Simulation of the Interaction of Space Radiation with the Martian Atmosphere and Surface

We have developed a Monte Carlo code based on Geant4 to simulate the interaction of cosmic rays with the Martian atmosphere and soil. The code allows to compute the differential and directional flux of secondary particles at user-defined positions, including secondaries produced in the soil. The application allows to predict the radiation level on the Martian surface due to galactic cosmic rays, and the effects of solar energetic particle events. We will discuss some aspects of the code and present first simulation results.