Plasma Propulsion Devices for Space Flight

An analysis of some of the more immediate space missions indicates that a large increase in payload can be achieved when electrical propulsion is used instead of chemical propulsion. For missions in the gravitational field of the Earth and to the Moon, the optimum specific impulse range for electrical propulsion is from about 1500 to 5000 seconds. Electrical propulsion with neutral plasma devices operate well in this specific impulse range as well as at higher specific impulses. Three different chambers have been described as examples of devices using neutral plasmas. Some of the factors which limit the range of efficient operation of such devices have been discussed.