Table of Contents

A Life-preserving Suit

Functions of the Spacesuit

Pressurized environment

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Spacesuits must provide an environment that is adequately pressurized in order for an astronaut’s body fluids to remain in a liquid state. Researchers have determined that a pressure of 29.6 kPa is sufficient for this purpose (maintaining higher pressures would be difficult at present since there are limits to the stress the spacesuit materials can tolerate). Although this pressure is clearly below that present at sea level, it enables astronauts to function almost normally, as long as the atmosphere inside the suit consists of pure oxygen.

Oxygen supply

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Because of the relatively low pressure inside spacesuits, using a gas composition similar to the air we breathe on Earth (78% nitrogen and 20% oxygen) would result in an oxygen concentration that is too low in the astronauts’ bloodstream. Astronauts, therefore, breathe pure oxygen inside the spacesuit.

Eliminating carbon dioxide

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In such a closed environment, it is essential for the suit’s systems to be able to effectively eliminate carbon dioxide produced each time the astronaut exhales. Cartridges made of layers of activated carbon and lithium hydroxide continually filter the contaminated air.

Protection against extreme temperatures

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It can be extremely hot or exceedingly cold in space. The temperature of objects exposed directly to the Sun’s rays can quickly reach 150 °C, whereas the temperature of objects located in the shade can drop as low as -120 °C. Spacesuits are insulated to protect astronauts from these variations. They are also covered with layers of white Mylar in order to reflect solar rays. The suits are equipped with an advanced air-conditioning system used to cool the environment that would otherwise become unbearably hot because of the physical activities performed by astronauts.

Protection against micrometeorites

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Should a micrometeorite pierce the spacesuit, the consequences for the astronaut could be catastrophic. In order to prevent this, suits have several layers of flexible and very resistant material such as Dacron and Kevlar.

Protection against radiation

The Mylar covering the suit also provides a level of protection against solar radiation.