The Galactic Empire constructed a collector-repulsor array at a hidden asteroid base during the Galactic Civil War. The array consisted of a large scanning bowl that focused the G-waves of hundreds of repulsors to create a field that was capable of affected the pressures of planetary crusts, resulting in violent groundquakes and volcanic activity. The array was small enough to be loaded onto a starship, and could be deployed into orbit. It lacked the power to destroy planets, but it could annihilate civilizations. The array was destroyed by a team of Alliance to Restore the Republic agents.