Astronomy & space
EVA spacesuit (EMU)
Spaceflight · Life support
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Space is freezing cold — so why is a spacesuit’s biggest problem keeping the astronaut cool?
A spacewalk suit is really a tiny spacecraft shaped like a person. Its layers hold in oxygen, keep the suit in human shape and block heat, cold and flying specks of dust, while the backpack supplies air and removes the carbon dioxide you breathe out. Vacuum does not carry body heat away, so the suit pumps cold water through tubes in a special undergarment.
NASA’s Extravehicular Mobility Unit is a self-contained spacecraft for one person: a layered pressure garment plus a backpack that supplies oxygen, removes carbon dioxide and rejects heat for spacewalks of up to eight hours. Each layer solves one physical problem — holding pressure, carrying the load, cooling the body, or shielding against temperature extremes and micrometeoroids.
Key facts
- Operating pressure
- 29.6 kPa (4.3 psi), 100% oxygen
- EVA duration
- Up to ≈ 8 h, plus ≈ 30 min emergency reserve
- Mass on Earth
- ≈ 130–145 kg including backpack
- Cooling garment tubing
- ≈ 90 m (300 ft)
- Surface temperatures faced
- ≈ −150 °C to +120 °C
- In service
- Since 1983 (STS-6); used for ISS assembly and maintenance
Parts you can explore (13)
- Liquid cooling garment
- Pressure bladder
- Restraint layer
- Hard upper torso
- Thermal micrometeoroid garment
- Helmet and visor
- Gloves
- Display and control module
- Life-support backpack
- Oxygen tanks
- Fan, pump and water separator
- Sublimator
- CO₂ removal cartridge
In the 3D model
Rotate and take apart the model, follow a guided tour of what each part does and why it’s needed, change it with a live slider, and test yourself with a short quiz. Free, no sign-up.
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