---
title: "Spacecraft electric propulsion"
chunk: 4/4
source: "https://en.wikipedia.org/wiki/Spacecraft_electric_propulsion"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:55:41.016044+00:00"
instance: "kb-cron"
---

Three families of electromagnetic thruster, pulsed plasma thrusters (PPTs), magnetoplasmadynamic thrusters (MPD), and pulsed inductive thrusters (PIT), rely on strong fields. The three differ in lifetime, efficiency, and power scaling, but share advantages common to electromagnetic acceleration: high specific impulse, precision suitable for satellite positioning, robustness, high power processing capability, and relatively simple system-level scaling with available spacecraft power. 
PPTs are the only electromagnetic thrusters used on operational satellites. Solid-propellant PPTs first flew in the Soviet Union in 1964 and in the United States in 1968; they initiate an arc discharge across a solid fluorinated polymer bar, ablating a small amount of propellant and accelerating it by the Lorentz body force. Their compact, low-power, pulsed configurations make them suited to satellite positioning and drag compensation, unlike later concepts that rely on inductive or steady-state operation.
MPDs generate thrust through the Lorentz force produced by the interaction of discharge currents with self-induced or externally applied magnetic fields, and have been investigated for both quasi-steady and steady-state spaceflight applications. MPD thrusters have also flown in space in experimental regimes.
The PIT concept originated in the late 1960s and evolved through successive experimental designs focused on performance scaling, circuit optimization, and propellant compatibility. PITs were developed to overcome the erosion and lifetime limitations of electrode-based systems by inducing plasma currents through time-varying magnetic fields, accelerating neutral propellants without physical contact between conductors and plasma. No PIT system has flown in space, but the thruster class remains of interest for high-efficiency, long-duration propulsion with minimal material degradation, particularly in missions requiring flexible propellant selection and reduced contamination risk.
Electron cyclotron resonance thrusters (ECR) use electron cyclotron resonance, in which microwaves transfer energy to electrons spiraling in a magnetic field, to ionize and accelerate a gaseous propellant (commonly xenon), particularly in ionospheric or high-altitude environments. ECRs using electron cyclotron resonance with microwave discharge have flown in space, most notably as the μ10 ion engine system on JAXA's Hayabusa and Hayabusa2 asteroid missions.
Stationary plasma thrusters (SPT), also called Hall-effect thrusters, accelerate ionized propellant (typically xenon) using perpendicular electric and magnetic fields and a circulating electron current. The concept was proposed by A. I. Morozov in the early 1960s, and a 1968 paper on near-wall conductivity in strongly magnetized plasma provided key theoretical grounding for the discharge channel physics. The first SPT was tested in space aboard a Meteor spacecraft launched in December 1971, with orbital firings conducted between February and June 1972; subsequent corrective propulsion units operated on further Meteor missions through 1980. By 2012, more than 270 SPD-70 and SPD-100 thrusters had operated on over 60 Russian spacecraft, and beginning in the 1990s qualified SPT units entered service on American and European spacecraft as well.
The Gießen RIT line used a radio-frequency, electrode-less xenon discharge, a design Löb described as avoiding electrode-related wear while offering high efficiency and high exhaust velocity.

=== Development and testing ===

These are concepts under active engineering development or testing that adapt electric or electromagnetic propulsion principles for new operational regimes.

==== Environment-fed electric propulsion ====
Atmosphere-breathing electric propulsion is a concept in which a spacecraft collects residual atmospheric particles in very low Earth orbit, ionizes them, and accelerates them electromagnetically instead of carrying all propellant onboard. A 2018 European Space Agency technology demonstration was described as the first firing of an air-breathing electric thruster using collected atmospheric molecules as propellant, but no such system has yet flown in space.
Related operational milestones in very low Earth orbit preceded true atmosphere-breathing concepts. ESA's Gravity Field and Steady-State Ocean Circulation Explorer (GOCE), launched on 17 March 2009, became the first-ever mission to fly drag free in low Earth orbit using an electric propulsion system that continually compensated atmospheric drag. JAXA's Super Low Altitude Test Satellite (SLATS) "TSUBAME", launched on 23 December 2017, transitioned to ion-engine orbit-keeping operations in April 2019 and later demonstrated maintenance of six orbital altitudes between 271.1 and 181.1 km, validating super-low-altitude Earth observation operations.

== Selected milestones ==
The following table summarizes selected systems and mission milestones in spacecraft electric propulsion, including both flight-proven applications and developmental concepts discussed in this article.

== See also ==

Bussard ramjet – Proposed spacecraft propulsion method
Emerging technologies – Technology still to be fully developed
Field propulsion – Propulsion concepts and technologies
History of aviation
History of rockets
History of spaceflight
New Millennium Program – NASA projects to test new space technologies
Non-rocket spacelaunch – Concepts for launch into space
Timeline of aviation
Timeline of rocket and missile technology
Timeline of spaceflight

== References ==
 This article incorporates public domain material from websites or documents of the United States government.