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Space station toilet flushes its way to a new milestone

When you gotta go, you gotta go, and according to the “flush” counter on one of the International Space Station’s three toilets, astronauts have gone more than 40,000 times over the past 20 years.

Current ISS crew member Thomas Pesquet broke the news in a post on Twitter on Wednesday, May 12.

Clearly delighted at seeing the toilet’s counter reach a new landmark figure, Pesquet tweeted, “40,000 times this space toilet has been used, a milestone!” He added, “We need to maintain it as clean sanitation and sewage treatment is a human right and a UN Sustainable Development Goal.”

40 000 times this space toilet has been used, a milestone! We need to maintain it as clean sanitation and sewage treatment is a human right and a @UN Sustainable Development Goal. #MissionAlpha #SDG6

— Thomas Pesquet (@Thom_astro) May 12, 2021

The space station currently has three toilets on board, so it should be noted that the habitable satellite has in fact hosted thousands more flushing events over the years.

Of course, the microgravity conditions aboard the ISS mean that going to the bathroom in space is a very different process from here on Earth. Indeed, space toilets are not really flushed in the way most earthlings understand the process. Rather, they use a suction mechanism to capture liquid waste before it has a chance to float away and cause a mess. (Interesting tidbit: Urine on the station is later filtered and processed for use as drinking water.)

Solid waste drops into a plastic bag before being sealed and put in a container located at the toilet’s base, which is emptied after around 30 deposits. And no, number twos are not transformed into food. Instead, it will burn up in the Earth’s atmosphere when ejected as part of the station’s trash, while a small amount will be sent to Earth for scientific analysis.

The most recent commode arrived at the space station last year. Known as the Universal Waste Management System, the compact contraption features a more ergonomic design than the other two toilets and has been built with more durable parts that should reduce the need for maintenance.

NASA astronaut Chris Cassidy last year revealed that the most common question he’s asked is, “How do astronauts go to the bathroom?” In the video below, he kindly offers a run-through of the process using the station’s newest toilet.

How to use the Bathroom in Space

The ISS usually hosts around six astronauts, though last month, during a busy crew rotation process, it briefly had 11 on board, putting a little more pressure on resources and possibly causing the occasional line outside a bathroom or two. Commenting on the unusual situation, former NASA astronaut Nicole Stott said, “It’s a blessing that there are three toilets up there now.”

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