[SUBSTANTIATION OF DOSE LIMITS FOR A NEW NORMATIVE DOCUMENT ON RADIATION SAFETY OF LONG-DURATION SPACE MISSIONS AT...

Area of Science:

• Space radiobiology
• Radiation protection
• Cosmonaut health

Context:

• Long-duration space missions pose significant radiation exposure risks to cosmonauts.
• Previous career dose limits for astronauts and cosmonauts focused primarily on limiting cancer death risk.
• There is a need for more stringent criteria to address delayed radiation risks in space.

Purpose:

• To substantiate revised dose limits for critical cosmonaut organs for long-duration orbital missions.
• To ensure cosmonaut performance and vitality by minimizing radiation-induced health damage.
• To align space radiation safety standards with terrestrial nuclear industry regulations.

Summary:

• A review of radiobiology and epidemiology data informed the revision of cosmonaut dose limits.
• The average tissue equivalent dose maximum was reduced fourfold to 1 Sievert (Sv).
• Calculations incorporated cancer, non-cancer risks, and reduced mean life expectancy (MLE) using a radiation-induced mortality model.

Impact:

• The revised career dose limit for cosmonauts is now consistent with Russian nuclear industry standards (NRB 99/2009).
• Dose limits for critical organs (bone marrow, lens, skin) were reduced to align with terrestrial planned over-exposure limits.
• These changes enhance radiation safety for cosmonauts on extended space missions.