High Fidelity Multi-Objective Design Optimization of a Downscaled Cusped Field Thruster

Thomas Fahey,Angus Muffatti,Hideaki Ogawa

doi:10.3390/aerospace4040055

Abstract

The Cusped Field Thruster (CFT) concept has demonstrated significantly improved performance over the Hall Effect Thruster and the Gridded Ion Thruster; however, little is understood about the complexities of the interactions and interdependencies of the geometrical, magnetic and ion beam properties of the thruster. This study applies an advanced design methodology combining a modified power distribution calculation and evolutionary algorithms assisted by surrogate modeling to a multi-objective design optimization for the performance optimization and characterization of the CFT. Optimization is performed for maximization of performance defined by five design parameters (i.e., anode voltage, anode current, mass flow rate, and magnet radii), simultaneously aiming to maximize three objectives; that is, thrust, efficiency and specific impulse. Statistical methods based on global sensitivity analysis are employed to assess the optimization results in conjunction with surrogate models to identify key design factors with respect to the three design objectives and additional performance measures. The research indicates that the anode current and the Outer Magnet Radius have the greatest effect on the performance parameters. An optimal value for the anode current is determined, and a trend towards maximizing anode potential and mass flow rate is observed.

Highlights

The implementation of electric propulsion (EP) thrusters on spacecraft is largely driven by weight reductions over traditional chemical propulsion thrusters
EP has a distinct payload reduction advantage over chemical propulsion and offers increased operational life, in excess of 10,000 h, and high specific impulse Isp, of 1500–4000 s, but relatively low thrust values of around 30–230 mN [1], which is useful for long range missions and small attitude adjustments for satellites [2]
This paper presents the outcomes of a multi-objective design optimization of a small-scale Cusped Field Thruster (CFT) analysis that has been conducted for three major objectives commonly targeted in spacecraft propulsion; that is, (1) thrust T, (2) efficiency η t, and (3) specific impulse Isp

Summary

Introduction

The implementation of electric propulsion (EP) thrusters on spacecraft is largely driven by weight reductions over traditional chemical propulsion thrusters. EP has a distinct payload reduction advantage over chemical propulsion and offers increased operational life, in excess of 10,000 h, and high specific impulse Isp , of 1500–4000 s, but relatively low thrust values of around 30–230 mN [1], which is useful for long range missions and small attitude adjustments for satellites [2]. EP offers improved specific impulse and operational lifetimes over chemical thrusters with a significant reduction in the amount of propellant required. The gridded ion thruster (GIT) and the Hall effect thruster (HET) are high efficiency flight tested examples of EP. Both of these propulsion concepts are well understood and have values of

Methods

Results

Conclusion