Why does the space station only fly at an altitude of 400 kilometers, instead of flying higher? -

At first, astronauts can only stay in the spaceship when they fly into space, and they won't sta

Why does the space station only fly at an altitude of 400 kilometers, instead of flying higher? -

At first, astronauts can only stay in the spaceship when they fly into space, and they won't stay too long. Now, astronauts can live in the space station for a long time, and they can also work outside the cabin, which is undoubtedly a great progress. However, the public still has a lot of confusion about the space station. For example, why does the space station fly only 400 kilometers high and no longer fly higher?

In the minds of ordinary people, the space station should fly as high as possible. After all, the higher the altitude, the farther away from the earth, which is the real "space". However, in reality, the determination of the height of the space station actually considers many factors, and I will explain them to you one by one.

First of all, we need to know the setting of "Carmen Line". Scientists have positioned the Carmen line as the boundary between the atmosphere and space, with a height of 100 km, so you don't have to worry that the 400-km space station is not space, but has actually entered space. The closer to space, the more "vacuum" the environment, and the vacuum environment is conducive to spacecraft movement.

The location of 400 kilometers has been able to avoid atmospheric interference as much as possible. Although it will still be affected under long-term operation, 400 kilometers can already be used as a more suitable height. Many people may think it is better to fly higher and get rid of interference completely.

This brings the second reason, that is, the protection of magnetic field. There are all kinds of radiation in the universe, which is extremely harmful to human body. Astronauts need to live in the space station for a long time, so the flying height of 400 kilometers can still protect the space station from the influence of the earth's magnetic field, thus protecting astronauts. As for the protection principle, it is actually the refraction of the earth's lower atmosphere, through which nearly one third of the radiation particles can be intercepted, and the remaining one third is reflected by the earth's magnetic field.

The third reason is the supply of materials, and the space station needs regular supplies. Some of these materials are needed for maintenance and research, and some are astronauts' daily necessities. As you may know, every material supply needs to spend a lot of money, and the higher the flying height, the more money you spend.

Therefore, the height of 400 kilometers is still relatively economical. After all, the number of times of replenishment is still very frequent. If the cost is very high every time, this way of "burning money" will not work.

The fourth reason is to consider the orbit. Unlike the orbit selection of satellites and other equipment, the orbit selection of space stations is more particular. Because the space station is inhabited, if you choose a very irregular orbit, then the astronauts inside will inevitably be affected.

In a word, it is a more suitable scheme for the space station to fly at 400 kilometers after synthesizing various influences. As for the view that "the higher you fly, the better", it is problematic. As mentioned above, the higher you fly, the more likely you are to escape from the protection of the earth's magnetic field and face all kinds of cosmic radiation.

So far, no astronauts have been exposed to large or full doses of cosmic radiation. If the altitude is raised blindly, it is hard to say what harm it will bring to the astronauts' health and what kind of sequelae it will leave.

However, the position of 400 kilometers is not permanently fixed. It can be said that the orbital height of the space station is always changing. Of course, it is not flying high, but falling. Therefore, it is very important to maintain the stability and orbit of the space station.

As early as when discussing why the space station needs to be more cautious when choosing the orbit, it was mentioned that the orbit of the space station is generally regular or "circular". Therefore, in order to maintain this orbit, the space station needs the thrust generated by the propulsion system to overcome the atmospheric resistance.

As for the value of Didi, it is uncertain and will be affected by many factors. For example, the phenomenon of solar magnetic storm will make the orbit of the space station fall faster. Judging from the impact of the solar magnetic storm on the International Space Station in 2004, the previous drop was about 150 to 200 meters per day, and the average drop height after the magnetic storm reached 300 meters.

Attitude control and stability subsystem is the basic component of the space station, which is very important for maintaining the normal operation of the space station. In a word, judging from the current situation, human beings still need to help the space station adjust its state regularly, which does not mean that the launch, assembly and operation will be completed once and for all. In addition, the service life of the space station is limited.

For example, Russia's Mir space station crashed into the South Pacific in 200 1 year. This space station was originally the third-generation manned space station of the Soviet Union, flying around the earth more than 80,000 times with a total journey of 3.5 billion kilometers. The Mir space station is also considered to have been retired. After all, its service life is only three to five years, but it has flown for more than ten years. Therefore, it is understandable that Mir, which often breaks down, was eventually crashed by human operation.

