The human body is not adapted to space, which is why astronauts rely on protective suits to explore the universe. So, what would happen if an astronaut removed their spacesuit and stepped into the vacuum of space?
Would their eyes explode and their blood vaporize? No, the reality is less dramatic but more fascinating. The answer is summarized through various incidents in space and laboratory environments, as well as animal experiments conducted in the 1960s.
Lack of Air
The first sensation we would experience in space is a feeling of suffocation. We would not lose consciousness immediately and could remain alert for about 15 seconds, as the body utilizes the stored oxygen in the blood. If we stop breathing, we could survive for up to two minutes without suffering permanent injury.
Loss of Control Over Bodily Functions
When there is a severe lack of oxygen, humans would lose the ability to control certain bodily functions. In 1965, researchers conducted an experiment with 100 dogs in a simulated vacuum environment. The results showed that in addition to their lungs being emptied of air, the dogs’ bodily waste was also expelled immediately.
If we breathe, the pressure differential between our bodies and space would cause the air in our lungs to expand, leading to ruptured lungs, and the gas would then infiltrate the circulatory system. Therefore, the first thing we need to do if we find ourselves in space is to exhale and then hold our breath to prolong survival while waiting for rescue.
Body Swelling
In addition, within about 10 seconds or longer, our skin and underlying tissues would begin to swell as the water in our bodies starts to evaporate in near-zero atmospheric pressure. We would not swell to the point of exploding because human skin is strong enough to prevent that, and if we were returned to a standard atmospheric pressure environment in time, our skin and tissues would return to normal.
Blood would also remain unaffected since our circulatory system can maintain normal blood pressure unless we go into shock.
Boiling Blood
The lower the pressure, the lower the boiling point of liquids (the boiling point is the temperature at which a substance changes from liquid to gas). This is why water boils faster at the top of a mountain than it does at sea level.
Remember that outer space has no pressure, so the boiling point can easily drop to body temperature. This means that even saliva could burn your tongue, and the liquids in your blood would begin to boil.
According to Jim LeBlanc, who experienced near-vacuum conditions in a test chamber in 1965, he remained conscious for about 14 seconds. The last thing he felt was the bubbling of saliva on his tongue. Jim LeBlanc was safely revived after researchers immediately restored pressure and air in the test chamber.
“Sunburned”
Due to exposure to cosmic radiation without any protection, we would experience severe sunburn and also suffer from discomfort due to decompression.
Freezing
However, we would not freeze immediately, despite the extremely low temperature of -440°F (-262°C). Due to the lack of convection and conductive materials, our body temperature would not drop quickly enough for us to freeze before suffocating.
Cell Mutations
You would be affected by radiation from stars such as harmful UV rays, gamma rays, and X-rays. These rays would alter your body cells, but they would not grant you supernatural powers like in the movies. Even if you were fortunate enough to be rescued back into the spacecraft, you would likely die later from radiation poisoning or cancer.
Mummification in Space
If a person dies in space, their body would not decompose in the usual manner due to the absence of oxygen. If near a heat source, the body would dry out and mummify; otherwise, it would freeze.
If a human body is wrapped in a spacesuit after death, it would decompose until all oxygen is used up. Depending on the conditions, a deceased body could exist for a very long time without being damaged by environmental conditions like on Earth. A human corpse could drift for millions of years in space.
Flying into space is associated with numerous challenges and extreme environments, making it crucial to create Earth-like conditions for life to evolve and thrive. The spacesuit allows astronauts to venture outside the spacecraft for a short period by providing air, water, pressure, and body protection. What would happen if humans did not wear this advanced suit? How long could a person survive if ejected into the vacuum of space?
According to Stefaan de Mey, a strategic officer at the European Space Agency (ESA), within a very short time, around 10 to 15 seconds, a person would lose consciousness due to lack of oxygen. In the darkness of space, oxygen becomes a critical issue. “Oxygen begins to expand and rupture the lungs, causing them to tear, resulting in boiling and bubbling blood, which immediately causes blockage and critically impacts the human body,” Mey explained.
In addition to providing essential oxygen and pressure regulation, spacesuits also protect astronauts from various threats and hazards. “There are issues related to temperature, radiation, and threats from micrometeoroids,” Mey elaborated. “Thus, spacesuits are designed to protect astronauts in space.” Regardless of whether an astronaut is in sunlight or shadow, they would experience extreme temperatures ranging from -150 to 120 degrees Celsius in Low Earth Orbit (LEO). This condition could cause burns or frostbite.
Spacesuits also block various types of radiation. In LEO, prolonged exposure to electromagnetic radiation from the Sun can lead to health issues such as radiation sickness and increased cancer risk. UV rays can also cause skin burns. Additionally, particles from solar storms that reach astronauts while they are in space exacerbate the problem.
Micrometeoroids and space debris pose another risk. They travel at speeds of tens of kilometers per second and are a threat to satellites, spacecraft, and spacewalk activities. Although they are less likely to affect human survival chances, the protective suit is designed with multiple layers to shield astronauts from any micrometeoroids or space debris orbiting nearby.
