NASA is funding new research to determine whether human urine and the carbon dioxide people exhale can be used to produce nutritional supplements, plastic parts and hand tools to help astronauts survive and thrive during prospective missions to Mars.
Early findings were presented Tuesday in Washington by Clemson University's Mark Blenner, an assistant professor of chemical and biomolecular engineering, who says Mars-bound astronauts could come to rely on hibernating yeast that grows when mingled with the nitrogen in their pee and the carbon in their breath.
“Having a biological system that astronauts can awaken from a dormant state to start producing what they need, when they need it, is the motivation for our project,” Blenner explained for the American Chemical Society ahead of its annual convention.
The United States has deployed exploratory spacecraft and robots to Mars since the 1970s to search for clues about the existence of water, prospects for habitability and any existence of life. NASA aims to send people there between the years 2030 and 2040, first to orbit the planet only and, later, to attempt landing there.
Billionaire entrepreneur Elon Musk endeavors to do it sooner — by 2025, he has said. President Trump, who has expressed bullish enthusiasm for America's space program, has indicated he'd like to see a crewed mission to Mars before he leaves office.
Aggressive preparations are well underway. Late last year, for instance, researchers traveled to the Mauna Ulu volcano on Hawaii's Big Island, terrain they believe to resemble the Red Planet's, for a simulated expedition to field test equipment and communications capabilities.
When considering the two planets' orbital alignment, officials assume a mission from Earth to Mars could span one to three years. First, though, scientists must determine how a crew would survive the months-long trip and then sustain themselves once there.
So think of Blenner's research as the ultimate recycling program. It assumes “atom economy will become really important,” he told the ACS, because space travel requires a light footprint.
In short, here's how it works:
Blenner’s biological system includes a variety of strains of the yeast Yarrowia lipolytica. These organisms require both nitrogen and carbon to grow. Blenner’s team discovered that the yeast can obtain their nitrogen from urea in untreated urine. Meanwhile, the yeast obtain their carbon from CO2, which could come from astronauts’ exhaled breath, or from the Martian atmosphere. But to use CO2, the yeast require a middleman to “fix” the carbon into a form they can ingest. For this purpose, the yeast rely on photosynthetic cyanobacteria or algae provided by the researchers.
The next phase, Blenner said, will focus on increasing output, which now is minimal. He's also exploring whether the science has other applications here at home, including in fish farming and for other human nutritional needs.
The science may seem a little out there, but bear in mind that astronauts already manufacture water — and consume it — from their pee, sweat and shower runoff. It's true. Watch this short video, which explains the science succinctly: