Liet Kynes would be proud of this approach and of NASA’s Environmental Control and Life Support System, which makes the recycling of water possible. In addition to urine and sweat, the Water Recovery System recycles the water used for showers and the moisture produced by breathing.
ISS astronauts aren’t equipped with Fremen stillsuits, so the recycling of urine is a bit more involved. The urine that’s gathered is pumped into a distillation assembly, where a centrifuge forces the urine to its outer walls. The urine is heated, causing water to evaporate from the waste. Condensation then returns the vapor to a liquid state. This still-unclean water is pumped into a tank, where it mixes with other recovered water, such as sweat and cabin moisture. Pressure in the tank removes any stinky gas from the liquid, which is then delivered to a reactor that kills unwanted organic compounds and microorganisms with intense heat.
The process provides upwards of 3,600 liters (950 gallons) of recycled water each year. Recent upgrades to the system mean that overall water recovery is approaching 94%, which is damned impressive. That said, NASA is striving for 98% total recovery as it prepares for the Artemis missions to the Moon and an eventual crewed mission to Mars. NASA says the same tech could be used on Earth in places where water is scarce—a prospect that’s both futuristic and dystopian at the same time. In case you’re wondering, fecal waste is not processed, but NASA is looking into that possibility.
NASA’s Water Recovery System is not a straightforward solution, and it’s a reminder of the hoops we have to jump through to provide water to people living and working in space. Which brings us to Mars.
Welcome to Arrakis—er, Mars
With its two moons and sprawling deserts, Mars is probably the most Arrakis-like planet in our solar system. And like Arrakis, the fourth planet from the Sun is seriously lacking in accessible water.
This wasn’t always the case. The Red Planet was once accented in blue, as sprawling oceans covered the surface over a billion years ago. Much of this water was lost to space, but a good portion of it managed to stay behind. There’s so much ice at the polar caps that, if it all melted, the resulting water would cover the planet to depth of 65 feet (20 meters), according to Stefano Nerozzi, a postdoctoral research associate from the Lunar and Planetary Laboratory at the University of Arizona.
Nerozzi says Mars is a hyper-arid desert by Earth’s standards.
“Due to the very low atmospheric pressure, water can only exist as vapor or ice near the surface,” he explained in an email. “The atmosphere is extremely dry, containing only a tiny fraction of the water vapor compared to Earth’s, far too little to extract any meaningful amount. In fact, water management on a Martian human base will need to be extremely strict to preserve what is likely the most precious resource on the planet—just like a sietch on Arrakis!”
Interestingly, research from 2020 suggests liquid water may lie buried at the Martian south pole, but this work remains controversial. If it is liquid, however, this water is probably very slushy and salty.
Researchers with the Subsurface Water Ice Mapping (SWIM) team have used satellites to find likely places where buried ice might be located on Mars—work that’s being used to support the selection of future landing sites. Matthew Chojnacki, a research scientist at the Planetary Science Institute, said these scientists “really did an excellent job of identifying subsurface frozen water ice across the northern mid-latitudes of Mars that could benefit future human explorers.”
Chojnacki and his colleagues at PSI are hoping to conduct a follow-up study in which they would map water-ice indicators, such as polygon-shaped terrain, glacial-like landforms, and concentric crater fill.
That water will be needed on Mars is obvious. Colonists will need to quench their thirst, grow crops, and process water into fuel for rockets. Trouble is, shipping water to Mars from Earth would be an awkward, time consuming, and—most importantly—prohibitively expensive ordeal.
More realistically, colonists will have to source water directly on Mars. Settlements might have to be built near the polar regions, allowing for quick access to the Martian ice sheets. This water probably won’t be immediately potable, requiring desalination and other measures to remove dust and ensure purity.
“Mars is hard, Mars is dry!” Chojnacki wrote in an email. “It’s going to take a big effort to actually make these ‘resources,’” he said. “While human Mars mission plans are still in the conceptual stage, accessing and utilizing that water will be a daunting challenge.”
Nerozzi said the polar caps “are some of the most inhospitable places on its surface,” which means “any future human explorers are more likely to settle closer to the equator, where the climate is warmer and more forgiving.” Problem is, sources of water near the equator are quite scarce.
“The soil is usually very dry, although in some places there might be hydrated minerals that hold water in their crystalline structure,” Nerozzi explained. “This water is difficult to extract, but not impossible: humans would need ovens to break the chemical bonds of water in hydrated minerals and a condensation and filtration system to make it drinkable.”
Debris-covered glaciers in the mid-latitudes could provide other sources of water, though settlers would likely have to use heavy excavation equipment to reach the concealed ice. Nerozzi said the “terrain on these glaciers is very rough to even walk on, making these abundant water ice reservoirs very difficult to access.”
Failing this, deliquescence might be another option for the prospective colonists, in which water is collected from the atmosphere similar to the fictional moisture vaporators in Star Wars (George Lucas, it needs to be said, borrowed heavily from Dune, which Frank Herbert published in 1965). Offworld, industrial-scale deliquescence remains within the realm of science fiction, and it’s not immediately clear if the Martian atmosphere can generate the required volumes of water.
Indeed, there’s still much we don’t know about how and where we’ll source water on Mars, but it’s a problem in need of a solution.
“Tell me about the waters of your birthworld”
Dune serves as a reminder that we should never take water for granted. Sadly, our species is increasingly dealing with water insecurity, frequent heat waves, and burgeoning rates of desertification.
Human-induced climate change has a lot to do with current environmental problems, and the result is that tiny versions of Arrakis are appearing across the globe. As Dune reminds us, we probably won’t find it easy to seek shelter in outer space, as the cosmos is filled with inhospitable hellscapes. So we must take care of Earth—the most valuable planet in the known universe. And not let our fear get the better of us.