A study publish in Scientific Reports fail to tell about exposure to space radiation with an increase risk of death; from cancer or cardiovascular disease among both astronauts and cosmonauts. It’s a surprising, if not encouraging, result, as it was long assume that exposure to damaging; ionizing radiation would eventually come back to retreat astronaut; in the form of diseases later in life, and possibly an early grave.

Excessive exposure to the Sun’s harmful rays is an occupational hazard endure by astronauts; who run the risk of contracting cancer and heart disease as a result. At least that’s what we thought. New research shows that astronauts are not dying prematurely; but scientists caution that long duration missions will pose serious risks.

That said, the lead author of the new study; Robert Reynolds from Mortality Research & Consulting, Inc., in California, cautioned that longer duration missions further away from Earth’s protective magnetic field, such as a mission to Mars, are likely to be dangerous and potentially life shortening. For the new study, Reynolds and his colleagues performed a statistical analysis of publicly available historical data. A total of 418 spacefaring individuals were include in the study, including 301 astronauts and 117 cosmonauts.

Cancer and cardiovascular disease

The study consider all NASA astronauts since 1959 and all Soviet or Russian cosmonauts since 1961, all of whom experienced a trip to space prior to July 2018 in the case of astronauts and December 2017 for cosmonauts. The average follow-up period for astronauts was 24 years and for cosmonauts it was 25 years.

A total of 89 deaths were record, 53 of them astronauts and 36 cosmonauts. These individuals die from various causes, but Reynolds and his team were only interest in two particular causes of death: cancer and cardiovascular disease; as those conditions had the potential to be linked to radiation exposure. Among astronauts, 30 % died from cancer and less than 15 % died of heart disease. The stats were a bit different for cosmonauts, half of whom died of heart disease and 28 % from cancer.

These stats may seem both high and alarming, but Reynolds’ analysis suggest these figures were nothing out of the ordinary. No trend or hiccup could be detect in the data pointing to a common cause of death, namely exposure to radiation. “If ionizing radiation is impacting the risk of death due to cancer and cardiovascular disease, the effect is not dramatic,” concluded the authors of the new study.

Risk profile for future astronauts and cosmonauts

But these are “historical doses of space radiation,” as the authors described it. Aside from the Apollo missions, astronauts and cosmonauts in low Earth orbit were still protect by the Earth’s magnetic field. The situation in the future, when astronauts journey deeper into space, will be markedly different, as noted in the new study:

It is important to note that future missions of deep space exploration will likely offer much greater doses of space radiation than have historical doses, which will lead to a different risk profile for future astronauts and cosmonauts. In the years to come it is imperative that epidemiologists continue to surveil the astronaut and cosmonaut populations for potential harmful effects of exposure to space radiation, using methods both novel and familiar. Doing so will be integral to supporting human ambitions for further exploration and eventual colonization of our solar system.