Integrated Optimization of Ascent Trajectory and SRM Design of Multistage Launch Vehicles

Abstract

This paper presents a methodology for the concurrent first-stage preliminary design and ascent trajectory optimization, with application to a Vega-derived Light Launch Vehicle. The reuse as first stage of an existing upper-stage (Zefiro 40) requires a propellant grain geometry redesign, in order to account for the mutated operating conditions. An optimization code based on the parallel running of several Differential Evolution algorithms is used to find the optimal internal pressure law during Z40 operation, together with the optimal thrust direction and other relevant flight parameters of the entire ascent trajectory. Payload injected into a target orbit is maximized, while respecting multiple design constraints, either involving the alone solid rocket motor or dependent on the actual flight trajectory. Numerical results for SSO injection are presented.

Optimization of the Conceptual Design of a Multistage Rocket Launcher

“…An additional restriction, aimed to address the heating damage on the structure, is also included, with a limit of 40 MW/m 2 [35]. The use of these variables to take into account the structural characteristics is a common recurrence in the assessment of trajectories [5,10,35,36,38]. For the optimization, a total of 124 total optimization variables (half relative to the angle of attack α and the rest relative to the heading angle β) are considered.…”