Space Station Life Support: Keep the Crew Breathing
See a closed system in action: a crew consumes oxygen and water and makes carbon dioxide, so machines powered by the Sun must turn water into oxygen, scrub the air and recycle the water.
Before you try
What if the water recycler broke? How many days would the crew last?
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What happened?
Move a control to see what changes and why.
Daily budgets with rounded figures for one crew member and illustrative tank sizes; real rates vary with activity and equipment.
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Try these ideas
- Run the default station for 30 days and watch which gauge moves first.
- Cut the solar panels to 2 and see which machine starves.
- Turn water recycling down to 0%. How long does the water last?
Why it works
Each astronaut uses about 0.84 kg of oxygen a day, breathes out about 1 kg of carbon dioxide and uses around 2.5 litres of water. Nothing arrives between supply flights, so the International Space Station recycles: an electrolysis unit splits water into hydrogen and oxygen, a scrubber pulls carbon dioxide out of the air, and the water system recovers about 90% of what the crew uses, including sweat and urine.
All of this needs electricity, which comes from the station’s solar panels. In this simulator you choose the crew size, the number of working panels and the settings of the oxygen maker, the scrubber and the water recycler, then run the days. Gauges show the tanks and the cabin air; if oxygen runs out, carbon dioxide builds up or water runs dry, the mission ends.
Check your understanding
Question 1 of 4
Where does the oxygen the crew breathes come from?
What happens if the CO₂ scrubber is switched off?
Why does the station recycle water so carefully?
Doubling the crew roughly doubles
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
What will you discover next?
Try Satellite Orbit Lab: Why the Space Station Never Falls Down next.
For parents & teachers
- Measure how much water your family uses in a day and compare it with 2.5 litres per astronaut.
- Ask: what would a station need to grow its own food?
- Discuss why sealed rooms on Earth (submarines, mines) face the same problems.