Flight control methodologies for Neptune aerocapture trajectories

Abstract

In this work, a comparison of potential flight control methodologies for Neptune aerocapture trajectories is presented. Lifting trajectories pertaining to bank angle modulation and direct force control as well as ballistic trajectories pertaining to continuously-variable drag modulation are investigated. A parametric study of vehicle configurations is explored to quantitatively compare the flight envelope between lifting and ballistic trajectories. A closed-loop numerical predictor–corrector aerocapture guidance architecture is utilized to unify each flight control technique for trajectory comparisons. A series of Monte Carlo simulations of blunt body Neptune aerocapture trajectories are conducted to assess each flight control’s robustness to uncertainties in vehicle aerodynamics, atmospheric knowledge, and entry state. Direct force control can achieve 100% successful science orbit insertion within a 120 m/s total ΔV budget. Bank angle modulation can achieve 100% successful science orbit insertion within a 300 m/s total ΔV budget. Continuously-variable drag modulation can achieve 99.3% successful science orbit insertion within a 190 m/s total ΔV budget but at 3 times lower peak stagnation point convective heating rate.