{ "spore": "profile", "id": "regolith-polymer-composite", "spore_version": "0.2", "family": "regolith-polymer composite", "name": "Regolith-polymer composite (80:20 LHS-1 lunar highlands simulant with PLA, fused-filament printed)", "abbreviation": "RPC", "role": "Printed structural building material made from regolith simulant and a bio-based polymer binder", "category": "regolith", "type": "lunar-concrete", "summary": "Regolith-polymer composite (RPC) is lunar highlands simulant LHS-1 mixed with polylactic acid (PLA) and printed layer by layer. In NASA's REACT tests, the 80:20 LHS-1:PLA blend reached 24 MPa flexural strength at 0 degrees and 16.6 MPa at 90 degrees in one independent laboratory's tests at ambient temperature. The project describes the material as approaching technology readiness level 5, and long-term lunar exposure is still untested.\n", "best_for": "Ground demonstrations of printed lunar shelter parts made from regolith simulant and a bio-based binder", "weakest_at": "Strength across the print layers, and untested long-term exposure to lunar vacuum, thermal cycling and UV", "identity": { "formula": "80:20 wt.% LHS-1 lunar highlands simulant and polylactic acid, (C3H4O2)n; a composite, not a single compound", "designations": [], "source": "nasa-ntrs-2023", "where": "Title and author record on the NTRS citation page 20230015024; mixture ratio from the Abstract and Table 4 of the paper (nasa-strives)" }, "tags": { "environments": [ "lunar-day", "lunar-night" ], "stresses": [ "thermal-cycling", "vacuum-and-outgassing", "uv", "micrometeoroids-and-debris" ], "applications": [ "structures", "in-space-manufacturing" ] }, "properties": [ { "benchmark": "flexural_strength", "label": "Flexural strength, 0 degrees, independent laboratory", "value": 24, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "composition": "80:20 wt.% LHS-1:PLA (the Beta material selected by the paper)", "orientation": "0 degrees, as the paper labels it", "test_environment": "ambient temperature, per the paper", "tested_by": "independent laboratory, not named in Table 4" }, "method": "Table 4 average of 24 MPa with standard deviation 3 MPa, testing by an independent laboratory; the paper labels the test as flexural strength at 0 degrees", "status": "ground", "source": "nasa-strives", "where": "Table 4 (Summary of the Selected Beta Material), Flexural Strength (MPa), 0 degrees column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "flexural_strength", "label": "Flexural strength, 90 degrees, independent laboratory", "value": 16.6, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "composition": "80:20 wt.% LHS-1:PLA (the Beta material selected by the paper)", "orientation": "90 degrees, across the print direction", "test_environment": "ambient temperature, per the paper", "tested_by": "independent laboratory, not named in Table 4" }, "method": "Table 4 average of 16.6 MPa with standard deviation 0.8 MPa, independent laboratory", "status": "ground", "source": "nasa-strives", "where": "Table 4, Flexural Strength (MPa), 90 degrees column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "flexural_modulus", "label": "Flexural modulus, 0 degrees, independent laboratory", "value": 5.3, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "composition": "80:20 wt.% LHS-1:PLA", "orientation": "0 degrees", "test_environment": "ambient temperature, per the paper", "tested_by": "independent laboratory, not named in Table 4" }, "method": "Table 4 average of 5.3 GPa with standard deviation 0.2 GPa, independent laboratory", "status": "ground", "source": "nasa-strives", "where": "Table 4, Flexural Modulus (GPa), 0 degrees column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "flexural_modulus", "label": "Flexural modulus, 90 degrees, independent laboratory", "value": 3.7, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "composition": "80:20 wt.