steam, Tudoreleuu told me stuff
Lunar Republic's secret projects were:
1. To drill a shaft to the lunar core.
2. To engineer a basic energy shield technology.
They then applied the shield technology to one of their colonial ships, and placed it above the shaft. When the drill reached the core, it destabilized it. A massive volcano-like erruption took place, propulsing the ship at very high speeds away from the moon. Asteroids start to rain down onto the earth.

The LR lunar colony is destroyed in the process.