Mission Applications of Electric Propulsion

The prospects for electric space propulsion are examined by considering the applicability of both electric propulsion and competitive propulsion systems to various manned and unmanned missions. The mission performance of the various systems is compared, and some consideration is given to development schedules, development costs, operational costs, growth potential and auxiliary applications. The paper is based primarily on NASA missions because military missions for high-energy propulsions are not well defined at the present time. It is shown that a single type of spacecraft, using electric propulsion systems currently under development, can be used for unmanned exploration of virtually the entire solar system. The competitive propulsion systems are incapable of performing many of these high-energy unmanned exploration missions. It is further shown that electric propulsion and nuclear rocket propulsion are competitive for manned Mars landing missions and lunar freighter missions. A combination of nuclear rocket propulsion and electric propulsion appears to offer the best performance for manned Mars missions.