NASA Space Cancer Risk (NSCR) Model 2020

The NASA Space Cancer Risk (NSCR) projection model evaluates space radiation health risks and their uncertainties for space missions. Originally developed in 2010, the model was successfully reviewed by the U.S. National Research Council (NRC) in 2012, leading to the first publicly released version in 2013. Improvements in the model occurred in revised versions [1-7] (NSCR-2016 and NSCR-2018), which included estimates of the risk of circulatory diseases, allowing the dose-rate modifiers to be distinct for the track core and penumbra terms of the space radiation quality factor (QFspace), updated QFspace parameters, dose and dose-rate reduction effectiveness factors (DDREF) based on Bayesian analysis of cell and animal tumor data. The potential for a higher tumor lethality for high LET radiation compared to photons was estimated in the revised approach [1,4]. The inclusion of estimates of non-targeted effects in QFspace based on radiobiology data is considered in NSCR-2018 and shown to increase cancer risk projections for a Mars mission by 2-3 fold over a targeted effects model. In this report, we discuss new developments in NSCR-2020. These include for the first time the development of relative risk models of cognitive detriments during space travel [8,9], and a revised approach to consider the energy dependence of delta-ray biological effectiveness and track-width in QFspace. Applications to Mars mission risk projections are described. [1] Cucinotta FA. Space Radiation Risks for Astronauts on Multiple International Space Station Missions. PLoS One 9(4) e96099, 2014. [2] Cucinotta FA. A New Approach to Reduce Uncertainties in Space Radiation Cancer Risk Predictions. PLoS One 120717, 2015. [3] Cucinotta, FA, Alp M, Rowedder B, Kim MY. Safe Days in Space with Acceptable Uncertainty from Space Radiation Exposure. Life Sciences in Space Research 2, 54-69, 2015 [4] Cucinotta FA, To K, Cacao E. Predictions of Space Radiation Fatality Risk for Exploration Missions. Life Sciences in Space Research 13, 1-11, 2017. [5] Cacao E, Hada, M., Saganti PB, George KA, Cucinotta FA. Relative Biological Effectiveness of HZE Particles for Chromosomal Aberrations and Other Surrogate Cancer Risk Endpoints. PLoS One 11(4): e0153998, 2016. [6] Cucinotta FA, Cacao E. Non-Targeted Effects Models Predict Significantly Higher Mars Mission Cancer Risk than Targeted Effects Model. Scientific Reports 7, 1832, 2017. [7] Cucinotta FA, Cacao E, Kim MY, Saganti PB. Cancer and Circulatory Disease Risks for a Human Mission to Mars: Private Mission Considerations. Acta Astronautica 166, 529-536, 2020. [8] Cacao E, Cucinotta FA. Meta-analysis of Cognitive Performance by Novel Object Recognition after Proton and Heavy Ion Exposures. Radiation Research 192, 463-472, 2019 [9] Cucinotta FA, Cacao E. Predictions of Cognitive Detriments from Galactic Cosmic Ray Exposures to Astronauts on Exploration Missions. Life Sciences in Space Research (on-line first), 2019.