% LHS-1:PLA", "orientation": "90 degrees, across the print direction", "test_environment": "ambient temperature, per the paper", "tested_by": "independent laboratory, not named in Table 4" }, "method": "Table 4 average of 3.7 GPa with standard deviation 0.6 GPa, independent laboratory", "status": "ground", "source": "nasa-strives", "where": "Table 4, Flexural Modulus (GPa), 90 degrees column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "flexural_strength", "label": "Flexural strength, 0 degrees, SpaceFactory testing", "value": 34.4, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "composition": "80:20 LHS-1/PLA", "orientation": "0 degrees, as the paper labels it", "tested_by": "SpaceFactory, the project partner that printed the samples" }, "method": "Average of 34.40 MPa in Table 3 (SpaceFactory testing); the paper reports these values above the independent laboratory's results and gives both sets side by side", "status": "ground", "source": "nasa-strives", "where": "Table 3 (Summary of the material testing results performed at SpaceFactory), row 80/20 LHS-1/PLA 0 degrees, Avg Ultimate Flexural Strength (MPa)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "flexural_strength", "label": "Flexural strength, 90 degrees, SpaceFactory testing", "value": 14.9, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "composition": "80:20 LHS-1/PLA", "orientation": "90 degrees, across the print direction", "tested_by": "SpaceFactory, the project partner that printed the samples" }, "method": "Average of 14.90 MPa in Table 3 (SpaceFactory testing)", "status": "ground", "source": "nasa-strives", "where": "Table 3, row 80/20 LHS-1/PLA 90 degrees, Avg Ultimate Flexural Strength (MPa)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "flexural_modulus", "label": "Flexural modulus, 0 degrees, SpaceFactory testing", "value": 7.43, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "composition": "80:20 LHS-1/PLA", "orientation": "0 degrees, as the paper labels it", "tested_by": "SpaceFactory, the project partner that printed the samples" }, "method": "Table 3 average of 7.43 GPa (SpaceFactory testing)", "status": "ground", "source": "nasa-strives", "where": "Table 3, row 80/20 LHS-1/PLA 0 degrees, Avg Flexural Modulus (GPa)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "flexural_modulus", "label": "Flexural modulus, 90 degrees, SpaceFactory testing", "value": 3.68, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "composition": "80:20 LHS-1/PLA", "orientation": "90 degrees, across the print direction", "tested_by": "SpaceFactory, the project partner that printed the samples" }, "method": "Table 3 average of 3.68 GPa (SpaceFactory testing)", "status": "ground", "source": "nasa-strives", "where": "Table 3, row 80/20 LHS-1/PLA 90 degrees, Avg Flexural Modulus (GPa)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength, 0 degrees, independent laboratory", "value": 15.2, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "composition": "80:20 wt.% LHS-1:PLA", "orientation": "0 degrees", "test_environment": "ambient temperature, per the paper", "tested_by": "independent laboratory, not named in Table 4" }, "method": "Table 4 average of 15.2 MPa with standard deviation 0.3 MPa, independent laboratory", "status": "ground", "source": "nasa-strives", "where": "Table 4, Tensile Strength (MPa), 0 degrees column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "elastic_modulus", "label": "Tensile modulus, 0 degrees, independent laboratory", "value": 7, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "composition": "80:20 wt.% LHS-1:PLA", "orientation": "0 degrees", "test_environment": "ambient temperature, per the paper", "tested_by": "independent laboratory, not named in Table 4" }, "method": "Table 4 average of 7.0 GPa with standard deviation 0.4 GPa, independent laboratory", "status": "ground", "source": "nasa-strives", "where": "Table 4, Tensile Modulus (GPa), 0 degrees column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "compressive_strength", "label": "Compressive strength, 0 degrees, independent laboratory", "value": 50, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "composition": "80:20 wt.% LHS-1:PLA", "orientation": "0 degrees", "test_environment": "ambient temperature, per the paper", "tested_by": "independent laboratory, not named in Table 4" }, "method": "Table 4 average of 50 MPa with standard deviation 2 MPa, independent laboratory", "status": "ground", "source": "nasa-strives", "where": "Table 4, Compression Strength (MPa), 0 degrees column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "density", "label": "Density, pellets, volumetric displacement", "value": 1.8, "bound": "exact", "unit": "g/cc", "scope": "material", "conditions": { "form": "compounded pellets of 80:20 LHS-1:PLA", "method_detail": "volumetric displacement, which the paper prefers over gas pycnometry for this material" }, "method": "Table 6 pellet displacement density printed as 1.80 g/cc for 80:20 LHS-1:PLA; the paper says 1.80 g/cc was used for LINA structural