NASA Langley Research Center, Hampton, Virginia 23681, USA.
NASA Langley Research Center, Hampton, Virginia 23681, USA.
Life Sci Space Res (Amst). 2019 Aug;22:98-124. doi: 10.1016/j.lssr.2019.07.003. Epub 2019 Jul 10.
The space radiation environment is a complex mixture of particle types and energies originating from sources inside and outside of the galaxy. These environments may be modified by the heliospheric and geomagnetic conditions as well as planetary bodies and vehicle or habitat mass shielding. In low Earth orbit (LEO), the geomagnetic field deflects a portion of the galactic cosmic rays (GCR) and all but the most intense solar particle events (SPE). There are also dynamic belts of trapped electrons and protons with low to medium energy and intense particle count rates. In deep space, the GCR exposure is more severe than in LEO and varies inversely with solar activity. Unpredictable solar storms also present an acute risk to astronauts if adequate shielding is not provided. Near planetary surfaces such as the Earth, moon or Mars, secondary particles are produced when the ambient deep space radiation environment interacts with these surfaces and/or atmospheres. These secondary particles further complicate the local radiation environment and modify the associated health risks. Characterizing the radiation fields in this vast array of scenarios and environments is a challenging task and is currently accomplished with a combination of computational models and dosimetry. The computational tools include models for the ambient space radiation environment, mass shielding geometry, and atomic and nuclear interaction parameters. These models are then coupled to a radiation transport code to describe the radiation field at the location of interest within a vehicle or habitat. Many new advances in these models have been made in the last decade, and the present review article focuses on the progress and contributions made by workers and collaborators at NASA Langley Research Center in the same time frame. Although great progress has been made, and models continue to improve, significant gaps remain and are discussed in the context of planned future missions. Of particular interest is the juxtaposition of various review committee findings regarding the accuracy and gaps of combined space radiation environment, physics, and transport models with the progress achieved over the past decade. While current models are now fully capable of characterizing radiation environments in the broad range of forecasted mission scenarios, it should be remembered that uncertainties still remain and need to be addressed.
空间辐射环境是一种由星系内外的粒子类型和能量组成的复杂混合物。这些环境可能会受到太阳圈和地磁条件以及行星体、飞行器或栖息地质量屏蔽的影响而发生变化。在近地轨道（LEO），地磁场会使一部分银河宇宙射线（GCR）和除了最强烈的太阳粒子事件（SPE）之外的射线发生偏折。此外，这里还有能量较低且中等、粒子计数率较高的动态电子和质子俘获带。在深空，GCR 辐射比 LEO 更为严重，且随太阳活动呈反向变化。如果没有足够的屏蔽，不可预测的太阳风暴也会对宇航员构成严重威胁。在近行星表面，如地球、月球或火星，当地的深空间辐射环境与这些表面和/或大气层相互作用时，会产生次级粒子。这些次级粒子进一步使当地的辐射环境变得复杂，并改变了相关的健康风险。在如此庞大的场景和环境中，对辐射场进行特征描述是一项具有挑战性的任务，目前需要结合计算模型和剂量学来完成。这些计算工具包括环境空间辐射环境模型、质量屏蔽几何形状以及原子和核相互作用参数模型。然后，这些模型与辐射传输代码耦合，以描述飞行器或栖息地内感兴趣位置的辐射场。在过去的十年中，这些模型取得了许多新的进展，本综述文章重点介绍了在同一时期，美国宇航局兰利研究中心的工作人员和合作者在这些模型方面取得的进展和贡献。尽管取得了巨大的进展，并且模型仍在不断改进，但仍存在重大差距，并在计划未来任务的背景下进行了讨论。特别值得关注的是，将各种审查委员会的调查结果（关于组合空间辐射环境、物理和传输模型的准确性和差距）与过去十年取得的进展进行并列对比。虽然当前的模型现在已经完全能够描述广泛预测的任务场景中的辐射环境，但仍应记住，不确定性仍然存在，需要加以解决。
