Researchers have a comprehensive approach for creating robust, elastic, designer Lunar and Martian regolith simulant (LRS and MRS, respectively) architectures using ambient condition, extrusion-based 3D-printing of regolith simulant inks. The LRS and MRS powders are characterized by distinct, highly inhomogeneous morphologies and sizes, where LRS powder particles are highly irregular and jagged and MRS powder particles are rough, but primarily rounded. The inks are synthesized via simple mixing of evaporant, surfactant, and plasticizer solvents, polylactic-co-glycolic acid (30% by solids volume), and regolith simulant powders (70% by solids volume). Both LRS and MRS inks exhibit similar rheological and 3D-printing characteristics, and can be 3D-printed at linear deposition rates of 1–150 mm/s using 300 μm to 1.4 cm-diameter nozzles. The resulting LRS and MRS 3D-printed materials exhibit similar, but distinct internal and external microstructures and material porosity (~20–40%). These microstructures contribute to the rubber-like quasi-static and cyclic mechanical properties of both materials, with young’s moduli ranging from 1.8 to 13.2 MPa and extension to failure exceeding 250% over a range of strain rates). Finally, they discuss the potential for LRS and MRS ink components to be reclaimed and recycled, as well as be synthesized in resource-limited, extraterrestrial environments.
They were able to rapidly 3D-printed, highly versatile and mechanically elastic composites comprised of approximately 90 wt.% lunar and martian regolith and 10 wt.% bio-derived polymer (polylactic-co-glycolic acid, PLGA) that have the potential to address the need for soft materials off-world.
The elastomeric binder was commercially available polylactide-co-glycolide (PLGA: Evonik), a commonly utilized medical polymer that can be synthesized from biologically derived, renewable reagents.
Researchers have developed a new approach for additively manufacturing with simulated lunar and Martian regolith. It represents a new, powder-bed-free and energy-beam-free, resource utilization scheme for fabricating user-defined, soft-material structures from unrefined, highly inhomogeneous regoliths. Processes for regolith ink synthesis appear to be primarily independent of regolith composition and particle morphology. Due to the purely physical nature of ink synthesis (simple mixing of components, with no chemical reactions/transformations involved this process is potentially scalable. Additionally, the simple, rapid extrusion nature of the regolith ink 3D-printing process is also likely amenable to application with parallel nozzle extruders, larger diameter extruders, large build-area platforms, mobile extruders, or any combinations thereof. Although not investigated in this work, the resulting printed structures (due to the high LRS and MRS particle packing densities) can also be processed to create hard regolith structures via post-3D-printing sintering, as described previously for 3D-printed metal, alloy, and metal oxide ink systems8,9. Collectively, this work represents an extension of a newly established, materials-centric 3D-printing platform to unrefined, physically and compositionally inhomogeneous powders, and also illustrates that soft-materials, can be fabricated from hard, inhomogeneous, native resources and components that can potentially be recycled and reused.
SOURCE - Nature Scientific Reports