Radiation protection for human exploration of the moon and mars: Application of the mash code system

The Monte Carlo Adjoint Shielding code system -- MASH, developed for the Department of Defense for calculating radiation protection factors for armored vehicles against neutron and gamma radiation, has been used to assess the dose from reactor radiation to an occupant in a habitat on Mars. The capability of MASH to reproduce measured data is summarized to demonstrate the accuracy of the code. The estimation of the radiation environment in an idealized reactor-habitat model is reported to illustrate the merits of the adjoint Monte Carlo procedure for space related studies. The reactor radiation dose for different reactor-habitat surface configurations to a habitat occupant is compared with the natural radiation dose acquired during a 500-day Mars mission