Mole-M Assembly

TL;DR

  • Purpose: Excavator robot, regolith mining
  • Mass: ~1500 kg
  • Power: 10 kV cable (no battery)
  • Power consumption: 30 kW
  • Assembly time: 46 hours per station

Overview

Mole-M is a heavy Gen-2 excavator robot for regolith mining. The six-wheeled platform with a 1 m³ bucket can dig up to 100 tons of regolith per day. Powered by a 10 kV cable (no battery), as it always operates at the quarry near the power system.

Key feature: The heaviest Gen-2 robot (1500 kg), maximum steel content (83%) for durability.

Mole-M Material Balance

Component Material Mass Source
Frame + chassis + bucket Steel Fe-6%Mn 1240 kg Frame Manufacturing
Housing, radiators, sensor housings Aluminum 220 kg Aluminum
NaS Battery — 0 kg No battery (cable)
Actuators (6 wheels + 4 bucket) Fe + Al + NaK 65 kg Actuators
Electronics (chips) — 0.5 kg Earth import
TOTAL — ~1500 kg >99% local

Material distribution: - Iron (Fe): 1240 kg = 83% - Aluminum (Al): 220 kg = 15% - Actuators: 65 kg = 4% - Import (chips): 0.5 kg = <0.1%

Electronics 20 kg = chips 0.5 kg (import) + camera/lidar housings, cables ~19.5 kg (Al, local)

Design

Dimensions

Parameter Value
Length 5.0 m
Width 3.0 m
Height 2.5 m
Ground clearance 0.6 m
Bucket volume 1 m³ (2.5 t regolith)

Wheel Base

6 wheels: 3 per side, independent suspension.

Parameter Value
Wheel diameter Ø1.2 m (unified with Crab-M)
Wheel width 0.6 m
Material Al rim + Fe-6%Mn band
Ground pressure ~0.14 kg/cm²
Drive Electric motors 5 kW × 6 = 30 kW + cycloidal gearbox 1:20

Assembly Process

Assembly Station (10 positions, 46 hours per position)

Position Stage Time Robots
1 Frame installation on station 3 hours 3 Centaur-M
2 Chassis mounting (6 wheels) 6 hours 3 Centaur-M
3 Al housing and radiator installation 6 hours 3 Centaur-M
4 Bucket and hydraulics mounting 8 hours 4 Centaur-M
5 Actuator mounting (6 wheel drives + 4 bucket) 6 hours 3 Centaur-M
6 10 kV power cable routing 4 hours 2 Centaur-M
7 Electronics installation (processor, sensors) 4 hours 2 Centaur-M
8 NaK cooling loop fill 2 hours 1 Centaur-M
9 Sensor calibration and testing 6 hours Automated
10 Digging test (idle) 1 hour Mole-M itself
TOTAL 46 hours

Stage 1: Frame Installation

Mole-M frame: - Mass: ~1440 kg (1240 kg Fe + 200 kg Al) - Design: Massive steel frame with aluminum panels - Production: WAAM 3D printing

Process: 1. Crane lifts frame from conveyor (heavy, requires 2 t crane) 2. Frame is placed on assembly station 3. Secured on 6 supports (more than other robots) 4. Geometry check (laser scanner)

Stage 2: Chassis Mounting (6 Wheels)

6 wheels (unified with Crab-M):

Parameter Value
Wheel diameter Ø1.2 m
Wheel width 0.6 m
Wheel mass ~50 kg
Material Al rim + Fe-6%Mn band

Process: 1. Install 6 hub assemblies with suspension 2. Mount 5 kW electric motors with cycloidal gearboxes 1:20 3. Install wheels on hubs 4. Check free rotation

Time: 6 hours (unified procedure)

Stage 3: Housing and Radiator Installation

Aluminum housing: - Mass: 200 kg - Design: Protective panels against dust - Function: Electronics protection, cooling radiators

Radiators: - Area: ~15 m² (facing shadow) - Material: Aluminum - Circuit: NaK motor cooling (30 kW → 3 kW heat)

Process: 1. Side panel installation (bolts + rivets) 2. Radiator mounting on roof 3. Joint sealing (regolith dust protection)

Stage 4: Bucket and Hydraulics Mounting

Bucket: - Volume: 1 m³ - Mass: 200 kg (steel Fe-6%Mn) - Load capacity: 2.5 t regolith - Design: Reinforced edges for digging

Bucket hydraulics: - 4 hydraulic cylinders (NaK) - Force: 50 kN per cylinder = 200 kN total - Stroke: 1.5 m (bucket lift)

Process: 1. Bucket installation on frame (M30 bolts) 2. 4 hydraulic cylinder mounting 3. NaK tubing routing 4. NaK hydraulic circuit fill 5. Bucket lift test (no load)

Time: 8 hours (complex hydraulics)

Stage 5: Actuator Mounting

10 actuators: - 6 wheel drives (electric, 5 kW each + cycloidal gearbox 1:20) - 4 bucket hydraulic cylinders (50 kN each)

Process: 1. Connect wheel motors to power bus 2. Power cable routing to transformer 3. Bucket hydraulic cylinder mounting 4. NaK hydraulic circuit fill

Details: Actuators

Stage 6: 10 kV Power Cable Routing

10 kV cable (MI type): - Length: 50 m (cable reel) - Cross-section: 50 mm² Al - Insulation: MgO (mineral, all materials local) - Voltage: 10 kV (stepped down to 400 V by transformer) - Current: 3 A (at 30 kW load)

Why 50 mm² at only 3 A? The cross-section is determined by mechanical strength, not electrical requirements. A 50 m cable on a reel experiences repeated bending during winding/unwinding, abrasive wear from regolith contact, and tensile loads during dragging. Minimum cross-section for mechanical strength is ~35 mm²; 50 mm² selected with margin.

