Unlike wastewater from the International Space Station, urine from spacewalking suits is not recycled, but the film Dune has inspired a solution.
The idea is to turn the science fiction of full-body “steamsuits” – like those in the blockbuster film franchise – into reality, absorbing and purifying water lost through sweat and urine, and recycling it into drinking water. A novel urine collection and filtration system prototype for spacesuits has been developed by researchers at Cornell University and is published in ‘Frontiers in Space Technology’.
“The design includes an external vacuum-based catheter leading to a combined forward and reverse osmosis unit, providing a continuous supply of drinking water with multiple safety mechanisms to ensure astronauts’ well-being,” said Sofia Etlin, a research staff member at Weill Cornell Medicine and Cornell University and first author of the study.
It is worth noting that in 2025 and 2026, NASA is planning Artemis II and III missions, in which a crew will orbit the Moon and land on its south pole, respectively. These missions are expected to be followed by manned missions to Mars in the early 2030s. However, astronauts have long complained about the lack of comfort and hygiene of existing maximum absorbency garments (MAGs), the waste management system of traditional NASA spacesuits, which has been used since the late 1970s and works like a multi-layered adult diaper made of super-absorbent polymer.
“MAG has reportedly leaked and caused health problems such as urinary tract infections and gastrointestinal distress. In addition, astronauts currently only have one litre of water available in beverage bags carried inside their suits. This is insufficient for the planned and longer lunar spacewalks, which can last ten hours and even up to 24 hours in an emergency,” Etlin insists.
Astronauts have also requested that future spacesuits reduce the time required to fill and degas the suit’s beverage bags, and that a separate supply of a decaffeinated energy drink be added.
With all these goals in mind, Etlin and his colleagues have designed a urine collection device that includes an undergarment made of several layers of flexible fabric and that connects to a collection container (with a different shape and size for women and men) made of molded silicone, to fit around the genitals.
The inner side of the collection container is lined with polyester microfibre or a nylon-elastane blend to draw urine from the body and direct it towards the inner side of the container, from where it is sucked by a vacuum pump. An RFID tag, linked to an absorbent hydrogel, reacts to moisture, activating the pump.
Once collected, urine is diverted to the urine filtration system, where it is recycled with 87% efficiency using an integrated two-step reverse and forward osmosis filtration system. This system uses a concentration gradient to remove water from the urine, as well as a pump to separate the water from the salt. The purified water is then enriched with electrolytes and pumped into the suit’s beverage bag, where it is once again available for consumption. Collecting and purifying 500 ml of urine takes just five minutes.
The system, which integrates control pumps, sensors and a liquid crystal display, is powered by a 20.5 V battery with a capacity of 40 ampere-hours. Its overall size is 38 by 23 by 23 centimetres, with a weight of approximately eight kilograms: compact and light enough to be carried on the back of a spacesuit.
Now that the prototype is available, the new design can be tested under simulated conditions and, later, during real spacewalks. “Our system can be tested under simulated microgravity conditions, as microgravity is the primary space factor we must consider. These tests will ensure the functionality and safety of the system before it is deployed on real space missions,” concludes Dr. Christopher E. Mason, a professor at the same institute as Etlin and senior author of the study.