Bulk MMOD Hatch
Reinforced Hatch with Multi-Stage MMOD Protection
The bulk micrometeoroid and orbital debris (MMOD) hatch is a 200-kilogram reinforced penetration assembly that allows personnel and robotic transit through a primary bulk protection wall. Movable penetrations represent critical weak points in habitat shielding, requiring the hatch to match the surrounding wall's ballistic performance through a multi-stage structure comprising an outer Whipple-grade plate, an intermediate aluminum and steel core, and an inner pressure seal. Driven by a 100-watt mechanical actuator, the assembly utilizes sealed bearings to maintain vacuum-exposed reliability, operating with an 80,000-hour mean time between failures across a 30-year service life.
Reinforced hatch with multi-stage MMOD protection (Whipple + thick metal core) for personnel/robot access through the bulk MMOD wall.
Purpose
Reinforced hatch with multi-stage MMOD protection (Whipple + thick metal core) for personnel/robot access through the bulk MMOD wall.
Context
Child of L2-MMD-BULK within the Lunar Ark system
Principles
- ▸Hatch matches MMOD performance of surrounding wall
- ▸Multi-stage: outer Whipple, intermediate metal core, inner pressure seal
- ▸Mechanical drive for opening/closing
- ▸Interlocked with L3-DST-LOCK-STAGE
- ▸Failsafe: failed-closed
Typical implementations
- ▸ISS hatch heritage
- ▸Aerospace airlock design
- ▸Nuclear facility containment doors
Lunar considerations
- ▸Hatch is the weak point — special attention required
- ▸Long-life mechanism with sealed bearings
- ▸Replaceable via L1-MNT
Specifications
Functional
| primary function | Reinforced hatch with multi-stage MMOD protection (Whipple + thick metal core) for personnel/robot access through the bulk MMOD wall. |
| mass kg | 200 |
| drive power w | 100 |
Physical
| mass kg | 200 |
| materials | Aluminum + steel composite, Whipple-grade outer plate |
| vacuum compatibility | True |
Operational
| power consumption w | 100 |
| thermal range c | -40, 70 |
| lifetime years | 30 |
| mtbf hours | 80000 |
Interfaces
Provides
- Access path through bulk wall
Requires
- Drive motor (~100 W transient)
Cite this entry
Lunar Ark Codex. "Bulk MMOD Hatch" (L3-MMD-BULK-HATCH). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-MMD-BULK-HATCH
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.