3. Conclusion

Nuclear space propulsion is a game changer that can revolutionize space transportation for many applications.

Nuclear thermal propulsion (NTP), which offers twice the propulsive efficiency (specific impulse) of the best cryogenic engines, combined with a comparable thrust level, offers decisive advantages, particularly for future manned missions to Mars (which require rapid transit and the ability to abort the mission) or for cislunar defense missions (which require maneuverability). It is these applications that are driving ongoing developments in the United States, including the DRACO project, which aims to demonstrate a NTP engine in orbit before the end of the 2020s. The success of major developments in the 1960s and 1970s in the United States and until 1988 in the Soviet Union, and the technological maturation work underway since the early 2010s in the United...