Ion thrusters for electric propulsion: Scientific issues developing a niche technology into a game changer

TLDR

The shift to new space and increased commercialization has made ion thrusters a primary propulsion system in space missions. The article examines how new space trends influence EP development, focusing on radio‑frequency ion thrusters and related research topics, and concludes with their spacecraft integration. The authors review EP history, missions, and technologies, discuss radio‑frequency ion thrusters, thruster modeling, test‑facility requirements, and space‑electronics aspects such as efficiency, EMC, and radiation hardness.

Abstract

The transition from old space to new space along with increasing commercialization has a major impact on space flight, in general, and on electric propulsion (EP) by ion thrusters, in particular. Ion thrusters are nowadays used as primary propulsion systems in space. This article describes how these changes related to new space affect various aspects that are important for the development of EP systems. Starting with a historical overview of the development of space flight and of the technology of EP systems, a number of important missions with EP and the underlying technologies are presented. The focus of our discussion is the technology of the radio frequency ion thruster as a prominent member of the gridded ion engine family. Based on this discussion, we give an overview of important research topics such as the search for alternative propellants, the development of reliable neutralizer concepts based on novel insert materials, as well as promising neutralizer-free propulsion concepts. In addition, aspects of thruster modeling and requirements for test facilities are discussed. Furthermore, we address aspects of space electronics with regard to the development of highly efficient electronic components as well as aspects of electromagnetic compatibility and radiation hardness. This article concludes with a presentation of the interaction of EP systems with the spacecraft.