Cable reel: - Automatic winding during movement - Capacity: 50 m (Mole-M operating radius from source)

Process: 1. Cable reel installation on housing 2. 10 kV → 400 V transformer mounting 3. Cable routing to electric motors 4. Insulation check (10 kV — high voltage!)

Stage 7: Electronics Installation

Mole-M electronics: - Processor: ARM Cortex-A72 (4 cores, 1.5 GHz) - Sensors: 8 cameras, 4 lidars, GPS, IMU - Communication: Wi-Fi, 2.4 GHz radio - Mass: 20 kg

Process: 1. Computer installation in protected enclosure 2. Camera and lidar connection 3. Sensor calibration 4. Communication antenna installation

Stage 8: NaK Cooling Loop Fill

NaK circuit: - Volume: ~80 liters (more than other robots) - Temperature: +50-100°C (operating) - Radiators: 15 m² Al panels

Process: 1. Circuit evacuation (air removal) 2. NaK fill through fill valve 3. Seal check (vacuum test) 4. NaK pump startup

Stage 9: Sensor Calibration and Testing

Test program:

Test Description Specification
Wheel movement 6 wheel check Speed 5 km/h
Bucket lift Hydraulics test (no load) Height 2 m
Idle digging Air digging test Smooth movement
Cooling Radiator test at 30 kW load T <+100°C
Autonomy Autopilot, programmed digging 100% success

Duration: 6 hours

Stage 10: Digging Test

First digging test: - Location: Test area with regolith - Volume: 10 m³ regolith (10 buckets) - Goal: Bucket and hydraulics verification

Process: 1. Mole-M drives to test area 2. Digs 10 buckets of regolith (2.5 t each) 3. Dumps regolith in pile 4. Returns to station

Time: 1 hour

Power Consumption

Mode Power Energy
Movement 10 kW —
Digging 30 kW —
Idle 1 kW —

Daily consumption: - 8 hours digging × 30 kW = 240 kWh/day - 2 hours movement × 10 kW = 20 kWh/day - 14 hours idle × 1 kW = 14 kWh/day - TOTAL: ~280 kWh/day per 1 Mole-M

Cable connection: - 10 kV cable from nearest substation - Operating radius: 50 m (cable length) - Mobility: cable relocation every 50 m

Maintenance

Operation Frequency Performer
MoS₂ wheel bearing recoating 3 months Magnetron station + Centaur-M
Bucket teeth replacement 1 month Centaur-M (welding)
Wheel replacement 1 year Centaur-M
Hydraulics replacement As needed Assembly station

Service life: - Frame: 10-15 years - Wheels: 1-2 years (band wear from regolith) - Bucket: 1-2 years (edge wear) - Hydraulics: 3-5 years - Electronics: 5-10 years - Robot overall: 5-10 years (with wheel and bucket replacement)

Applications

Mole-M main tasks:

Task Description % time
Regolith digging 100 t/day (40 buckets × 2.5 t) 80%
Site leveling Construction preparation 10%
Trench digging For cables, pipelines 5%
Backfilling Trench backfill 5%

Productivity: - 1 Mole-M: 100 t regolith/day - 6 Mole-M at quarry: 600 t regolith/day

Regolith Quarry

Typical quarry:

Parameter Value
Area 100×100 m
Depth 3-5 m
Productivity 600 t/day (6 Moles-M)
Dump 50 m from quarry
Transport 20 Crabs-M (to factory)

Quarry coverage: The 50 m cable covers a sector of ~80×60 m. A mobile substation is relocated by Crab-M as each sector is depleted. A 100×100 m quarry is processed in 2-3 stages with substation relocation.

Process: 1. Mole-M digs regolith (1 m³ bucket) 2. Dumps into Crab-M bed 3. Crab-M transports regolith to factory (5 t per trip) 4. Cycle repeats

Wear and Spare Parts

Critical components:

Component Service life Stock per 1 complex
Wheels (band) 1-2 years 36 pcs (6 Moles × 6 wheels)
Bucket teeth 1 month 120 pcs (10 buckets)
Hydraulic cylinders 3 years 24 pcs (6 Moles)

Spare parts production: - Wheels: WAAM 3D printing of rim (Al) + band (Fe-6%Mn) - Bucket teeth: Casting + heat treatment - Hydraulic cylinders: Turning

See Also