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ESDMD #0505: In-Situ Additive/Subtractive Construction on the Lunar Surface

Building with regolith-derived feedstock on the Moon, by additive or subtractive methods: pathways, launch and landing pads, walls and shelters (bin 3, rating 29 of 57). It is new in Rev C. The challenges include depositing material in low gravity, in-situ inspection, and scaling up to structures. The state of the art is subscale tests with simulant in thermal vacuum chambers. It is named in the Moon Base Users Guide (near-term), for regolith manipulation (Tech gaps spreadsheet, ESDMD #0505; Users Guide, pp. 12–13).

Quotations below are from row ESDMD #0505 of the tech gaps spreadsheet unless marked otherwise. ADD Rev C's Appendix D prints the same table for this gap, and it matches the row field for field (ADD Rev C, p. 228).

Description

"In situ additive and subtractive construction has been identified as a key capability target to enable the development of scalable technologies. Additive and subtractive construction is common in terrestrial industry but new technology is needed to adapt to the lunar surface environment and use feedstock derived from in-situ materials (regolith). Significant challenges include material deposition in low gravity, in-situ inspection, in-situ structure outfitting, material characterization, and scaling up to structural applications. Potential scalable applications include, but are not limited to, the construction of pathways, launch/landing pads, walls, and shelters."

Impacts and benefits: "With gap closure, this infrastructure can provide a variety of services to surface assets such as easily traversable pathways, dust and blast ejecta mitigation, and protection from the harsh thermal and radiation environments."

New in Rev C. The 2025 Architecture Update lists #0505 as one of two technology gaps that Rev C adds (with #0504). It describes it this way: "Additive and subtractive manufacturing on the lunar surface would use in-situ resources (e.g., lunar regolith) to build pathways and walls. This technology gap captures systems that use feedstock derived from local resources for construction" (2025 Architecture Update, p. 14; gaps index).

Current state of the art

"Subscale technology testing in thermal vacuum chambers using regolith simulant."

Performance target

Moon: "Enable in-situ additive/subtractive construction technologies on the lunar surface."

Child gaps

  • 0502-02*: In-situ evaluation, verification, and validation of manufactured components
  • 0502-04*: Manufacturing of materials and components from ISRU-derived feedstock
  • 0806-01*: Affordance recognition, grasp planning, and execution for autonomous object and interface manipulation
  • 0505-01: Deposition of materials in low-pressure and low-gravity environment
  • 0505-02: Non-destructive in-situ verification and validation of constructed products and structures

The starred child gaps also appear under #0502 (0502-02, 0502-04) and under #0501, #0504 and #0806 (0806-01). The asterisk marks "a child gap with multiple parents" (ADD Rev C, p. 199).

Traceability

  • Use cases and functions: UC-I-202 L -- FN-I-205 L
  • Definition tasks: none listed

Segments and sub-architectures

Priority

Priority bin 3, overall prioritization rating 29 of 57. The rating is "the gap's location in the prioritized list of gaps", so 1 is the highest priority, and bins group gaps of similar priority, bin 1 highest. Criticality, urgency, breadth and depth set the order; cost is not considered (ADD Rev C, pp. 78, 199; method on the gaps index).

Moon Base relevance

The Users Guide names #0505 for the associated challenge "Manipulating regolith": "Manipulating lunar regolith at scale for excavation, compaction, and site preparation requires in depth understanding of regolith properties and large scale excavation and construction" (Users Guide, pp. 12–13). The same challenge cites #0605 and data gaps DN-008 L, DN-009 L, DN-010 L and DN-019 L. The guide ties its challenges to "near-term Moon Base development efforts": missions in phase one "offer opportunities to collect data and mature technologies to enable essential phase two and phase three capabilities" (p. 11). See Technology and knowledge challenges.

Same subject in the Ignition material (the pairing is the wiki's; the deck names no gap). The Moon Base Program's Ignition deck's ISRU key mission includes "Converting regolith into durable and sustainable materials with techniques such as Corbelling, 3D printing, sintering", with ISRU "experiment & demo" in Phases 1 and 2 and "begin implementation" in Phase 3 (slide 35) (Ignition deck 2, slide 35). For the sites this gap's structures would serve, it has partners' "Landing & habitation site prep rover demo(s)" in Phase 2 and "Landing & habitation site prep rovers" in Phase 3 (slide 57), and Phase 3's goal "Regolith manipulation & site preparation capable" (slide 28) (Ignition deck 2, slide 57). The deck doesn't name pads, pathways, walls or shelters, this gap's applications. The regolith manipulation lines by phase are on #0605.

Sources

Tech gaps spreadsheet, ESDMD #0505 · ADD Rev C, pp. 78, 199, 228 · Users Guide, pp. 12–13 · 2025 Architecture Update, p. 14 · Ignition deck 2, slides 28, 35, 57