Editing Propellant (section)

===Electrically powered===
{{Main|Electrically powered spacecraft propulsion}}

Electrically powered reactive engines use a variety of usually ionized propellants, including atomic ions, plasma, electrons, or small droplets or solid particles as propellant.

====Electrostatic====
{{Main|Ion thruster}}
If the acceleration is caused mainly by the [[Coulomb force]] (i.e. application of a static [[electric field]] in the direction of the acceleration) the device is considered electrostatic. The types of electrostatic drives and their propellants:
* [[Gridded ion thruster]] – using positive ions as the propellant, accelerated by an electrically charged grid
** [[NASA Solar Technology Application Readiness]] (NSTAR) – positive ions accelerated using high-voltage electrodes
** [[High Power Electric Propulsion|HiPEP]] – using positive ions as the propellant, created using microwaves
** [[Gridded ion thruster|Radiofrequency ion thruster]] – generalization of HiPEP
* [[Hall-effect thruster]], including its subtypes Stationary Plasma Thruster (SPT) and Thruster with Anode Layer (TAL) – use the Hall effect to orient electrons to create positive ions for propellant
* [[Colloid thruster|Colloid ion thruster]] – electrostatic acceleration of droplets of [[Ionic liquid|liquid salt]] as the propellant
* [[Field-emission electric propulsion]] – using electrodes to accelerate ionized liquid metal as a propellant
* [[Nano-particle field extraction thruster]] – using charged cylindrical [[carbon nanotubes]] as propellant

====Electrothermal====
These are engines that use electromagnetic fields to generate a [[plasma (physics)|plasma]] which is used as the propellant. They use a nozzle to direct the energized propellant. The nozzle itself may be composed simply of a magnetic field. Low molecular weight gases (e.g. hydrogen, helium, ammonia) are preferred propellants for this kind of system.<ref>{{cite web|url=http://novosti-kosmonavtiki.ru/content/numbers/198/35.shtml|title=Native Electric Propulsion Engines Today|publisher=Novosti Kosmonavtiki|year=1999|issue=7|archive-url=https://web.archive.org/web/20110606033558/http://www.novosti-kosmonavtiki.ru/content/numbers/198/35.shtml|archive-date=6 June 2011|language=ru}}</ref>
* [[Resistojet rocket|Resistojet]] – using a usually inert compressed propellant that is energized by simple [[Joule heating|resistive heating]]
* [[Arcjet rocket|Arcjet]] – uses (usually) hydrazine or ammonia as a propellant which is energized with an [[electrical arc]]
* [[Ion thruster#Microwave electrothermal thrusters|Microwave]] – a type of [[Radiofrequency ion thruster]]
* [[Variable specific impulse magnetoplasma rocket]] (VASIMR) – using microwave-generated plasma as the propellant and magnetic field to direct its expulsion

====Electromagnetic====
{{Main|Plasma propulsion engine}}
Electromagnetic thrusters use ions as the propellant, which are accelerated by the [[Lorentz force]] or by magnetic fields, either of which is generated by electricity:
* [[Electrodeless plasma thruster]] – a complex system that uses [[cold plasma]] as a propellant that is accelerated by [[ponderomotive force]]
* [[Magnetoplasmadynamic thruster]] – propellants include xenon, neon, argon, hydrogen, hydrazine, or lithium; expelled using the Lorentz force
* [[Pulsed inductive thruster]] – because this reactive engine uses a radial magnetic field, it acts on both positive and negative particles and so it may use a wide range of gases as a propellant including water, hydrazine, ammonia, argon, xenon and many others
* [[Pulsed plasma thruster]] – uses a Teflon plasma as a propellant, which is created by an electrical arc and expelled using the Lorentz force
* [[Helicon Double Layer Thruster]] – a plasma propellant is generated and excited from a gas using a helicon induced by [[high frequency]] band radiowaves which form a magnetic nozzle in a cylinder