Artemis II's toilet is a moon mission milestone

When astronauts first made their way to the moon, they did so without a toilet. The Apollo program’s system of plastic bags and funnels was so unwieldy and messy that crew members found it “objectionable” and “distasteful,” according to a subsequent NASA report. But now, more than a half century since the last crewed lunar voyages and their toilet troubles, the four astronauts of NASA’s Artemis II mission will take flight with a more commodious bathroom in tow.

The space agency’s Universal Waste Management System (UWMS)—more colloquially called just “the toilet”—was created to solve longstanding potty problems faced by astronauts and to offer a more familiar bathroom experience on the final frontier. Lunar astronauts will now be spoiled by amenities that include handles to help them stay steady in microgravity, a system that can handle both urine and feces simultaneously, urine-collection devices that work for both male and female astronauts, and even a door for the helpful illusion of privacy in a cramped crew capsule.

The new design is more than a decade in the making. Space infrastructure company Collins Aerospace first entered into a contract with NASA to develop the project in 2015. In that time, project scientists have overcome fundamental issues with past space toilets while imagining and meeting future needs so that the same system used by Artemis II astronauts could be adapted for moon and Mars missions in decades to come.

“I think of waste management as an evolution of design,” says Melissa McKinley, project manager and principal investigator for NASA’s UWMS team. “The toilet has built on designs from Apollo, the space shuttle and even the International Space Station.... There is so much learning that goes into it.”

In the tight quarters of Apollo crew capsules, astronauts strapped adhesive-rimmed plastic bags and tubes to themselves whenever they had to defecate or urinate. Attaching the awkward bags was difficult enough in weightless conditions, but the astronauts also had to manually mix in a packet of germicide to prevent the buildup of bacteria and gases within the sealed bag.

The system was infamously prone to leaks, such as during the Apollo 10 mission, when astronauts noticed “a turd floating through the air,” and during the Apollo 8 mission, when the crew had to chase down blobs of vomit and feces that escaped into the cabin. A NASA report released after the end of the Apollo missions noted that waste disposal “must be given poor marks” when it comes to crew satisfaction.

“I used to want to be the first man to Mars,” said astronaut Ken Mattingly during the Apollo 16 mission, after describing the system. “This has convinced me that, if we got to go on Apollo, I ain’t interested.”

Based on these scathing reviews, NASA scientists knew they had to create a more streamlined system. After all, “the toilet is a ‘mission-critical’ system, so if it breaks down, the whole mission is in jeopardy,” says David Munns, a science and technology historian at the City University of New York.

So before the space shuttle program, they engineered a toilet that could work in a low-gravity environment. It looked much like a typical terrestrial toilet but required the astronauts to strap in and use a vacuum hose to prevent waste from floating back up into the spacecraft.

Early toilets on both the space shuttle and the International Space Station (ISS) used this vacuum system—with the key difference being that the ISS model recycled some wastewater, whereas the space shuttle’s version vented it into space. Both systems were significantly improved over the “toilets” of the Apollo years but still had big limitations. They weren’t built with female anatomy in mind and couldn’t process urine and feces at the same time, and while they provided some semblance of privacy with a curtain, there wasn’t yet a solid door.

The UWMS is the aerospace-engineered culmination of all these pent-up problems with the user experience. 3D-printed from titanium, its lightweight, standardized design means it can easily fit in many different types of spacecraft, including the ISS, the Artemis missions’ Orion capsule and potential future vehicles that have yet to be built.

The first version of the UWMS was tested on the ISS in 2020, and final installation was completed in 2021. It featured urine and feces systems that could be used simultaneously, modifications to make these systems more unisex and the much-coveted bathroom door. With further modifications to help the same system function on a lunar mission, a version of the UWMS has also been installed in the Orion capsule for Artemis II, the program’s first crewed launch—and UWMS project scientists are on the edge of their seats, eager to learn whether the mission’s four astronauts are happy with the design.

“I am very excited for the crew to use this,” McKinley says. “We’ll know so much more when this mission comes back.... It’s really going to drive [waste management] on future Artemis missions and the lunar campaign—as well as the Mars campaign to come.”