design", "status": "ground", "source": "nasa-strives", "where": "Table 6, 80:20 LHS-1: PLA row, Pellet Densities, Disp. column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "density", "label": "Density, ambient print, volumetric displacement", "value": 1.82, "bound": "exact", "unit": "g/cc", "scope": "material", "conditions": { "form": "printed in ambient conditions, 80:20 LHS-1:PLA", "method_detail": "volumetric displacement" }, "method": "Table 6 ambient print displacement density printed as 1.82 g/cc", "status": "ground", "source": "nasa-strives", "where": "Table 6, 80:20 LHS-1: PLA row, Ambient Print Densities, Disp. column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "density", "label": "Density, pure PLA pellets, volumetric displacement (comparison only)", "value": 1.28, "bound": "exact", "unit": "g/cc", "scope": "material", "conditions": { "material": "pure PLA, the binder alone, with no regolith", "form": "pellets", "method_detail": "volumetric displacement" }, "method": "Table 6 Pure PLA row, pellet displacement density printed as 1.28 g/cc; a comparison value for the binder, not a value for the composite", "status": "ground", "source": "nasa-strives", "where": "Table 6, Pure PLA row, Pellet Densities, Disp. column", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "porosity", "label": "Porosity, pellets, calculated from displacement density", "value": 13.8, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "form": "compounded pellets, 80:20 LHS-1:PLA", "basis": "calculated from displacement density and TGA mass fractions" }, "method": "Calculated by the paper from displacement density and mass fractions (Table 7)", "status": "calculated", "source": "nasa-strives", "where": "Table 7, 80:20 LHS-1: PLA row, Pellet Porosity (%)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "porosity", "label": "Porosity, ambient print, calculated from displacement density", "value": 15.1, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "form": "printed in ambient conditions, 80:20 LHS-1:PLA", "basis": "calculated from displacement density and TGA mass fractions" }, "method": "Calculated by the paper from displacement density and mass fractions (Table 7)", "status": "calculated", "source": "nasa-strives", "where": "Table 7, 80:20 LHS-1: PLA row, Ambient Print Porosity (%)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "porosity", "label": "Porosity, TVAC print, calculated from pycnometer density", "value": 8.8, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "form": "printed in simulated lunar dirty thermal vacuum, 80:20 LHS-1:PLA", "basis": "calculated from pycnometer data" }, "method": "Table 7 footnote: calculated from pycnometer data because displacement density was not available for this sample", "status": "calculated", "note": "Calculated from a different density method than the other two porosity rows, so the three values are not directly comparable.", "source": "nasa-strives", "where": "Table 7, 80:20 LHS-1: PLA row, TVAC Print Porosity (%), footnote marked with an asterisk", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "porosity", "label": "Porosity, ambient print, X-ray CT scan", "value": 0.76, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "form": "printed in ambient conditions, 80:20 LHS-1:PLA", "basis": "CT-scan reconstruction" }, "method": "CT-scan porosity from Table 7; the paper says the true porosity lies between the calculated and CT-scan values, and that CT-scan values are likely an underestimate", "status": "ground", "source": "nasa-strives", "where": "Table 7, 80:20 LHS-1: PLA row, Ambient Print CT-Scan Porosity (%)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "porosity", "label": "Porosity, TVAC print, X-ray CT scan", "value": 1.24, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "form": "printed in simulated lunar dirty thermal vacuum, 80:20 LHS-1:PLA", "basis": "CT-scan reconstruction" }, "method": "CT-scan porosity from Table 7; the paper says the true porosity lies between the calculated and CT-scan values", "status": "ground", "source": "nasa-strives", "where": "Table 7, 80:20 LHS-1: PLA row, TVAC Print CT-Scan Porosity (%)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "ultimate_tensile_strength", "label": "Tensile strength of pure PLA at 77 K (cryogenic, comparison only)", "value": 87, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "material": "pure PLA, the binder alone, with no regolith", "temperature": "77 K" }, "method": "Value