Understanding how do astronauts breathe in space requires looking at the harsh environment beyond Earth’s atmosphere. Outside the protective blanket of our planet, there is a vacuum with no oxygen, extreme temperatures, and no pressure to keep liquids from boiling away. To survive this environment, astronauts rely on sophisticated life support systems that create a personal, breathable atmosphere around them. These systems manage oxygen delivery, carbon dioxide removal, pressure regulation, and humidity, allowing humans to function far from home.
Life Support Systems on Spacesuits
The primary interface between an astronaut and the vacuum of space is the spacesuit, a complex garment that acts as a miniature spacecraft. Each suit has its own independent life support system, which is critical for survival during spacewalks, or extravehicular activities. This system is worn like a backpack and contains the necessary components to supply breathable air and maintain a safe pressure level for the body.
Oxygen Supply and Regulation
Inside the suit’s backpack, a high-pressure tank stores oxygen in a gaseous state. A pressure regulator reduces this high pressure to a level that is safe and comfortable for the astronaut to breathe. This regulated oxygen flows into the suit’s helmet and torso, creating a slight positive pressure that prevents suit collapse and keeps the astronaut’s bodily fluids from boiling. The suit also monitors oxygen levels and alerts the crew if the supply begins to deplete, ensuring the astronaut always has enough to breathe comfortably.
Removing Carbon Dioxide
Breathing in oxygen results in the production of carbon dioxide as a waste product, which must be removed immediately to prevent poisoning and fatigue. In the suit’s life support system, a canister of lithium hydroxide or a similar chemical absorbent captures and scrubs carbon dioxide from the circulating air. This process is essential for maintaining air quality and ensuring that the astronaut can continue to breathe easily without the dangerous buildup of exhaled gas.
Spacecraft Environmental Control
While spacesuits handle personal survival, the spacecraft or space station provides the main living environment for astronauts during their missions. These vehicles and modules are designed as closed-loop ecosystems that recycle air and manage the crew’s needs over long periods. The environmental control system is the central hub that manages all the air the crew breathes.
Oxygen Generation and Air Circulation
On the International Space Station, oxygen is primarily generated through a process called electrolysis, which splits water into hydrogen and oxygen using electricity from solar panels. The oxygen is then added to the cabin atmosphere, while the hydrogen is vented into space. Large fans continuously circulate the air to ensure that the mixture is uniform and that no pockets of stale air form. This constant circulation also allows the air to pass through filters that trap dust and contaminants, keeping the environment healthy.
Carbon Dioxide Management on Station
Unlike the suits, which use chemical scrubbers, the space station employs a more advanced system to remove carbon dioxide. The Environmental Control and Life Support System uses devices like the Carbon Dioxide Removal Assembly, which passes air over specialized beds that capture the CO2. The captured carbon dioxide can then be either vented into space or, in some cases, broken down to recover oxygen, showcasing a sophisticated approach to resource management in orbit.
The Role of Nutrition and Fire Safety
Maintaining the ability to breathe is not only about managing gases; it is also tied to the crew’s overall health and the safety of the habitat. Astronauts follow strict nutritional plans to ensure their bodies efficiently use oxygen and produce energy. Furthermore, the materials used in spacecraft construction are carefully selected to be fire-resistant, as a fire in a confined space with limited oxygen would be catastrophic and make the air impossible to breathe.
