Reverse Osmosis Membrane
Spiral-Wound Polyamide TFC RO Membrane
The spiral-wound polyamide thin-film composite reverse osmosis membrane is a water-purification stage that removes over 99% of dissolved solids from melted lunar ice. Housed in a 316L stainless steel pressure vessel, the 8-kilogram module operates at 10 to 15 bar to deliver 5 liters per hour of permeate at an 80% recovery ratio while consuming 200 watts of power. Processing feedstock extracted from lunar permanently shadowed regions is complicated by dissolved sulfur compounds, ammonia, and organics, necessitating a 5-micrometer pre-filter to protect the assembly from suspended particulates.
Spiral-wound polyamide TFC reverse-osmosis stage removing >99% of dissolved solids from melted ice water.
Purpose
Spiral-wound polyamide TFC reverse-osmosis stage removing >99% of dissolved solids from melted ice water.
Context
Child of L2-WTR-PURE in L1-WTR water processing chain
Principles
- ▸Polyamide TFC membranes reject >99% NaCl and >95% dissolved organics
- ▸Operating pressure 10-15 bar drives water through membrane
- ▸Spiral-wound geometry maximises surface area
- ▸Pre-filter (5 um) protects membrane from particulates
- ▸Periodic forward flush + chemical clean restore flux
- ▸Membrane life ~5 years with proper pre-treatment
Typical implementations
- ▸Dow FilmTec / Toray RO membranes (terrestrial)
- ▸ISS WPA RO option (research config)
- ▸Sustainable Water Systems in Space (Wiley WRR 2026)
- ▸NASA ICES-2024-353 lightweight water recovery
Lunar considerations
- ▸Lunar PSR water contains dissolved S compounds, NH3, organics — RO well-suited
- ▸Low pressure differential reduces pump energy
- ▸Modular cartridge replaceable via L1-MNT every 5 years
Specifications
Functional
| primary function | Spiral-wound polyamide TFC reverse-osmosis stage removing >99% of dissolved solids from melted ice water. |
| rejection percent | 99 |
| permeate lph | 5 |
| recovery ratio percent | 80 |
Physical
| mass kg | 8 |
| materials | PA TFC membrane, PP feed spacers, 316L SS pressure vessel |
| vacuum compatibility | True |
Operational
| power consumption w | 200 |
| thermal range c | -40, 70 |
| lifetime years | 15 |
| mtbf hours | 80000 |
Interfaces
Provides
- RO permeate for polishing
- Brine reject
Requires
- Pre-filtered feed
- 10-15 bar pressurized feed
- Pump energy (~200 W)
Cite this entry
Lunar Ark Codex. "Reverse Osmosis Membrane" (L3-WTR-PURE-RO). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-WTR-PURE-RO
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.