Simultaneous Sizing of a Rocket Family with Embedded Trajectory Optimization

TL;DR

This paper introduces an integrated sizing and trajectory optimization method for designing a rocket family capable of multiple missions, aiming to maximize commonality and reduce costs through a unified optimal control framework.

Contribution

It develops a novel combined sizing and trajectory optimization approach for rocket families, enabling feasibility analysis and cost minimization within a shared design space.

Findings

Successfully applied to a rocket family with expendable and reusable launchers

Demonstrated cost savings through shared components and optimized designs

Provided a tractable method for simultaneous sizing and trajectory optimization

Abstract

This paper presents a sizing procedure for a rocket family capable of fulfilling multiple missions, considering the commonalities between the vehicles. The procedure aims to take full advantage of sharing a common part across multiple rockets whose payload capability differs entirely, ultimately leading to cost savings in designing a rocket family. As the foundation of the proposed rocket family design method, an integrated sizing method with trajectory optimization for a single rocket is first formulated as a single optimal control problem. This formulation can find the optimal sizing along with trajectory results in a tractable manner. Building upon this formulation, the proposed rocket family design method is developed to 1) determine the feasible design space of the rocket family design problem (i.e., commonality check), and 2) if a feasible design space is determined to exist, minimize the cost function within that feasible space by solving an optimization problem in which the optimal control problem is embedded as a subproblem. A case study is carried out on a rocket family composed of expendable and reusable launchers to demonstrate the novelty of the proposed procedure.