HDPE Polyethylene Shielding Panels
High-Density Polyethylene Panel Stack for Neutron Protection
High-density polyethylene (HDPE) shielding panels are polymer stacks mounted on aluminum frames inside habitat walls to thermalize and absorb secondary neutrons generated by galactic cosmic ray interactions with lunar regolith. Because the Moon lacks a protective magnetosphere, high-energy cosmic rays penetrate surface shielding, creating hazardous secondary radiation cascades. With a density of 950 kg/m³ and approximately 14 percent hydrogen by mass, HDPE stops incident protons up to 200 MeV and moderates neutrons. Positioned in a 10 to 30 cm layer behind two meters of regolith, the passive material remains stable in vacuum with low outgassing over a 50-year operational lifetime.
High-density polyethylene (HDPE) panel stack inside habitat walls — high hydrogen content optimal for thermalising and absorbing secondary neutrons from GCR-regolith interaction.
Purpose
High-density polyethylene (HDPE) panel stack inside habitat walls — high hydrogen content optimal for thermalising and absorbing secondary neutrons from GCR-regolith interaction.
Context
Child of L2-RAD-POLY within the Lunar Ark system
Principles
- ▸HDPE is ~14% hydrogen by mass — best per kg for neutron moderation
- ▸Inner 10-30 cm HDPE behind 2 m regolith optimises dose vs mass
- ▸Protons up to 200 MeV stopped in PE; higher-energy decelerated
- ▸Stable in vacuum (low outgassing) and radiation
- ▸Panel layout permits L1-MNT replacement
Typical implementations
- ▸NASA HDPE shielding studies (NTRS 20110012713)
- ▸ISS Heritage HDPE shielding around crew sleep quarters
- ▸Mars HabEx polyethylene shielding studies
Lunar considerations
- ▸At least 30-50% PE by mass needed in regolith mix for significant gain
- ▸HDPE light enough that Earth launch not prohibitive (~1 t for full Ark)
- ▸Long-life polymer (>50 yr proven in space)
Specifications
Functional
| primary function | High-density polyethylene (HDPE) panel stack inside habitat walls — high hydrogen content optimal for thermalising and absorbing secondary neutrons from GCR-regolith interaction. |
| thickness cm | 20 |
| density kg per m3 | 950 |
| h mass percent | 14 |
Physical
| mass kg | 2000 |
| materials | High-density polyethylene panels (UHMW-PE alternative), Aluminum mounting frames |
| vacuum compatibility | True |
Operational
| power consumption w | 0 |
| thermal range c | -40, 70 |
| lifetime years | 50 |
| mtbf hours | 1000000 |
Interfaces
Provides
- Internal neutron shielding
- Neutron-shielded cryo vault wall
Requires
- Mounting frames
- Panel replacement
Cite this entry
Lunar Ark Codex. "HDPE Polyethylene Shielding Panels" (L3-RAD-POLY-HDPE). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-RAD-POLY-HDPE
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.