A marvel of the “Dune” sci-fi film franchise is the survival suit worn by the desert-dwelling Fremen — the “stillsuits” that recycle all bodily fluids into drinking water. Now such technology appears to be on the horizon, with scientists revealing a spacesuit system prototype which turns urine into drinking water.
Astronauts may spend a considerable amount of time outside their space habitat performing extravehicular activities, or EVAs. There have been 37 spacewalks carried out between 2021 and 2023 for scientific experiments or to carry out repairs to the International Space Station (ISS), and they lasted an average of 6 hours and 26 minutes, according to a study by scientists at Cornell University published on Friday (12) in the journal Frontiers in Space Technology. Spacewalks can last more than 8 hours.
When spending these long periods on spacewalks, astronauts currently wear the familiar fluffy white EVA suits, which contain maximum absorbency clothing. These disposable garments are essentially diapers that collect urine and feces. They must be capable of holding up to one liter of urine and 75 grams of fecal matter per day for each crew member.
However, these EVA suits were designed more than 40 years ago, and NASA (the United States space agency) currently has no concrete plans to renew or replace them. The space agency announced in June that it was canceling contracts worth more than $100 billion with Collins Aerospace to create next-generation spacesuits, although at least two other U.S. companies are currently working on spacewalk suits and NASA may request additional contractors, the space agency confirmed to CNN.
“You would think that in the 21st century, astronauts wouldn’t be wearing diapers,” he told CNN on Friday Sofia Etlin, lead author of the study, astrobiologist and research team member at the Mason Lab at Weill Cornell Medical College in New York.
Although diapers can effectively absorb waste, they can harm astronauts’ health and cause discomfort. Astronauts have reported leaking diapers, making them unable to distinguish between their urine and sweat, and have complained of rashes and odor problems. Crew members face medical risks such as cross-contamination with fecal matter, urinary tract infections and gastrointestinal problems, which are worsened by astronauts’ reduced access to medical care.
Some even reduced their meals several days before an EVA to avoid having to use one, which could impact their performance on strenuous spacewalks, according to the researchers.
Simply being in space causes dehydration, and physically demanding spacewalks cause more dehydration, which impairs astronauts’ performance. However, the in-suit drink pouch, which currently provides astronauts with about 900 grams of water and a small dose of glucose, also has “significant problems,” including being time-consuming to prepare, contributing to reduced work efficiency, according to the researchers. Astronauts said the current amount of water provided is not enough.
“Dune” System
To “promote astronaut well-being,” researchers designed a new in-suit urine collection and filtration system, or “Dune” system, Etlin said.
The system would recycle urine using forward and reverse osmosis, a model used by the current wastewater treatment system aboard the space station, to remove contaminants from urine and filter it into drinking water.
One aspect of the system is a urine collection device, which would feature a silicone cup, shaped differently for men and women. The device would have multiple layers of fabric, including an antimicrobial fabric, to allow urine to move away from the body quickly to the outer surface where it can be pumped away, reducing the health risk from prolonged exposure to urine.
The liquid would then enter the filtration system, a two-stage device that removes water from urine into a saline solution, with a pump separating the pure water from the salt.
The study authors proposed that a volume of 500 milliliters of urine could be processed in less than five minutes, effectively recycling more than 86.8% of it into drinking water.
The water would then be pumped into the drink pouch in the suit, where it would be replenished with electrolytes and, potentially, carbohydrates, to meet nutritional and energy needs.
The entire device would be in a bag that could be mounted on the back of an EVA suit, adding 8 kilograms (17.6 pounds) to its total weight.
While “weight is certainly a concern for upcoming lunar missions, we believe the increased comfort and resource efficiency provided by the system will more than offset the slight increase in volume,” the study authors said.
Reinvented spacesuits
Etlin said this is an “ideal time” to develop this technology, as “spacesuits as we know them are being reinvented.”
Although NASA canceled its contract with Collins Aerospace for spacesuits to be used on the ISS, it still has a nearly $230 million contract to develop lunar suits with the Houston-based company Axiom Space.
Designed to have better flexibility and mobility, provide more visibility and insulation, and have a portable life support system, the suits could play a crucial role in NASA’s Artemis III mission, which seeks to return astronauts to the Moon later this decade, to go further than ever before.
However, even these new costume designs still have the old diaper style, according to Etlin. Axiom did not immediately respond to a request for comment on its spacesuit design.
“On Artemis missions, astronauts may be out there for hours and hours on end, or there may be emergency scenarios where they need to return to base, but their rover has broken down. You have all kinds of contingency scenarios where you need water and a waste system that is not limited to what a diaper can hold,” she said.
In addition to the Artemis program, which seeks to land a woman and a person of color on the Moon for the first time, the race is on to Mars, where clean water would be a luxury.
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