What are some of the special features of a spacesuit?
A spacesuit is really a small spacecraft, with all the features that are required to keep its occupant healthy and productive over many hours of extravehicular activity (EVA). Since there is no atmospheric pressure in space and no oxygen to sustain life, human beings must take their environment with them. And just like inside the Shuttle cabin, the atmosphere inside the suit can be controlled and regulated. Thus, spacesuits must primarily supply oxygen (O2) for breathing while maintaining a pressure around the body to keep body fluids in the liquid state; in vacuum or at very low air pressures body fluids would boil just like warm water on top of a high mountain. Spacesuits for the Space Shuttle era are pressurized at 4.3 pounds per square inch (psi), which is only approximately a third of normal atmospheric pressure (14.7 psi, equal to one atmosphere). But because the gas in the suit is 100 percent oxygen instead of containing only 20 percent O2 as we are used to in the Earth’s atmosp
