cylonlover writes "Nuclear-powered rocket engines are not new. In the 1960s, both the U.S. and the Soviet Union developed and tested thermal nuclear rockets fitted with flight-worthy components. However, Project Rover and NERVA (Nuclear Engine for Nuclear Rocket Application) programs were defunded in the early 1970s just before test flights were to start. Now, as part of the Advanced Exploration Systems program at NASA, the Nuclear Cryogenic Propulsion Stage team is tackling a three-year project to demonstrate the viability of and to evaluate materials for thermal nuclear propulsion systems for use in future deep space missions."
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