This thesis, carried out within the Space It Up! program, focuses on the development of physics-based models for the sizing of the propulsion system of a pressurized lunar rover. The topics addressed begin with an in-depth study of the state of the art of batteries, solar cells, fuel cells, and more complex technologies such as Radioisotope Thermal Generators, also providing an outlook on the future of these technologies by highlighting expected progress not only in terms of performance but also from a sustainability perspective. A general overview of the lunar environment in which the rover will operate is presented, together with possible technological solutions to the documented critical issues of this environment.