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Now that the Biden’s administration has expressed its support for NASA’s Artemis mission to the moon, perhaps we should think about the dangers facing astronauts when they get there, and what might happen during a longer trip to Mars .
Of all the things to worry about while traveling in space – equipment misuse, the strange effects of weight loss, accidents with space debris, and just being far away – one of the most difficult problems deal with the effects of radiation from the sun or cosmic events. This radiation involves atoms losing their electricity as they accelerate in an intergalactic space, approaching the speed of light – something that happens right after a star explodes, for example. It comes in three forms: particles locked in the Earth’s magnetic field; particles burned into space by solar flames; and galactic cosmic rays, which are high-energy proteins and heavy ions from outside our solar system.
It is also one of the “red threats” identified by a NASA study published last year on the highest priority health problems facing astronauts. Radiation damages DNA and can lead to mutations that trigger cancers. It can also cause cardiovascular health problems such as heart damage, narrowing of arteries and blood vessels, and brain problems that can lead to brain damage, according to the NASA website.
On Earth, humans are exposed to 3 to 4 millisieverts (mSv) of radiation each year, mostly from natural sources such as certain types of rocks and the few cosmic rays that receive through the atmosphere. On the International Space Station, astronauts receive about 300 mSv per year. Until now, a 55-year-old NASA male astronaut was limited to an effective dose of 400 mSv over his career, while a 35-year-old female astronaut could not be exposed to 120 mSv.
Now that NASA plans to send humans on much longer missions, the agency is considering raising that threshold to 600 mSv for astronauts of any gender or age. Under the current status, some veterans ’astronauts may be excluded from long-term space missions because they violate the limits of lifelong radiation. Younger astronauts have less time to fly in space and therefore less visibility, but the success of a major mission may require childhood experience.
The new limit proposed by NASA would still be lower than those for other space agencies; European, Russian and Canadian astronauts can be exposed to up to 1,000 mSv before their space officers land. But NASA officials have no excuse for their more conservative stance. “It’s a different risk situation in what we feel is a potential threat,” said David Francisco, a technician for human space lighting standards at NASA’s Chief Medical Officer’s Office. “We chose 600 because we feel it is more in tune with our culture. It’s something we’re always working on and going back and forth. We were discussing going to 1,000, which is one of the questions: Are we still conserving 600? ”
To solve that question, the space agency has asked a panel of experts from the National Academy of Sciences to find out which number is best to use. The panel began meeting last month and is expected to complete its work in the summer. The experts will look at how NASA has measured their new exposure limits, and how these match the existing clinical data and animal studies.
To understand the links between radiation and cancers, medical researchers have long followed the atomic bomb explosions in Japan during World War II (as well as the health of their children). Studies have also been carried out on medical workers exposed to x-rays, and nuclear facility workers, who receive low doses of radiation over the course of their life course. But NASA has little data on the health effects of radiation on space on astronauts.