As NASA makes plans for humans to live in space long term, how to build habitats on other planets is a major challenge. One possibility the US space agency is considering is "growing" homes using mushrooms. Though it sounds like something out of a fairy tale, the science is solid. Traditional space habitat designs for Mars use metal and glass as construction materials. While the plan is reliable, huge amounts of energy would be required to transport these heavy materials. The new project proposes using mycelia, unseen threads inside of fungi such as mushrooms, as a lighter replacement that can grow locally upon arriving at other planets. Researchers are picturing homes with three layers. The outer layer would consist of water and ice. A middle layer would contain bacteria that produce oxygen. And in the innermost layer, fungus would grow around a frame to create a habitat in which humans could live. This is one technology that could truly mushroom in the future!