Buzz Aldrin remembers feeling “buoyant” and “full of goose pimples” when he stepped onto the moon in 1969, becoming the second person to touch the surface of another world. The view was magnificent.
The first thing he did was examine the ground beneath his boots. “I immediately looked down at my feet and became intrigued with the peculiar properties of the lunar dust,” the Apollo astronaut recalled in one of his memoirs. “If one kicks sand on a beach, it scatters in numerous directions with some grains traveling farther than others. On the moon the dust travels exactly and precisely as it goes in various directions, and every grain of it lands very nearly the same distance away.”
The second thing he did was pee.
Aldrin, the first person to urinate on the moon (into a special collection device worn around his waist) is one of hundreds of astronauts who, in between doing extraordinary things, have done the most mundane thing. In the nearly 60 years since human beings first went to space, engineers have worked carefully on the technology inside spacesuits, shuttles, and capsules to accommodate this very earthly act, and the effort continues today: Astronauts are preparing to install a brand-new toilet on the International Space Station soon.
NASA spent $23 million on the Universal Waste Management System, which might make it the most expensive toilet in the universe. The privy represents the state of the art in NASA’s off-world bathroom facilities. It is smaller and lighter than the old version. It’s easier to maintain, which is handy because when a space toilet springs a leak, astronauts can’t call in a plumber. Its metal pipes are now 3-D-printed, and still capable of withstanding the acid used to treat astronauts’ urine before it becomes their drinking water.
But the most important new feature is the one that allows astronauts to do something that the rest of us mostly take for granted on Earth. There’s no artful way to put this, so I’m just going to say it: The current toilets on the International Space Station aren’t conducive to peeing and pooping at the same time.
This matters more for the women in the astronaut corps, for whom the two bodily functions can be trickier to separate. For years, women astronauts have been carefully positioning themselves over the bowl, exchanging tips with their colleagues on best practices, and trying to make do with hardware that wasn’t built for their bodies.
Space toilets don’t look quite like the one in your bathroom. With the older latrine models on the ISS, astronauts urinate into a handheld funnel and defecate into a device that looks like a smaller version of a traditional toilet seat. A fan inside each apparatus suctions the waste away from the body, an important function in an environment where everything floats. The urine is transformed into the next day’s water, while the feces are compressed in a removable container and eventually dispatched on a special trash spacecraft that burns up in the atmosphere in the majestic manner of a shooting star. It’s careful business for men and women alike. Hold the funnel too close to the body, cutting off airflow, and liquid can end up pooling near the top. Lose contact with the seat, and waste might escape. Forget to turn on those fans before you start, and things can get messy.
This configuration is more challenging for women, who more commonly perform “dual ops,” a popular NASA euphemism for simultaneous evacuation. “It’s a little bit difficult to be on the seat and still get the funnel where it needs to go,” Jessica Meir, a NASA astronaut, told me. Special instructors train the astronauts on how to use and repair the toilet, in the same building at Houston’s Johnson Space Center where astronauts practice spacewalking around a replica of the station inside a swimming pool. (They wear diapers for that activity, in rehearsals and during the real thing.)
Meir said the training is crucial for understanding the old toilets’ plumbing, but the best advice for actually using them comes from her fellow astronauts. When Meir flew to the ISS last year, her best friend, Christina Koch, was already there. Koch showed her how to situate herself and which handrails and foot restraints helped most. “I actually found that I could do it with the existing toilet, even though other females haven’t been able to. So, definitely some anatomical differences, or maybe just some technique differences,” Meir said. “I was so relieved to realize that I could do it, because I was just like, This is going to be really annoying if I can’t do it.”
The newest lavatory was designed specifically with female anatomy in mind. In this way, the Universal Waste Management System is more than a toilet. It is a symbol of a changing American space program that for its first two decades took only men to space. Although men still make up the majority of NASA’s astronaut workforce, there are more women astronauts than ever before, and the agency has recognized that it must adapt its technology to meet their needs. “It’s about time,” Nicole Stott, a retired NASA astronaut who flew two missions to the space station, told me.
NASA consulted women astronauts in the design for the new system, including Stott. While the basic setup is unchanged, engineers have “completely recontoured” the urine funnel to better accommodate the female anatomy, according to Melissa McKinley, the project manager for the effort. They also made changes to the positioning of both the urine funnel and the toilet seat, allowing women to more comfortably use them at the same time. As an added bonus, astronauts don’t have to turn on the toilet before relieving themselves; as soon as they remove the urine funnel from its cradle or lift the toilet lid, the fan kicks on.
It might seem baffling, even a little absurd, that the organization that put men on the moon more than half a century ago did not, until this year, enable them to go number one and number two at the same time. But the problem originates in that very achievement: NASA put men on the moon. The existing toilet on the American side of the space station was developed in the 1990s, using a Soviet model. The gender balance of astronauts in the United States and Russia was even more lopsided at the time than it is today, so male anatomy and needs drove the design. Astronauts used a similar design on the space shuttles, which delivered the hardware to assemble the ISS.
Stott and Meir likened the clumsy toilet design to NASA’s supply of spacesuits for astronauts working outside the space station. Last year, the agency was forced to reshuffle a spacewalking assignment because there weren’t enough spacesuits on board to fit Koch and Anne McClain, who both wore a size medium. A male astronaut replaced McClain on the spacewalk. NASA’s current spacesuit wardrobe, much of it designed in the 1970s, was meant to be customizable, with mix-and-match parts. Production on the smallest sizes was halted in the ’90s because of budget cuts, and because NASA had never planned a two-woman spacewalk before 2019, the ISS simply wasn’t prepared with enough garments for its female crew members.
NASA’s vision for the next line of spacesuits is tailored for the more diverse group of astronauts that the agency hopes will return to the moon later in this decade. NASA wants to send the first woman to the moon as part of its Artemis program for lunar exploration, named for Apollo’s sister in Greek mythology. The latest space toilet technology is expected to follow her there; in addition to the toilet NASA sent to the ISS, the agency created one for the capsule, still in development, that will deliver her crew to the moon.
As a beloved, best-selling children’s book put it, everyone poops—but it’s far more interesting when an astronaut does it. There’s an entire catalog of YouTube videos of astronauts describing how they do mundane things in space. People want to know how they brush their teeth, wash their hair, sleep, exercise, and even cry in microgravity. In space, the tedious tasks of human existence become curiosities.
And although astronauts can’t give as realistic a walk-through of their lavatories as they do of the onboard gym and bunks, they’re willing to talk about the bathroom process, sometimes even eager to. Consider Michael Collins, one of the Apollo 11 astronauts, who remained in orbit around the moon while Aldrin and Neil Armstrong descended to the surface. In the decades since the mission, reporters have bombarded Collins with questions about what it was like to be so alone, even though he’s always insisted that he was just fine. When I asked him last year whether he wishes people would ask about something else, he replied with: “How do you go potty in space?” No one had ever asked him that, and he was eager to reveal the answer: “Carefully.”
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