Researchers in Hong Kong have developed a method for 3D-printing building material on Mars using bioengineered yeast and gelatin mixed with simulated Martian soil, avoiding the energy-intensive heating usually required to turn regolith into usable building blocks. The technique, described in a paper published on Thursday by teams from The Hong Kong University of Science and Technology and The Hong Kong Polytechnic University, could make it far cheaper and more practical to construct shelters for future astronauts on Mars.

The process combines yeast engineered to produce binding proteins with an artificial gelatin growth medium and Martian dirt, extruded through a 3D-printing nozzle to create a foam. When exposed to Mars's cold, dry atmosphere, this foam freeze-dries as its ice sublimates, leaving a light, porous but strong material with a compressive strength comparable to low-grade concrete. The energy needed is one to two orders of magnitude lower than heat-based methods, and the material may even be reusable, though researchers have so far only tested small 45mm beehive-shaped prototypes and still need to verify properties such as pressure retention and radiation shielding before it could form part of a real habitat.