Radiation risk estimation and its application to human beings in space

Area of Science:

• Space radiation
• Astrobiology
• Radiation biology

Background:

• Increasing human presence in space necessitates understanding radiation exposure.
• Average space radiation near Earth is ~10 rad/year, with potential for non-stochastic and stochastic health effects.
• Previous risk assessments by UNSCEAR and BEIR committees (1970-1980) require updates due to new information.

Purpose of the Study:

• To discuss uncertainties in space radiation risk assessment.
• To propose appropriate comparisons for setting acceptable stochastic risk levels.
• To consider lifetime exposure limits for space workers.

Main Methods:

• Review of existing radiation exposure data and risk assessment reports.
• Analysis of stochastic effects and their associated uncertainties.
• Comparison of potential space radiation limits with occupational limits for ground-based radiation workers.

Main Results:

• Space radiation can cause non-stochastic effects (e.g., eye damage) and stochastic effects (cancer, genetic damage).
• Stochastic risks are present at all exposure levels, with uncertainties requiring further investigation.
• A lifetime exposure limit, comparable to ground-based workers but received over a shorter period, is proposed.

Conclusions:

• Setting acceptable space radiation limits requires careful consideration of stochastic risks and appropriate comparisons.
• Lifetime limits may be suitable for astronauts given typical mission durations.
• Further examination by bodies like the NCRP is needed to address space radiation hazards effectively.