Medium Earth Orbit Breeder Reactor

Nuclear energy is critical for further space exploration. I recommend a safer way of achieving this goal.

Current nuclear reactors use enriched Uranium and Plutonium. Which are quite radioactive. If the space rocket fails during a launch, they would pollute the environment. High altitude dispersion would affect large arrays. One approach could be to use Thorium. Thorium 232 half-life is greater than the age of the universe. Therefore, in case of an accident the environment would not be polluted by the decaying radioactive particles.

I propose a Medium Earth Orbit (MEO, altitude between 2,000 and 35,786 km) robot only modular space station for Lunar and Planetary refueling and payload hub for space rockets. The robot only design would allow smaller diameter for the modules which could be launched using smaller rockets. Distant orbit requirement is due to space debris in Low Earth Orbit. Additionally, if the space station explodes the effect on Earth would be much less due to large area dispersion and higher falling speed would melt most of the parts.

One of the modules of the space station can be a Thorium Breeder Reactor (a nuclear reactor that generates more fissile material than it consumes). Thorium can be decayed into Radium and Radon to generate heat and electricity. The initial decay of Thorium requires a lot of energy. The initial reaction can be triggered by the solar energy. The breeder design would allow sustained fissile material production. As a summery, we send a mostly safe material to space and turn it into a fissile fuel in space.

Finally, the byproduct of the Reactor, Thorium 228 and Radium 224, can be used as rocket fuel. Their decaying yields heat and Radon 220 gas which would generate thrust.