Incredible survival skills of astronauts, which one can you do?

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On the morning of April 16, the return capsule of the Shenzhou 13 manned spacecraft successfully landed in the designated area of ​​the Dongfeng landing site. Astronauts Zhai Zhigang, Wang Yaping and Ye Guangfu returned safely after 183 days of working and living in the space station, successfully completing the Shenzhou 13 manned flight mission.

The hero returned triumphantly, and my childhood dream of space travel seemed to be rekindled! So, what skills do I still lack to become an astronaut?

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01

Weightlessness and overweight

The biggest difference between space and Earth is that the gravity that is everywhere on Earth cannot be felt in space. We call this phenomenon "weightlessness" - we have lost the gravity that is everywhere like air. So how does gravity "disappear" in space? In fact, even if we go to space and reach the space station, we are only 400 kilometers away from the surface of the earth, and the average radius of the earth is 6371 kilometers, which is about 1/16 of the radius of the earth. According to Newton's universal gravitation formula, F=GMm/r2, compared with the gravity of the earth on the ground, the gravity of the earth on the space station is only reduced by 1/162-1/172≈0.045%. But we can indeed feel the "disappearance" of gravity - the suspended people and objects in the space station are the best proof. So what's the problem?

Let's consider a simple case. Assuming that the person is stationary, when on the surface of the earth, the support force on the person is N=mg, and everything is normal at this time. In the space station, the person will also be subject to the gravitational force from the earth (approximately equal to that near the ground), as well as the support force from the space station (the direction and magnitude are unknown). When the space station is approximately doing uniform circular motion around the earth (actually an ellipse), the person and the space station should have the same acceleration a=wv, pointing to the center of the earth, so we solve N'=mg-ma=mg-mwv.

Doing the same force analysis on the space station, we find that the space station can only be subject to gravity, because there is no object that can provide it with this "support" - it is in space. So we can solve wv=g, and substituting this result into the expression of N', we find that the support force on people is also 0. More generally, any object that is stationary with the space station will also receive 0 support force, which means that people and objects will be suspended in the space station. Of course, in reality, the space capsule will not be completely weightless, but microgravity with an acceleration of 10-6~10-4g.

The opposite situation occurs during the launch of a spacecraft. At this time, the acceleration of the spacecraft is very large, and the direction is exactly opposite to the previous weightless situation, pointing outward. For the astronauts inside, their acceleration should satisfy a = N/mg. When a>0, N>mg, the supporting force is greater than the gravity, which is overweight. In summary, we find that the force felt by people is actually only determined by the supporting force N. In other words, people can't actually perceive how great the real acceleration is, and they can only feel how great the "push back feeling" is.

During the actual launch, the experience brought by overweight is far more than just a "pushing back feeling". Taking into account possible emergencies, astronauts generally have to withstand overweight training in a centrifuge with an acceleration of more than 8g during ground training; and untrained normal people are almost reaching their limit at an acceleration of 2g-4g.

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02

Fancy Fitness

The first problem caused by weightlessness is the change in physical condition. On Earth, our muscles and bones are constantly fighting against gravity, so we can maintain our muscle strength and bone density without additional exercise. In space, no object has weight, and the human body does not need to fight against gravity, so muscles and bones will "lack exercise", leading to problems such as muscle atrophy and osteoporosis.

Even astronauts who are physically fit must be cautious about this issue. Therefore, when they are in space, they exercise for about two hours every day, mainly running, cycling, pulling bands, and static exercises. (Zhai Zhigang: The last one is my strong point

How to run in the absence of gravity? It's very simple. Just tie two springs to your body and connect them to the treadmill. In this way, every time you jump up, you will be pulled down by the springs. Since running will produce violent vibrations, our treadmill also needs to be designed with a shock-absorbing device.

The riding equipment also has its own requirements. Scientists have specially set up shoes with buckles for astronauts to ensure a stable connection between the shoes and the pedals during riding.

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03

Feeding

For astronauts in the space station, they not only have to overcome their own weightlessness, but also the weightlessness of everything around them, such as food.

Precision feeding is essential for space survival. If you hit the target, you will feel great. If you miss, you will have to clean the table and floor and "clean the air".

