Sensitivity Analysis of stage Separation Parameters in Launch Vehicles Utilizing Sobol Method

Abstract

As a critical component of aerospace engineering, the stability and reliability of launch vehicles directly influence the success of space missions. During the launch process, stage separation is one of the essential steps that ensures the safe and smooth transition of the vehicle into space. This study aims to systematically assess the sensitivity of key parameters during stage separation using Sobol sensitivity analysis. A dynamic model for stage separation of launch vehicles is first established, accounting for uncertainties in physical parameters and forces acting on the vehicles. The sensitivity analysis focuses on various parameters including thrust, fuel sloshing, and center-of-mass offset. By calculating the Sobol indices for these parameters, their significance concerning displacements, attitudes and minimum clearance between stages during separation are quantified. The results indicate that residual thrust has a more substantial impact on axial displacement, roll angle, and minimum clearance than other factors. Additionally, offsets in the mass centers of both first and second stages significantly affect pitch angle, yaw angle, and radial displacement during this critical phase of the separation.