Optimization of an Aero Assisted Launch Vehicle

Abstract

A comprehensive simulation model for a three-stage solid-propellant launch vehicle has been combined with a genetic algorithm to show that aerodynamic assist during early flight of a launch vehicle can substantially improve vehicle performance. Three studies were completed which include a comparison model for the Minuteman-III intercontinental ballistic missile, an improvement to the suborbital phase of flight for a modern ICBM, and the design of a generic three-stage orbital launch vehicle. Significant performance enhancement was achieved by attaching wings to the first stage for providing aerodynamic assist. Optimization was performed by varying the geometric definition of the attached wings and core vehicle design parameters. Significant decreases in initial system weights and propellant mass fractions were achieved for a given payload with the addition of wing structure. These final results are presented in the form of effective specific impulse boost for the aerodynamically assisted vehicle. Nomenclature݃ = gravitational acceleration at Earth's surface ‫ܫ‬ ௦ = specific impulse ‫ܯ‬ = stage initial mass ‫ܯ‬ = stage burnout mass ‫ܯ‬ = stage payload mass ‫ܯ‬ = stage propellant mass ‫ܴܯ‬ = mass ratio ‫ܯ‬ ௦ = stage structural mass Δܸ = change in velocity ߝ = structural coefficient ߣ = payload coefficient

A novel metamodel management strategy for robust trajectory design of an expendable launch vehicle

“…Examples of deterministic trajectory design optimization are presented in various studies. [22][23][24][25][26][27][28][29][30][31][32][33][34][35] The investigation of the effects of initial flight path angle error and constraints on the permissible angle of attack, on the optimal ascent trajectory of a typical two-stage LV, is presented by Joshi et al 36 Dileep et al 37 proposed the ascent trajectory optimization of a single-stage liquid propellant hypersonic LV through particle swarm optimization (PSO) algorithm to achieve desired terminal conditions using the angle of attack as a control variable. Sometimes, deterministic trajectory planning problem of a rocket-powered vehicle is formulated as an optimal control problem.…”

A Method for Optimizing Launch Vehicle Aero-Assist Including Path Optimization

“…Similar optimization based trade studies have been used to improve the design for launch vehicles without using aerodynamic assist 3 and it has been shown that the addition of some aerodynamic surfaces can, in some cases improve performance even without trajectory optimization included except for launch angle. 4,5 This effort expands significantly on that work by incorporating a new path optimization approach based on solving the inverse problem for following paths proposed by an optimizer with the help of dynamic spline fitting 6 and by improving the fidelity of the vehicle modeling capability.…”