Astronauts
Astronauts breathe oxygen stored in tanks or made on the ship. Spacesuits and spacecraft are sealed and keep that air at a safe pressure. Filters pull out carbon dioxide, the waste gas we exhale, so the air stays usable.
On this page: how astronauts breathe, why space has no air, what a suit does, and how the space station makes oxygen.
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Astronauts
Outside a ship, space is a vacuum. That means almost no air to inhale. Astronauts live in sealed rooms: a spacecraft cabin or a spacesuit. Both hold oxygen and keep pressure on the body. On a spacewalk, a backpack called a portable life support system feeds oxygen and removes carbon dioxide. On the International Space Station, machines make fresh oxygen by splitting water with electricity, a process called electrolysis. Tanks are backup. Every breath is planned.
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Breathable air outside
O₂
Gas they breathe
Sealed
Suit and cabin air
H₂O → O₂
Station oxygen trick
Air is a mix of gases held near Earth by gravity. The farther you go, the thinner it gets. In orbit and beyond, the leftover bits are so spread out that your lungs would find almost nothing. There is no wind, no outdoor breath, no sky-blue scatter of light the way we see it from the ground. That empty stretch is why rockets carry their own oxygen to burn fuel, and why people carry theirs to live.
A spacesuit is a wearable spacecraft. It holds pressure so body fluids do not boil in the vacuum. It feeds oxygen, removes carbon dioxide and moisture, and helps control temperature. Layers block some radiation and flying dust. Gloves, a helmet, and a gold-tinted visor let an astronaut work in hard sunlight and deep shade. The suit is not a costume. It is life support you can walk in.
The station splits water into hydrogen and oxygen with electricity from solar panels. That is electrolysis. Crew also recycle a lot of water from breath and sweat. Cargo ships still bring water and backup oxygen tanks. Carbon dioxide is scrubbed out of the cabin air. The station is a careful loop: water, power, air, and people, all sharing a metal tube above Earth.
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