How Space Suits Work

Space suits provide oxygen, temperature control and some protection from radiation.
Photo courtesy NASA

Think about how you suit up when you go outside on a ­cold winter's day. You have your shirt, pants, sweater, perhaps long underwear, jacket, gloves, hat or hood, scarf and boots. You put on quite a bit of clothing to protect you from the cold.

Now, imagine what you would have to put on to protect you from outer space. Space suits must provide all of the comfort and support that the Earth or a spacecraft does, addressing issues like atmosphere, water and protection from radiation.


Outer space is an extremely hostile place. If you were to step outside a spacecraft and you weren't wearing a space suit, the following things could happen:

  • You could become unconscious within 15 seconds because there's no oxygen.
  • Your blood and body fluids could "boil" and then freeze because there is little or no air pressure.
  • Your tissues (skin, heart, other internal organs) could expand because of the boiling fluids.
  • You could face extreme changes in temperature. For example, in the sunlight temperatures might reach 248 degrees F (120 degrees C) and plummet to -148 F ( -100 C) in the shade.
  • You would be exposed to various types of radiation, such as cosmic rays, and charged particles emitted from the sun (solar wind).
  • You could be hit by small particles of dust or rock that move at high speeds (micrometeoroids) or orbiting debris from satellites or spacecraft.

So, to protect you from these dangers, a space suit must:

  • Have a pressurized atmosphere
  • Give you oxygen and remove carbon dioxide
  • Maintain a comfortable temperature despite strenuous work and movement into and out of sunlit areas
  • Protect you from micrometeoroids and from radiation to some degree
  • Allow you to see clearly, move easily inside the space suit and outside of the spacecraft, and communicate with others (ground controllers, fellow astronauts)

That's a big job. In this article, we will examine the problems of walking in outer space and how space suits are made to cope with them.