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Breathing Easy on the Space Station

Keeping the Air "Clean"

A Science@NASA story by Patrick L. Barry

At present, carbon dioxide is removed from the air by a machine on the Zvezda Service Module based on a material called "zeolite," which acts as a molecular sieve, according to Jim Knox, a carbon dioxide control specialist at MSFC.

The removed CO2 will be vented to space. Engineers are also thinking of ways to recycle the gas.

In addition to exhaled CO2, people also emit small amounts of other gases. Methane and carbon dioxide are produced in the intestines, and ammonia is created by the breakdown of urea in sweat. People also emit acetone, methyl alcohol and carbon monoxide -- which are byproducts of metabolism -- in their urine and their breath.

Activated charcoal filters are the primary method for removing these chemicals from the air.

This diagram shows the flow of recyclable resources in the Space Station's Environmental Control and Life Support System (ECLSS)
This diagram shows the flow of recyclable resources in the Space Station's Environmental Control and Life Support System (ECLSS).

Maintaining a healthy atmosphere is made even more complex by the dozens of chemicals that will be used in the science experiments on board the ISS.


Curator: Kim Dismukes | Responsible NASA Official: John Ira Petty | Updated: 04/07/2002
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