The fundamental capability of Nuclear Thermal Propulsion ( NTP ) is game changing for space exploration . A first generation Nuclear Cryogenic Propulsion Stage ( NCPS ) based on NTP could provide high thrust at a specific impulse above 900 s , roughly double that of state of the art chemical engines . Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance . The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation . Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion ( NEP ) .