How does an airlock work in space

Science in dialogue

What would happen if you opened a window in a spaceship?

Since there is a vacuum in space, whereas pressure conditions in the spaceship are similar to those on earth, the vacuum would suck all air out of the spaceship in a few seconds when a hatch is opened. The space travelers would be exposed to the extreme temperatures and the vacuum in space without protection. That would have a number of unpleasant and ultimately fatal consequences for them within a few seconds.

Due to the lack of pressure from outside, trapped air expands in the body. So if the passengers hold their breath, what happens to even inattentive divers when quickly ascending from great water depths happens to them: the overpressure causes the lungs to burst. The eardrums can also burst if the connection between the middle ear and the oral cavity is swollen and closed, for example due to a cold.

After a few seconds in a vacuum, the body fluids change into a vapor state - the blood begins to boil. This is due to the fact that the lower the pressure, the lower the boiling temperature of water and other liquids. At an altitude of around 19 kilometers, the boiling point of the water is only 37 degrees Celsius, which is the normal human body temperature. This is why pilots of very high-flying military aircraft also wear space suits. When the blood begins to boil, the blood pressure or blood pressure regulation breaks down. The brain no longer receives oxygen. The person passes out and dies. The water in the cells would also boil and the cells would burst. The gas would collect in cavities in the body, and these, too, would eventually yield to the excess pressure.

The extreme temperatures, which are between minus 270 degrees Celsius and plus 100 degrees Celsius in sunlight, are also deadly. The body would cool down very quickly through heat radiation. If the core body temperature drops by ten degrees, there is no longer any chance of survival.

With all these problems, space travelers are unlikely to be bothered by the sun's aggressive UV radiation. The ozone layer protects us from this on earth. In space, the rays would cause severe sunburn within a few seconds.

After a few seconds of unprotected space in space, the space travelers would initially be unconscious and shortly afterwards dead. How long a person can actually survive in this situation is not known, as this has never happened before. As NASA reports, there was an accident in a vacuum chamber in 1965. The test person's spacesuit had a hole in it. The person passed out 14 seconds after exposure to negative pressure. 15 seconds later the pressure in the chamber was normal again. Presumably no vacuum was reached during the entire time in the spacesuit. The test person survived. The last thing she could remember was the water starting to boil on her tongue.

The question was answered by Prof. Dr. Hanns-Christian Gunga, spokesman for the Center for Space Medicine Berlin.