Purpose
Overview and perspectives are provided of radiation hazards associated with deep space human missions, such as to Mars.
Recent Findings
Significant associations between radiation dose and effects of principal concern from space radiation (cancer, cardiovascular, CNS) have not yet been detected in astronauts. Therefore, estimates of radiation-induced health consequences from extended deep space missions are based on studies available from radiation-exposed human populations on Earth (e.g., A-bomb survivors) supplemented with data from biological experiments (primarily rodents) using space-type radiations obtained at specialized radiation facilities. This approach (the best available at this time) has large uncertainties, which strongly influence the number of days permitted in deep space.
Summary
Based on current NASA risk limits, the length of time permitted in space may not be sufficient for a human mission to Mars, even with substantial shielding of the spacecraft. Risk mitigation strategies beyond shielding may therefore be required. Research is continuing to advance in these and related fields.