Materials

Structural, shielding, transparent and ISRU materials discussed in the thread.

Key results

Structural

• Steel.
• Isotropic, cheap, and available from the Moon lamontagne, 2023-09-21. Starship-style stainless rolls are 3.6 mm LMT, 2023-01-11.
• Stainless needs 16–18% chromium, but lunar iron and chromium exist lamontagne, 2022-11-10.
• Ni-rich asteroidal or lunar iron could make "naturally strong" sheet lamontagne, 2023-09-28.
• Coastal Ron worries about stainless steel producing secondary radiation Coastal Ron, 2023-09-18.
• Aluminium. If a module is the size of the fairing, aluminium is cheaper and lighter than an inflatable Jim, 2018-07-03.
• Carbon fibre composite. ~1500 MPa design strength used in lamontagne's calculations lamontagne, 2023-01-11. Composites damp vibration, though they have their own resonances Coastal Ron, 2018-08-05; Paul451, 2018-08-05.
• UHMWPE (Dyneema, Spectra). Excellent strength-to-weight and hydrogen-rich shielding, but creeps under sustained load Paul451, 2023-09-19. Coastal Ron still favours custom UHMWPE and PE for combined structure and shielding Coastal Ron, 2023-09-19; Coastal Ron, 2023-02-23.
• Basalt and carbon fibre as creep-free alternatives Paul451, 2023-09-19.
• Post-tensioned concrete for tunnel-like habitats (like Boring Company tunnel liners and 1970s MIT studies) lamontagne, 2023-09-29.
• Barley: reinforced concrete as a pressure membrane needs more steel than a plate. Use concrete only for stiffening floors Barley, 2023-09-29; Barley, 2023-09-29.
• lamontagne's Avalon uses 5 m of post-stressed concrete for the ring4 Mars habitat lamontagne, 2023-04-18.
• Titanium, FeTi, ilmenite. Ilmenite ((Fe,Ti)₂O₃) is a lunar feedstock JohnFornaro, 2023-01-08. FeTi reacts with atomic oxygen, forming stable TiO₂ JohnFornaro, 2023-01-09. Unreactive metals are preferred in low orbit LMT, 2023-01-08.
• Atomic oxygen in LEO/VLEO degrades lightweight materials; see Dooling 1999 LMT, 2023-01-08.
• Lunar anhydrous glass for pressure hulls (Soilleux, JBIS 2019), with a metal coating against water lamontagne, 2022-12-15; lamontagne, 2023-01-07.
• Cold welding.
• LMT promoted cold-welding Mars FeNi plates in orbit, needing <100 N clamp force (Barilaro et al. 2023) LMT, 2023-06-12; LMT, 2023-06-14.
• Paul451: macroscopic "cold welding" is stiction or galling, not a real weld, except press-welding of soft metals Paul451, 2023-09-19.
• Friction stir welding (FuseRing) and helical seam pipe mills for in-space tube making Asteroza, 2022-12-15; PMN1, 2022-12-14; Asteroza, 2023-06-12.
• Electron-beam welding. Demonstrated in space in 1969, robotically in 1980 Habitant, 2025-10-17. Vent the weld zone to vacuum for internal welds Twark_Main, 2024-01-30.
• Magnetically inflated superconducting cables (Powell) Cedalion, 2015-10-21.

Transparent

• Glass is cheap in principle (silica + oxygen, an oxide needing little energy) but fragile. Curtain walls show large glazing is affordable lamontagne, 2023-03-06.
• Laminated glass for the short term; polycarbonates degrade; alumina and ALON for the future lamontagne, 2023-02-27.
• ALON (aluminium oxynitride): armour-qualified and good shielding, but >$10 per square inch LarryCanuck, 2023-01-19; LarryCanuck, 2023-02-24.
• SiO₂ aerogel fibres under 3 nm allow thick, haze-free windows (MIT) Lampyridae, 2023-11-17.
• NASA windows are fused silica with borosilicate or aluminosilicate panes and small gaps Paul451, 2023-02-28.

Shielding materials

• See radiation shielding. In brief: hydrogen-rich materials (polyethylene, water, LH₂) best for GCR secondaries; regolith ≈ air per tonne; per unit mass most low-Z substances are similar for ionization Shevek23, 2019-10-26.

Open questions

• Which space-fabricated material is first viable for pressure hulls: lunar steel, lunar glass, or asteroidal FeNi?
• Long-term UV and atomic-oxygen durability of polymer structures.