stated in the paper's polymer comparison text; the paper does not give a cryogenic strength for the composite", "status": "ground", "source": "nasa-strives", "where": "Polymer evaluation text, PLA paragraph (statement on cryogenic tensile strength)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } }, { "benchmark": "elongation", "label": "Elongation of pure PLA at 77 K (cryogenic, comparison only)", "value": 5.7, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "material": "pure PLA, the binder alone, with no regolith", "temperature": "77 K" }, "method": "Value stated in the paper's polymer comparison text, with 6.4 percent at room temperature for the same polymer; not a value for the composite", "status": "ground", "source": "nasa-strives", "where": "Polymer evaluation text, PLA paragraph (elongation statement)", "source_detail": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" } } ], "corrosion": [ { "environment": "Lunar vacuum, outgassing and mass loss", "headline": "Mass loss from outgassing has not been measured for the composite.", "effect": "The paper lists vacuum mass loss as a remaining test. During vacuum printing, the residual gas analyser showed mostly air peaks and the paper reports no substantial off-gassing, but this is a printing-time check and not a long-term lunar exposure test.", "rating": "unknown", "conditions": { "exposure": "vacuum printing in simulated lunar dirty thermal vacuum", "test": "residual gas analyser during printing of 85:15 BP-1:PLA and 80:20 LHS-1:PLA cubes" }, "source": "nasa-strives", "where": "Vacuum Off-Gassing Characterization section and Conclusions" }, { "environment": "Thermal cycling across the lunar temperature range", "headline": "Thermal fatigue has not been tested for the composite.", "effect": "The REACT slides list strength across the lunar temperature range and thermal fatigue as tests still to do. The composite has not been cycled through lunar temperatures in any source held.", "rating": "unknown", "conditions": { "status": "not tested" }, "source": "nasa-react", "where": "Slide 20, Conclusions (remaining tests)" }, { "environment": "Ultraviolet exposure on the lunar surface", "headline": "UV degradation is named as a risk and has not been tested.", "effect": "The paper says exposure to the Moon's environment can limit the useful life of the composite through thermal cycling fatigue, mass loss from outgassing and UV degradation, and that further testing is needed.", "rating": "unknown", "conditions": { "exposure": "lunar surface, long-term", "test": "no UV test reported" }, "source": "nasa-strives", "where": "Conclusions and Recommendations, lifecycle paragraph" }, { "environment": "Moisture during extrusion, and sunlight heat", "headline": "PLA absorbs moisture and has a low heat distortion temperature, which the paper says limits it.", "effect": "The paper says PLA absorbs moisture, which may hydrolyze during extrusion and reduce mechanical properties, and that vacuum on the Moon mitigates this. It also says PLA has a low heat distortion temperature that would limit performance in direct sunlight.", "rating": "moderate", "conditions": { "basis": "qualitative statement about PLA in the paper, not a test of the composite" }, "source": "nasa-strives", "where": "Polymer evaluation text, PLA paragraph" } ], "risks": { "hazards": [ { "text": "The PLA datasheet describes Ingeo biopolymers as having very low toxicity in normal use, but says handling can generate vapours and dusts that irritate the eyes and upper airways, and advises an approved dust respirator in dusty air.", "ghs": [], "source": "nw-3d850", "where": "Safety and Handling Considerations, Hazards and Handling Precautions" }, { "text": "The datasheet says dust layers can ignite, and dust suspended in air can pose an explosion hazard.", "ghs": [], "source": "nw-3d850", "where": "Hazards and Handling Precautions, Combustibility" }, { "text": "The datasheet says that at melt temperature polymer can release fumes, and that for polyesters such as PLA, thermal decomposition can produce flammable vapours containing acetaldehyde and carbon monoxide.", "ghs": [], "source": "nw-3d850", "where": "Safety and Handling Considerations (decomposition paragraph)" }, { "text": "The paper gives no hazard classification for the composite, and no safety data sheet for the composite was found in the sources held.", "ghs": [], "source": "nasa-strives", "where": "Full text read in this run; no