Water Containment and Transfer
Insulated Liquid-Water Holding Tank with Transfer Pump
The insulated liquid-water holding tank is a 50-liter, 12-kilogram buffer vessel that collects intermittent 5-kilogram daily batches of water from cold-trap extraction cycles and pumps it to downstream purification systems at rates up to 5 liters per hour. Operating in the lunar environment requires active freeze protection, as severe surface temperature swings drive heater duty cycles and parasitic power loads. To maintain liquid inventory between 4 °C and 40 °C, the 316L stainless steel tank integrates multi-layer insulation, an internal polyimide heater patch, and a seal-less diaphragm metering pump rated for 10,000 operational cycles.
Insulated holding tank that receives liquid water from the cold-trap warm-up cycle, maintains it above freezing for transfer, and pumps it onward to L1-WTR purification and L3-ESS-FC-WTR closed-loop reservoir.
Purpose
Buffer the discontinuous output of the cold-trap cycle (batches of ~5 kg every 24 hr) into a continuous flow to downstream purification, ensuring no water freezes in transfer lines and providing local storage during downstream maintenance.
Context
Sits between L3-ISR-ICE-COND (intermittent batch source) and L1-WTR (continuous purification consumer). Maintains liquid water above freezing using thermal interface to warm portion of Ark. Includes mass gauge for production-rate telemetry.
Principles
- ▸Insulated tank with internal heater maintains liquid water above 4 °C in lunar thermal environment
- ▸Mass gauge (load cell, capacitance probe, or differential pressure) measures inventory
- ▸Diaphragm pump or metering pump moves water to downstream — no shaft seals to leak
- ▸Standpipe + vent to vacuum prevents pressurization during fill; vapor recapture loop
- ▸Multi-tank parallel configuration for redundancy and continuous downstream supply
- ▸Cleanliness standards (ISO Class 7 equivalent) for water-handling internal surfaces
Typical implementations
- ▸ISS Water Storage tanks heritage (closed-loop water management)
- ▸Apollo / Shuttle potable water reservoirs
- ▸Industrial pharmaceutical water-for-injection tanks
- ▸NASA LADI water collection tanks (NTRS 20230013485)
Lunar considerations
- ▸Lunar surface temperature swings drive heater duty cycle — insulated tank reduces parasitic load
- ▸Robotic transfer to L1-WTR requires standardized quick-disconnect fluid couplings
- ▸Long-life elastomer in pump seals limited; metal bellows preferred for 100-year-equivalent service
- ▸Anti-microbial integrity (chlorine/UV) needed if water is later for biological use; lower priority for RFC-only use
- ▸Mass-gauge calibration drift over years — periodic refill-from-known-mass calibration
Specifications
Functional
| primary function | Receive, store, and meter water from cold-trap output to L1-WTR |
| inputs | Liquid water from L3-ISR-ICE-COND warm-up cycle, Power for heater + pump from L1-PDM, Thermal interface to maintain >4 °C |
| outputs | Metered water flow to L1-WTR, Inventory and flow telemetry, Vent vapor (small) to recapture loop |
| tank capacity l | 50 |
| operating temperature c | 4, 40 |
| transfer rate l per hour max | 5 |
| mass gauge accuracy percent | 1 |
| freeze protection temperature c min | 4 |
| design cycles | 10000 |
Physical
| mass kg | 12 |
| dimensions | 300 × 300 × 600 mm insulated cylindrical tank |
| materials | 316L stainless inner tank, Polyimide heater patch (radiation-tolerant), MLI + foam insulation jacket, Outer aluminum jacket, Diaphragm metering pump (vacuum-rated), Stainless quick-disconnect fittings |
| operating temperature c | -180, 50 |
| vacuum external | True |
Operational
| power consumption w pump | 20 |
| power consumption w heater | 50 |
| thermal range c | -180, 50 |
| lifetime years | 25 |
| mtbf hours | 100000 |
Interfaces
Provides
- Water feed at ambient temperature for purification
- Inventory level, transfer rate
Requires
- Liquid water from cold-trap warm-up
- Heater + pump (~70 W max)
- Heat to maintain >4 °C
Cite this entry
Lunar Ark Codex. "Water Containment and Transfer" (L3-ISR-ICE-CONT). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-ISR-ICE-CONT
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.