The first problem that human beings have to overcome when entering space is naturally gravity. The first cosmic speed of the earth is 7.9 km / s. to reach this speed, we can fly around the earth without falling down. To get rid of the gravity, we must reach 11.2 km / s.

The second problem is temperature. Because there is no air to cycle the heat, the temperature will rise very high on the side facing the star, and the side facing the star will cool down very quickly due to the heat radiation. The temperature difference between the sunny side and the sunny side will be very terrible in a short time.

The third question is high vacuum, which is easy to understand? In space, the number of atoms or molecules per unit volume is extremely rare, and the atmospheric pressure is zero. In this case, people will die if they go out

The fourth problem is high radiation. In addition to projecting visible light to us, the sun also releases a large number of electromagnetic waves and high-energy particles (commonly known as solar wind) into the universe. The electromagnetic waves are good. As long as the wavelength is not particularly low, the damage to the human body is not great, but the high-energy charged particles are not always terrible. They can penetrate the human body, and can destroy the DNA in cells, leading to the loss of human cells Ability to disintegrate (radiation sickness, very sour)

The sixth problem is air. Space is a high vacuum. To breathe, one must maintain a normal atmospheric environment, including air pressure, oxygen content and composition.

The seventh problem: Food: the food source in space is extremely scarce. At present, it can only be supplied by the earth. Without the earth, there will not be enough food produced in space.

The eighth problem: physiology and psychology, the living environment in space is very narrow, there are not many people, and the noise of spaceship is quite large at present (watching the video feels like the noise at the wing of the aircraft). Being in this kind of environment for a long time is a great test for human psychology. In addition, the human body is evolved under the gravity environment, and although the body skills are highly adaptable, they are very easy to guide under the weightlessness condition It can cause bone calcium loss, inadequate blood circulation, muscle atrophy and other problems.

The ninth problem: weightlessness. In the weightlessness state, in addition to the changes in the physiological structure of the human body, people’s sense of space will produce confusion, light will not be able to distinguish up and down, heavy will produce a serious sense of vertigo, and people without weightlessness training will suddenly experience weightlessness, there will be an illusion of infinite fall.

The tenth problem: acceleration. At present, in order to accelerate and maintain the orbit as soon as possible, the speed of human spacecraft is usually much higher than the first escape speed. In a few minutes, the acceleration of 0 meters per second is nearly 8 kilometers per second. The acceleration is very large. People with weak physique are estimated to faint in a few seconds. In addition, the huge noise and vibration during the launch is an extreme test for human body.