hazard section found" } ], "failure_risks": [ { "mode": "Failure along the print layers", "trigger": "Loading across the printed layers, such as the 90 degree direction", "consequence": "Fracture runs along layer interfaces, which the paper reads as poor adhesion between layers. The independent laboratory measured 16.6 MPa flexural strength at 90 degrees against 24 MPa at 0 degrees.", "severity": "moderate", "source": "nasa-strives", "where": "Table 4; Microscopy section (fracture surfaces)" }, { "mode": "Porosity from the extrusion process", "trigger": "Printing with the extruder in simulated lunar dirty thermal vacuum", "consequence": "Calculated porosity ranges from 8.8 to 15.1 percent depending on the method used. The paper says porosity is concentrated at layer interfaces and comes from extrusion more than from the printing environment.", "severity": "moderate", "source": "nasa-strives", "where": "Table 7; Porosity Characterization; Conclusions" } ], "side_effects": [ { "text": "During vacuum printing, the residual gas analyser showed mostly air peaks (nitrogen, oxygen, carbon dioxide and water). The paper reports no substantial off-gassing from the material.", "affects": "Vacuum chamber and hardware in the printing environment", "source": "nasa-strives", "where": "Vacuum Off-Gassing Characterization" } ], "handling": [ { "text": "Keep dust down with good housekeeping and dust control when handling PLA pellets, because dust layers can ignite.", "source": "nw-3d850", "where": "Hazards and Handling Precautions; Combustibility" }, { "text": "Use an approved dust respirator in dusty atmospheres.", "source": "nw-3d850", "where": "Hazards and Handling Precautions" }, { "text": "Provide good general ventilation of the polymer processing area, since fumes can be released at melt temperature.", "source": "nw-3d850", "where": "Safety and Handling Considerations" }, { "text": "Dry the PLA before compounding, as the paper did, because PLA absorbs moisture.", "source": "nasa-strives", "where": "Polymer evaluation text (PLA moisture statement); Beta Materials Drying Procedure" } ], "mitigations": [ { "text": "Optimise pellet extrusion and print parameters to reduce porosity, and move to single-step compounding during printing, as the paper recommends.", "source": "nasa-strives", "where": "Porosity Characterization; Conclusions and Recommendations" } ] }, "uses": [ { "application": "structures", "device": "Lunar Infrastructure Asset (LINA), an unpressurized protective shelter printed from the composite", "example": "The IEEE paper says LINA is designed to support 2.3 m of regolith overburden; a sub-scale LINA was printed on regolith simulant in dirty vacuum as the project's final test.", "source": "nasa-strives", "where": "Abstract; Conclusions" }, { "application": "in-space-manufacturing", "device": "Fused filament fabrication printer with a heated extruder head (ground demonstration only)", "example": "The REACT team printed the composite one layer at a time in simulated lunar dirty thermal vacuum, per the IEEE paper. This is a ground demonstration; the REACT slides recommend a small CLPS demonstration mission next.", "source": "wikipedia-fff", "where": "Lead paragraph (FFF process definition); printing conditions from the IEEE paper (nasa-strives); CLPS recommendation on REACT slide 20 (nasa-react)" } ], "supply": [ { "subject": "Lunar highlands simulant LHS-1 (regolith stand-in used in tests)", "abundance": "Not a mined material. LHS-1 is a commercial simulant that stands in for lunar highlands regolith in tests. The users guide names Exolith Lab at the University of Central Florida, now Space Resource Technologies, as its source.", "producers": [], "critical_lists": [], "recycling": "Not stated in the sources held.", "substitutes": [], "source": "nasa-guide-2024", "where": "Table 2 (LHS-1 row, Exolith Labs/Space Resource Technologies) and the text on Exolith Lab" }, { "subject": "Polylactic acid (binder)", "abundance": "The monomer is typically made from fermented plant starch, such as from corn, cassava, sugarcane or sugar beet pulp. Producer shares were not found in the sources held.", "producers": [], "critical_lists": [], "recycling": "Not stated in the sources held.", "substitutes": [], "source": "wikipedia-pla", "where": "Article text on the monomer feedstock" }, { "subject": "Lunar regolith (the in-situ feedstock the composite is meant to use)", "abundance": "Regolith covers almost the entire lunar