Astronauts Aren’t Dying from Space Radiation, New Research Suggests

The latest study published in Scientific Reports couldn’t associate space radiation exposure with an increased risk of death from cancer or heart disease among astronauts and cosmonauts. It was a bit surprising because it was long assumed that exposure to ionizing radiation could be damaging to astronauts in their later life in the form of diseases that could lead to an early death.

Astronauts are not Dying because of Space Radiations

Scientists used to think that excessive exposure to the harmful sun rays is an occupational hazard endured by astronauts who are on space missions. According to their assumption, they are at risk of contracting cancer and cardiovascular disease. However, new research shows that astronauts aren’t dying prematurely due to space exposure. Although scientists are still cautious that long-duration missions could pose serious risks.

Astronauts NOT Dying from Space Radiation

Image: NASA

The lead author of new research, Robert Reynolds from Mortality Research and Consulting, Inc., California, stated that space missions of longer durations that take astronauts further away from the protective magnetic field of Earth could be dangerous and potentially life-shortening for them. Mission to Mars is one such project that could haunt astronauts and cosmonauts in the form of life-threatening diseases.

For the research, they performed a statistical analysis of the historical data of a total of 418 spacefaring individuals publicly available. Out of 418 individuals, 301 were astronauts while the rest 117 were cosmonauts.

They considered all astronauts from NASA since 1959 and all cosmonauts from Russia since 1961 in their study. The astronauts had a space trip prior to July 2018, while the cosmonauts had their space trip prior to December 2017.

They considered an average follow-up period of 24 years for astronauts and 25 years for cosmonauts. They recorded a total of 89 deaths. Out of 89, 53 of them were astronauts, while the rest were cosmonauts. Although they died from different causes, Reynolds and his team were only concerned with two particular causes of death: cancer and heart diseases. Because these two conditions are associated with radiation exposure.

According to their findings, 30% of the astronauts died from cancer and less than 15% of them died of heart disease. In the case of cosmonauts, 50% of them died of heart disease and 28% of them died from cancer.

Though these stats seemed both high and alarming, Reynolds’ analysis suggested these figures were nothing out of the ordinary. Since, no trend or hiccup could be detected in the data pointing to a common cause of death, namely radiation exposure.

So, they concluded that the impact of ionizing radiation on the risk of death due to cancer and heart diseases is not much.

However, this research was related to historical doses of space radiation. Except the Apollo missions, the astronauts and cosmonauts were still protected by the Earth’s magnetic field in low Earth orbit during other missions. In the future, the situation will be quite different, because the astronauts would have to journey deeper into space.

One of the NASA researches from 2013 concluded that without sufficient protection, the astronauts on Mars mission could get impacted by as much space radiation as they’d have received from a full-body CT scan once a week for an entire year. Thus, it’s vital to develop special spacesuits or shielding to protect individuals from life-threats due to space radiation exposure.


The future missions of deep space exploration will likely offer much greater doses of space radiation compared to historical doses. This could lead to a different risk profile for future astronauts and cosmonauts. So, it’s important that epidemiologists continue to suggest safety measures for the astronauts and cosmonauts at risk of potentially harmful effects of exposure to space radiation. Doing so will be essential to supporting human ambitions for further explorations and eventual colonization of our solar system.

Study Reference:

Contrapositive logic suggests space radiation not having a strong impact on mortality of US astronauts and Soviet and Russian cosmonauts.
Authors: Robert J. Reynolds, Igor V. Bukhtiyarov, Galina I. Tikhonova, Steven M. Day, Igor B. Ushakov & Tatyana Y. U. Gorchakova.