Source Review: Lunarpedia "Mass Drivers"

Summary

Claim 1: 2.4 MJ/kg lunar mass driver energy (including 20% losses)

Quote: "2.4 MJ/kg" Verdict: Consistent Why: Used as the energy input in my calc. Confirms Handmer's 2026 figure tracks the canonical Lunarpedia number; the value has been stable across decades.

Claim 2: 45× energy advantage vs aluminum-O2 rocket

Quote: "rockets... require 45 times more energy" Verdict: Not relevant Why: Comparison is to aluminum-oxygen rocket, not to hydrolox or methalox. The multiplier shifts for other propellants. Not used as a calc input.

Claim 3: Track-length-vs-acceleration tradeoff

Quote: "Cargo at 200g acceleration: 0.5 km" / "Cargo at 20g acceleration: 10 km" / "Linear concept for 2g passenger acceleration: 100 km" Verdict: Consistent Why: Matches Handmer's 128 m at 1000 g (Lunarpedia's 0.5 km at 200 g extrapolates to ~125 m at 1000 g, exact agreement). Cross-validates the engineering envelope.

Claim 4: 200 kg circular design payload, 110 min orbital rendezvous cadence

Quote: "Circular mass driver payload: about 200 kilograms" Verdict: Consistent Why: Matches Handmer's 200 kg per shot. Convergence across two independent sources on this anchor.

Claim 5: Linear-launch projectiles cannot reach orbit without circularization

Quote: "any item launched at lower than escape velocity will return to the launch point following orbital mechanics and hit the surface." Verdict: Merits investigation Why: Architectural constraint that informs the calc — confirms that a mass driver alone cannot deliver to LEO; downstream propulsive maneuver (or downstream catcher) is required. This is the structural reason my $50/kg late-era figure includes a SEP transfer stage that Handmer's $10/kg figure does not.

Anti-hallucination check

All quotes verbatim from extract.md. No hallucinated content.

Lunarpedia — mass driver parameters

Community-maintained reference focused specifically on lunar applications.

energy-and-dimensions

• Energy per kg: "2.4 MJ/kg" for lunar mass driver launches (including 20% energy losses)
• Energy advantage vs chemical: "rockets... require 45 times more energy" for aluminum-oxygen propulsion (compares aluminum-O2 ISRU rocket to electromagnetic launcher)
• Linear track length for 2g passenger acceleration: "100 km"
• Cargo at 20g acceleration: "10 km"
• Cargo at 200g acceleration: "0.5 km"
• Circular design payload: "about 200 kilograms"

throughput

• First lunar driver concept: "10 kilogram loads launched once a minute or better"
• Circular track: "orbital rendezvous every 110 minutes"
• Power requirements for circular design: "43 kilowatts average power"

structural-constraint

"Any item launched at lower than escape velocity will return to the launch point following orbital mechanics and hit the surface."

This is the critical architectural constraint: a lunar mass driver alone cannot put payload into a stable orbit. Either (a) the driver achieves escape velocity (2.38 km/s for the Moon) plus a small downstream correction, or (b) the projectile uses an attached propulsion stage for circularization, or (c) a downstream catcher (e.g., at L2) collects the projectiles.

relevance-to-q2

The 2.4 MJ/kg energy figure is the canonical anchor. At $2.50/kWh assumed lunar power (Handmer 2026), this is 2.4 MJ × $2.50/kWh × (1/3.6 MJ/kWh) = $1.67/kg in raw electricity cost. The full delivered-to-LEO cost via mass driver is dominated by:

• Capital amortization of the driver track + reactor
• Propellant for circularization / LEO insertion
• Lunar-ops premium on everything

This source confirms the "energy is cheap, capital is expensive" framing.

limitations

• Community wiki — vintage of specific numbers unclear
• Does not provide an integrated cost-per-kg estimate to LEO
• The 45× energy advantage figure compares to a specific aluminum-O2 ISRU rocket, not to imported hydrolox; the multiplier is different for other propellants