surface. The composite is designed to use it as filler, but the simulant, not lunar regolith, was used in the tests.", "producers": [], "critical_lists": [], "recycling": "Not applicable.", "substitutes": [], "source": "wikipedia-regolith", "where": "Moon section of the article" } ], "media": [], "documents": [ { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference 2024, NTRS 20230015024)", "type": "paper", "url": "https://ntrs.nasa.gov/citations/20230015024", "year": 2024 }, { "title": "REACT: Selection, Production and Properties of Regolith Polymer Composite for Lunar Construction (slides, NTRS 20240003076)", "type": "report", "url": "https://ntrs.nasa.gov/api/citations/20240003076/downloads/REACT%20Selection%20Production%20and%20STRIVES.pdf", "year": 2024 }, { "title": "Lunar Regolith Simulant Users Guide, Rev A (NASA/TM-20240011783)", "type": "report", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024 }, { "title": "Ingeo Biopolymer 3D850 Technical Data Sheet (NatureWorks)", "type": "datasheet", "url": "https://www.natureworksllc.com/getContentAsset/6d5ea62c-7872-4297-aff7-67b8a53fe47f/53ffd608-340f-457b-b656-6b8cc0000bd4/TechnicalDataSheet_3D850_monofilament.pdf?language=en" } ], "gaps": [ "No flight, long-term lunar exposure or thermal-cycling result for the composite was found. The remaining tests listed by the REACT slides are strength across the lunar temperature range, thermal fatigue, vacuum mass loss, and assessment of lunar environmental impacts.", "The two independent flexural data sets disagree: the paper's text gives different 0 degree and 90 degree values for the independent laboratory from its Table 4. The table values are recorded above, both sets side by side.", "The composite's cryogenic strength, glass transition and heat distortion temperature were not found. The 77 K values above are for pure PLA only.", "The achieved mixture of 75:25 by TGA (REACT slide 11) is recorded in the recipe text only; it is not a measured property row.", "Vacuum pressures and the lunar vacuum levels quoted in the paper print as exponents, so they are not recorded here.", "Compressive strength and porosity are not canonical benchmark names in the property list; they are kept as short snake_case names.", "Production shares for PLA and for LHS-1 were not found in the sources held, so the supply entries name producers without country shares.", "No PubChem GHS record or safety data sheet for the composite was found. The PubChem page could not be opened in this run (a verification challenge), so hazard data come from the PLA datasheet and the paper.", "No CAS number, because the composite is a mixture. The formula is a description of the mixture.", "The hazard from the regolith simulant's dust was not assessed in any source held.", "The paper says higher-fidelity simulants with agglutinates and nanophase iron should be used later, so these results are for simulant only." ], "story": { "why": "Regolith-polymer composite (RPC) is a building material that mixes lunar regolith simulant with a plastic binder and prints it layer by layer, so a shelter could be built from local soil. NASA's REACT project printed it in simulated lunar dirty thermal vacuum and built a sub-scale protective shelter, the Lunar Infrastructure Asset (LINA). The project describes the work as \"approaching TRL 5\", and long-term lunar exposure tests remain to be done. The paper says the LINA structure was driven more by stiffness than by strength.", "uses": [ { "where": "Lunar shelter structure", "line": "The Lunar Infrastructure Asset (LINA) is an unpressurized shelter designed to support 2.3 m of regolith overburden. A sub-scale LINA was printed on regolith simulant in dirty vacuum as the project's final test." }, { "where": "Ground demonstration, not flight", "line": "The composite has not yet flown. The slides recommend a small Commercial Lunar Payload Services (CLPS) demonstration mission as the next step, after a large-scale demonstration at NASA's 3D printed habitat Centennial Challenge." } ], "can_do": [ { "label": "Flexural strength", "line": "In one independent laboratory's tests, 80:20 LHS-1:PLA reached 24 MPa flexural strength in the 0 degree direction and 16.6 MPa across the print at 90 degrees.", "benchmark": "flexural_strength", "scope": "material", "value": "24 MPa at 0 degrees; 16.6 MPa at 90 degrees" }, { "label": "Stiffness", "line": "In the same independent tests, flexural modulus was 5.3 GPa at 0 degrees and 