Mars astronauts could live in houses 3D-printed from freeze-dried yeast

In order to survive, the first humans to reach Mars will immediately need a safe and reliable place to set up shop. But building on Earth’s neighbor is immensely more challenging than construction projects at home. The Martian surface is a practically airless vacuum, constantly bombarded with radiation, and regularly reaches temperatures as low as -81 degrees Fahrenheit.
However, there is a very specific process on Earth that approximates similar conditions to the Red Planet: freeze-drying. According to researchers at The Hong Kong University of Science and Technology, the same method used to preserve perishable foods could also inspire sturdy and even recyclable 3D-printed houses on Mars. The secret ingredients? Everyday gelatin and yeast. The novel approach is detailed in a study published today in the journal Chem Circularity.
“My inspiration came from freeze-dried fruits that become harder. So I asked myself if we can take advantage of that and make some materials,” Jishen Qiu, a study co-author and civil engineer, said in a statement.
The combination of materials are simple: sand and an adhesive binder. Since gluing tiny rocks together requires specialized stickiness, Qiu’s team invented a new concoction from gelatin and lab engineered yeast. When mixed, the yeast microbes become coated with adhesive proteins similar to those used by mussels to anchor on stones underwater. The goop is then extruded through a 3D printer nozzle into an extremely cold, low-pressure environment, where it solidifies as the water instantly freezes and converts from ice to vapor. The final result is a light, porous, foam-like material that remains very resilient.
“This is actually strong enough to build a one- or two-story building on Earth—whose gravity is three times that of Mars,” explained Qiu. “So, you can probably easily build a multistory building on Mars with the material.”
Qiu and his collaborators know they must first start small before expanding to Martian neighborhoods. Their prototype domes are only about the size of a wine cork at this point, but their compressive strength is comparable to low-grade concrete.
Engineers have experimented with 3D-printed structures to use on the moon and Mars for years, but many of these still require steps like melting down rocks or lunar regolith. These methods usually require a lot of extra energy, which may limit their utility. Qiu’s technique requires comparatively little energy, although he admits it’s still unclear if yeasts can withstand life on Mars. That said, the team’s early results are a promising step towards simple, efficient, and sturdy buildings beyond Earth. If nothing else, yeast also lends itself to trial-and-error.
“As long as there’s one yeast that’s still alive, you can grow them again,” added Qiu.
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