Cancer and circulatory disease risks for the largest solar particle events in the space age

In this paper we use the NASA Space Cancer Risk (NSCR version 2022) model to predict cancer and circulatory disease risks using energy spectra representing the largest SPE's observed in the space age. Because tissue dose-rates behind shielding for large SPE's lead to low dose-rates (<0.2 Gy/h) we consider the integrated risk for several historical periods of high solar activity, including July-November, 1960 events and August-October 1989 events along with the February 1956 and August 1972 events. The galactic cosmic ray (GCR) contribution to risks is considered in predictions. Results for these largest historical events show risk of exposure induced death (REID) are mitigated to < 1.2 % with a 95 % confidence interval with passive radiation shielding of 20 g/cm(2) aluminum, while larger amounts would support the application of the ALARA principle. Annual GCR risks are predicted to surpass the risks from large SPEs by similar to 30 g/cm(2) of aluminum shielding.

Automated summary

In this paper, the NASA Space Cancer Risk (NSCR version 2022) model is used to predict the risks of cancer and circulatory diseases caused by the largest observed solar particle events (SPEs) in the space age. The contribution of galactic cosmic rays (GCRs) to the risks is also considered. The results show that with proper shielding, the risks can be mitigated, and the annual GCR risks are predicted to surpass the risks from large SPEs.