You're an astronaut orbiting 400 kilometers above Earth when suddenly an alert flashes across your display.
The system responsible for producing the breathable air on board has failed.
Now, you and your crewmates must work with Mission Control to identify the problem and fix it as quickly as possible.
This might seem like a scene from a sci-fi thriller, but for astronauts on the International Space Station, dealing with situations like this is a reality of life.
For over twenty-five years, ISS's air supply systems have revolutionized space missions, yet the need for regular maintenance, repairs, and upgrades has pushed engineers to develop even more reliable systems for future spacecraft.
Creating breathable air in space has two requirements: supplying oxygen and removing exhaled carbon dioxide before it builds up.
Every astronaut in space needs, on average, about 0.8 kilograms of oxygen a day.
Most early space missions met this demand by storing oxygen on board in pressurized tanks.
For example, the eight-day Apollo 11 mission to the Moon carried three astronauts, along with around fifty kilograms of oxygen for life support, more than enough for the crew to survive on.
Canisters containing lithium hydroxide would chemically react with carbon dioxide, scrubbing it from the cabin.
