Astronauts Could Mix Their Pee With Moon Dust to Build Lunar Bases

Photo credit: Aidan Monaghan/20th Century Fox

Researchers have made a 3D-printable building material by mixing urea and moon dust.

As NASA plans to return to the moon, scientists are looking for ways to protect and shelter astronauts.

The combined material is homogeneous in texture and can be piped into shape.

Was The Martian a documentary after all? In a new paper in the Journal of Cleaner Production, scientists looked at the ways space travelers might end up building structures on the moon, and one avenue they studied combines urea (from urine) with different materials to utilize urea’s unique chemical properties.

The researchers say this is a way to capitalize on what the moon already has, which is tons of rock, regolith (smaller rock particulate), and fine, silky lunar soil. By combining some distillate of urea from astronaut urine and the lunar silt, scientists have made a kind of geopolymer cement that can be piped using a 3D printer. In their experiments, they used a syringe to pipe the composite material in a similar way to a 3D printer.

Why urea? Well, once you decouple the ick factor, it’s a useful chemical. “Urea can break hydrogen bonds, and therefore reduces the viscosities of many aqueous mixtures. Since urea is the second most abundant component in urine (after water), it is readily available anywhere there are humans,” the researchers explain.

In the experiment, the scientists used powdered urea, which is available for purchase as a fertilizer, adhesive, and beauty additive. It’s also given to patients with very specific kidney problems and diseases. Humans naturally produce urea, of course, but it can also be derived from animals and plants.

Once blended with water, this liquid is combined with fine rock powder. We colloquially call all moon surface gravel regolith, but what this team used is technically more like lunar soil.

Photo credit: Journal of Cleaner Production
On Earth, we think of soil as something that’s often pretty damp and filled with organic material and microorganisms. Moon soil is simply rocks that have been ground down until they’re the consistency of dust—it’s just the pure mineral component, without the enlivening nutrients and living things that plants need.

This dry, lifeless dust is made almost exclusively by wind erosion. What results is more like plaster of Paris or Portland cement, ideal for mixing into a paste.

In their tests, the researchers found their piped urea mixture dried into a strong solid that they hope will be structural grade for things astronauts might need. They explain:

“Further studies are needed in order to assess how these lunar regolith geopolymers will behave under the severe lunar conditions, with a vacuum that can cause the volatile components to evaporate, and large temperature fluctuations which might cause crack formation.”

There are logistical and safety challenges, too. How could astronauts set up and shelter a 3D printing environment? Even if the material holds up to the extreme vacuum conditions on the moon’s surface, it’s not very useful if it can’t withstand meteor activity or shelter astronauts from powerful cosmic radiation. All of this is work for subsequent tests.

Caroline Delbert
Popular Mechanics

How deadly is new coronavirus? It’s still too early to tell

LAURAN NEERGAARD

WASHINGTON (AP) — Scientists can’t tell yet how deadly the new virus that’s spreading around the globe really is — and deepening the mystery, the fatality rate differs even within China.

As infections of the virus that causes COVID-19 surge in other countries, even a low fatality rate can add up to lots of victims, and understanding why one place fares better than another becomes critical to unravel.

“You could have bad outcomes with this initially until you really get the hang of how to manage” it, Dr. Bruce Aylward, the World Health Organization envoy who led a team of scientists just back from China, warned Tuesday.

WHAT DO WE KNOW ABOUT THE DEATH RATE?

In the central China city of Wuhan, where the new coronavirus first exploded, 2% to 4% of patients have died, according to WHO. But in the rest of hard-hit China, the death rate was strikingly lower, 0.7%.

There’s nothing different about the virus from one place to another. Instead, the never-before-seen strain of coronavirus struck Wuhan fast — before anyone knew what the illness was — and overwhelmed health facilities. As is usual at the beginning of an outbreak, the first patients were severely ill before they sought care, Aylward said.

By the time people were getting sick in other parts of China, authorities were better able to spot milder cases — meaning there were more known infections for each death counted.

And while there are no specific treatments for COVID-19, earlier supportive care may help, too. China went from about 15 days between onset of symptoms and hospitalization early in the outbreak, to about three days more recently.

Still, Aylward expressed frustration at people saying: “’Oh, the mortality rate’s not so bad because there’s way more mild cases.’ Sorry, the same number of people that were dying, still die.”

WHAT ABOUT DEATHS OUTSIDE OF CHINA?

Until the past week, most people diagnosed outside of China had become infected while traveling there.

People who travel generally are healthier and thus may be better able to recover, noted Johns Hopkins University outbreak specialist Lauren Sauer. And countries began screening returning travelers, spotting infections far earlier in places where the medical system wasn’t already strained.

That’s now changing, with clusters of cases in Japan, Italy and Iran, and the death toll outside of China growing.

Aylward cautioned that authorities should be careful of “artificially high” death rates early on: Some of those countries likely are seeing the sickest patients at first and missing milder cases, just like Wuhan did.

HOW DOES COVID-19 COMPARE TO OTHER DISEASES?

A cousin of this new virus caused the far deadlier severe acute respiratory syndrome outbreak in 2003, and about 10% of SARS patients died.

Flu is a different virus family, and some strains are deadlier than others. On average, the death rate from seasonal flu is about 0.1%, said Dr. Anthony Fauci of the U.S. National Institutes of Health.

That’s far lower than what has been calculated so far for COVID-19. But millions of people get the flu every year around the world, leading to an annual death toll in the hundreds of thousands.

WHO’S MOST AT RISK FROM COVID-19?

Older people, especially those with chronic illnesses such as heart or lung diseases, are more at risk.

Among younger people, deaths are rarer, Aylward said. But some young deaths have made headlines, such as the 34-year-old doctor in China who was reprimanded by communist authorities for sounding an early alarm about the virus only to later succumb to it.

In China, 80% of patients are mildly ill when the virus is detected, compared with 13% who already are severely ill. While the sickest to start with are at highest risk of death, Aylward said, a fraction of the mildly ill do go on to die — for unknown reasons.

On average, however, WHO says people with mild cases recover in about two weeks, while those who are sicker can take anywhere from three to six weeks.