Washington: The US is preparing to return humans to the Moon this decade, one of the biggest dangers future astronauts will face is space radiation that can cause lasting health effects, from cataracts to cancer and neurodegenerative diseases. The Apollo missions of the 1960s and 1970s proved it was safe for people to spend a few days on the lunar surface, NASA did not take daily radiation measurements that would help scientists quantify just how long crews could stay. The radiation of the Moon is between two and three times higher than what you have on the ISS (International Space Station. So that limits your stay to approximately two months on the surface of the Moon. The radiation levels measured on the Moon are about 200 times higher than on the surface of the Earth and five to 10 times higher than on a flight from New York to Frankfurt.
There are several sources of radiation exposure: galactic cosmic rays, sporadic solar particle events (for example from solar flares), and neutrons and gamma rays from interactions between space radiation and the lunar soil. Radiation is measured using the unit sievert, which quantifies the amount absorbed by human tissues. The team found that the radiation exposure on the Moon is 1,369 microsieverts per day about 2.6 times higher than the International Space Station crew’s daily dose. The reason for this is that the ISS is still partly shielded by the Earth’s protective magnetic bubble, called the magnetosphere, which deflects most radiation from space. Earth’s atmosphere provides additional protection for humans on the surface, but we are more exposed to the higher up we go.