For decades, the concept of inhabiting Mars has captivated the imagination, often depicted in science fiction. However, with successful landings on the Red Planet over the past fifty years, this once far-fetched idea is becoming increasingly plausible. The challenge lies in how to construct viable structures millions of miles from Earth, especially when traditional methods of sending rockets laden with construction materials are neither practical nor economical.
Enter Dr. Congrui Grace Jin from Texas A&M University, who, along with her colleagues from the University of Nebraska-Lincoln, has been pioneering research in bio-manufacturing engineered living materials. Their latest breakthrough involves a synthetic lichen system capable of forming building materials autonomously, without any external intervention. This groundbreaking study, published in the Journal of Manufacturing Science and Engineering, focuses on applying this technology for the autonomous construction of structures on Mars, utilizing the planet's regolith, which consists of dust, sand, and rocks.
This advancement could potentially revolutionize extraterrestrial construction by enabling the development of structures in the harshest environments with minimal resources. "We can build a synthetic community by mimicking natural lichens," explains Dr. Jin. "We've developed a method to engineer synthetic lichens that bond Martian regolith particles into coherent structures." This innovative approach allows for the fabrication of a wide array of structures, including buildings, houses, and furniture, through advanced 3D printing techniques.
While various research initiatives have explored methods for bonding Martian regolith particles—such as magnesium-based and sulfur-based approaches, as well as geopolymer creations—most require significant human assistance. This presents a major obstacle given the evident lack of manpower on Mars. Alternative methods, including microbe-mediated self-growing technology, have shown promise. Techniques like bacterial biomineralization and the use of fungal mycelium as a bonding agent have been developed, but they still require ongoing human intervention due to the need for nutrient supplies.
To address these challenges, Dr. Jin's team has engineered a completely autonomous self-growing technology by designing a synthetic community that leverages the strengths of multiple species. This innovative system eliminates the need for external nutrient supplies. The design incorporates heterotrophic filamentous fungi as the primary bonding material producers, which excel at producing large quantities of biominerals and can withstand the harsh conditions on Mars. These fungi work in tandem with photoautotrophic diazotrophic cyanobacteria to create the synthetic lichen system.
The functioning of this system is remarkable. The diazotrophic cyanobacteria fix carbon dioxide and dinitrogen from the Martian atmosphere, converting them into oxygen and organic nutrients essential for the growth of filamentous fungi. Additionally, they increase the concentration of carbonate ions through photosynthesis. The filamentous fungi bind metal ions onto their cell walls and serve as nucleation sites for biomineral production while enhancing the growth of cyanobacteria by providing necessary water, minerals, and carbon dioxide. Both components secrete biopolymers that strengthen the adhesion and cohesion among Martian regolith and precipitated particles, resulting in a consolidated structure.
This innovative system grows using only Martian regolith simulant, air, light, and an inorganic liquid medium—eliminating the need for human labor. The potential of this self-growing technology for long-term extraterrestrial exploration and colonization is profound, states Dr. Jin. The next phase of the project, which is already underway, involves creating regolith ink to facilitate the printing of bio-structures using the 3D printing technique known as direct ink writing.
Dr. Congrui Grace Jin serves as an assistant professor in the Mechanical and Manufacturing Engineering Technology program at Texas A&M University. Her research team from the University of Nebraska-Lincoln includes Dr. Richard Wilson, Nisha Rokaya, and Erin Carr, who are all dedicated to advancing the future of construction on Mars.
