Spaceflight medical countermeasures: a strategic approach for mitigating effects from solar particle events.

NASA was recently charged with returning humans to the lunar surface within the next five years. This will require preparation for spaceflight missions of longer distance and duration than ever performed in the past. Protecting the crew and mission from the hazards associated with spaceflight will be a priority. One of the primary hazards to address is the challenging radiation environment. Space is unforgiving when it comes to radiation. There is galactic cosmic radiation (GCR) that is pervasive in space and the possibility of solar particle events (SPE) that release high energy particles from the sun that can result in high doses of radiation to the crew if unprotected. NASA has been preparing and evaluating several means of ensuring that crew health is not compromised during these missions. Physical shielding, space weather monitoring, and more recently storm shelters are all possible means of protecting crew during a SPE. Medical countermeasures have not been necessary for operations in low Earth orbit; however, future human exploration missions should consider including therapies onboard to address radiation-induced health effects. While the likelihood of experiencing a significant SPE is very low, serious adverse health effects or even death could occur if no medical countermeasures were available. Having a Food and Drug Administration (FDA) approved medical countermeasure on board that could mitigate acute radiation-induced hematopoietic syndrome due to a SPE could provide life saving measures for the crew. This paper discusses the mitigation strategies that can be implemented for Artemis missions and identifies numerous areas of research for future improvements.