Astronauts on the moon or Mars may be growing their homes, rather than building them, according to NASA

Transporting habitats or even the materials for habitats that astronauts can safely inhabit during a lunar mission, or an extended stay on Mars will be expensive. And they will likely take up a lot of space to shuttle them from one planet to another, when other valuable resources may be needed.

One of the projects at NASA’s Ames Research Center in California focuses on myco-architecture. This would allow for more organic habitats grown from fungi and the threads that comprise their architecture, known as mycelia. The project is part of NASA’s Innovative Advanced Concepts program that considers different aspects of life as technology.

“Right now, traditional habitat designs for Mars are like a turtle — carrying our homes with us on our backs — a reliable plan, but with huge energy costs,” said Lynn Rothschild, the principal investigator on the early-stage project. “Instead, we can harness mycelia to grow these habitats ourselves when we get there.”

Astronauts could bring a much more compact habitat made from lightweight materials embedded with fungi. These could survive long-term spaceflight and once the habitat was placed on the surface, all the astronauts would need to do is activate the fungi by adding water.

The habitat would protect humans while also protecting the lunar or Martian surface because the fungi would be contained within the structure.

The mycelia will be genetically altered so they can’t exist if separated from the habitat, preventing the surface of Mars from becoming contaminated. This would also prevent any false positive reading for life on the Martian surface that’s really from Earth. The mycelia structure will also be baked to reinforce its structure and further prevent contamination.

Fungi feed off of organic material and produce spores. Underneath, mycelia acts like roots that actively build the fungi. They can spread out into a multitude of mushrooms. Or, in this example of synthetic biology, they can actually be used to create a different kind of detailed structure like the literal building blocks of a habitat.

Mars won’t just be a harsh environment for humans, but the fungi as well. The fungi will need cyanobacteria to survive. Cyanobacteria uses solar energy to convert dioxide and water in oxygen and food.

To support that, the project team has designed a domed habitat with three layers. On the outside will be a layer of frozen water ice, which can serve as a barrier between the astronauts and radiation. The frozen layer can also provide water for the second layer comprised of cyanobacteria, which will convert it into oxygen for the astronauts. The final layer will be made of mycelia, which can gather nutrients from the cyanobacteria layer.

“Mycelial materials, already commercially produced, are known insulators, fire retardant, and do not produce toxic gasses,” according to the project description. “Metrics for these materials show compression strengths superior to dimensional lumber, flexural strength superior to reinforced concrete, and competitive insulation values.”

Mycelia could also be used to provide bioluminescent lighting, filter water, extract minerals, regulate humidity and even repair itself.

“When we design for space, we’re free to experiment with new ideas and materials with much more freedom than we would on Earth,” Rothschild said. “And after these prototypes are designed for other worlds, we can bring them back to ours.”