Researchers from NASA explained that astronauts are constantly faced with the threat of radiation, as particles flying from the Sun and high-energy cosmic rays constantly affect their bodies.
If left unchecked, radiation can cause all sorts of health problems, raising the risk of cancer in the first place. Therefore, in flight planning, NASA uses radiation exposure limits to determine how long astronauts can be in space. But this limit is not the same for all astronauts. Independent experts now support NASA’s proposal to change these numbers.
NASA is now calculating this limit based on its risk assessment. The limit is the amount of total exposure that increases the likelihood of an astronaut dying from cancer during the remainder of his life by 3%.
However, the susceptibility to cancers that radiation can cause depends on age and reproductive organs, so the limitation does not allow everyone to spend the same amount of time in space. Therefore, under current regulations, NASA astronauts will not be able to spend as much time in orbit as astronauts, and younger professionals less time than their older counterparts, who do not have much time to develop cancer in their bodies.
NASA has decided that the average radiation limit will be 600 millisieverts over a career with the agency. For comparison, one chest x-ray in a doctor’s office gives about 0.1 millisievert, and the natural background radiation of the Earth – about 3 millisieverts per year. Workers who were near the zero mark of the Chernobyl nuclear power plant in 1986 received 6 thousand millisieverts.
Meanwhile, according to a new report, an astronaut gets between 50 and 120 millisieverts in six months on the International Space Station. More distant destinations, such as Mars, are subject to more radiation.