Life in Space: How much oxygen do astronauts carry and what happens if it runs out in an emergency?

Staying alive in space is no simple task. On Earth, breathing is effortless because oxygen is everywhere. But in space, there is none. Astronauts rely on carefully designed systems to survive. Their lives depend on oxygen supplies and backup plans.

How Astronauts Get Oxygen in Space
Oxygen is available only up to 120 kilometres above Earth. Beyond that, the lack of gravity means gases do not stay together. Without an atmosphere, astronauts cannot breathe naturally. So how do they survive?

Inside spacecraft, oxygen is supplied through built-in systems. This allows astronauts to breathe without carrying extra tanks. However, when stepping outside, they need special suits. These suits have oxygen tanks and filtration systems. They ensure astronauts get enough air to breathe.

How Much Oxygen Do Astronauts Carry?
Spacecraft are designed to maintain a stable oxygen level. While inside, astronauts do not need extra cylinders. But outside the spacecraft, they carry oxygen tanks. Their space suits contain two types of gases—oxygen and nitrogen. These ensure they can breathe in the vacuum of space.