3.7 GPa at 90 degrees.", "benchmark": "flexural_modulus", "scope": "material", "value": "5.3 GPa at 0 degrees; 3.7 GPa at 90 degrees" }, { "label": "Density", "line": "Pellets of the 80:20 LHS-1:PLA blend measured 1.80 g/cc by volumetric displacement, and ambient prints measured 1.82 g/cc.", "benchmark": "density", "scope": "material", "value": "1.80 g/cc for pellets" }, { "label": "Void content", "line": "Porosity ranged from 8.8 to 15.1 percent depending on the method and print condition, and the paper says it is concentrated at layer interfaces.", "benchmark": "porosity", "scope": "material", "value": "8.8 to 15.1 percent" }, { "label": "Cold PLA", "line": "The paper quotes an 87 MPa tensile strength at 77 K for pure PLA. This is the binder alone, not the composite, and no cryogenic strength for the composite is reported.", "benchmark": "ultimate_tensile_strength", "scope": "material", "value": "87 MPa at 77 K, pure PLA" } ], "compare": "The 80:20 LHS-1:PLA blend is much denser than its binder alone: 1.80 g/cc for pellets against 1.28 g/cc for pure PLA pellets, both by volumetric displacement. Its strength depends on print direction. In the independent laboratory's tests it reached 24 MPa flexural strength at 0 degrees and 16.6 MPa at 90 degrees. In SpaceFactory's tests the same blend reached 34.40 MPa and 14.90 MPa. The paper says its flexural strength is significantly higher than that of lumber and concrete, but it gives no cryogenic strength for the composite.", "compare_rows": [ { "label": "Density, pellets", "benchmark": "density", "scope": "material" }, { "label": "Flexural strength, 0 degrees", "benchmark": "flexural_strength", "scope": "material" }, { "label": "Flexural modulus, 0 degrees", "benchmark": "flexural_modulus", "scope": "material" } ], "handling": [ "Keep dust down with good housekeeping and dust control, because dust layers can ignite.", "Use an approved dust respirator in dusty air, and ventilate the processing area, since fumes can be released at melt temperature.", "Dry the PLA before compounding, because PLA absorbs moisture that can degrade it during extrusion." ], "good_for": [ "Ground demonstrations of printed shelter structures made from regolith simulant and a bio-based binder.", "Stiffness-driven structural design. The paper says the LINA design was driven more by modulus than by strength." ], "watch_out": [ "Strength across the print layers is lower than along them: 16.6 MPa at 90 degrees against 24 MPa at 0 degrees, by the independent laboratory.", "Porosity of 8.8 to 15.1 percent, depending on the method, concentrated at layer interfaces.", "Long-term lunar exposure is untested: thermal fatigue, vacuum mass loss and UV are all listed as remaining tests.", "PLA has a low heat distortion temperature, which the paper says would limit its performance in direct sunlight." ], "verdict": "A promising ground-tested lunar construction material. Its strength is adequate on paper, but long-term lunar exposure is untested and it is weaker across the print layers.", "recipe": { "line": "Regolith-polymer composite is lunar highlands simulant LHS-1 mixed with polylactic acid (PLA) and compounded into pellets. The paper's target mix is 80:20 by weight, and the REACT slides report an achieved mix of \"75:25\" by TGA. Fused filament fabrication (FFF) then feeds the pellets as a filament through a heated, moving extruder head that deposits one layer at a time.", "parts": [ { "name": "LHS-1 lunar highlands simulant", "role": "Mineral filler that stands in for lunar highlands regolith. The paper describes it as mostly anorthosite with glass-rich basalt.", "share_percent": 80, "source": "nasa-strives", "where": "Target mix 80:20 wt.% (Table 4); simulant description in the Comparative Analysis section" }, { "name": "Polylactic acid", "symbol": "(C3H4O2)n", "role": "Thermoplastic binder that holds the simulant particles together and flows through the extruder. It is a bio-based polyester.", "share_percent": 20, "source": "nasa-strives", "where": "Target mix 80:20 wt.