Mars is often touted as the next planet people could inhabit, but the amount of radiation we would be exposed to would significantly raise the risk of fetal abnormalities, and existing technologies can’t get around it.
Compared with Earth, the surface of Mars is exposed to much higher levels of radiation, which can kill cells and cause cancer.
Amid plans to explore more of our solar system, of the University of Health Sciences in Istanbul, Turkey, and his colleagues wondered how safe pregnancy may be beyond Earth, both during the journey to other planets and if we set up living there.
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The team looked at various possible durations of flights to Mars and estimations of the amount of radiation exposure that would occur. For example, the Curiosity rover received an average of 1.8 millisieverts of radiation per day as it journeyed towards Mars – 455 millisieverts for the entire 253-day journey.
An astronaut receives around 100 millisieverts of radiation over a four-month stay aboard the International Space Station, compared with an average of just 2.4 millisieverts over the same time period on Earth.
But the amount of radiation exposure in space also depends on solar weather, so other voyagers to Mars may experience daily exposure rates as low as 0.5 millisieverts.
These measurements are made up of exposure to both galactic cosmic rays – high-energy radiation from beyond our solar system, which is considered particularly dangerous – and solar energetic particles emitted from the sun.
Based on a review of data such as this, the researchers calculated that during a six-month space flight to Mars, a crew member would accumulate between 90 millisieverts and 324 millisieverts of galactic cosmic rays and solar radiation.
That level of exposure would probably increase the risk of fetal abnormalities, they say. The US Nuclear Regulatory Commission recommends a maximum safe radiation dose throughout pregnancy of 5 millisieverts. On Mars itself, the exposure is around 0.64 millisieverts a day, which would exceeded the recommended safe maximum dose in just over a week.
One of the uncertainties of the research is that relatively little is known about the actual impacts of galactic cosmic rays, but they can easily penetrate spacecraft and the human body, raising safety concerns.
“While Mars has less radiation than deep space, the thin atmosphere and lack of magnetic shielding still allow substantial amounts of radiation to reach the surface,” says Demir. Future innovations in shielding may make pregnancy on Mars safe, “however, achieving this would require a technology well above present norms”, he says.
at Australia’s Nuclear Science and Technology Organisation in Sydney says that some people who live on mountains are exposed to between 70 millisieverts and 110 millisieverts of different types of radiation annually, without an increase in conditions linked to such exposure. However, like the researchers, she thinks that the greatest risk on a deep space mission is from increased exposure to galactic cosmic rays.
“When you are in space, it’s not like single-source radiation on Earth, it is like a punch cocktail – you have everything,” says Safavi-Naeini. “While we don’t know the impacts, maybe the best approach is to hold off on pregnancy in space. Further research in this area is necessary to make space exploration safer for all astronauts, including women, rather than creating barriers.”
Life Sciences in Space Research
