The study of the dosimetric effects of space radiation on astronauts is an important concern of space missions for the exploration of the Solar System. To protect the crew, shielding must be designed, the environment must be anticipated and monitored and a warning system must be put in place. A Geant4 simulation has been developed for a first quantitative study of existing vehicle concepts and Moon/Mars surface habitat designs, and the radiation exposure of crews therein. We will show the results of the dosimetric analysis of proposed innovative shielding solutions in various geometrical set-ups, complemented with a critical analysis of Geant4 tools currently available for this type of studies. This work represents the first approach in the European AURORA programme to estimate quantitatively a crucial issue in the manned exploration of the Solar System.