Using the energy of fission for spacecraft propulsion has been studied and some prototypes have been already constructed. Most of these nuclear engines should b

Using the energy of fission for spacecraft propulsion has been studied and some prototypes have been already constructed. Most of these nuclear engines should be used only outside of Earths atmosphere. https://en.wikipedia.org/wiki/Nuclear_propulsion https://en.wikipedia.org/wiki/Nuclear_propulsion https://en.wikipedia.org/wiki/NERVA https://en.wikipedia.org/wiki/NERVA Most interesting and promising are direct nuclear propulsions, like fission-fragment rockets. https://en.wikipedia.org/wiki/Fission_fragment_rocket https://en.wikipedia.org/wiki/Fission_fragment_rocket