Prolonged exposure to the galactic cosmic ray (GCR) environment is a potentially limiting factor for manned missions in deep space. Evaluating the risk associated with the expected GCR environment is an essential step in planning a deep space mission. This requires an understanding of how the local interstellar spectrum is modulated by the heliospheric magnetic field (HMF) and how observed solar activity is manifested in the HMF over time. While current GCR models agree reasonably well with measured observations of GCR flux on the first matter, they must rely on imperfect or loose correlations to describe the latter. It is more accurate to use dose rates directly measured by instruments in deep space to quantify the GCR condition for a given period of time. In this work, dose rates observed by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument are used to obtain the local GCR intensity and composition as a function of time. A response function is constructed that relates observed dose rates to solar modulation potential using a series of Monte Carlo radiation transport calculations. The record of observed solar modulation potential vs. time is then used to calculate a recent historical record of permissible mission duration (PMD) according to NASA's permissible exposure limits (PEL). Tables are provided for extreme values of PMD. Additional tables include risk of exposure-induced death (at upper 95% confidence interval) accrual rates and NASA effective dose rates as a function of solar modulation potential, astronaut age, sex, and shielding thickness. The significance of the PMD values reported in relation to likely transit duration requirements for future exploration missions is discussed. There is general agreement between CRaTER observations and the prescription of solar modulation vs. time given by the Badhwar–O'Neill 2014 GCR model. However, CRaTER observations do capture the effects of significant heliospheric transients, among other features, that are missing from the prescription of solar modulation potential vs. time.

长时间暴露于银河宇宙射线（GCR）环境是执行载人太空任务的潜在限制因素。评估与预期的GCR环境相关的风险是计划深空任务的重要步骤。这需要了解局部星际光谱如何被日光层磁场（HMF）调制，以及随着时间的推移在HMF中如何观察到太阳活动。尽管当前的GCR模型在第一件事上与GCR通量的实测观测值相当吻合，但它们必须依靠不完美或松散的相关性来描述后者。使用深空仪器直接测量的剂量率来定量给定时间段内的GCR条件更为准确。在这项工作中 由宇宙射线望远镜观测的辐射效应剂量率（CRaTER）用于获得随时间变化的局部GCR强度和组成。使用一系列蒙特卡洛辐射传输计算，构建了一个将观察到的剂量率与太阳调制电位相关联的响应函数。然后，根据NASA的容许暴露极限（PEL），使用观测到的太阳调制电位随时间变化的记录来计算最近的容许任务持续时间（PMD）的历史记录。提供了PMD极值的表格。其他表格包括暴露引起的死亡风险（在较高的95％置信区间内）应计比率和NASA有效剂量率随太阳调制电位，宇航员年龄，性别和屏蔽厚度的变化。讨论了所报告的PMD值与未来勘探任务可能的运输持续时间要求相关的意义。巴赫瓦尔-奥尼尔2014年GCR模型给出的CRaTER观测值与太阳调制相对于时间的处方之间存在普遍的共识。但是，CRaTER观测的确捕获了重要的日球瞬变的影响以及其他特征，而太阳调制电势随时间变化的处方中缺少这些影响。