First Factory Assembly (Bootstrap)

TL;DR

  • Critical checkpoint: Energy autonomy within 12-24 hours — after this, assembly time is NOT critical
  • Total time: 7-32 days (depending on conditions), but post-checkpoint constraint is only Gen-1 lifespan (2-3 years)
  • Gen-1 batteries: Li-S (not Li-Ion!) — operates down to -60°C
  • In-flight charging: Panels on lander module (~50 m²) charge robots during 3-4 month flight
  • Dome: Pre-assembled inflatable module from Earth (deployment in 4-8 hours)

Site Selection: Polar Crater

Critical: Bootstrap takes place at Mercury’s pole (Prokofiev crater, 85°N), NOT at the equator. This fundamentally changes the thermal regime.

Why the Pole, Not the Equator?

Parameter Mercury Equator Pole (Prokofiev crater)
Day temperature +430°C Peaks: ~+100°C (low sun angle)
Night temperature -180°C Crater floor: -150°C (permanent)
Day/night cycle 176 Earth days No cycle — eternal shadow + eternal light
Li-S compatibility (-60°C…+60°C) Impossible Yes (operation in shadow/terminator)

Crater Thermal Zones

A polar crater has three thermal zones:

  1. Peaks of eternal light (crater rims) — permanently lit (~+100°C), solar panels are placed here
  2. Terminator zone (slopes) — variable lighting (-50°C…+50°C), Gen-1 robot work zone
  3. Eternal shadow (crater floor) — permanent -150°C to -180°C, storage, cooling, water ice

Gen-1 operating mode: Robots operate in the terminator zone and on illuminated slopes. If overheating, they retreat to shadow for cooling. Li-S batteries (-60°C…+60°C) are fully compatible with this regime.

The 88-day “night” myth: This applies only to the equator. At the poles, “peaks of eternal light” are lit continuously (24/7/365). The 88-day night problem does not apply to the polar base.

Why This is a Unique Phase

Bootstrap is the only moment in the project when there are no local resources and nowhere to charge robots. After factory startup, standard production with self-replication begins.

Aspect Bootstrap Standard Production
Robots Gen-1 (Ti + Li-S) Gen-2 (Fe/Al + NaS)
Materials 100% imported 97% local
Dome Pre-assembled inflatable On-site assembly
Energy Limited by batteries Unlimited
Critical path Energy autonomy Throughput
Repair Spare parts limited Local manufacturing

Key insight: Until charging infrastructure is deployed, robots operate on batteries (15-24 hours). After checkpoint they can recharge → further assembly time is constrained only by Gen-1 lifespan (2-3 years).

Checkpoint: Energy Autonomy

Goal: Robots can recharge → further assembly time is not critical.

gantt
    title Critical Path to Checkpoint (12-24 h)
    dateFormat HH:mm
    axisFormat %H:%M

    section Phase A: Energy Autonomy
    A1. Unload energy modules      :a1, 00:00, 2h
    A2. Deploy solar panels        :a2, after a1, 4h
    A3. Lay power cables           :a3, after a2, 4h
    A4. Charging station           :a4, after a3, 2h

    section Checkpoint
    ENERGY AUTONOMY                :milestone, after a4, 0d

    section Phase B: Dome (parallel)
    B1. Level site                 :b1, 00:00, 8h
    B2. Deploy dome                :b2, after b1, 4h

Critical Path Calculation

Operation Robots Hours Parallel with Result
A1. Unload energy modules Crab-Z ×12 2 - Modules in position
A2. Deploy panels Spider-Z ×16 4 B1 5 MW available
A3. Lay cables Centaur-Z ×8 4 B1 Power system
A4. Charging station Centaur-Z ×4 2 B2 Checkpoint!
Critical path 12 h

With ×2 buffer: 24 hours to energy autonomy (margin for unexpected issues).

Note on parallelism: The diagram shows phases as “parallel”, but this is a simplification. In practice, B2.1 and C1.x start after A1.2 (dependency: “unloading complete”). After A1.2, all 12 Crab-Zs are free → B2.1 (4 units) + C1.1 (4 units) can run in parallel. Centaur-Zs (24 units) cover all parallel operations of phases A/B/C.

