International Space Station's Cooling System: How It Works (Infographic)

Infographic: How the ISS's Ammonia Cooling System Works
The ammonia system is one of several cooling loops that circulate liquids throughout the International Space Station. (Image credit: Karl Tate, Infographics Artist)

The International Space Station’s active thermal control systems (ATCS) pump fluids through closed-loop pipes. A liquid-ammonia coolant loop along the station’s main truss keeps the station’s electricity-generating solar panels cool.

An ammonia pump on the main truss failed in 2010 and had to be replaced by spacewalking astronauts. The Expedition 35 crew on the International Space Station reported an ammonia leak near the same location on May 9, 2013.

The International Space Station: Inside and Out (Infographic)

Liquid ammonia circulates through the pipes, carrying waste heat from the solar panels to the photovoltaic radiator panels, where the heat escapes into space. This keeps the solar panels cool.

Video Flashback: Spacewalk Marathon to Fix Space Station Cooling System in 2010

The International Space Station is the largest man-made structure ever built in space. From end to end, it is as long as a football field and can be seen from the ground by the unaided eye by observers who know when and where to look.

The $100 billion space station is the product of international cooperation among 15 different countries and five national space agencies representing the United States, Russia, Europe, Canada and Japan. Construction began in 1998 and the first crew, Expedition 1, took up resident in 2000. Rotating crews of between three and six crewmembers have kept the space station permanently manned ever since.

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Karl Tate contributor

Karl's association with goes back to 2000, when he was hired to produce interactive Flash graphics. From 2010 to 2016, Karl worked as an infographics specialist across all editorial properties of Purch (formerly known as TechMediaNetwork).  Before joining, Karl spent 11 years at the New York headquarters of The Associated Press, creating news graphics for use around the world in newspapers and on the web.  He has a degree in graphic design from Louisiana State University and now works as a freelance graphic designer in New York City.