A short review of the status of electric propulsion (EP) is presented to se
rve as an introduction to the more specialized technical papers also appear
ing in this Special Issue (Journal of Propulsion and Power, Vol. 14, No, 5,
Sept.-Oct. 1998). The principles of operation and the several types of thr
usters that are either operational or in advanced development are discussed
first, followed by some considerations on the necessary power sources. A f
ew prototypical missions are then described to highlight the operational pe
culiarities of EP, including spacecraft interactions. We conclude with a hi
storical summary of the accumulated flight experience using this technology
.