Why Time After Checkpoint is Not Critical

Factor Before checkpoint After checkpoint
Robot battery LIMIT (15-24 h) Rechargeable
Work shift LIMIT (one shift) 24/7
Robot breakdown CRITICAL Time for repair
Overall time CRITICAL Only Gen-1 lifespan

Gen-1 Robots: Specifications

Batteries: Li-S (Lithium-Sulfur)

Why Li-S instead of Li-Ion:

Parameter Li-Ion Li-S (2025-2026)
Specific energy 150-250 Wh/kg 400-500 Wh/kg
Temperature range -20°C…+60°C -60°C…+60°C
Capacity retention at -40°C 50-60% 85%
Mass (at equal capacity) 100% 60% (40% lighter)

Sources: NASA Li-S, Lyten ISS 2025, ESA Li-S

Gen-1 Specifications

Robot Mass Li-S Battery Capacity Power Autonomy Role
Spider-Z 120 kg 10 kg 4.5 kWh 300 W 15 h Panel, mirror mounting
Centaur-Z 250 kg 25 kg 11 kWh 500 W 22 h Assembly, docking
Crab-Z 950 kg 80 kg 36 kWh 1500 W 24 h Module logistics
Mole-Z 800 kg 70 kg 31 kWh 2000 W 15.5 h Site preparation

Calculation: Li-S specific energy 450 Wh/kg (conservative, theoretical limit 2500 Wh/kg)

Assembly Team Composition

Type Qty Unit Mass Total Role in bootstrap
Spider-Z 16 120 kg 1.9 t Panel mounting (critical path)
Crab-Z 12 950 kg 11.4 t Unloading and module logistics
Centaur-Z 24 250 kg 6.0 t Assembly and connections
Mole-Z 4 800 kg 3.2 t Site leveling
Total 56 22.5 t

On robot autonomy: Gen-1 robots perform routine operations (unloading, mounting, cable laying), not scientific research. This is closer to autonomous mining equipment (Rio Tinto/Caterpillar) than to Mars rovers.

Factory Equipment (Modular Delivery)

Module Mass Contents
Power Module 3.0 t Mirrors (2000 m²) + frame + GaAs cells + radiators
MRE Module 4.0 t Furnace + crucible + electrodes + MHD + frame
Dome Module 4.0 t Shell + airlock + ladle + internal radiators (components for on-site assembly; inflatable Bootstrap module 10-12 t — see below)
CCM Module 6.0 t Crystallizer + stand + roller table (on skids)
Rolling Module 10.0 t Mill (6 stands) + drawing + winding
Finishing Module 6.0 t WAAM + grinding + assembly jig + manipulators
Total Equipment ~35 t Modular pre-assembly

First Year Consumables

Category Mass Notes
MRE anodes (spare) 0.2 t
Oils, lubricants 0.1 t
β-Al₂O₃ electrolytes 0.3 t For first 50 batteries
Total consumables ~0.6 t

Vitamins (Electronics, Rare Elements)

Category Mass Notes
Control units (for new robots) 0.5 t For 100 robots
Sensors 0.2 t
Misc electronics 0.3 t
Rare earths (Nd, Sm for magnets) 0.1 t
Tungsten wire drawing dies 0.05 t For WAAM wire
Total vitamins ~1.15 t

First Expedition Manifest Summary

Category Mass
Assembly brigade (56 robots) 22.5 t
Repair kit 1.6 t
Factory equipment (modules) 35.0 t
Consumables (1 year) 0.6 t
Vitamins (electronics) 1.15 t
TOTAL first expedition ~61 t

In-flight Charging

Problem

Flight to Mercury takes 3-4 months. How do robots arrive charged if batteries last only 15-24 hours?

Solution: Panels on Lander Module

The lander module is equipped with deployable solar panels for charging robots in flight:

Parameter Value
Panels on module ~50 m² GaAs
Power (near Mercury) ~180 kW (GaAs 35%)
Total battery capacity (56 robots) ~890 kWh
Full charge time ~5 hours

Flight Mode

flowchart LR
    A["Launch<br/>100% charge"] --> B["Cruise phase<br/>3-4 months"]
    B --> C["Mercury approach<br/>panels at full power"]
    C --> D["Full charge<br/>before landing"]
    D --> E["Landing<br/>100% charge"]

    style A fill:#E8F5E9,stroke:#4CAF50
    style E fill:#E8F5E9,stroke:#4CAF50

  1. Launch: Robots charged to 100% (on Earth)
  2. Cruise phase (3-4 months): Panels deployed, trickle charge compensates self-discharge
  3. Li-S self-discharge: ~2-3%/month — minimal losses
  4. Before landing: Final full charge
  5. Landing: Robots at 100% charge, ready for bootstrap

Li-S batteries are optimal for long-term storage in space: low self-discharge (~2-3%/month) and resistance to temperature variations. Detailed comparison with Li-Ion and NaS — in Batteries section.

Pre-assembled Inflatable Dome

Inflatable module (10-12 t) deploys in 4-8 hours.

Analog: Bigelow Aerospace BEAM module on ISS (16 m³, 1.4 t) — operating successfully since 2016.

