Debris
Debris is what is left behind from ships that are destroyed in combat. Whenever a ship is lost in battle, 30% of the ore and crystal cost of that ship remain floating in orbit around the planet.
Debris can be harvested by Dionysus Class Recyclers using a harvest mission. Many attacks are intended solely for debris collection, as the resulting debris field of a large battle will often contain many times as much resources as the planet's plunder.
Debris can also result in the creation of a moon. A moon is a celestial body formed from the debris of a large fleet that has been destroyed. For every 150,000 debris left behind after a battle, there is a 1% chance that a moon will be created. The maximum chance that a moon can be created is 20% (3m debris).