New Outlook on the Space Radiation Risk Paradigm for Remote beyond-Magnetosphere Missions to the Moon and Mars

摘要

The paper discusses the approaches to and criteria of setting limits to radiation loads on cosmonauts in missions of varying duration. The available radiobiological data about effective dose formation and damages to organism and tissues from different space radiation sources have been analyzed. Revision of the hazards to cosmonauts from solar cosmic rays (SCRs) during relatively powerful solar proton events (SPEs) led to a more than two orders of magnitude reduction in the mean tissue dose equivalent values, and equivalent doses for radiosensitive tissues imparted by SPEs with various fluences and spectrum rigidity due to the attenuation of radiation by the protection of spacecraft during the stay of cosmonauts in special radiation shelters. It has been found that due to rapid cell reparative processes the SCR effects on bone marrow, skin, GIT, corneal epithelium and cortex neurons may reduce 1.5- to 5-fold. According to the literature, in missions to Mars the galactic cosmic rays are particular hazardous because of potential severe damages to various structures of the brain cortex. This is fraught with a great risk to the cosmonauts’ ability to work during transit and the emergence of delayed negative consequences, growth of the total radiation risk over career of cosmonauts.