Comparison with the Radiation Safety Limits of the Dose Values to Critical Organs of the Human Body in Long-Term Missions to Orbital Stations Mir and ISS

We analyzed the averaged through the year power of local tissue absorbed doses measured by the standard instruments over 15 years of Mir operation (28 missions) and analogous data over 22 years of the International Space Station (ISS) operation (67 missions) within solar cycles (SCs) 22–25. This is a huge set of daily measurements of R-16 dosimeters (ioinization chamber D2) and four DB-8 semiconductor dosimeters, located in different compartments. We also present the experimental and calculated absorbed and equivalent doses to the skin, lens, and hematopoietic system (HPS) received within a day and year in space. It was found that in all Mir and ISS missions the equivalent doses to these tissues were below the limits adopted for orbital missions. In many missions from 6 to 8 months, the effective and equivalent doses to the HPS, lens, and skin did not exceed even the lower dose limits prescribed by Russian radiation safety standard NRB-99/2009 for the nuclear industry. Maximal equivalent dose values to the lens and skin in a year-long mission did not exceed 404 mSv. These values are less than the existing limits for space missions by 32% for the lens and 5 times for the skin.