Hydrogen as a Nuclear Thermal Rocket Propellant

Nuclear Thermal Propulsion (NTP) is a successfully developed technology, though it hasn’t been officially used in the propulsion system of an astronautical mission. It is the technology most likely to make long distance journeys in space possible. It is considerably more efficient than the traditional chemical rocket engines, regarding propellant consumption for each unit of thrust generated. The reason for that is the greater number of choices regarding the propellant composition. Therefore, in this work, Hydrogen has been chosen as propellant due to its low molecular mass compared to other possible substances. The main aim is to explain how the propellant molecular mass impacts a rocket performance, and to show, by Computational Fluid Dynamics (CFD) simulations that, indeed, hydrogen seems to be the best choice available among possible nuclear thermal rocket propellants.