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! Spacesuits must provide all of the comfort and support that the Earth or a spacecraft does, addressing issues like atmosphere, water and protection from radiation.

Spacesuit Image Gallery 

an astronaut on a spacewalk
Photo courtesy NASA
Spacesuits provide oxygen, temperature control and some protection from radiation.  See more spacesuit pictures.

In this article, we will examine the problems of walking in outer space and how spacesuits are made to cope with them.

Outer space is an extremely hostile place. If you were to step outside a spacecraft such as the International Space Station, or onto a world with little or no atmosphere, such as the moon or Mars, and you were not wearing a spacesuit, the following things would happen:

  • You would become unconscious within 15 seconds because there is no oxygen.
  • Your blood and body fluids would "boil" and then freeze because there is little or no air pressure.
  • Your tissues (skin, heart, other internal organs) would expand because of the boiling fluids.
  • You would face extreme changes in temperature:
    • sunlight: 248 degrees Fahrenheit / 120 degrees Celsius
    • shade: -148 F / -100 C
  • 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.
astronaut on Apollo mission walking on the moon
Photo courtesy NASA
So, to protect you from these dangers, a spacesuit must:
  • Have a pressurized atmosphere
  • Give you oxygen
  • Remove carbon dioxide
  • Maintain a comfortable temperature despite strenuous work and movement into and out of sunlit areas
  • Protect you from micrometeoroids
  • Protect you from radiation to some degree
  • Let you see clearly
  • Allow you to move your body easily inside the spacesuit
  • Let you talk with others (ground controllers, other astronauts)
  • Let you move around the outside of the spacecraft

We'll discuss these necessities, and how a spacesuit provides for them, in detail in the next section.