Speaking of which, the space menu I saw when I was a child was still like "squeezing toothpaste". With the upgrading of food processing technology, it has now expanded to 127 kinds of food, including fish-flavored pork shreds, Kung Pao chicken, black pepper beef tenderloin, spicy lamb, pepper goose, hot and sour bamboo shoots, spicy dried tofu, assorted fried rice, red stewed pork chops, hot pepper potatoes, cabbage beef soup, rice dumplings, spicy tuna, milk-flavored chicken rice, mushroom meat, soy sauce and oil lettuce, crab roe broad beans, crispy chocolate, freeze-dried ice cream, etc. You can even eat fresh fruits and three kinds of dumplings in the space station: pork and cabbage dumplings, Spanish mackerel dumplings and day lily dumplings. The dumplings are processed on the ground and can be reheated when eating.

It may seem fancy, but it is actually well-intentioned. Space food must not only be safe and hygienic, and provide sufficient energy and nutrition, but also take into account the taste and eating habits of astronauts, and try to meet the standard of "one bite to eat", and be edible in a microgravity environment, without bones, small pieces, or residue. So I wonder if I will have a space hot pot the next time I go to space? (Rubbing hands

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04

Space Haircut

I wonder how many more Tonys there are in the world during the pandemic? Anyway, the space station already has its own "King Tony" -

Goddess Yaping becomes Tony teacher in the space station

Source: CCTV.com

Due to the lack of gravity, the cut hair will not fall to the ground, but will float throughout the space station. Therefore, when getting a haircut in space, you will need to use a residue collector to collect it - that is, use a "vacuum cleaner" to suck away all the hair debris.

The Space Station Barber Shop is now open!

Source: CCTV.com

The same problem applies to shampooing. Since there is no gravity, forget about showering. Just use three head covers to solve the problem.

1) Put on a headgear filled with shampoo and rub it repeatedly;

2) Change to a headgear filled with clean water and rub repeatedly;

3) Change to a dry head cover and rub it repeatedly.

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05

“Just drink some water”

The amount of water and oxygen required by astronauts during the entire mission is huge. If all of it is delivered from the ground to the space station by "express delivery", it will undoubtedly greatly increase the cost of maintaining the space station and reduce the feasibility of long-term residence in the space station. Therefore, a complete set of drinking water and oxygen regeneration and circulation systems is essential. In the space station, we use electrolysis of water to obtain oxygen, and the byproduct hydrogen reacts with carbon dioxide to obtain water and methane. Methane is discharged into space, and water is processed to become drinking water. In addition to this, some of the water comes from human urine. Scientists have designed a device that can process urine into drinkable water by distillation and filtration.

Whether it is drinkable or not is a question that of course only those who drink the water can decide. Astronauts regularly test drinking water for microorganisms. The testing method is to culture the microorganisms in the water, assuming that there are microorganisms in the water. If the cultured microorganisms are within the standard, it can be drunk. Otherwise, it cannot be drunk.

Drinking water microbial testing

Source: Xinhua News Agency

The End

It is said that the universe is the ultimate romance of mankind. In the long and silent night, it is mankind who uses their dreams and courage to gradually build up this small world of space station, using the efforts of the previous generation to attract the efforts of the next generation.

I pay tribute to every astronaut. Every day of your hard work in the space station is shining and like a song. I also pay tribute to every person who works hard for aerospace engineering. It is you who have created a pair of strong hands to firmly support those who reach for the stars.

April 24th is China's Space Day. Let us wish and look forward to the vigorous development of China's space industry!

Our journey is to the sea of ​​stars!

Source: Science Popularization China

References

Eating in space: Let you experience the mysterious astronauts' space meals (thepaper.cn)

【Technology·Aerospace】A brief discussion on space fitness - Zhihu (zhihu.com)

Wang Yaping's pink sportswear steals the spotlight while Zhai Zhigang runs in small steps_哔哩哔哩_bilibili

"Wash, cut and blow dry" in space? Space hair clipper unveiled, Wang Yaping turns into a hairstylist_哔哩哔哩_bilibili

How do astronauts wash their hair in space? Zhai Zhigang's answer is so emotional! _哔哩哔哩_bilibili

How do astronauts live in space for 3 months? How do they take a shower? Let's reveal the secrets of life in space

It smells like that! Purifying urine for drinking, efficient water recycling in the space station

China's space station daily life updated again: simply drink water_哔哩哔哩_bilibili

Heroes Return丨A perfect triumph, the pride of China! (gmw.cn)

Special thanks to: Banyan Tree

Editor: Banana

Source: Institute of Physics, Chinese Academy of Sciences