October 24, 2016 – Astronauts have been known to joke about how they turn yesterday’s coffee into tomorrow’s coffee. (Hint: It involves urine.) While this may seem like a gross scenario, it has become a reality on the International Space Station with the help of work done at NASA’s Johnson Space Center.
After a urine distiller on the space station clogged in 2009, it became clear that the Urine Processor Assembly (UPA), the water-recovery system in place on the orbiting laboratory, needed to be able to process fluids more effectively.
While the UPA was able to recover 75 percent of water from urine, station occupants needed to be able to reclaim more water and have a more reliable system.
Engineers at Johnson worked with other NASA centers to develop a new chemical solution called Alternate Urine Pretreatment (AUP). When the toilet is flushed on the station, a few milliliters of AUP are administered along with the flush. This enables a higher water-recovery percentage while minimizing mineral buildup inside the tubes, which is known to cause clogging.
AUP was installed on the station this past May 17 by NASA astronaut Jeff Williams. It has the potential to reach a 90 percent recovery rate, achieving the goal set in 2009 to process urine more efficiently. Once the urine is treated with AUP, it is distilled and polished in the Water Reclamation System before being consumed by the crew members in space.
This development has implications beyond lowering resupply costs and having extra water available. AUP marks a major milestone in the progress of water-recycling technologies that are a necessity for long-duration space flight, including our journey to Mars
“The goal is not to take large amounts of water with us to space, but to be able to take the water cycle itself to space,” said Dean Muirhead, an engineer with Barrios Technology. “This project was another step in facing the water-cycle challenge and creating a closed life support system in space.”
Systems such as AUP will ensure astronauts have the resources necessary to survive longer space excursions.
“Where other people see urine, I see a vital resource that is going to help astronauts survive,” Muirhead said. “To accomplish long-duration spaceflight, we need to develop these technologies that allow us to live independently of Earth. We have to close the water loop.”
While Johnson played a major role in developing AUP, Muirhead stressed that this solution wasn’t developed by Johnson alone. Important contributions arrived from other NASA centers and international partners.
“With six humans from all over the world depending on your technologies to work while orbiting through the vacuum of space at five miles per second, the stakes are high,” Muirhead said. “The engineers and scientists who support space station do such an amazing job on a daily basis. In this project I got to work with smart problem solvers who are able to communicate in the unique language of collaboration.”
As is the case with many NASA innovations, AUP has Earthly benefits, too.
“Cities and countries on Earth are struggling for clean water, so anytime we can understand how to conserve and reuse water, it is not only helping space exploration, but we are benefiting all of humanity,” Muirhead said.
Even with AUP, we may not be Earth independent—but it’s another key step in NASA’s exploration of space and getting to the Red Planet.
“Although we’ve made great strides with this project, the only functioning example of an independent, closed-loop life support system remains our planet Earth,” Muirhead said. “But I think we are now closer to understanding what we need to do to support life on other planets.”