Spacecraft shielding for a Mars mission

The stationary, source-free, one-dimensional solution to the cosmic-ray heliospheric transport equation has been applied to the treatment of cosmic-ray fluxes at solar minimum between the orbits of Earth and Mars. The effective dose rate from these radiations were calculated for cylindrical spacecraft hulls of various compositions both in space and on the surface of Mars. The spatial gradient of the flux between Earth and Mars is quite small so that the cosmic-ray dose-rate can be assumed spatially uniform in the interval between these orbits, between one and one and a half astronomical units. The resulting dose rates for a 2.5-year mission, assuming six months on the surface of Mars, were slightly over one sievert.