The Mortality of Space Explorers

Abstract

Outer space exploration poses unique risks to human survival. Here, we review the current literature on United States astronauts and Soviet and Russian cosmonauts and provide updated and original research findings. As in previous research, both astronauts and cosmonauts are shown to have reduced risk of death by natural causes, particularly from chronic diseases such as cardiovascular disease and cancer, compared with appropriately matched general populations. Simultaneously, space explorers are at increased risk of death by external forces, particularly accidents such as plane crashes and spacecraft accidents. In total, both astronauts and cosmonauts are at reduced risk of all-cause mortality in comparison to the general populations of the United States and Russia. However, in comparison to astronauts, cosmonauts have been at equal risk of accidental death, but increased risk of death by chronic disease. We conjecture that the lack of risk from chronic disease may be due to the excellent health and medical monitoring of space explorers coupled with the deliberate attempts to limit their radiation exposure levels below those that would be detrimental. The differences in the astronaut and cosmonaut mortality experiences are likely due to lifestyle factors and the background rates of mortality in the two nations.

Cancer Incidence and Mortality in the U.S. Astronaut Corps, 1959-2017

“…25 Consistent with this hypothesis, prior studies of cardiovascular disease among astronauts show reductions in both incidence and mortality in comparison to the general population. [4][5]26 Large differences in incidence and mortality rates between a largely never-smoker population and the US population as shown in table 4 are to be expected. However, due to changing smoking patterns in the US population over time, determining whether this difference in lung cancer is entirely due to healthy behavior or whether space ight exposures are contributing to a cancer risk would require a more detailed analysis.…”

“…The database has been used extensively in prior publications concerning astronaut mortality. [5][6][7] Counts of tumors and cancer deaths were obtained from the 2019 issue of the newsletter of the Lifetime Surveillance of Astronaut Health (LSAH) at NASA, with input from the LSAH on speci c tumor and death counts. 8 In comparison to the original source table, 2 cancers (1 melanoma and 1 testicular) were removed from the tumor counts, as they were diagnosed prior to time of selection to the Astronaut Corps.…”

“…4 Within the full cohort and with follow-up through October 2017, astronauts were reported to be at only 62% the risk of the general population for mortality from all cancers (95% CI = 37-97%). 5 Finally, in comparison to professional basketball players, astronauts were at no differential risk of cancer mortality, with only a nominal and non-signi cant 10% lower mortality rate for astronauts. 6 In the present work, we analyze standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) to compare astronaut cancer incidence and mortality rates with those of the general population.…”

Mortality of US astronauts: comparisons with professional athletes

“…NBA players are selected at age 23 on average and have an average career length in the NBA of about 6 years 12. In contrast, astronauts are selected at age 35 on average and have an average tenure in the Astronaut Corps of 12 years 2. Presumably this means that astronauts maintain career-level fitness for a longer period after selection, which equates to a longer period overall (to age 47 years on average).…”

“…For the astronaut cohort we used the rates in the 5×10 format. We calculated cause-specific SMRs based on causal categories used in prior astronaut mortality research 2. In addition to all causes, we divided deaths into the major categories of external causes and natural causes.…”