First demonstration on direct laser fabrication of lunar regolith parts

TLDR

Developing in‑situ fabrication methods is essential for constructing and maintaining lunar or Martian outposts. The study assesses the feasibility of directly fabricating lunar/Martian regolith simulant parts with LENS™ additive manufacturing. Using a LENS™‑750, regolith simulant parts were fabricated at 50 W, 20 mm/s, 12.36 g/min and analyzed by XRD, DSC, SEM, and XPS to assess microstructural and compositional changes. Optimal laser energy of 2.12 J/mm² produced defect‑free parts, converting crystalline regolith into nanocrystalline/amorphous structures with only minor compositional changes, confirming LENS™ can fabricate net‑shape regolith parts.

Abstract

Purpose The purpose of this paper is to evaluate the feasibility of direct fabrication of lunar/Martian regolith simulant parts, in a freeform environment, using Laser Engineering Net Shaping (LENS™) – an additive manufacturing technology. Design/methodology/approach Bulk lunar regolith simulant structures were fabricated using a LENS™‐750. Dense parts without any macroscopic defects were produced at a laser power of 50W, a scan speed of 20 mm/s, and a powder feed rate of 12.36 g/min. The laser processed parts were characterized using X‐ray diffraction, differential scanning calorimetry, scanning electron microscope and X‐ray photoelectron spectroscopy to evaluate the influence of laser processing on the microstructure, constituent phases and chemistry of lunar regolith simulant. Findings A combination of laser parameters resulting in a 2.12 J/mm 2 laser energy appeared to be ideal for generating a melt pool necessary for lunar regolith powder deposition without excessive liquid pool spreading and cracking of solidified parts. The results show that LENS™ based laser processing transformed crystalline regolith into nanocrystalline and/or amorphous regolith structures as a result of complete melting followed by resolidification. Laser processing also resulted in marginal changes in the composition of the regolith. Originality/value Establishment of a lunar/Martian outpost necessitates the development of methods to utilize in situ mineral resources for various construction and resource extraction applications. Fabrication technologies are critical for habitat structure development, as well as repair and replacement of tools and parts at the outpost. Current experimental results presented in the paper clearly demonstrate that net shape regolith simulant parts can be fabricated using LENS™ by exploiting its capabilities.