When astronauts travel to space, they need to carry along basic life support elements from Earth, such as the ability to produce food, purify their water, regenerate oxygen, and remove harmful microbes and elements from the air. The environmental control systems (in addition to other life-support systems) on the space shuttle and the International Space Station perform these functions, which keep the passengers and crew onboard alive.

Space Shuttle Climate

Temperature, which is controlled by an air revitalization system (ARS), is vital for the operation of a space shuttle, but heating and cooling systems need to be delicately monitored because some portions of the shuttle need cool air to operate, whereas others need warm air. The ARS maintains a relative humidity level of between 30 percent and 75 percent, in addition to keeping the carbon dioxide and carbon monoxide at safe levels. The ARS also regulates temperature, ventilation...