Editing Propellant (section)

===Nuclear===
Nuclear reactions may be used to produce the energy for the expulsion of the propellants.  Many types of nuclear reactors have been used/proposed to produce electricity for electrical propulsion as outlined above. [[Nuclear pulse propulsion]] uses a series of nuclear explosions to create large amounts of energy to expel the products of the nuclear reaction as the propellant. [[Nuclear thermal rocket]]s use the heat of a nuclear reaction to heat a propellant. Usually the propellant is hydrogen because the force is a function of the energy irrespective of the mass of the propellant, so the lightest propellant (hydrogen) produces the greatest [[specific impulse]].