BEAM → Helios scaling: BEAM is a rigid module with full life-support (1 atm, 87 kg/m³). The Helios dome is a lightweight structure: shell only (no life support — no humans), multi-layer composite instead of metal, 0.1 atm. Under these conditions, specific mass of ~1.3-1.6 kg/m³ is realistic.

Deployment process:

  1. Unload module (Crab-Z ×4, 1 hour)
  2. Position on site (Centaur-Z ×6, 1 hour)
  3. Inflate with N₂ (imported; subsequent domes use local O₂) (automatic, 30 min)
  4. Connect airlock (Centaur-Z ×4, 1 hour)
  5. Leak check (30 min)
  6. Dome ready (4 hours)

Full Operations List

Phase A: Energy Autonomy (CRITICAL, 12 h)

# Operation Robots Hours Dependency Robot-hours
A1.1 Open cargo bay Centaur-Z ×2 0.5 - 1
A1.2 Unload energy modules Crab-Z ×12 1.5 A1.1 18
A1.3 Transport to installation site Crab-Z ×12 0.5 A1.2 6
A2.1 Deploy panel frame Spider-Z ×8 1 A1.3 8
A2.2 Install GaAs cells Spider-Z ×16 2 A2.1 32
A2.3 Connect sections Spider-Z ×8 1 A2.2 8
A3.1 Lay main cable (500 m) Centaur-Z ×4 2 A2.2 8
A3.2 Install distribution nodes Centaur-Z ×4 1 A3.1 4
A3.3 Connect to panels Centaur-Z ×4 1 A3.2 4
A4.1 Install charging station Centaur-Z ×4 1 A3.3 4
A4.2 Testing and calibration Centaur-Z ×2 1 A4.1 2
Phase A Total 12 h 95 robot-hours

CHECKPOINT: Energy autonomy achieved!

Phase B: Dome (parallel with A, 12 h)

# Operation Robots Hours Dependency Robot-hours
B1.1 Mark site (50×30 m) Centaur-Z ×2 1 - 2
B1.2 Remove top regolith layer Mole-Z ×4 3 B1.1 12
B1.3 Compact surface Mole-Z ×4 2 B1.2 8
B1.4 Create foundation supports Mole-Z ×4 2 B1.3 8
B2.1 Unload dome module Crab-Z ×4 1 A1.2 4
B2.2 Position on site Centaur-Z ×6 1 B1.4, B2.1 6
B2.3 Inflate with N₂ (0.1 atm, imported; subsequent domes use local O₂) Automatic 0.5 B2.2 0
B2.4 Connect airlock Centaur-Z ×4 1 B2.3 4
B2.5 Leak check Centaur-Z ×2 0.5 B2.4 1
Phase B Total 12 h 45 robot-hours

Phase C: Equipment Installation (24-48 h)

# Operation Robots Hours Dependency Robot-hours
C1.1 Unload MRE module Crab-Z ×4 1 A1.2 4
C1.2 Transport to dome Crab-Z ×4 0.5 C1.1 2
C1.3 Install MRE on foundation Crab-Z ×4 + Centaur-Z ×4 1 B2.5, C1.2 8
C1.4 Connect MRE power Centaur-Z ×4 1 C1.3 4
C1.5 Connect MRE cooling Centaur-Z ×4 1 C1.4 4
C2.1 Unload caster module Crab-Z ×4 1 A1.2 4
C2.2 Transport into dome Crab-Z ×4 1 C2.1, B2.5 4
C2.3 Install in position Crab-Z ×4 + Centaur-Z ×6 2 C2.2 20
C2.4 Level and secure Centaur-Z ×6 2 C2.3 12
C3.1 Unload rolling module Crab-Z ×6 1.5 A1.2 9
C3.2 Transport into dome Crab-Z ×6 1.5 C3.1, B2.5 9
C3.3 Install rolling mill Crab-Z ×4 + Centaur-Z ×6 3 C3.2 30
C3.4 Install wire drawing Centaur-Z ×4 2 C3.3 8
C4.1 Unload finishing module Crab-Z ×4 1 A1.2 4
C4.2 Transport into dome Crab-Z ×4 1 C4.1, B2.5 4
C4.3 Install WAAM Centaur-Z ×4 2 C4.2 8
C4.4 Install grinding cell Centaur-Z ×4 2 C4.3 8
C4.5 Install assembly jig Centaur-Z ×8 2 C4.4 16
C5.1 Lay internal cables Centaur-Z ×8 2 C1.3, C2.3 16
C5.2 Connect all modules Centaur-Z ×12 2 C5.1 24
Phase C Total ~28 h 198 robot-hours

Phase D: Commissioning (20-40 h)

Note on calibration time: The times shown are minimum under ideal conditions. After transport (3-4 months, vibrations, thermal cycling), actual calibration may take ×2-3 longer. This is accounted for in the 20-40 h range and does not affect checkpoint.

