Carbon Extraction (Optional)

Carbon Extraction (Optional Module)

Status: Optional extension. The base factory operates WITHOUT carbon.

Why Carbon?

Application Consumption Priority
Carbon anodes for MRE ~10 kg/day High (replaces expensive iridium)
Graphite lubricants ~1 kg/day Medium
Alloyed steel 1-1.4% C Low (Fe-6%Mn is sufficient)

Conclusion: The main application is replacing iridium anodes with carbon ones. This reduces import dependency.

Carbon Source

LRM (Low Reflectance Material) — dark zones on Mercury’s surface. This is ancient graphite crust formed 4.6 billion years ago when the magma ocean cooled.

Parameter Value
Carbon content in LRM 1-3% (MESSENGER, Peplowski et al. 2016)
Origin Graphite floated to the surface of the magma ocean
Form Crystalline graphite (not amorphous carbon)
Sublimation temperature 3640°C (does not melt during MRE)

Extraction Process

During MRE electrolysis of LRM-enriched regolith, graphite does not melt (T_sublimation = 3640°C > T_melt = 1500°C). Graphite particles float to the melt surface as foam and are skimmed off along with slag.

Stage Description
Mining Robots collect regolith from LRM zones (dark areas)
Smelting MRE at 1500°C — graphite does not dissolve
Flotation Graphite (ρ=2.2 g/cm³) floats to the surface
Collection Skimmer removes graphite foam
Purification Thermal sublimation of impurities

Yield: Processing 200 t LRM-regolith/day (~2-3% C): 4-6 t graphite/day.

Source: Peplowski, P.N. et al. (2016). “Evidence for geochemically distinct regions on Mercury.” Nature Geoscience. Johns Hopkins APL

“Carbon” Complexes: Mini-Factories for Graphite Extraction

Problem: LRM zones (with graphite) are located at equatorial latitudes, while main factories are at the poles.

Crater Latitude Distance to pole Carbon content
Rachmaninoff 27°N ~2800 km up to 4%
Tolstoj 16°S ~5800 km 2-3%

There is NO graphite at the poles — only regular regolith + water ice.

Carbon Complexes are complete mini-factories, not just “collection stations”. They:

  1. Mine and process LRM-regolith
  2. Extract graphite (main product → to pole)
  3. Extract Al, Fe, Si (for their own needs)
  4. Build their own mini mass driver for graphite delivery

Architecture: Two Complexes

Night at the equator lasts ~88 Earth days. A single complex would be idle half the time.

Solution: Two complexes on opposite hemispheres. When one has night — the other works.

        NORTH POLE (factory "Point Zero")
                    ●
                   /|\
    [MD-graphite] ←─────── Carbon-North (Rachmaninoff, 27°N)
                   │
    [MD-graphite] ←─────── Carbon-South (Tolstoj, 16°S)
                   \|/
                    ●
        SOUTH POLE
Complex Location Crater diameter Distance to pole
Carbon-North Rachmaninoff, 27°N, 58°E 305 km ~2800 km
Carbon-South Tolstoj, 16°S, 163°W 390 km ~5800 km

Technological Process at the Complex

LRM-regolith (200 t/day) → Crushing → MRE-smelting (1500°C)
                                            ↓
                          ┌─────────────────┼─────────────────┐
                          ↓                 ↓                 ↓
                     GRAPHITE            HEAVY              SLAG
                   (floats)           (Fe, sinks)        (Al, Mg, Si)
                          ↓                 ↓                 ↓
                     Skimmer           MHD-pump         Distillation
                          ↓                 ↓                 ↓
                     Packaging          Casting          Separate
                     → MD               → rails           metals

Material output (200 t LRM-regolith/day):

LRM-regolith contains the same elements as regular regolith, plus 2-3% graphite:

Element In LRM-regolith Output (200 t/day) Purpose
Graphite (C) 2-3% 4-6 t/day → pole (MD)
Aluminum (Al) ~7% ~14 t/day MD rails, windings
Iron (Fe) ~2% ~4 t/day MD tunnel frame
Silicon (Si) ~25% ~50 t/day Slag (not used)

Summary: Carbon Complex vs Main Factory

Parameter Main factory Carbon Complex
Regolith/day 600 t 200 t
Main product Mirrors Graphite
By-products All metals → industry Al, Fe for itself
Mass driver 3 km, 1300 t 500 m - 1 km, ~330 t
Robots ~60 ~10
Power ~165 MW ~5 MW
Bootstrap from Earth 62 t ~10 t

Mini Mass Drivers

Purpose

Graphite delivery from equatorial LRM zones to polar factories. Each Carbon Complex builds its own mini mass driver from local materials.

