Skip to main content

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 pic.twitter.com/ekQYXB3CTc

— Thomas Pesquet (@Thom_astro) May 12, 2021

Image used with permission by copyright holder

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.”

Editors' Recommendations

Trevor Mogg
Contributing Editor
Not so many moons ago, Trevor moved from one tea-loving island nation that drives on the left (Britain) to another (Japan)…
Russian Soyuz on its way to ISS after being delayed due to electrical issue
The Soyuz MS-25 spacecraft lifts off from the Baikonur Cosmodrome in Kazakhstan on March 23, 2024

A trio of crew members are on their way to the International Space Station (ISS) on board a Soyuz spacecraft following a rescheduled launch spurred by an electrical issue. The Russian Soyuz MS-25 was originally supposed to launch on Thursday, March 21, but the launch was scrubbed at the last minute due to a problem with the launch vehicle.

The launch was rescheduled for Saturday, March 23, with the rocket lifting off from the Baikonur Cosmodrome in Kazakhstan at 8:36 a.m. ET. The crew are now safely in orbit and are on their way to the ISS, where they should arrive on Monday morning.

Read more
Crewed Soyuz launch to space station suffers rare late abort
The Soyuz rocket and MS-25 spacecraft on the launchpad.

The Soyuz rocket and MS-25 spacecraft on the launchpad. NASA/Bill Ingalls / NASA/Bill Ingalls

The latest launch of Russia’s usually reliable Soyuz rocket was called off just seconds before liftoff on Thursday, with the three crewmembers -- including one NASA astronaut -- now waiting for their next opportunity to fly to the International Space Station (ISS).

Read more
Here’s the new science that’s launching to the ISS today
A SpaceX Falcon 9 rocket carrying the Dragon spacecraft lifts off from Launch Complex 39A at NASA’s Kennedy Space Center in Florida on Thursday, Nov. 9, 2023, on the company’s 29th commercial resupply services mission for the agency to the International Space Station.

Today will see the launch of not only a group of astronauts visiting the International Space Station (ISS), but also an uncrewed cargo mission sent to resupply the station. Scheduled for 4:55 p.m. ET on Thursday, March 21, a SpaceX Cargo Dragon will launch from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida. The cargo ship is expected to arrive at the ISS at 7:30 a.m. ET on Saturday, March 23.

A SpaceX Falcon 9 rocket carrying the Dragon spacecraft lifts off from Launch Complex 39A at NASA’s Kennedy Space Center in Florida on Thursday, Nov. 9, 2023, on the company’s 29th commercial resupply services mission for the agency to the International Space Station. SpaceX

Read more