Radiation Analysis for Moon and Mars Missions (1805.01643v4)

Abstract: This paper provides an overview of the radiation aspects of manned space flight to Moon and Mars. The expected ionizing radiation dose for an astronaut is assessed along the Apollo 11 flight path to the Moon. With the two dose values, the expected and the measured total dose, the radiation shielding and the activity of the Sun are estimated. To judge the risk or safety margin the radiation effects on humans are opposed. The radiation from the Sun has to be set to zero in the computer model to achieve the published radiation dose value of the Apollo 11 flight. Galactic and cosmic particles have not been modelled either. The Apollo 11 astronauts must have been lucky that during their flight the Sun was totally quiet in the solar maximum year 1969 - and also their colleagues of the subsequent Apollo flights, i.e. until 1972, where the published dose values still require a quiet Sun. The here built mathematical model allows assessing the total dose of a journey to Mars by only changing the flight duration. Even if in the meantime much thicker and/or active radiation shielding is proposed the radiation risk of manned space flight to Moon and Mars remains still huge.

• The paper presents a rigorous radiation risk analysis using Apollo 11 data to extrapolate exposure levels for future Moon and Mars missions.
• It employs computational modeling to simulate solar conditions and predicts that during solar maximum, Mars mission radiation can exceed 11,500 mSv.
• The study recommends upgrading shielding from traditional materials to advanced composites and active protection systems to mitigate radiation risks.

Radiation Analysis for Moon and Mars Missions: A Critical Examination

The paper "Radiation Analysis for Moon and Mars Missions" by Andreas Märki provides a rigorous analysis of the potential radiation exposure faced by astronauts on missions to the Moon and Mars. The insights presented stem from an assessment of the Apollo 11 mission data, extrapolated to future missions beyond Low Earth Orbit (LEO). The primary focus of the paper is to evaluate the radiation risks and necessary shielding requirements for human spaceflight traversing the Van Allen Belt and encountering cosmic and solar radiation.

Summary of Findings

Märki's analysis emphasizes the variability in ionizing radiation exposure depending on solar activity levels. The paper uses computational modeling to reconstruct the radiation conditions encountered by Apollo 11 crew members, accounting for cosmic and solar particles, yet notably excludes the influence of galactic particles and solar radiations outside of quiet solar periods. This exclusion is significant as it highlights the potential underestimation of radiation risk during periods of solar activity. The paper records that Apollo astronauts traversed the Van Allen Belt with minimum dose values: 0.18 rad (1.8 mGy) during quiet solar conditions, significantly lower than terrestrial dose rates and space mission estimates with higher solar activity forecasts.

Implications of Solar and Cosmic Radiation

The research identifies a critical limitation in current understanding and preparation for radiation risk during manned missions beyond LEO. The Van Allen Radiation Belt remains a formidable challenge due to its high density of protons and electrons. Even with advanced shielding strategies, the paper cautions that the radiation exposure on a journey to Mars could reach unmanageable levels. For instance, during a solar maximum, the dose during a Mars mission could reasonably be expected to exceed 11,500 mSv, considerably above safety thresholds for human health.

Shielding and Safety Measures

Despite NASA declaring that radiation did not pose operational issues during Apollo missions, Märki's paper recommends significant increases in shielding—suggesting improvements from the Apollo-era aluminum honeycomb composite structures to more substantial shielding materials, potentially incorporating water barriers or innovative active radiation protection technologies, such as those involving superconducting magnets envisioned by ESA.

Theoretical Implications and Future Research Directions

The findings have profound implications for manned interplanetary travel, mandating caution and advanced planning regarding radiation safety measures. The paper encourages the development of enhanced predictive models for solar and galactic radiation, alongside the exploration of potential technological advancements in both passive and active shielding solutions. Future research should continue to focus on mitigating radiation exposure through trajectory optimization, and potentially exploiting contemporary materials science advancements.

Conclusion

In summary, Andreas Märki's research provides an essential technical assessment of radiation risks in human space exploration. The combination of historical data analysis and computational modeling underscores the substantial challenges posed by solar and cosmic radiation. The paper suggests that without significantly improved shielding and predictive capabilities, the execution of safe, long-duration manned missions to Mars remains fraught with risk. As such, ongoing advancements in radiation protection technology and mission planning will be indispensable for the future of human space exploration.