Comparison with Main MD

Parameter Main MD (pole) Mini MD (Carbon)
Purpose Launch mirrors to orbit Deliver graphite to pole
Distance To orbit (infinity) 2800-5800 km
Target velocity 5 km/s 2-3 km/s
Length 1 km 500 m - 1 km
Mass ~450 t ~330 t
Acceleration 1275g 20-25g
Payload/launch 116 kg (mirror) 100 kg (graphite container)
Energy/launch 3.6 GJ 0.5-1 GJ

Why Lower Velocity?

For ballistic flight within the planet, orbital velocity is not needed. It’s enough to reach the parabola apex and fall to the receiver.

Flight time ≈ 2 × √(2h/g)

For h = 300 km (apogee):
t ≈ 2 × √(600000 / 3.7) ≈ 800 sec ≈ 13 min

With horizontal component: 20-30 min flight

Mini Mass Driver

Components: frame (steel ~200 t), rails + windings (Al ~130 t), electronics (~2 t import)

Mini MD Construction

The Carbon Complex produces materials and builds the mini MD itself.

Accumulation rate (200 t LRM-regolith/day):

Material Output/day Needed for MD Days to accumulate
Aluminum ~14 t ~130 t ~10 days
Iron ~4 t ~200 t ~50 days

Construction stages:

Stage Duration Robots
Material accumulation ~30 days —
Trench digging (1 km) ~30 days 3 Mole-M
Frame installation ~15 days 3 Centaur-M
Rails and coils mounting ~15 days 3 Centaur-M
TOTAL ~3 months

Power Consumption

Parameter Value
Kinetic energy (100 kg, 2.5 km/s) ~0.31 GJ
At 40% efficiency (electricity cost) ~0.8 GJ
At 50 launches/day ~40 GJ/day
Average power ~0.5 MW

Calculation: E = mv²/2 = 100 kg × (2500 m/s)² / 2 = 312.5 MJ ≈ 0.31 GJ. With 40% efficiency: 0.31/0.4 ≈ 0.8 GJ per launch.

Graphite Delivery to Pole

Delivery Parameters

Parameter Carbon-North Carbon-South
Distance ~2800 km ~5800 km
Launch velocity ~2 km/s ~3 km/s
MD length ~500 m ~1 km
Flight time ~20 min ~30 min
Payload/launch ~100 kg ~100 kg
Launches/day ~50 ~50
Graphite output 4-6 t/day 4-6 t/day

Receiver at Pole

Component Description
Catch net Diameter ~500 m, cable-net
Dampers Impact absorption (containers arrive at ~100 m/s velocity)
Crab-M 2 robots collect containers
Buffer Container storage before processing

Operating Schedule

Mercury solar day (176 Earth days):

Complexes are positioned with ~140° longitude offset (Rachmaninoff 58°E, Tolstoj 163°W).
Their day/night cycles are shifted by approximately 68 Earth days.

Approximate schedule:
- Day 1-88:   Carbon-North operates (day), Carbon-South in twilight/night
- Day 68-156: Carbon-South operates (day), Carbon-North in twilight/night

Periods overlap → at least one complex is always active.

Total: Shift operation ensures continuous supply of ~5 t graphite/day (from active complex).

Carbon Complex Deployment

Phase 1: Bootstrap (first 6 months)

Carbon Complex:

Bootstrap from Earth (~10 t):

  • Robots: 3 Mole-M, 3 Centaur-M, 2 Crab-M (~5 t)
  • Mini MRE furnace (~2 t)
  • Solar mirrors (~1 t)
  • MD electronics (~2 t)

Deployment stages:

Month Activity
1-2 MRE furnace assembly, start LRM-regolith mining
3-4 Material accumulation for mini MD
5-6 Mini MD construction
7+ Operation — graphite delivery to pole

Phase 2: Operation

After mini MD launch: - Graphite is sent to the pole (4-6 t/day from active complex) - Two complexes in shifts provide ~5 t/day continuously

When to Build Carbon Complexes?

Condition Decision
Iridium anodes wearing out Build Carbon for carbon anodes
Need alloyed steel Add carbon to Fe-6%Mn
Base factory operating Not needed — continue without carbon

Conclusion: Carbon Complexes are an optional extension. The base factory is fully functional without them.

Sources