Source Review: Wikipedia "Mass driver"

Summary

Claim 1: 50-90% conversion efficiency for superconducting coils

Quote: "50% to 90+%, depending on design" Verdict: Consistent Why: Matches Handmer's 90% efficiency assumption. Calc uses 2.4 MJ/kg input which is consistent with 1.6 MJ/kg kinetic at 67% efficiency, well within the published envelope.

Claim 2: 10.5 km/s theoretical envelope at 5,600 g

Quote: "A 1 km long mass driver made of superconducting coils can accelerate a 20 kg vehicle to 10.5 km/s at a conversion efficiency of 80%" Verdict: Novel supporting Why: Demonstrates that Handmer's 1.6 km/s design is conservative compared to the physics envelope. Confirms that 200 kg per shot at moderate velocity is engineering-feasible. Not a calc input but a feasibility check.

Claim 3: $47M for 10 kg projectile to 6000 m/s

Quote: "A mass driver firing a 10 kilogram projectile at 6000 m/s would cost $47 million" Verdict: Not relevant Why: This is a one-off / research-scale figure, not an industrial throughput cost. Marked as loosely sourced in the extract.

Claim 4: <$1/kg electrical energy to LEO

Quote: "under $1 of electrical energy cost per kilogram shipped to LEO" Verdict: Consistent Why: Matches my mass-driver energy line ($0.33-3.33/kg across eras). The point that "total costs would substantially exceed electricity alone" matches my finding that the binding constraint is capital amortization (early era) and SEP transfer (mid-late era), not energy.

Anti-hallucination check

All quotes appear in extract.md. The $47M figure is flagged as "lacks proper citation verification" in the extract — that uncertainty is carried forward.

Mass driver — physics envelope

Reference for mass-driver physics, efficiency assumptions, and historical economic estimates.

physics-and-efficiency

• Superconducting coil efficiency: "50% to 90+%, depending on design"
• Demonstrated lab acceleration: O'Neill's 1976-1977 prototype reached 40 m/s at 33 g with a $2,000 budget; subsequent prototypes pushed to "an order-of-magnitude greater acceleration"
• Theoretical envelope: "A 1 km long mass driver made of superconducting coils can accelerate a 20 kg vehicle to 10.5 km/s at a conversion efficiency of 80%" with average acceleration of 5,600 g

cost-figures-historical

• University of Texas estimate (cited, sourcing weak): "a mass driver firing a 10 kilogram projectile at 6000 m/s would cost $47 million"
• Electrical-energy-only cost to LEO: "under $1 of electrical energy cost per kilogram shipped to LEO" — but the article emphasizes total costs would substantially exceed electricity alone (capital amortization dominates)

relevance-to-q2

The Wikipedia article confirms two things:

1. The physics envelope for a lunar mass driver is well within demonstrated lab regimes (Handmer 2026's 1.6 km/s, 1000 g is conservative compared to the 10.5 km/s / 5600 g theoretical envelope).
2. The economic case is heavily dominated by capital cost and amortization, not energy cost. This matches Handmer's $10/kg assumed-price framing — that price reflects capital amortization + lunar-ops premium, not power.

limitations

• General physics reference, not a recent cost analysis
• The $47M / $1-per-kg figures are loosely sourced
• No direct lunar-surface-to-LEO modeling