# Operation Robots Hours Dependency Robot-hours
D0.1 Mine regolith for MRE (~2 t) Mole-Z ×4 1 B1.4 4
D0.2 Transport regolith to MRE Crab-Z ×2 0.5 D0.1 1
D1.1 Calibrate MRE (temp, current) Centaur-Z ×4 4 C1.5, D0.2 16
D1.2 Test melt (100 kg Al) Centaur-Z ×2 2 D1.1 4
D2.1 Calibrate caster (speed, cooling) Centaur-Z ×4 3 C2.4 12
D2.2 Test casting (50 kg) Centaur-Z ×2 2 D2.1 4
D3.1 Calibrate rolling mill Centaur-Z ×4 3 C3.4 12
D3.2 Test rolling (billet → rod) Centaur-Z ×2 2 D3.1 4
D3.3 Calibrate wire drawing Centaur-Z ×2 2 D3.2 4
D3.4 Test drawing (rod → wire) Centaur-Z ×2 1 D3.3 2
D4.1 Calibrate WAAM Centaur-Z ×4 2 C4.3 8
D4.2 Test deposition (bracket) Centaur-Z ×2 2 D4.1 4
D4.3 Calibrate grinding Centaur-Z ×2 2 C4.4 4
D4.4 Test grinding Centaur-Z ×2 1 D4.3 2
D5.1 Integration test (full cycle) Centaur-Z ×8 4 D1.2, D2.2, D3.4, D4.4 32
D5.2 First production melt Centaur-Z ×4 4 D5.1 16
Phase D Total ~35.5 h 129 robot-hours

Phase E: First Gen-2 Robot (24-30 h)

# Operation Robots/Equipment Hours Dependency Robot-hours
E1.1 Melt Al for frame (300 kg) MRE (auto) 4 D5.2 0
E1.2 Melt Fe for tracks (560 kg) MRE (auto) 4 D5.2 0
E2.1 Cast billets (caster) Caster (auto) 6 E1.1, E1.2 0
E2.2 Roll frame profile Rolling (auto) 4 E2.1 0
E2.3 Draw wire for WAAM Drawing (auto) 2 E2.2 0
E3.1 WAAM: body and complex parts WAAM (auto) 4 E2.3 0
E3.2 Grinding: finish processing Centaur-M + abrasive (auto) 2 E3.1 0
E4.1 Assemble chassis Centaur-Z ×4 2 E3.2 8
E4.2 Install motors Centaur-Z ×2 1 E4.1 2
E4.3 Install NaS battery Centaur-Z ×2 1 E4.2 2
E4.4 Install electronics (vitamins) Centaur-Z ×2 1 E4.3 2
E5.1 Calibration and testing Centaur-Z ×2 2 E4.4 4
E5.2 First Gen-2 deployment — — E5.1 —
Phase E Total ~30 h 18 robot-hours

Summary: Total Time and Robot-Hours

Phase Description Hours Robot-hours Criticality
A Energy autonomy 12 95 CRITICAL
B Dome (12) 45 Parallel with A
C Equipment installation 28 198 After checkpoint
D Commissioning 35.5 129 After C
E First Gen-2 30 18 After D
Total ~106 h 485 robot-hours

Sequential time: ~106 hours = ~4.5 days (excluding nights, recharges, issues)

Note: Phase B runs in parallel with A (12 h ≤ 12 h critical path of A), so it’s not added to total time.

Three Scenarios

Scenario Before checkpoint After checkpoint Total Rationale
Optimistic 12 h 6 days 7 days Everything works perfectly
Realistic 24 h 10-15 days 11-16 days Typical delays, recharges
Pessimistic 48 h 20-30 days 22-32 days Equipment issues, breakdowns

Conclusion: After checkpoint (12-24 h) time is not critical — constrained only by Gen-1 robot lifespan (2-3 years). Even 30-day assembly keeps the project viable.

Bootstrap Phase Risks

Risk Impact Mitigation
Robot breakdown before checkpoint Critical 20% robot reserve, repair kit
Panel malfunction Critical Spare sections in manifest
Dome damage High Sealant repair kit, spare airlock
MRE module failure Medium Spare electrodes
Module incompatibility Low Earth pre-assembly, testing

Repair Kit (updated)

Component Qty Mass Note
Spare legs (Spider-Z) 32 160 kg 2 sets per robot
Spare tracks (Crab-Z) 48 300 kg 4 sets per robot
Li-S batteries (Gen-1) 15 750 kg Reserve (not NaS!)
Control units 8 80 kg Brains — critical
Sensors (cameras, lidars) 30 50 kg
Actuators (motors) 50 250 kg
MoS₂ lubricant — 15 kg
Repair kit total ~1.6 t

See Also