Space miso and moon glass

Extraterrestrial fermentation

If there is a future where people regularly travel through space, what will they eat? Today’s astronaut food, although a novelty for those of us with our feet firmly planted on Earth, is not particularly appetizing. Maggie Coblentz, research affiliate at the Massachusetts Institute of Technology, thinks fermented foods could provide a nutritious—and tasty—addition to an extraterrestrial diet.

People around the world have eaten fermented food since time immemorial. Curious how astronauts might leverage that history, Coblentz was thrilled when the opportunity to send a fermentation experiment to the International Space Station (ISS) arose. The project was ripe for collaboration, and Coblentz reached out to sustainable food researcher Joshua Evans of the Technical University of Denmark for his expertise in the evolution of fermented foods on Earth. Together, the team selected miso—a fermented paste made from soybeans—to send to space.

In early 2020, the team prepared a miso starter from soybeans, rice koji, and salt. The mixture was split into three samples and packaged into boxes outfitted with environmental sensors. Two would remain earthbound as controls; one would catch a ride on a SpaceX rocket carrying supplies to the ISS.

When the ISS miso returned to Earth, Coblentz and her colleagues were in strict COVID isolation, so the miso was delivered to her home instead of the laboratory. She’ll never forget the day she got the box. On the side, “in this big black Sharpie, it just said, ‘space miso,’ ” she tells Newscripts. “The whole thing was so surreal.”

Although the smell, texture, and taste of the space-fermented paste made it easily recognizable as miso, metagenomic testing revealed that it contained microbial communities slightly different from those of the control misos fermented on Earth (iScience 2025, DOI: 10.1016/j.isci.2025.112189). The researchers also identified higher concentrations of volatile compounds, primarily esters and pyrazines, coming off the ISS-fermented bean paste. And, as far as taste goes, the space miso had “deeper, richer flavors. It tasted like it could almost be more mature,” Coblentz says.

The ISS-fermented miso experienced so many unique circumstances—microgravity, radiation, heat, and vibration—that to say one specific thing changed how the space miso fermented would be pure speculation, Coblentz says. Instead, the team simply attributes the difference in fermentation to “space terroir,” all the environmental factors that make the miso taste like space.

Marvelous moon glass

If people are going to make miso soup on the moon, they’ll need a place to live. How those future dwellings will be powered remains an open question.

Making solar panels from lunar regolith, the abrasive, rocky material coating the moon’s surface, is “a brilliant idea,” materials scientist Felix Lang of University of Potsdam tells Newscripts. After all, manufacturing solar cells directly on the moon would save shipping costs.

When Lang met researchers from the Technical University of Berlin (TU Berlin) who made building materials and glass from lunar regolith, it sparked an idea. Could the glass be used as a support for the light-harvesting perovskites his group makes?

The light-absorbing properties of perovskites—manufactured polycrystalline semiconducting minerals—are tunable, and the material is defect tolerant. “Even if you make it imperfectly, it’s quite likely that your device will work,” Lang says. If astronauts were provided with a perovskite solution made on Earth, they could put it on a suitable substrate in space. So Lang struck up a collaboration with the TU Berlin scientists to make a perovskite-based solar cell on a moon glass substrate.

The test panel, only a couple centimeters square, was more stable than they expected but also harder to fabricate for high efficiencies than they hoped (Device 2025, DOI: 10.1016/j.device.2025.100747). Surprisingly, when the moon glass was irradiated, it didn’t darken or turn opaque like conventional glass. The boon could be due to impurities in the regolith. Ultimately, “using the regolith on the moon and the perovskite is a beautiful combination,” Lang says.

Please send comments and suggestions to newscripts@acs.org