, a heavy vehicle with a prescribed 18 ton total mass, carrying the heaviest possible payload.