Ebullism And Asphyxiation: The Brutal Consequences Of A Spacesuit Breach

Picture yourself as an astronaut in the vastness of space, and suddenly — you're accidentally pushed out of your spacecraft's airlock.

Image credit: Freepik

If your body were exposed to the vacuum of space without a spacesuit, here's what would happen.

A vacuum means a space that has no air, gas, or any other matter. In space, a vacuum is an area with no atmosphere or air pressure.

The first thing to understand is that many Hollywood portrayals of this situation are exaggerated.They often show people without helmets or spacesuits either exploding or freezing to death immediately.In reality, the same things would happen, but they wouldn’t be as extreme.

An astronaut floating in space without a suit wouldn’t survive, but death would occur in minutes rather than seconds. It would be a brutal process, with body fluids boiling and their nose and mouth freezing.

Space is an empty vacuum with no air, which means there’s no atmosphere and no air pressure like we have on Earth.

Air pressure affects the temperature at which liquids boil and become gas.

When the air pressure outside a liquid is high, like it is at sea level on Earth, it becomes more difficult for gas bubbles to form, move up to the top, and escape.

In space, where there is almost no air pressure, liquids boil at much lower temperatures. This means that even at cooler temperatures, liquids can start to boil quickly in space.

Dr. Kris Lehnhardt, a scientist for NASA's Human Research Program, explained to Live Science that this is a big issue because about 60% of the human body is made up of water.

Without pressure, the liquid water in our bodies would start to boil and quickly turn into gas."In other words, all the water-containing tissues in your body would begin to swell," he said.

Some people have actually been exposed to almost no air pressure and have lived to share their experiences.

In 1966, NASA aerospace engineer Jim LeBlanc was testing spacesuit prototypes in a large vacuum chamber. During the testing, the hose that was supplying air to his suit got disconnected."I remember stepping backward and feeling the saliva on my tongue starting to bubble just before I passed out, which means right before I lost consciousness. That was the last thing I recalled," he shared in the 2008 documentary series "Moon Machines" episode about the spacesuit.

The formation of gas bubbles in bodily fluids, called ebullism, can also happen to deep-water scuba divers who come up too quickly. This is because they move from an area with high pressure underwater to a low-pressure environment at the surface. 

In high pressure, the gases in the body stay dissolved in the fluids. When they rise quickly and pressure drops, those gases can suddenly form bubbles, which can be dangerous.

For astronauts without suits, the blood in their veins boils more slowly than the water in their tissues because the circulatory system has its own internal pressure. However, the body's tissues would still experience a lot of bubbling, known as ebullism, very quickly.

A 2013 study published in the journal Aerospace Medicine and Human Performance examined past cases of animals and humans exposed to vacuums. It found that they lost consciousness in less than 10 seconds.

Some of them couldn't control their bladder and bowel movements, and the swelling in their muscles blocked blood flow to their hearts and brains. This happened because their muscles expanded and acted like a vapor lock.

Vapor lock refers to a condition where the flow of liquid is obstructed due to the formation of vapor or gas in the system, causing a blockage.

Lehnhardt stated that it is impossible for a person to survive this, and death is probable in less than two minutes.

As per information from NASA's bioastronautics data book, the lack of pressure in space would draw the air out of your lungs, leading to suffocation in just a few minutes. This happens because in the vacuum of space, there is no air pressure to keep the air in your lungs, causing it to be pulled out rapidly, making it impossible to breathe.

Once the first rush of air escapes, the vacuum of space would keep pulling gas and water vapor from your body through your air passages. This means that in the absence of pressure, the air and moisture inside your body would be continuously pulled out, making it impossible for you to breathe or survive in space.

The ongoing boiling of water in your body would create a cooling effect. As water molecules evaporate, they would take heat energy from your body, causing the areas around your nose and mouth to almost freeze. 

The rest of your body would also get colder, but this would happen at a slower pace since there would be less evaporation occurring.

(Girish Linganna is a Defence and Aerospace Analyst based out of Bengaluru. He is also Director of ADD Engineering Components, India, Pvt. Ltd, a subsidiary of ADD Engineering GmbH, Germany. The views expressed in this article are of the author only.)