Jakarta, CNBC Indonesia – NASA limits the time astronauts can spend in space. It turns out that male astronauts can spend much longer time outside the Earth’s atmosphere than female astronauts.

The reason NASA limits the length of astronaut missions is radiation. On Earth, humans are protected from radiation bombardment by the atmosphere. In outer space, radiation takes the form of high energy waves that are capable of hitting electrons from the human body, causing them to flow chaotically.

If the human body loses electrons due to long-term exposure to ionizing radiation, the risk of cancer and other diseases increases.

Therefore, astronauts serving on the International Space Station (ISS) face the threat of high radiation exposure. The longer time astronauts spend outside the protection of Earth’s atmosphere, the higher their risk of developing cancer.

The current limit for astronaut service time, set by NASA in 1989, is 3 percent of the lifetime risk of cancer death. This limit is determined by age and gender.

The lowest radiation limit is 189 mSv, which applies to women aged 30 years. The highest limit is 700 mSv, namely for men aged 60 years.

Julian Preston, an official at the US Environmental Agency (EPA), explained why the radiation limits for male astronauts are much higher than female astronauts.

According to him, the reason for the difference in maximum radiation limits is that women have twice the risk of developing lung cancer than women if exposed to radiation at the same level.

“In general, based on people who survived the impact of the atomic bomb explosion in Japan, women are more sensitive to ionized radiation,” he was quoted as saying LiveScience.

The consequence of this difference in limits is that the careers of female astronauts are shorter than those of male astronauts. For example, Peggy Whitson, who in 2018 held the position of head of NASA’s astronaut corps, had to retire at the age of 57 because she had reached the radiation limit.

The differences in astronaut career boundaries are expected to change in the near future. In 2021, NASA has formed an expert panel to change the radiation limit to 600 mSv for all ages and all genders.

The 600 mSv limit is equivalent to 4 to 6 months of radiation exposure on the ISS. For comparison, every year humans on the Earth’s surface are exposed to 3.6 mSv of radiation. On the ISS, annual radiation exposure reaches 300 mSv.

“This means female [astronaut] could have a longer career,” said Preston.

However, determining equivalent boundary changes must also take ethical considerations.

“To be equal, [wanita] could be exposed [radiasi] higher than currently set. We had a long discussion about ethical issues. “It’s a question of balancing the impact of slightly higher radiation exposure with equality of career opportunity,” Preston said.

Apart from that, NASA will also determine different treatments for longer missions, for example a trip to Mars which is estimated to reach radiation exposure of 900 mSv. This level is still lower than the 1,000 mSv limit set by Europe, Canada and Russia for astronauts from their countries.

[Gambas:Video CNBC]

(dem/dem)