Medical Implications of Space Radiation Exposure Due to Low Altitude Polar Orbits

TL;DR

This study models radiation exposure for a MOL-like spacecraft in polar orbit, assessing health risks from cosmic rays and solar particle events to inform future low-Earth orbit missions.

Contribution

It provides the first detailed modeling of radiation doses during a 30-day polar orbit mission, including analysis of a large solar particle event impact.

Findings

Projected doses from large SPEs could significantly impact crew health.

Polar orbits with minimal shielding increase radiation exposure risks.

Modeling approach can inform safety protocols for future missions.

Abstract

Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and Solar Particle Events may pose a critical health risk to future spaceflight crews and can have a serious impact to all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960's Manned Orbiting Laboratory program's space vehicle and the high inclination polar orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-day mission using high performance, multi-core computers. Projected doses from a historically large SPE (e.g. the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent contingencies.It is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.