Skip to content
Know.itKnow.it
Create an animated lesson
On request

This article is free to read. Creating a lesson uses your daily or stored credits; review the language and settings before starting.

How does a spacesuit work?

ScienceLesson on requestFree to readयह पेज हिंदी में पढ़ें

Quick answer

A spacesuit is a personal spacecraft that maintains a survivable pressure, supplies pure oxygen, scrubs carbon dioxide, and controls temperature. Its many layers block radiation and micrometeoroids while allowing the astronaut to bend and work. A backpack provides life support, power and communication for hours outside a spacecraft.

A spacesuit works by wrapping an astronaut in a flexible, pressurized bubble that supplies oxygen, removes carbon dioxide and moisture, and keeps temperature and pressure at levels the body can survive. Layers of insulation, cooling tubes and shielding handle the vacuum, radiation and extreme temperatures outside.

Step by step

  1. The astronaut puts on a liquid cooling garment and ventilation tubing that carries oxygen around the body.
  2. The outer suit layers go on over that, including insulation, a pressure bladder and a protective shell.
  3. The helmet and gloves lock into place, sealing the suit so that pure oxygen can fill it at about one-third of normal atmospheric pressure.
  4. A backpack unit supplies oxygen, removes carbon dioxide and water vapour, and circulates chilled water through the cooling garment.
  5. The astronaut enters the airlock, the pressure is reduced, and the suit is checked for leaks before the outer hatch opens.
  6. During the spacewalk, the suit's systems constantly adjust oxygen flow, temperature and radio contact with the spacecraft.

Key things to understand

  1. The suit maintains a pressure of about one-third of Earth's atmosphere, enough to keep body fluids from boiling in vacuum.
  2. Pure oxygen flows into the helmet, a lithium hydroxide or metal-oxide canister absorbs exhaled carbon dioxide, and a separator removes moisture.
  3. A liquid cooling garment circulates chilled water through tubes next to the skin to remove the astronaut's body heat.
  4. Multiple layers of aluminized Mylar and Kevlar insulate against temperatures that swing from about -150°C to 120°C in sunlight and shadow.
  5. The suit connects to a backpack life-support system that holds oxygen tanks, batteries, a radio and a cooling pump.

Labelled diagram

  1. Cooling garment

    Tubes carry chilled water next to the skin to remove body heat.

  2. Pressure bladder

    A rubbery layer holds pure oxygen at about one-third of Earth's sea-level pressure.

  3. Insulation

    Aluminized Mylar sheets reflect heat and block the vacuum's extreme temperatures.

  4. Outer shell

    Kevlar and other fabrics resist cuts and micrometeoroid impacts.

  5. Life-support backpack

    Tanks, scrubbers, batteries and radio keep the astronaut alive and in contact.

Layers of a spacesuit

Real-world examples

  • The Apollo moonwalkers wore suits with a portable life-support backpack that let them stay outside for up to seven hours.
  • Astronauts on the International Space Station perform spacewalks in the Extravehicular Mobility Unit, a reusable suit assembled from many interchangeable parts.
  • The Russian Orlan suit is a one-piece design used on the space station, with a built-in backpack that can be put on through a hatch in the back.
  • Future Mars suits will need to handle fine dust and a thin carbon-dioxide atmosphere, so engineers are testing new materials in desert and vacuum chambers.

Common mistake

✗ Myth: A spacesuit is just a thick, airtight suit that holds in air like a balloon.

✓ Fact: A spacesuit is a complex life-support system with circulating coolant, carbon-dioxide scrubbers, oxygen tanks and a radio. The pressure layer is only one part; without the backpack, the astronaut would quickly overheat or run out of breathable air.

People also ask

What happens if you take your helmet off in space?
You would lose consciousness within about 15 seconds because oxygen escapes from your lungs and blood into the vacuum, and oxygen-poor blood soon reaches the brain. The remaining oxygen in your body would keep you alive for a minute or two, but without a suit you would not survive long enough for rescue.
How do astronauts go to the bathroom in a spacesuit?
They wear a maximum absorbency garment, essentially a super-absorbent diaper, inside the suit. For longer missions, spacecraft have toilets, but during a spacewalk the diaper is the only option. Astronauts also limit food and water before a spacewalk to reduce the need.
Why do astronauts float inside the space station but not in the spacesuit?
Inside the station they are in free fall around Earth, so they float. In a spacesuit they also float, but the suit is bulky and pressurized, so movement feels stiff and they must use tethers and handrails to stay attached to the spacecraft and avoid drifting away.
Why do astronauts wear a diaper inside a spacesuit?
Spacewalks can last six to eight hours, and the suit cannot be removed quickly. A maximum absorbency garment collects urine and faeces so the astronaut can stay outside without returning to the airlock.
How does a spacesuit protect against micrometeoroids?
The outer layers combine tough woven fabrics such as Kevlar, Nomex and Gore-Tex with several sheets of aluminized Mylar. These layers absorb the impact of tiny dust particles travelling at orbital speeds, preventing them from puncturing the pressurized inner bladder.
What happens if a spacesuit gets a small hole?
The suit loses pressure slowly, and the astronaut would notice a drop in oxygen and suit pressure. Mission control would order an immediate return to the airlock, because a complete loss of pressure causes unconsciousness within seconds.
How long does it take to put on a spacesuit?
Putting on the suit and checking all systems takes about 45 minutes to an hour. Astronauts also pre-breathe pure oxygen for a while to purge nitrogen from their blood and avoid decompression sickness.

Part of the guide: Space & Astronomy →