An Inside Look at the Water/Urine Recycling System on the Space Station

International Space Station Commander Chris Hadfield “lifts the lid” on the Water Recovery System, the first liquid recycling system to be flown in space that cleans almost all the “water” (greywater, urine, sweat) produced by crew members so that it can be used again. As previous space station resident Don Pettit has said, “Yesterday’s coffee becomes today’s coffee.”

Previously, Russia’s space station Mir recycled cosmonaut’s sweat, but this system on the ISS can recycle about 93 percent of the liquids it receives. The ISS’s water recycler uses a distiller that looks like a keg. On Earth, distilling is a simple process of boiling water and cooling the steam back into pure water. But without gravity, the contaminants in water never separate from the steam no matter how much heat is used. So, the keg-sized distiller spins to produce an artificial gravity field while boiling the water. The contaminants in the urine or greywater press against the sides of the drum while the steam gathers in the middle and is pumped to a filter.