Fluid Transport Lines
Thermal Fluid Distribution Piping and Manifold Network
The thermal fluid distribution piping and manifold network consists of rigid tubing, flexible hoses, manifolds, and fittings that route thermal working fluid between pumps, heat exchangers, cold plates, and radiators. On the lunar surface, external line segments face vacuum exposure and micrometeorite impacts from particles traveling at 20 km/s, requiring protective Kevlar overwraps or regolith burial. Environmental temperature swings across a 300 °C range cause rigid stainless steel lines to expand approximately 5 mm per meter, requiring expansion loops and bellows joints every few meters, while abrasive surface dust mandates sealed covers and positive-pressure purges at maintenance connection interfaces.
The network of rigid tubing, flexible hoses, manifolds, and fittings that route thermal working fluid between all loop components including pumps, heat exchangers, cold plates, radiators, and accumulators.
Purpose
Provide sealed, low-pressure-drop fluid pathways connecting all thermal loop components. Must accommodate structural thermal expansion, tolerate micrometeorite impacts on external segments, and support robotic disconnection for maintenance. The piping network defines the physical topology of each thermal loop.
Context
Fluid lines route through the Ark structure (L1-STR), penetrating pressure boundaries and thermal insulation layers. External line segments exposed to vacuum and micrometeorite flux require armored conduit or regolith burial. Internal segments must be routed to minimize parasitic heat gains/losses. Flexible segments are needed at structural joints and equipment interfaces to accommodate differential thermal expansion across the 300C temperature range.
Principles
- ▸Pressure drop through piping follows the Darcy-Weisbach equation: proportional to length, flow velocity squared, and inversely proportional to diameter
- ▸Thermal expansion of metal tubing creates significant length changes over the lunar temperature range: expansion loops, bellows joints, or flexible hoses required
- ▸Orbital tube welding provides hermetic, high-reliability joints for rigid stainless steel and titanium tubing
- ▸Manifold design balances flow distribution across parallel branches to ensure uniform heat transport to all served components
- ▸Quick-disconnect fittings at maintenance interfaces enable robotic line segment replacement without full loop drain-down
Typical implementations
- ▸ISS ETCS ammonia fluid lines: stainless steel tubing with orbital-welded joints and flex hoses at truss joints
- ▸ISS ITCS water lines: stainless steel rigid tubing with Swagelok compression fittings in pressurized modules
- ▸Shuttle Orbiter Freon loop lines: aluminum tubing with brazed joints
- ▸Nuclear submarine reactor coolant piping (heritage for high-reliability welded piping design)
Lunar considerations
- ▸External line segments need micrometeorite shielding: multi-layer Whipple bumper or Kevlar/Nextel overwrap
- ▸Buried routing through regolith provides micrometeorite protection and thermal mass buffering
- ▸Thermal expansion over 300C range: stainless steel expands ~5mm per meter, requiring expansion compensation every few meters
- ▸Lunar dust contamination at quick-disconnect interfaces: sealed dust covers and positive-pressure purge during connection
- ▸100-year corrosion compatibility between tubing material and working fluid is essential: passivated stainless steel or titanium
Specifications
Functional
| primary function | Route working fluid between all thermal loop components with minimal pressure drop and zero external leakage |
| inputs | Working fluid at various temperatures and pressures from connected components |
| outputs | Working fluid delivered to downstream components at required flow rates |
| total pressure drop kpa | TBD (target <30% of pump head per loop circuit) |
| leak rate | Zero measurable external leakage over 10-year inspection interval |
| thermal expansion accommodation | Full range -80C to +80C operational without stress exceedance |
| micrometeorite survivability | No penetration of fluid boundary from particles <1mm at 20 km/s |
Physical
| materials | Stainless steel 316L (rigid tubing, manifolds, fittings), Titanium Grade 2 (lightweight segments, flex couplings), PTFE-lined flexible hose assemblies (flexible segments at joints), Kevlar/Nextel fabric (micrometeorite shielding overwrap), Aerogel blankets (thermal insulation for external segments) |
| operational temp range c | -80, 80 |
| survival temp range c | -173, 127 |
| vacuum exposure | External segments in hard vacuum |
| micrometeorite flux | Lunar surface meteoroid environment |
Operational
| power consumption w | 0 |
| thermal range c | -80, 80 |
| lifetime years | 100 |
| notes | Passive component. Trace heaters (L3-TCS-HTR-TRCE) may be bonded to external segments to prevent fluid freezing. Quick-disconnect fittings at maintenance points enable segment replacement. |
Interfaces
Provides
- Sealed fluid pathways connecting all loop components: pumps, valves, heat exchangers, cold plates, radiators, accumulators
Requires
- Structural support brackets, clamps, and routing channels; structural penetration feedthroughs for pressure boundary crossings
- Trace heaters bonded to external fluid line segments to prevent freezing during lunar night
- Robotic access for line segment inspection, leak detection, and quick-disconnect operations during maintenance
Cite this entry
Lunar Ark Codex. "Fluid Transport Lines" (L3-TCS-FLOP-LINE). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-TCS-FLOP-LINE
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.