The Regolith Castle
The earliest orbital structure that makes engineering sense is not a lightweight station
or a precision-built habitat, but a castle.
When construction must begin with minimal refinement, limited tooling, and high environmental
risk, the only viable approach is to build with mass, redundancy, and enclosure.
On Earth, this led to stone fortifications. In orbit, it leads to regolith castles.
This page describes the baseline, lowest-technology method for constructing
orbital depots once bulk mass can be launched from a planetary surface.
This approach describes a baseline construction primitive that functions
before refined materials, precision fabrication, or large prebuilt modules
are available.
→ View Concept Art & Visual References
Baseline Geometry: The Regolith Drum
The chosen baseline structure is a fully enclosed regolith drum, assembled
incrementally from repeated rings and filled discs. The geometry is rotationally symmetric,
single-radius, and tolerant of irregular material.
Bulk regolith is launched from the surface using EMU systems and delivered to orbit as
solid shot. Rather than requiring precision placement, this mass is
captured and shaped in orbit.
- thick rather than delicate,
- massive rather than lightweight,
- enclosed rather than exposed.
This immediately provides radiation shielding, micrometeoroid protection,
thermal inertia, and structural robustness.
Design choice: The drum geometry provides complete MMOD protection,
repeated construction steps, and two usable flat internal work planes.
Construction Method: Catch, Bundle, Assemble
Mass launched from the surface is captured in large nets deployed across
a defined intercept plane.
- Captured regolith is gathered by robotic systems.
- Material is bundled into netted mass cells.
- Cells are joined into rings and spanned into discs.
By repeating this process, fully enclosed orbital depots are built
incrementally, without precision machining or high-grade materials.
Why Nets?
Nets are the most effective early-stage orbital construction tool available.
- cheap,
- strong,
- flexible,
- extremely low mass.
A net can hold large quantities of regolith while adding very little mass of its own.
Thousands of nets can be launched with negligible mass penalty.
- capture incoming mass,
- bundle loose material,
- shape irregular aggregates,
- enable robotic handling without rigid containers.
From Surface Material to Scalable Orbital Infrastructure
An initial small depot is assembled first. Once operational, it begins processing regolith
locally: oxygen is extracted for propellant or storage, while remaining material is reused
as construction mass.
As a larger depot grows, the original depot is freed and can be relocated to seed new
infrastructure elsewhere. Each depot becomes a manufacturing seed.
Key idea: The same mass is used twice — first for oxygen extraction,
then as structural material.
Quick Build Summary (Lowest-Tech Path)
- Deploy compliant multi-layer capture wall.
- Robot-braced early captures.
- Low-relative-velocity regolith arrivals.
- Bag captured material into mass cells.
- Lace cells into chains.
- Form chains into rings.
- Span rings into filled discs.
- Stack rings between discs to form drum.
Key Construction Elements
| Element |
Implementation |
Function |
| Regolith shot |
Sintered pucks / rounded shot |
Bulk mass, shielding, inertia |
| Mass cells |
Lightweight nets |
Contain and modularize material |
| Rings |
Laced chains of mass cells |
Primary geometry |
| Filled discs |
Spanned membranes |
Flat work planes |
Refueling and Manufacturing Use
Refueling
- Propellants stored in lightweight tanks inside the drum.
- Imported manifolds provide standardized interfaces.
- Regolith structure provides shielding and thermal stability.
Manufacturing
- Interior discs act as tooling planes.
- Robotic operations dominate.
- Pressure modules are independent inserts.
Important: The regolith drum is not a pressure vessel.
Pressure boundaries are separate engineered modules.
Cost and Competitiveness
- Bulk mass is free at the source.
- Structure is tension-based.
- Single-radius geometry repeats.
- Failures are localized.
- Precision is bounded.
- Usable capability appears early.
Cost driver realism: The dominant cost is capture and handling automation,
not the nets or regolith.
Engineering Considerations
- Momentum transfer is expected and managed.
- Staged capture minimizes loads.
- Compartments prevent progressive failure.
- Patch sintering is a wear layer only.
- Attitude control via slow spin or small thrusters.
- All precision hardware is localized and replaceable.