Investigating and defining radiation dose risk factors, derived from terrestrial risk assessments, for probabilistic risk assessments for radiation exposure during very high altitude ‘near space’ flights for varying space weather conditions

Current space tourism ventures focus on three specific areas: long duration very high-altitude flights; also referred to as ‘near space’ flights, sub-orbital flights and visits to Low Earth Orbit (LEO). In the forthcoming decades, space travel is expected to become as commonplace as transatlantic flights. Consequently, it becomes crucial to consider the potential health implications of cosmic radiation exposure during these commercial ventures, particularly in light of sudden changes in space weather, such as ground-level enhancements (GLEs) or solar particle events (SPEs), which can have profound effects on the well-being of crew members and passengers.

This paper focuses on the exposure environment and associated risk assessment for very high altitude ‘near space’ flights to the stratosphere. The current probabilistic risk assessment of the hazards for such flights is severely constrained, as the necessary dose risk factor for potential radiation exposure remains undefined for prospective space tourists. Here we examine the existing terrestrial approach to deterministic and probabilistic risk assessment for radiation exposure, specifically within the civil nuclear industry, and its applicability to ‘near space’ very high-altitude flights.

We propose a revised probabilistic risk assessment methodology, including a bespoke dose risk factor, for ‘near space’ flights. Furthermore, we delve into the distinctive exposure events associated with ‘near space’ flights, explore the impact of potential variations in space weather on radiation exposure, and evaluate potential dose risk factors for utilization in probabilistic risk calculations for flight participants.

Plain Language Summary: An investigation into the acceptability and probability of risks associated with potential radiation exposure from flying to ‘near space’ within newly designed craft at very high altitude in the upper atmosphere above the Earth. Comparing and assessing the applicability of terrestrial nuclear industry risk assessment methodology to space tourism and the associated radiation risks.