COMPARISON OF 2 MULTIDISCIPLINARY OPTIMIZATION STRATEGIES FOR LAUNCH-VEHICLE DESIGN

The investigation focuses on development of a rapid multidisciplinary analysis and optimization capability for launch-vehicle design. Two mu ltidisciplinary optimization strategies in which the analyses are inte grated in different manners are implemented and evaluated for solution of a single-stage-to-orbit launch-vehicle design problem. Weights and sizing, propulsion, and trajectory issues are directly addressed in e ach optimization process. Additionally, the need to maintain a consist ent vehicle model across the disciplines is discussed. Both solution s trategics were shown to obtain similar solutions from two different st arting points. These solutions suggests that a dual-fuel, single-stage -to-orbit vehicle with a dry weight of approximately 1.927 x 10(5) lb, gross liftoff weight of 2.165 x 10(6) lb, and length of 181 ft is att ainable. A comparison of the two approaches demonstrates that treatmen t of disciplinary coupling has a direct effect on optimization converg ence and the required computational effort. In comparison with the fir st solution strategy, which is of the general form typically used with in the launch vehicle design community at present, the second optimiza tion approach is shown to be 3-4 times more computationally efficient.