Cislune and PISCES propose a joint/node design using lunar regolith as a building material for truss-based structures. We aim to directly cast joint and bracket components from lunar regolith, which can be used to cast various structural elements like brackets, tools, anchors, small enclosures, tiles, and pavers. The proposed solution fulfills the desires of the subtopic Z14.02, and enables a number of desired deliverables articulated in the “Extraterrestrial Surface Construction: Assembly of Tall Truss-Based Power Towers” scope. The proposed innovation is significant because it reduces the energy inputs and avoids issues associated with molten oxide electrolysis and refinement, and offers a method to generate structural elements for assembly and joining structural elements. The technical objectives of this proposal are to analyze the efficacy of using cast regolith for truss joints, design applicable truss joints, and create a prototype cast regolith joint. The team will use both mare- and highland-like regolith to cast test samples for structural analysis, and then subject them to compressive, flexural, and tensile strength tests. Based on the results, the team will design truss joint elements optimized for cast regolith and compatible with available robotic hardware, and use computer modeling (FEA, CAD, topology optimization) to simulate their structural behavior. The proposed deliverables include a proposed cast regolith joint design that meets NASA's requirements for the power tower, a final report detailing the maturity of the technology, and a foundation for Phase II work to advance the system to TRL 5+ through benchtop prototyping and testing of the various nodes in the power tower, and constructing 5 meter sections of the power tower for structural analysis.

Cast basalt joints from ISRU feedstock are important for lunar exploration and development. These innovations directly map to NASA STMD’s Strategic Framework thrusts of Live - ISRU, and Advanced Materials, Structures, and Construction. This technology will make lunar power less expensive to produce and therefore more abundant. Importantly, the underlying process and expertise needed to cast basalt joints is an enabling technology for an array of products that can be produced for a wide range of tasks (e.g brackets, containers, pipes, etc).

Commercial infrastructure on the Moon and Mars need abundant power enabled by ISRU derived products like truss joint nodes. Cislune and PISCES FEA anchored to results from material testing will demonstrate a lower cost, reliable ISRU product which will enable lower cost development and utilization of the lunar surface.