3 percent increase in the Risk of Exposure Induced Death (REID). The PEL standards are approved by the NASA Chief Health and Medical Officer.

NASA has updated its Space Radiation Cancer Risk Model based on recent developments including the following:

•   BEIR-VII, UNSCEAR-2006, and other reports in the scientific literature have made new assessments of human radio-epidemiology data and DDREFs;

•   New research results from NSRL have begun to modify the understanding of radiation quality and dose-rate effects; and

•   NASA’s revised evaluation of uncertainty factors.

Because it is used to project the cancer risk for current ISS crews and future explorations missions, this NASA update to its Space Radiation Cancer Risk Model requires independent review and validation.


1. The committee will evaluate proposed updates to the NASA cancer projection model taking into consideration the following:

•   Current knowledge of low-LET radiation cancer epidemiology,

•   Effects of tissue weighting factors, radiation weighting factors, and DDREFs used in projecting risks, and

•   Current uncertainties in Quality Factors, DDREFs and organ dose assessment.

This will be done taking into consideration possible qualitative differences between low LET and heavy ion biological effects to determine if the use of quality factors are appropriate or inappropriate for GCR risk assessments.

2. The committee will identify gaps in NASA’s current research strategy for reducing the uncertainties in cancer induction risks.

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