% (Table 4)" } ] }, "risk_groups": [ { "title": "For people", "lead": "No hazard classification for the composite appears in the sources held. The PLA datasheet describes low toxicity, with dust and fume precautions.", "points": [ { "label": "Dust", "line": "Handling can release dust and vapours that irritate the eyes and upper airways. The datasheet advises an approved dust respirator in dusty air, and says suspended dust can be an explosion hazard." }, { "label": "Heating", "line": "At melt temperature, PLA can release fumes. Long holds at high temperature can decompose it into flammable vapours containing acetaldehyde and carbon monoxide." }, { "label": "Regolith dust", "line": "The regolith simulant's dust was not assessed in any source held, so its respiratory effect is not known from this record." } ], "level": 1, "verdict": "Low toxicity, but dust needs control" }, { "title": "Failure in service", "lead": "The strength results come from small test specimens, not full shelters.", "points": [ { "label": "Layers", "line": "Fracture follows the layer interfaces. The independent laboratory measured 16.6 MPa at 90 degrees against 24 MPa at 0 degrees." }, { "label": "Porosity", "line": "Calculated porosity ranges from 8.8 to 15.1 percent by method. The paper says it is concentrated at layer interfaces." } ], "level": 2, "verdict": "Weaker across print layers" }, { "title": "Lunar exposure", "lead": "Long-term lunar exposure has not been measured for this composite.", "points": [ { "label": "Thermal cycling", "line": "Thermal fatigue across the lunar temperature range is still to be tested." }, { "label": "Ultraviolet", "line": "The paper names UV degradation as a lunar risk, with no test reported." }, { "label": "Vacuum mass loss", "line": "Mass loss from outgassing over the life of a lunar facility is still to be measured." } ], "verdict": "Untested: thermal, UV and vacuum" } ] }, "updated": "2026-11-01", "review": { "status": "draft", "method": "assistant", "checked_values": 21, "unreachable": 0, "caveats": 2, "note": "Written by an AI assistant on 2026-11-01 from the NASA IEEE paper (NTRS 20230015024), the REACT slides (NTRS 20240003076), the NASA simulant users guide, the NatureWorks 3D850 datasheet and two Wikipedia articles, all read in this run. Two caveats: the two flexural data sets disagree, and the porosity values come from different methods." }, "sources": { "nasa-strives": { "title": "Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (IEEE Aerospace Conference paper, NTRS 20230015024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/api/citations/20230015024/downloads/STRIVES%20IEEE-Selection%20Production%20and%20Prop%20FINAL.pdf", "year": 2024, "kind": "paper", "license": "public domain (NASA)" }, "nasa-react": { "title": "Selection, Production and Properties of Regolith Polymer Composite for Lunar Construction (REACT slides, 2024 IEEE Aerospace Conference, NTRS 20240003076)", "id": "NTRS 20240003076", "url": "https://ntrs.nasa.gov/api/citations/20240003076/downloads/REACT%20Selection%20Production%20and%20STRIVES.pdf", "year": 2024, "kind": "report", "license": "public domain (NASA)" }, "nasa-guide-2024": { "title": "Lunar Regolith Simulant Users Guide, Rev A (NASA/TM-20240011783)", "id": "NTRS 20240011783", "url": "https://ntrs.nasa.gov/api/citations/20240011783/downloads/Lunar_Regolith_Simulant_Users_Guide_Rev_A_28OCT.pdf", "year": 2024, "kind": "report", "license": "public domain (NASA)" }, "nasa-ntrs-2023": { "title": "NTRS citation record 20230015024, Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction (presented at the 45th International IEEE Aerospace Conference, March 2024)", "id": "NTRS 20230015024", "url": "https://ntrs.nasa.gov/citations/20230015024", "year": 2024, "kind": "paper", "license": "public domain (NASA)" }, "nw-3d850": { "title": "Ingeo Biopolymer 3D850 Technical Data Sheet (3D printing monofilament), NatureWorks", "url": "https://www.natureworksllc.com/getContentAsset/6d5ea62c-7872-4297-aff7-67b8a53fe47f/53ffd608-340f-457b-b656-6b8cc0000bd4/TechnicalDataSheet_3D850_monofilament.pdf?language=en", "kind": "datasheet", "license": "supplier document, linked not reproduced" }, "wikipedia-pla": { "title": "Polylactic acid, Wikipedia (monomer feedstock; CAS number in the identifiers section)", "id": "CAS 26100-51-6", "url": "https://en.wikipedia.org/wiki/Polylactic_acid", "kind": "web", "license": "CC BY-SA 4.0" }, "wikipedia-fff": { "title": "Fused filament fabrication, Wikipedia (lead paragraph and process description)", "url": "https://en.wikipedia.org/wiki/Fused_filament_fabrication", "kind": "web", "license": "CC BY-SA 4.0" }, "wikipedia-regolith": { "title": "Regolith, Wikipedia (definition; Moon section)", "url": "https://en.wikipedia.org/wiki/Regolith", "kind": "web", "license": "CC BY-SA 4.0" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/regolith-polymer-composite/" }