For nearly 60 years, scientists and astronauts have been warned that space travel can lead to an increased risk for cancer. The reasoning has been that because voyaging beyond Earth’s protective atmosphere offers far less protection against the sun’s cancer-causing radiation (despite the fortification of space vessels), these travelers are at greater risk. But new research on the health effects of man’s voyages into space has found no greater cancer risk among space travelers compared with the general population, reports.

Published in Scientific Reports, the findings are likely to assuage the fears of space scientists and travelers alike. 

For the study, researchers with Mortality Research & Consulting, the Izmerov Institute of Occupational Health and the Russian State Research Center reviewed the medical files of all astronauts and cosmonauts (as Russian astronauts are called) who went on space missions between 1959 and 2018. Overall, the group included 117 cosmonauts and 301 astronauts.

Of the 89 people in the study cohort who have died so far, more than 30% of astronauts died of cancer. Among cosmonauts, 28% died of cancer. Researchers also found that 15% of astronauts and 50% of cosmonauts died of cardiovascular disease—another assumed risk of space travel. The rest died of other causes.

Study authors noted that none of these numbers was statistically significant, meaning they could have occurred by chance.

However, researchers acknowledged that their findings may have little bearing on many future missions (such as those planned for Mars) since all but 24 of the space travelers surveyed never left Earth’s magnetic field. Those who did venture further, notably to the moon, are considered too small a group for a meaningful study.

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