Rocket Propulsion Elements, 9th Edition

CHAPTER 17ELECTRIC PROPULSION

Chapters 1 and 2 present information on rocket propulsion devices that use electrical energy for heating and/or directly ejecting propellant thus utilizing an energy source that is separate from the propellant itself. The purpose of this chapter is to provide a more complete presentation of the various thrusters, power supplies, applications, and flight performance. Vector notation is used in several background equations. At present, most electric propulsion concepts are not suitable for earth liftoffs.

In electric propulsion the term thruster is used the same way as engine is in liquid propellant and motor in solid propellant rockets. In addition to a separate energy source, such as solar or nuclear with its auxiliaries (concentrators, heat conductors, pumps, panels, and radiators), the basic subsystems of a typical space electric propulsion system are: (1) conversion devices to transform the spacecraft's electrical power to voltages, frequencies, pulse rates, and currents suitable for particular electrical propulsion systems; and (2) one or more thrusters to convert the electric energy into kinetic energy of the propellant exhaust. Additionally needed are: (3) a propellant system for storing, metering, and delivering the propellant and/or propellant fill provisions; (4) several controls for starting and stopping power and propellant flow; and some also need (5) thrust vector control units (also called TGAs—thrust/gimbal assemblies).

Electric propulsion ...