Reducing Human Radiation Risks on Deep Space Missions

This paper uses systems engineering approaches to address radiation exposure risks for humans on early missions to Mars. Alternatives are reviewed in the areas of current Mars mission architectures, contemporary shielding technologies, and medical treatment options to mitigate the risks of radiation doses received. The over-arching goal of this study is to determine whether any alternatives will reduce astronaut radiation exposure on a mission to Mars to meet the NASA space worker limits, while concurrently minimizing launch weight, costs, and other risks. Alternatives are compared via a combination of existing trade studies and swing matrices. Using these tools, it is determined that Boronated Nitride Nanotubes (BNNTs) are the highest potential composite for vehicle shielding, and it is recommended that Martian regolith should be used in parallel for any long stay by crews on the Martian surface. Two medical countermeasures, already FDA-approved, (Amifostine and Neupogen) have the highest potential for use. Further, no single shielding alternative will reduce crew exposure below existing limits, but further research may determine that a combination of composite shielding and regolith barriers could improve this outlook. Notably, the systems engineering techniques utilized herein to analyze a human mission to Mars are easily extensible to other deep space mission, such as a lunar outpost. This paper is summarized from the first author's master's thesis [1] and readers should refer there for detail beyond this paper.