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Now that The Biden administration has signaled its support for NASA’s Artemis mission to the moon, maybe we should think about the risks astronauts will face 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 malfunctions, strange weight effects, collisions with space debris and just the fact that they are far away – one of the most difficult to treat is the effects of solar or cosmic radiation. on health. evenimente. This radiation consists of atoms that have lost their electrons as they accelerate in interstellar space, approaching the speed of light – something that happens immediately after the explosion of a star, for example. It comes in three forms: particles trapped in the Earth’s magnetic field; particles thrown into space during solar flares; and galactic cosmic rays, which are high-energy protons and heavy ions outside our solar system.
It is also one of the “red risks” identified by a NASA study published last year on the highest priority health issues facing astronauts. Radiation damages DNA and can lead to mutations that can trigger cancer. It can also cause cardiovascular health problems, such as heart damage, narrowing of arteries and blood vessels, and neurological problems that can lead to cognitive impairment, according to a NASA website.
On Earth, humans are exposed to 3 to 4 millisieverts (mSv) of radiation per year, mainly from natural sources, such as some types of rocks and the few cosmic rays that pass through the atmosphere. On the International Space Station, astronauts receive about 300 mSv per year. Until now, a 55-year-old man, NASA astronaut, was limited to an effective dose of 400 mSv during his career, while a 35-year-old astronaut could only be exposed to 120 mSv.
Now, when NASA intends to send people on much longer missions, the agency is considering raising the threshold to 600 mSv for astronauts of any gender or age. According to the existing standard, some veteran astronauts could have been excluded from longer-term space missions because they face the limits of radiation for life. Younger astronauts have less time to fly in space and therefore less exposure, but the success of a large mission may require experience in youth.
The new limit proposed by NASA would still be lower than for other space agencies; European, Russian and Canadian astronauts can be exposed to up to 1,000 mSv before being tied to space officials. But NASA officials do not apologize for their more conservative stance. “It’s a different risk position in what we consider an acceptable risk,” said David Francisco, a human space flight technician at NASA’s Medical Director’s Office. “We chose 600 because we consider it more acceptable for our culture. It’s something we’re constantly working on and going back and forth. We debated going to 1,000 and this is one of the questions: Are we still conservatives with 600? ”
To solve this question, the space agency asked a group of experts from the National Academy of Sciences to determine which is the best number to use. The panel began meeting last month and is expected to complete its work by this summer. The experts will look at how NASA has calculated its new exposure limits and how they match existing clinical data and animal studies.
To understand the links between radiation and cancer, medical researchers have long traced the survivors of the atomic bomb blast in Japan during World War II (as well as the health of their children). There have also been studies on medical workers exposed to X-rays and workers in nuclear power plants who receive low doses of radiation during their careers. But NASA doesn’t have much data on the health effects of space radiation on its astronauts.