Electric Propulsion (EP) is that in which electrical energy, rather than chemical energy, is used to accelerate a propellant to produce thrust. This paper surveys the EP technologies applicable for use on small spacecraft, paying attention to the unique constraints imposed by this application. The very high specific impulse that can be generated by an EP system offers the potential of greatly expanding the scope of missions that can be achieved by small spacecraft. The paper considers the various missions already identified, and outlines a promising small deep space probe using ion propulsion