Related pages

• Pressure vessels · ISRU · Lighting and windows

Sources

Forum posts

• Cedalion, 2015-10-21 (reply #707): MIC cables. Post.
• Jim, 2018-07-03 (reply #857, 2 likes): Al cheaper if module = fairing. Post.
• Coastal Ron, 2018-08-05 (reply #1152): Composites damp. Post.
• Paul451, 2018-08-05 (reply #1153, 1 like): Composites have resonances. Post.
• Shevek23, 2019-10-26 (reply #1694): Bethe-Bloch material comparison. Post.
• lamontagne, 2022-11-10 (reply #2355): Stainless needs Cr; lunar Fe & Cr. Post.
• PMN1, 2022-12-14 (reply #2652): Helical seam pipe mill (JBIS 2013). Post.
• Asteroza, 2022-12-15 (reply #2653): FuseRing friction stir. Post.
• lamontagne, 2022-12-15 (reply #2656): Soilleux: lunar glass hulls. Post. Attachments: JBIS-v72-no07-July-2019_f838tt.pdf.
• lamontagne, 2023-01-07 (reply #2792, 1 like): Lunar anhydrous glass paper (1985). Post. Attachments: 1985lbsa.pdf.
• LMT, 2023-01-08 (reply #2809): Atomic oxygen: Dooling 1999. Post. Attachments: Dooling 1999 Tables 2 and 4.png.
• JohnFornaro, 2023-01-08 (reply #2812): Ilmenite feedstock. Post.
• LMT, 2023-01-08 (reply #2823): Unreactive metal for LEO; Mars chromite. Post.
• JohnFornaro, 2023-01-09 (reply #2835): FeTi → TiO₂ stable. Post.
• LMT, 2023-01-11 (reply #2854): Starship stainless roll 3.6 mm. Post. Attachments: 3.6mm.png.
• lamontagne, 2023-01-11 (reply #2866): CFRP 1500 MPa. Post.
• LarryCanuck, 2023-01-19 (reply #2991): ALON. Post.
• Coastal Ron, 2023-02-23 (reply #3403): Polyethylene as structure + shield. Post.
• LarryCanuck, 2023-02-24 (reply #3404): ALON cost. Post.
• lamontagne, 2023-02-27 (reply #3435, 1 like): Laminated glass; polycarbonate; ALON. Post.
• Paul451, 2023-02-28 (reply #3440): NASA window construction. Post.
• lamontagne, 2023-03-06 (reply #3482): Glass cheap in theory. Post. Attachments: table 4.1.png.
• lamontagne, 2023-04-18 (reply #3615): Mars ring4: post-stressed concrete 5 m. Post.
• LMT, 2023-06-12 (reply #3838): Space welding methods review; cold welding. Post. Attachments: Kalpana-24_Ba2-1920.jpg.
• Asteroza, 2023-06-12 (reply #3839): FuseRing. Post.
• LMT, 2023-06-14 (reply #3859): Cold welding <100 N. Post.
• Coastal Ron, 2023-09-18 (reply #3966): Stainless secondary radiation concern. Post.
• Paul451, 2023-09-19 (reply #3982): Dyneema creep. Post.
• Paul451, 2023-09-19 (reply #3983): Cold welding is not a macro weld. Post.
• Paul451, 2023-09-19 (reply #3985): Carbon or basalt fibre instead. Post.
• Coastal Ron, 2023-09-19 (reply #3992): UHMWPE structure + shielding. Post.
• lamontagne, 2023-09-21 (reply #4007): Steel used for simulation; isotropic. Post.
• lamontagne, 2023-09-28 (reply #4034): Ni-rich steel sheets. Post.
• lamontagne, 2023-09-29 (reply #4064): Post-tensioned concrete; MIT 1970s. Post.
• Barley, 2023-09-29 (reply #4068, 1 like): Concrete only for stiffening. Post.
• Barley, 2023-09-29 (reply #4070): RC membrane needs more steel. Post.
• Lampyridae, 2023-11-17 (reply #4357, 1 like): SiO2 aerogel fibre windows. Post.
• Twark_Main, 2024-01-30 (reply #4435): EBW for permanent joins. Post.
• Habitant, 2025-10-17 (reply #5012): EBW history. Post.

External references

• Dooling, D. (1999). Material selection guidelines to limit atomic oxygen effects on spacecraft surfaces. NASA MSFC.
• Barilaro, L., Wylie, M. & Olivieri, L. (2023). Cold welding adhesion for spacecraft repair. Acta Astronautica.
• Naden, N. & Prater, T. J. (2020). A review of welding in space and related technologies.
• Merstallinger, A. et al. (2009). Assessment of cold welding between separable contact surfaces. ESA STM-279.
• Soilleux, R. (2019). JBIS 72(7), lunar glass pressure hulls.