Spacesuit Prototype Turns Pee Into Drinking Water

Researchers are working to develop a system for extracting drinkable water from urine that astronauts could use during spacewalks. Though the system as a whole still needs to be tested on people, astronauts could one day use it to improve their hygiene and performance during extravehicular activity, the researchers reported last week in the journal Frontiers in Space Technologies.

The system is inspired by the stillsuits worn by people in the deserts of Arrakis in the science fiction epic Dune, Sofia Etlin, first author of the study and an astrobiologist at Cornell University, tells Science News’ Adam Mann.

“I’ve been a fan of the Dune series for as long as I can remember,” Etlin tells the publication. “Building a real life stillsuit was always a bit of a dream.”

“Even in the absence of a large desert planet, like in Dune, this is something that could be better for astronauts,” Christopher Mason, a co-author of the study and genomicist at Cornell University, says to the Guardian’s Hannah Devlin.

Astronauts on the International Space Station (ISS) performed 37 spacewalks between 2021 and 2023, which lasted as long as nearly nine hours, and, on average, almost 6.5 hours. During these trips outside the station, astronauts wear an adult diaper called a Maximum Absorbency Garment (MAG) that can hold up to two liters of waste.

But these diapers can cause discomfort and health issues for astronauts, according to the new study. Astronauts eat less in advance of spacewalks to reduce their chances of having to use the MAG, which can impact their performance during the spacewalk, the paper’s authors write. Astronauts have reported that the MAGs smell bad, and they’ve caused skin rashes, urinary tract infections and gastrointestinal issues.

“You’d think in the 21st century, astronauts would not be using diapers,” Etlin tells CNN’s Amarachi Orie.

“It’s commonplace for the MAG to leak,” Etlin says to the Guardian. “The astronauts talk about how at a certain point they can’t tell whether it’s urine or sweat any more.”

Astronauts have also said that the amount of drinking water they’re provided in spacesuits currently is not enough for spacewalks, according to the paper. Not only are spacewalks exhausting, causing astronauts to sweat a lot, but people also urinate more in space as fluid shifts in the body due to the lack of gravity.

As NASA prepares for crewed trips to the moon as part of the agency’s Artemis missions, astronauts may also have to spend as much as 24 hours a week outside of their spacecraft.

“Astronauts currently have only one liter of water available in their in-suit drink bags,” Etlin says to the Guardian. “This is insufficient for the planned longer-lasting lunar spacewalks, which can last 10 hours, and even up to 24 hours in an emergency.”

The researchers aim to design a system that’s more comfortable and healthier for the astronauts. A silicone cup surrounding the astronaut’s genitalia and lined with a moisture-wicking fabric will collect urine. A vacuum pump will carry the urine to the filtration system on the astronaut's back, which will first separate water from the urine and then remove salt from the water. The system could process half a liter of urine in five minutes and could return 87 percent of it as drinkable water.

The pack that the astronauts would have to wear is expected to weigh a little more than 17 pounds, according to the study.

Houston-based Axiom Space, contracted by NASA, is currently designing a spacesuit for spacewalks. Etlin tells CNN that new spacesuit designs still rely on the MAG.

Human trials for the proposed system will start in November, per New Scientist’s Matthew Sparkes.

Such a system “would be amazing for us,” Julio Rezende, a researcher at the Federal University of Rio Grande do Norte in Brazil who leads a Mars analog mission called Habitat Marte, says to Science News. “I believe this technology would bring a lot of benefits.”

Will Sullivan | | READ MORE

Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next.