Plasma Propulsion Possibilities

Plasma propulsion systems are arranged in three categories according to the cyclic nature of the jet produced; 1) steady, 2) alternating or wave-accelerated, and 3) pulsed. Typical systems within each category are described with emphasis on work being done at the NASA Lewis Research Center. The criteria for evaluating the relative merits of these systems are listed and the advantages and disadvantages pointed out. Such parameters as energy efficiency and propellant utilization must be measured before conclusions can be reached as to the eventual applicability of any of these systems.