Before revision: Conceptual overviewThe key elements to NEP are: A compact reactor core An electric generator A compact waste heat rejection system such as heat pipes An electric power conditioning and distribution system Electrically powered spacecraft propulsion History United States A 1963 paper by Myron Levoy proposed a hybrid nuclear-electric engine design, which would have been able to work both in open-cycle mode as a nuclear thermal engine during mission phases requiring high thrust, as well as in closed-cycle mode as a nuclear-electric engine with low thrust, but high efficiency during remaining mission phases.
After revision: History United States A 1963 paper by Myron Levoy proposed a hybrid nuclear-electric engine design, which would have been able to work both in open-cycle mode as a nuclear thermal engine during mission phases requiring high thrust, as well as in closed-cycle mode as a nuclear-electric engine with low thrust, but high efficiency during remaining mission phases.