3D Printed Extra Terrestrial Bricks Could Solve the Challenges of Space Building

With space roots that date back to its foundation in 1963, the University of Central Florida (UCF) serves as a major driver for the space industry across the state. For half a century, UCF faculty, students, and alums have been at the forefront of space exploration, with involvement in several of NASA’s missions, including the Lunar Reconnaissance Orbiter mission that is currently orbiting the Moon and NASA’s Gateway outpost that will orbit the Moon as part of the Artemis program. One of the latest achievements at UCF is the discovery of 3D printed bricks made out of lunar regolith (superficial deposits covering solid rock) that can withstand the extreme environments of space and are an ideal candidate for cosmic construction projects.

To create the bricks, a UCF research group used a combination of binder jet 3D printing, saltwater as a binding agent, and regolith powder made by UCF’s Exolith Lab, a non-profit organization that makes martian, lunar, and asteroid simulants. The binder jetting process resulted in weak cylindrical bricks called green parts that were then baked at high temperatures to produce a more robust structure. Bricks baked at lower temperatures crumbled, while those exposed to heat of up to 1200 degrees Celsius could withstand a pressure of up to 250 million times the Earth’s atmosphere.

Microscopic images of the top view of the cylindrical regolith brick samples at 10X magnification. Image courtesy of the University of Central Florida.

Led by UCF’s Ranajay Ghosh, an associate professor at the Department of Mechanical and Aerospace Engineering and Complex Structures and Mechanics of Solids (COSMOS) Lab director, the team’s work paves the way for the use of binder jetting technology in the construction of materials and structures off-Earth.

So far, proposed studies that have experimented with bricks for space masonry (such as the Martian concrete Marscrete) require transportation of either raw materials or equipment from Earth to complete the proposed manufacturing processes. But relying on resources found in space to construct off-world structures can drastically reduce the need to transport building materials for programs like Artemis.

Applying additive manufacturing to the sustainable use of local resources, better known as in-situ resource utilization (ISRU), in space poses several critical challenges. Different AM feedstock “recipes,” formulated based on combinations of the materials found in the lunar regolith, are already being studied using AM facilities at the International Space Station and here on Earth, NASA’s Marshall Space Flight Center (MSFC) has already printed subscale structures using a 3D printed paste, including Martian simulated regolith. On the commercial side, pioneering space companies are turning to recycled materials to create the resources needed for long-duration missions on the Moon, Mars, and beyond.

Ghosh says the UCF’s work paves a path for using binder jetting to construct materials and structures in space. The team’s findings, detailed in a recent issue of Ceramics International and featured in New Scientist magazine before publication, also demonstrate that off-world structures can be built using resources found in space, which can drastically reduce the need to transport building materials for missions like Artemis.

“BJT is uniquely suitable for ceramic-like materials that are difficult to melt with a laser. Therefore, it has great potential for regolith-based extraterrestrial manufacturing in a sustainable way to produce parts, components and construction structures,” Ghosh explains. “This research contributes to the ongoing debate in the space exploration community on finding the balance between in-situ extraterrestrial resource utilization versus material transported from Earth. The further we develop techniques that utilize the abundance of regolith, the more capability we will have in establishing and expanding base camps on the moon, Mars, and other planets in the future.”

According to the paper titled Effect of sintering temperature on microstructure and mechanical properties of molded Martian and Lunar regolith, published by Ghosh and his graduate research assistant and first author Peter Warren, both Martian and Lunar regolith have the potential to be 3D printed using binder jetting. The authors state that thanks to the sustainable saltwater binder solution, the material held together “adequately.” Furthermore, the team concludes that a binder jetting printing method could be implemented in either Martian or Lunar extraterrestrial environments, as the final printed and sintered components would be well suited to laying the foundation, erecting structures, and fabricating miscellaneous components.

UCF Mechanical and Aerospace Engineering Associate Professor Ranajay Ghosh and graduate research assistant Peter Warren display the cylindrical bricks they created using simulated lunar and Martian regolith. Image courtesy of UCF.

As part of NASA’s Artemis program to establish a long-term presence on the Moon, the agency aims to build a base camp that includes a modern lunar cabin, rover, and mobile home. These structures could benefit from the UCF discovery and potentially be constructed with bricks made of lunar regolith and saltwater.

Resources that can be found in situ are optimal, explains the team. For example, the loose dust, rocks, and materials that cover the surface of the Moon and Mars, known as regolith, can be sourced on-site. Still, in the case of salt water, the material would certainly be challenging to retrieve in an extraterrestrial environment. Still, the researchers pointed out that salts have been found preserved in the rocks and soil on Mars from when the planet was wetter, while sodium –albeit less prevalent on the Moon – has been detected in the regolith. In addition, water deposits have recently been reported on Mars and the Moon, although accessing the water would be tough.

A simple yet potentially sustainable saltwater binder combined with 3D-printed regolith shows excellent potential for UCF researchers. The team sees these exciting experiments with great potential, envisioning how such binder materials can also form the basis of extraterrestrial binder jet printing technology.