State-of-the-art review of metal in-space servicing, assembly, and manufacturing (ISAM) technologies
COMPILED NOTES
Comprehensive review of metal ISAM approaches — PBF and DED dominate, but friction stir methods offer better robustness in space
State-of-the-art Review of Metal ISAM Technologies
Key Contributions
- Comprehensive taxonomy of metal manufacturing approaches viable for space: powder bed fusion (PBF), directed energy deposition (DED), friction stir welding (FSW), additive friction stir deposition (AFSD), and hybrid methods
- PBF and DED currently dominate research but face challenges in microgravity (powder containment, thermal management)
- Friction stir methods emerging as superior for in-space conditions — no melting required, better material properties, more process robustness
- Reviews technology readiness levels across all approaches
Key Claims
- ISAM enables construction of structures too large to launch whole — space stations, solar power arrays, telescope mirrors
- FSW and AFSD produce joints with better mechanical properties than fusion-based methods in many alloys
- Microgravity actually benefits some processes (no gravity-induced sagging) but complicates others (powder handling, convection)
- Commercial viability depends on reducing launch costs (Starship) + increasing on-orbit demand (mega-constellations, space stations)
Technology Readiness
| Method | TRL | Key Challenge |
|---|---|---|
| PBF | 4-5 | Powder containment in microgravity |
| DED | 4-5 | Thermal management, power requirements |
| FSW | 3-4 | Fixturing in zero-g, reaction forces |
| AFSD | 2-3 | Early stage, limited space testing |
| Hybrid | 2-3 | Integration complexity |
Source: State-of-the-art review of metal ISAM technologies — ScienceDirect, 2026
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