Isolated from the world, the mood is low, and the astronauts rely on writing diaries and planting vegetables to solve the problem

Source: Science and Technology Daily

The Shenzhou 13 manned spacecraft was successfully launched on the 16th, opening China's longest manned flight so far. The three astronauts will remain in orbit for 6 months in the core module of the Tiangong space station in China. Astronauts work and live in the space environment for a long time, how will the body change? How to ensure their health?

American astronaut Scott Kelly stayed on the International Space Station for 340 consecutive days, holding the record for the longest duration of a single space mission by an American astronaut. Astronaut Paige Whitson has spent 665 days in space, making him the longest-accumulated American astronaut.

To study the effects of the space environment on the human body, NASA conducted a controlled study of Scott Kelly and his twin brother Mark Kelly. Between March 2015 and March 2016, Scott Kelly stayed on the International Space Station for 340 days, while Mark Kelly lived on Earth. A comparative study of the two men's physical condition showed that about a year's space mission resulted in Scott Kelly's weight loss, carotid artery dilation, changes in DNA methylation levels, and changes in intestinal flora. Some indicators returned to their previous levels within 6 months of Scott Kelly's return to Earth, but some remained unresolved and some gene expressions interfered.

NASA said that tracking changes in the human body in the space environment and conducting related research can help optimize the design and function of spacesuits, develop astronaut health standards and fitness plans, and conduct physiological and psychological adaptation training to prepare for longer human deep space exploration missions in the future.

NASA-related research shows that the impact of the space environment on astronauts is mainly in five aspects, including space radiation, the physical and psychological impact of isolation from the outside world, the inconvenience of staying away from the earth, the impact of microgravity environment on health, and the impact of long-term closed environment on the human body.

Astronauts are exposed to much higher radiation in space than earth, and the longer they stay, the greater the amount of radiation, and the risks they face include radiation-induced diseases and central nervous system changes. Researchers simulate cosmic ray environments on the ground, study their effects on human health, and respond to the effects of space radiation by measuring radiation more precisely and developing more advanced radiation shielding materials.

Astronauts are isolated from the outside world during space missions, and are in a closed environment for a long time, and may have sleep problems, fatigue, low mood, immune system changes and other conditions. NASA-related research has improved the impact of the closed environment on the human body by adjusting the brightness of the light in the space capsule and using virtual reality equipment to simulate a relaxed environment, and encouraged astronauts to reduce stress by writing diaries and "planting vegetables" in space.

The microgravity or weightless environment of space can also have an impact on the human body. According to NASA, during space, the mineral density of weight-bearing bones of astronauts decreases by an average of 1% to 1.5% per month; muscle mass is lost faster; and human body fluids flow to the head in microgravity, which may put pressure on the eyes and cause vision problems. The researchers are addressing these effects through a range of measures, including having astronauts wear negative pressure devices to control fluid flow and developing potassium citrate drugs to combat the risk of kidney stones.

NASA has also developed a method to collect and measure the urine produced by astronauts in space, by analyzing different levels of urine material to determine whether astronauts are at risk of kidney stones during the mission period, and adjusting their diet, exercise habits and water intake accordingly to intervene. (Tan Jingjing)