What happens when the human body enters space unprotected?

When the human body suddenly faces an environment of rapid decompression to near vacuum:

One. If you don't try to hold your breath, exposure to a vacuum for about half a minute is unlikely to cause you permanent harm. If you hold your breath, it may hurt your lungs. Even if the pressure in your lungs is only 1psi, it is enough to cause your lungs to rupture and die. Trained astronauts know how to face this situation. Once exposed to a vacuum, it will not cause immediate damage.

Two. You won't explode: steel high-pressure oxygen cylinders can prevent oxygen cylinders with hundreds of atmospheres from bursting. Although the strength of our skin is far less than that of steel cylinders, it is still enough to keep us from exploding in space. Animal experiments show that rapidly evaporating water in skin and subcutaneous tissue can cause swelling.

Three. Your blood will not boil immediately: due to the protection of skin and circulatory system, your blood will not boil immediately. The vapor pressure of water at 37℃ is 47mmHg, and the blood pressure in our blood vessels will be higher than this, so it will not boil immediately. The human body has the function of regulating blood pressure. For example, if you are in water at a depth of 10 feet, your blood vessels will not rupture due to pressure.

Four. You won't freeze immediately: although the environment in space is very cold, the heat dissipation rate of human body will not be very fast, because the heat conduction in vacuum environment mainly depends on thermal radiation, and its conduction efficiency is lower than air convection.

Five. You won't lose consciousness immediately: after losing the oxygen supply in the blood, the human body will lose consciousness in about 10 to 15 seconds. Another noteworthy problem is that if our skin is exposed to direct sunlight in space, it will get very serious sunburn in a short time.

The human body may live in space 1 to 2 minutes, and then it will face death. As for the time limit that the human body can bear, it is not clear.

An accident occurred in a spacesuit test at the Johnson Space Center in the United States. The hose connecting the ventilation system of the spacesuit broke, causing the astronauts to directly face a vacuum chamber with a pressure much lower than 1 psi. The astronauts only stayed awake for about 65,438+04 seconds, and then fell into a coma. These times are almost the time for blood to reach the brain from the lungs. After 65,438+05 seconds, the closed cabin begins to pressurize. The astronauts didn't wake up until the air pressure was about equal to 15000 feet of atmospheric pressure. The astronaut later recalled that in his last memory before he lost consciousness, he felt and heard the sound of air overflowing and saliva boiling on his tongue.

1960.8. 16 Joe kittinger set a world record for skydiving. When the helium balloon he was riding rose to a height of 43,000 feet, his right hand burst and lost pressure. He felt that his right hand was too painful to use, but he decided to continue to complete the challenge. After about 12 minutes, he arrived at 12.

Data reference from:

Effects of rapid decompression to near vacuum on chimpanzees. , NASA CR-329( 1 1 month 1965).

(Experiment of Chimpanzees Rapid Decompression Near Vacuum)

Decompression of experimental animals to near-vacuum environment, edited by R.W. Bancroft and J.E. Dunn, report.

Sam-TR-65-48 (June 1965), AFB School of Aeronautics and Astronautics, Brooks, Texas.

(Animal experiment when rapid decompression approaches vacuum)