Last week, NASA astronaut Scotty Kelly embarked on a historic mission: He plans to spend the next 361 days on the International Space Station.

That's longer than anyone has ever spent on the ISS, as well as the longest stretch that any American has ever spent in space, period.

In honour of the occasion, NASA tweeted out the following "fun" fact:

The International Space Station can recycle about 93 percent of the liquids it receives - in this case, urine and sweat. Although it sounds gross, the liquid - which takes eight days to recycle - is actually even more pure than the water that most people drink at home. 

For reference, 730 litres is equivalent to nearly 200 gallons.

Learn more about the purification process in this video:

(Also, in case you're curious, astronaut poop gets collected by an unmanned space ship that will get burned up when it returns to Earth).

This article was originally published by Business Insider.

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