Editing Ion thruster (section)

=== Microwave electrothermal thrusters ===
{{multiple image
 | align         = right
 | header        = [[Microwave electrothermal thruster]]
 | caption_align = center
 | header_align  = center
 | total_width   = 500

 | image1   = MET Sketch 1.jpg
 | width1   = 1221
 | height1  = 629
 | alt1     = Thruster components
 | caption1 = <small style="font-size:90%;">Thruster components</small>

 | image2   = MET Sketch 2.jpg
 | width2   = 1233
 | height2  = 1297 
 | alt2     = Discharge Chamber
 | caption2 = <small style="font-size:90%;">Discharge chamber</small>
 }}

Under a research grant from the [[Glenn Research Center|NASA Lewis Research Center]] during the 1980s and 1990s, Martin C. Hawley and Jes Asmussen led a team of engineers in developing a microwave electrothermal thruster (MET).<ref>{{cite news|title=Less Fuel, More Thrust: New Engines are Being Designed for Deep Space|newspaper=The Arugus-Press|location=Owosso, Michigan|page=10|volume=128|number=48
|date=26 February 1982}}</ref>

In the discharge chamber, [[microwave]] (MW) energy flows into the center containing a high level of [[ion]]s (I), causing neutral species in the gaseous [[Rocket propellant|propellant]] to ionize. Excited species flow out (FES) through the low ion region (II) to a neutral region (III) where the ions complete their [[Plasma recombination|recombination]], replaced with the flow of neutral species (FNS) towards the center. Meanwhile, energy is lost to the chamber walls through heat [[Thermal conduction|conduction]] and [[Convection (heat transfer)|convection]] (HCC), along with [[radiation]] (Rad). The remaining energy absorbed into the gaseous propellant is converted into [[thrust]].