Radiobiological assessment of the physical protection of cosmonauts by the elements of the spaceship

The urgency of the problem of ensuring the radiation safety of cosmonauts in long-distance space flights is quite obvious. Protons account for more than 50% of the absorbed dose. An additional contribution to the radiation dose of astronauts is made by secondary radiation formed during the interaction of cosmic radiation with the wall, structures and equipment of the spacecraft, as well as the astronaut's body. Of course, one should take into account the induced radioactivity inside the spacecraft. Purpose of the study: to conduct a radiobiological assessment of the radioprotective properties of the shell of the projected transport ship (PTS). The experiments were performed on 106 outbred mice. Mice were irradiated with 170 MeV protons at a dose of 1.0 Gy at an average dose rate of 0.5 Gy / min. For the study, a three-layer structure of the PTS aggregate compartment frame was provided, consisting of a layer of thermal protection on a carbon-fiber substrate. Additionally, an aluminum plate with a thickness of 4 mm, plexiglass with a thickness of 50 mm, and water phantoms with a thickness of 160 mm and 250 mm were used. It was found that the PTS shell, together with an aluminum plate, minimally protects the body of animals (mice) from the damaging action of 170 MeV protons. The use of protection in the form of 50 mm plexiglass also further weakened the damaging effect of protons in the chromosomal aberration test. Additional water protection with a water layer thickness of 250 mm proved to be effective. The experimental results showed the high importance of secondary radiation and its significant contribution to the development of radiobiological effects, even under conditions of complete screening from the primary proton flux. In the course of the experiment, it was found that in the medical cabin of the phasotron during the sessions of the accelerator operation, induced radioactivity is formed. In conclusion, it is worth noting that in radiobiological experiment established important evidence of the exceptional complexity of the problem of radiation safety of cosmonauts.