Extreme solar event of AD775: Potential radiation exposure to crews in deep space

Townsend, L. W.; Porter, Jared M.; deWet, W. C.; Smith, W.J.; McGirl, Natalie A.; Heilbronn, L.; Moussa, Hanna

doi:10.1016/j.actaastro.2016.03.002

Cited by 9 publications

(2 citation statements)

References 20 publications

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“…They suggest that these protons came from high-energy, impulsive events erupting on the Sun from the borders of the optimum connection region to Earth (W40-70 longitude on the Sun) and were accelerated by quasi-perpendicular shocks. Estimates of doses from the 774/775 AD event, using an earlier Band Fit parameterization of the 1956 event [13], scaled to the fluence of the 774/775 AD event, presented in [14], were reported by [15]. More recently, updated spectral parameters for the February 956 event spectrum, based upon the Band function [16], and another based upon a new parameterization using a modified Band function form [17] were published.…”

Section: Introductionmentioning

confidence: 99%

Radiation Risks in Cis-Lunar Space for a Solar Particle Event Similar to the February 1956 Event

Zaman

Townsend

2021

Aerospace

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Solar particle events (SPEs) can pose serious threats for future crewed missions to the Moon. Historically, there have been several extreme SPEs that could have been dangerous for astronauts, and thus analyzing their potential risk on humans is an important step towards space exploration. In this work, we study the effects of a well-known SPE that occurred on 23 February 1956 on a mission in cis-Lunar space. Estimates of the proton fluence spectra of the February 1956 event were obtained from three different parameterized models published within the past 12 years. The studied geometry consists of a female phantom in the center of spherical spacecraft shielded by aluminum area densities ranging from 0.4 to 40 g cm−2. The effective dose, along with lens, skin, blood forming organs, heart, and central nervous system doses, were tallied using the On Line Tool for the Assessment of Radiation In Space (OLTARIS), which utilizes the High Z and Energy TRansport code (HZETRN), a deterministic radiation transport code. Based on the parameterized models, the results herein show that thicknesses comparable to a spacesuit might not protect against severe health consequences from a February 1956 category event. They also show that a minimum aluminum shielding of around 20 g cm−2 is sufficient to keep the effective dose and critical organ doses below NASA’s permissible limits for such event. In addition, except for very thin shielding, the input models produced results that were within good agreement, where the doses obtained from the three proton fluence spectra tended to converge with slight differences as the shielding thickness increases.

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Section: Introductionmentioning

confidence: 99%

Radiation Risks in Cis-Lunar Space for a Solar Particle Event Similar to the February 1956 Event

Zaman

Townsend

2021

Aerospace

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“…Nevertheless, there remains a significant health risk for humans [Cucinotta et al, 2013] and radiation hazards at a level critical for the modern technology from a large SPE without proper shielding. Moreover, immediate harm is expected from an extreme SPE with an order-of-magnitude increase in fluence to very hard spectrum of the 23 February 1956 SPE event [Vainio et al, 2009;Atri and Melott, 2014;Townsend et al, 2016], whose frequency is estimated as once per century by the distribution of terrestrial data [Schrijver et al, 2012;Usoskin and Kovaltsov, 2012]. In addition, many small SPEs can disrupt mission operations and lead to excessive costs.…”

Section: Introductionmentioning

confidence: 99%

Using spectral shape and predictor fluence to evaluate temporal dependence of exposures from solar particle events

et al. 2017

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Real‐time estimation of exposure levels has been considered in NASA's operational strategies and structural capability for the protection of astronauts from exposure to large solar particle events (SPEs). The temporal profile of organ dose rates is also important for the analysis of dose‐rate‐dependent biological responses and the optimization of radiation shielding and future mission planning. A realistic temporal estimation of exposure profiles relies on (1) the complete energy spectrum of SPE that defines the boundary condition for radiation transport simulation, (2) the radiation transport simulation with detailed shielding and body geometry models that determines particle transmission at each critical body organ, and (3) the assessment of organ dosimetric quantities and biological risks by applying the corresponding response models. This paper introduces a process of rapidly estimating temporal exposures to SPEs by implementing the distributions of the organ doses and the spectral‐shape characterization of the major SPEs. Simultaneously, the unconditional probability exceeding the NASA 30 day limit of a blood‐forming organ dose is estimated by taking into account the variability of detailed spectra of SPEs for a given predictor fluence. These temporal evaluations of SPEs can be applied to the development of real‐time guidance and protection system on improving mitigation of adverse effects during space missions.

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Effects of Space Radiation on Humans in Space Flight

Townsend

2021

Space Weather Effects and Applications

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Extreme solar event of AD775: Potential radiation exposure to crews in deep space

Cited by 9 publications

References 20 publications

Radiation Risks in Cis-Lunar Space for a Solar Particle Event Similar to the February 1956 Event

Radiation Risks in Cis-Lunar Space for a Solar Particle Event Similar to the February 1956 Event

Using spectral shape and predictor fluence to evaluate temporal dependence of exposures from solar particle events

Effects of Space Radiation on Humans in Space Flight

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