Mass Driver Testing

TL;DR

  • Purpose: Verify Mass Driver functionality before operation
  • Duration: 1-2 weeks
  • Stages: Geometry -> Electrical -> Cooling -> Test Launches
  • Criterion: 10 successful launches in a row -> Mass Driver ready

Overview

Mass Driver testing is the final stage before commissioning. Goal: ensure all systems work correctly and the Mass Driver can safely launch mirrors.

Testing Program

Full Sequence

Stage Duration Description
1. Geometric Control 2 days Track straightness verification
2. Electrical Tests 2 days Circuit and insulation testing
3. Cooling Tests 1 day NaK circuit check, temperature
4. Dry Runs 2 days Empty container acceleration (no mirror)
5. Live Launches (test) 3 days Mirror launches (real mass and dimensions)
6. Continuous Mode 2 days 100 launches in 24 hours
7. Acceptance and Certification 1 day Documentation
TOTAL ~2 weeks

Stage 1: Geometric Control

Straightness Verification

Parameter Control Method Tolerance Action on Deviation
Horizontal straightness Laser level +/-5 mm per 100 m Support adjustment
Vertical straightness Theodolite +/-5 mm per 100 m Support adjustment
Rail parallelism Laser gauge +/-1 mm Fastener tightening
Coil perpendicularity Goniometer +/-0.1 deg Correction

Instruments: - Laser level (accuracy +/-1 mm per 100 m) - Theodolite (accuracy 1”) - Laser rangefinder (accuracy +/-0.1 mm)

Personnel: 5 Centaurs-M + automation

Stage 2: Electrical Tests

Circuit Verification

Test Equipment Tolerance Goal
Coil resistance Ohmmeter <0.1 Ohm per coil No breaks
Coil insulation Megohmmeter >10 MOhm No breakdowns
Coil inductance LCR meter Within +/-5% Uniformity
Sequential switching Oscilloscope Delay <1 us Synchronization

Power Electronics Verification

Test Description
MOSFET switches On/off test 1000 times
Capacitors Charge to 1000 V, hold 1 hour, discharge
Sensors Calibration of all 2,150 sensors
Communication Fiber optic check, delay <1 ms

Personnel: Automation + 2 Centaurs-M (supervision)

Stage 3: Cooling Tests

NaK Circuit Verification

Parameter Control Tolerance Action
NaK temperature Thermocouples -150 deg C +/- 10 deg C Flow rate adjustment
NaK flow rate Flow meter 100 L/min Pump check
Circuit pressure Manometer 2-3 atm Leak check
Coil temperature Thermocouples <-140 deg C Contact improvement

Radiator Test

Parameter Control Tolerance
Radiator temperature IR camera -170 deg C to -180 deg C
Heat dissipation Thermal imager Uniform distribution

Duration: 24 hours of continuous cooling operation

Personnel: Automation + 1 Centaur-M (inspection)

Stage 4: Dry Runs

Test Parameters

Parameter Value
Projectile Empty container (no mirror)
Projectile mass 10 kg (lighter than nominal 116 kg)
Target velocity 1.5 km/s (30% of nominal 5 km/s)
Number of shots 10

Goal: Verify system operation without risking a valuable mirror.

Controlled Parameters

Parameter Control Tolerance
Acceleration Accelerometers in projectile 115g +/- 10g
Exit velocity Laser Doppler 1.5 +/- 0.1 km/s
Coil sequence Oscilloscope Synchronization
Coil temperature Thermocouples <-130 deg C
Frame vibrations Accelerometers <1g

Personnel: Automation + 5 Centaurs-M (observation)

Stage 5: Live Launches (test)

Test Parameters

Parameter Value
Projectile Real mirror 100x100 m
Projectile mass 116 kg (nominal)
Target velocity 5 km/s (nominal)
Number of shots 20

Goal: Verify Mass Driver operation in nominal mode.

Additional Checks

Test Method Success Criterion
Mirror deployment Telescope + cameras Mirror fully deployed
Trajectory Radar + optics Orbit within +/-10 km
Orientation Telemetry Mirror oriented toward Sun
Light reflection Photometer Brightness matches calculated

Personnel: Automation + 10 Centaurs-M (mirror feed)

Stage 6: Continuous Mode

Test Parameters

Parameter Value
Duration 24 hours
Launches 100 (every ~15 min)*
Mode Nominal (116 kg, 5 km/s)

*Reduced test rate. Nominal operational rate: 600 launches/day (every 2.4 min).

Goal: Verify Mass Driver reliability during extended operation.

Controlled Parameters

Parameter Control Success Criterion
Launch success rate Statistics >95% (no more than 5 failures)
Rail wear Visual inspection Wear marks <0.1 mm
Cooling stability Thermocouples T = -150 deg C +/- 10 deg C
Energy consumption Meter 4.7 GJ +/- 0.3 GJ per shot

Personnel: Automation + 20 Crabs-M (mirror logistics)

Stage 7: Acceptance and Certification

Documentation

Document Contents
Test protocol All test results
Mass Driver passport Technical specifications
Operating manual Operating modes, maintenance
Defect log Identified problems and their resolution

Readiness Criteria

Criterion Tolerance
Track geometry Deviations within tolerances
Electrical All circuits operational
Cooling Stable temperature -150 deg C
Dry runs 10/10 successful
Live launches 18/20 successful (>90%)
Continuous mode 95/100 successful (>95%)

Acceptance: Signing of commissioning certificate.

Typical Problems and Solutions

Problem Cause Solution
Projectile stuck at 1 km Coil overheating Improve cooling
Velocity below calculated Poor synchronization Delay calibration
Frame vibrations Resonance Dampers on supports
Insulation breakdown Electric arc Coil replacement

Testing Energy Consumption

Stage Shots Energy TOTAL
Dry runs 10 0.04 GJ x 10 0.4 GJ
Live launches 20 4.7 GJ x 20 94 GJ
Continuous mode 100 4.7 GJ x 100 470 GJ
TOTAL 130 ~564 GJ

In power: 564 GJ / (14 days x 86400 sec) = ~0.47 MW average power for testing.

See Also