Pressure Vessel Shell
Cylindrical Pressure Shell with Stiffening Rings
The pressure vessel shell is a cylindrical, ring-stiffened structure fabricated from aluminium-lithium alloys that maintains a 1 atm internal atmosphere against the lunar vacuum. Operating in the lunar environment imposes severe structural demands: the shell must sustain a continuous 1 atm pressure differential, support external regolith overburden applied for radiation and micrometeorite shielding, and maintain a 100-year fatigue life under thermal cycling. Constructed from an Al-Li 2195 skin with Al 2219 ring stiffeners joined by friction stir welds, the structure resists buckling under external loads and relies on a leak-before-burst design to ensure cracks vent detectably before catastrophic failure occurs.
Primary pressure containment shell maintaining 1 atm internal pressure in lunar vacuum
Purpose
Primary pressure containment shell maintaining 1 atm internal pressure in lunar vacuum
Context
Child of L2-STR-PRES
Principles
- ▸Cylindrical geometry provides optimal hoop stress distribution (sigma = pr/t)
- ▸Ring-stiffened skin construction prevents shell buckling under external pressure loads
- ▸Al-Li alloy or titanium provides high specific strength for pressure containment
- ▸Leak-before-burst design ensures cracks become detectable leaks before catastrophic failure
Typical implementations
- ▸ISS pressurized module shells (Al 2219-T87, ~4.8mm wall)
- ▸Orion crew module pressure vessel (Al-Li 2195)
- ▸ESA ATV pressure shell construction
Lunar considerations
- ▸Full 1 atm differential across shell in lunar vacuum
- ▸100-year fatigue life from thermal cycling requires conservative wall thickness
- ▸Shell must support regolith overburden loading for radiation/MMOD shielding
Specifications
Functional
| primary function | Primary pressure containment shell maintaining 1 atm internal pressure in lunar vacuum |
Physical
| materials | Al-Li 2195 shell, Al 2219 ring stiffeners, Friction stir weld joints |
Interfaces
Provides
- Pressurized volume for habitat and equipment
Requires
- Frame support for pressure vessel
Cite this entry
Lunar Ark Codex. "Pressure Vessel Shell" (L3-STR-PRES-SHELL). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-STR-PRES-SHELL
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.