In addition, many people may not know. At present, the international space station is also in a very long service state, and because it is built in cooperation, in many aspects, the United States and Russia cannot reach an understanding. So in February 2022, NASA said it planned to officially retire the International Space Station in 20031year, and the crash site was in the Pacific Ocean.

In addition, although the location of 400 kilometers can help the space station resist most of the space radiation, the space station still faces many threats, among which the destructive power of space debris is very strong.

I believe many people have read articles accusing humans of leaving a lot of rubbish in space. Indeed, space junk is actually space junk, mainly composed of abandoned aircraft wreckage, which becomes more finely divided after explosion or collision.

There are three main sources of space debris. The first is the invalid load, mainly the failed spacecraft. The second type is operational debris, which is the garbage generated during the launch of launch vehicles or spacecraft, such as rocket shells and fairings. The third kind of disintegration debris refers to the debris produced by the disintegration of satellites, and of course it will also produce rocket explosions.

In order to clearly judge the threat of debris to the space station, scientists also divide it into large debris, dangerous debris and small debris according to its size. Debris of different sizes pose different threats to the space station. Among them, by 2065,438+04, more than 65,438+06,000 large fragments with a diameter greater than 65,438+06 cm and 2,500 with a mass greater than 2 kg were found. At present, the number of debris is still multiplying.

So, what impact will space junk have on the space station and astronauts? Space junk will change the performance of the space station, which is called "sand erosion" effect. In addition, the high-speed impact of space debris will also perforate the surface or make high-pressure air explode. The space station is where astronauts live. Once there is an accident in the space station, it is difficult to guarantee the life safety of astronauts.

The International Space Station has been put into use for a long time, and astronauts from many countries have lived in it. In order to successfully complete the future moon landing plan, China will definitely camp in space, so it is a very wise choice to set up its own space station.

Therefore, the construction of China Space Station has been proceeding in an orderly way. On April 29th, 20021year, the Tianhe core module of China Tiangong Space Station was successfully launched into orbit, which indicated that China Space Station entered the implementation stage. The construction of Tiangong Space Station can not only ensure the long-term life and work of China astronauts in space, but also lay a solid foundation for the future moon landing.

Many people joke that building a space station is actually building blocks in space, which is true, because the main components will be transported by launch, and all we have to do is assemble them there.

The assembly of Tiangong Space Station can be roughly divided into five steps. The first step is to launch the space and core cabin and complete the on-orbit verification of the construction technology. Step 2, launch the candlestick experimental module and dock with the Tianhe core module. The third step is to adjust the position so that the two can form an L-shaped combination. The Meng Tian experimental module launched for the fourth time is docked with the Tianhe core module to form a three-module module. Finally, the position of Meng Tian experimental module was adjusted to a T-shape.

After the space station is completed, astronauts can conduct more experiments there. The space station enables astronauts to live in space for a longer time, which is more conducive to various scientific experiments and the processing of special materials.

Take the materials processed in the space station as an example, the semiconductor materials processed there can overcome various defects of conventional processing, thus improving the quality.

In addition, astronauts' extravehicular activities are very important for future space exploration. You know, our goal is the sea of stars, and it is inevitable that astronauts will walk on the moon in the future. This practice now can just accumulate experience for the future.

After the completion of the space station, China will be able to carry out scientific research in the fields of astrophysics, basic physics and life science research in the laboratory. Take space life science as an example, this should be the most interesting thing for everyone. One of its research contents is our traditional artistic ability "growing vegetables".

After all, in the future, mankind will complete interstellar migration and establish an immigration base in a foreign land. At that time, they will not be able to rely on the earth to continuously transport resources for replenishment like the space station now. We should know that the supply distance will not be 400 kilometers by then, and such a long voyage will lead to very high supply cost and long cycle. Therefore, to be self-sufficient, it is very important to experiment how to grow vegetables smoothly in the microgravity environment in space in advance!

Of course, all these attempts need to wait for our space station to complete the "building blocks". Judging from the current smooth progress, it is not far from completion. I look forward to the day when the China Space Station is officially completed and put into use!