Calculation of Doses and Biological Damage for Astronauts Exposed to Space Radiation

Space research is an object of renewed interest, also considering that human missions to the Moon, and possibly Mars, are being planned; astronauts’ exposure to space radiation is one of the highest-priority problems in such missions. In the framework of the ARES project funded by INFN, we calculated absorbed, equivalent and effective doses for astronauts exposed to Galactic Cosmic Rays (GCR) and Solar Particle Events (SPEs) under different shielding conditions, that is different materials and thickness values. While absorbed doses were calculated by the FLUKA Monte Carlo radiation transport code, equivalent doses were obtained by interfacing FLUKA with BIANCA, a biophysical model developed within our group that allows calculating RBE (relative biological effectiveness) values both for cell death, which is related to non-cancer effects, and for chromosome aberrations, some of which are related to cancer induction. Notably, this approach takes into account that the RBE depends not only on particle type, but also on particle energy and dose. Such calculations were performed in a male and a female voxel phantom, and the results were then compared with the dose limits established by various space agencies including NASA; comparisons between male and female doses were also carried out, confirming that female doses tend to be higher than male doses, especially behind light shielding. In this paper sample results will be presented, focusing on the August 1972 SPE, which is the most intense of the modern space era