Pure electric propulsion

Intro

In this wiki pure electric propulsion will refer to electric propulsion where the conversion from electric power to rocket thrust is done by a non thermal means as is done in an arc jet. Electric propulsion has the advantage of high propellant efficiency because of a high specific impulse while pure electric propulsion implies a greater energy efficiency for a given specific impulse as a consequence of reduced entropy in the rocket exhaust. Thus by this definition deep space-1 would be the first space vehicle to use pure electric propulsion but not the first space vehicle to use electric propulsion since arc jets were used for station keeping in satellites prior to deep space 1.