Why can't uranium be used as rocket fuel?

First of all, rockets are launched from earth, and launch facilities are super expensive so, we want to use them for multiple launches but nuclear radioactive fuel would make them facilities useless after first launch. read more

In conventional fuel, maybe we can get 5 moles of gases by burning 1 mole of fuel, and lets assume, uranium gives the same. So, for example, if we need to produce 1 million moles of exhaust gases to reach orbit, we need 200k moles of fuel. read more

Bimodal Nuclear Thermal Rockets - conduct nuclear fission reactions similar to those employed at nuclear power plants including submarines. The energy is used to heat the liquid hydrogen propellant. The vehicle depicted is the "Copernicus" an upper stage assembly being designed for the Space Launch System (2010). read more