Very Cool Sounding NON-propellant based space propulsion

I'd never heard of this but it sounds very cool and Star Trekky.......I will Google it for sure. John

http://www.space-travel.com/reports/Aerojet_High_Power_Hall_System_Propels_USAF_AEHF_Satellite_999.html

Well....I Googled......there IS a propellant, but in vastly smaller amounts and with zero combustion.

http://en.wikipedia.org/wiki/Hall_effect_thruster