4. Conclusion

Because they offer exceptional energy density, nuclear systems for power generation in space and for space propulsion began to be developed as early as the late 1950s. Thermoelectric radioisotope generators (a few hundred We) and radioisotope heaters have been used in space since the early 1960s, and have made possible a number of emblematic space exploration missions, enabling humankind to make considerable progress in its knowledge of the solar system. Fission electronuclear generators of a few kWe were widely used by the Soviet Union until the late 1980s to power military observation satellites in Earth orbit. Major developments in the USA and the Soviet Union in the 1960s-1970s demonstrated that nuclear thermal propulsion systems met all the requirements for a transport system to the Moon, as well as for manned missions to Mars. The opening of a new era of human space exploration, against...