When astronauts leave the International Space Station (ISS), they venture into the vacuum of space dressed in a white, pressure-tight spacesuit. That may seem like overkill for an environment that’s almost devoid of any other materials, but it’s a necessary precaution. In addition to being aesthetically pleasing, these outfits are also functional. The white coloring helps to reflect sunlight and heat while the pressure-tight design prevents any leaks of air during the harsh conditions of space. Below, we list six reasons why do astronauts wear white space suits when venturing into space.
1. Protection From the Sun
When it comes to the environment outside the ISS, the sun is the most significant hazard. The sun’s ultraviolet radiation (UVR) is harmful to human health, and with no ozone layer in the upper atmosphere to block it, astronauts are susceptible.
In addition to causing skin cancer, the intensity of UVR at the ISS’s orbital distance is capable of causing sunburn and eye damage. The white spacesuits worn by astronauts reflect sunlight and provide adequate protection against the sun.
2. Avoid Space Debris
The ISS orbits the Earth at a height of around 400 kilometers from the surface. At this altitude, there is a real risk of colliding with space debris. The ISS makes contact with space debris about once a year. Though the likelihood of a fatal collision is extremely low, the risk is still significant.
Although astronauts usually wear helmets during spacewalks, the helmets themselves are susceptible to damage from space debris. The white spacesuits worn by astronauts provide a shield against potential space debris.
This is because the white coloration makes the suits highly visible to telescopes and other sensors monitoring for incoming objects.
3. Preserving Body Temperature
When the sun is blocked by the Earth, temperatures in the thermosphere, or upper layers of the atmosphere, drop dramatically. The temperature can drop to -100C at night, and as such, the ISS is equipped with thermal insulation to prevent the interior panels from freezing and rupturing.
The white spacesuits worn by astronauts retain the body’s heat and protect against the risk of freezing outside the station. The white coloring of the suits also helps to absorb heat from the sun, preventing overheating during the day.
4. Pressure-Tight Design
The main purpose of the spacesuit is to provide pressure and keep out the harsh environment of space. The pressure of the atmosphere inside the suit is significantly lower than the pressure outside. This is to prevent the loss of air from the suit that would cause the astronaut to implode.
The spacesuit is made of multiple layers of fabric that are stitched or glued together to form a sealed pressure-tight barrier against the outside environment.
Wearing a white spacesuit provides a good contrast against the light-colored interior of the suit. This allows the astronaut to visually check for any potential breaches in the lawsuit.
5. Water and Oxygen Supply
Humans need to consume oxygen to survive in space, and a common misconception is that the spacesuits worn by astronauts are pressurized with oxygen. However, this isn’t the case. Instead, the spacesuits are fitted with an oxygen-inlet valve and water-cooling system.
The oxygen-inlet valve is used to connect the suit to an onboard supply of liquid oxygen. The water-cooling system is designed to strip out the water vapor from inside the spacesuit. The spacesuit is also fitted with a carbon dioxide removal system.
This uses a chemical reaction between lithium perchlorate and the carbon dioxide in the suit’s atmosphere to produce lithium carbonate. The lithium carbonate is then removed and discarded.
6. Cleaning of the Suits
The cleanliness of the spacesuits is essential given that they are the only barrier between the astronauts and the harsh environment of space. This is because microorganisms can thrive in the warm, moist environment inside the suit.
In addition to posing a risk of infection, they can also lead to the formation of dangerous gases. To prevent this, the spacesuits are cleaned after each use. A mixture of water and baking soda is used to soak and remove any microbes. The suits are then air-dried to prevent any bacterial growth.
Conclusion
Astronauts wear white, pressure-tight spacesuits when venturing outside the ISS. The suits are designed to protect against the sun, space debris, freezing temperatures, and potential breaches to the suit’s integrity. The suits are also cleaned after each use to prevent the growth of microbes. Fortunately, the risk of a fatal collision is extremely low, and astronauts can look forward to the next spacewalk when the first commercial crew vehicles visit the ISS.
