Antimatter & Metallic Hydrogen Fuel

Collective starships use antimatter to power their engines. Large quantities of quark matter are mined from "strange asteroids," containing quark nuggests in their core. This quark matter can be catalyzed into antimatter, but doing so is dangerous without the correct containment methods, which are difficult to maintain on their own. To counter this, Collective ships carry quantities of more stable quark matter as fuel, which is then catalyzed into antimatter and baryonic matter on the way to the exhaust nozzle, where the particles are thrown into each other to create thrust through matter-antimatter collision explosions.

Metallic hydrogen is an older form of fuel used by the Collective and now used by the Tyche Concord. Metallic hydrogen particles are produced when hydrogen gas is compressed to extremely high pressures. In its metallic form, it can become metastable at high pressures, and with a little more compression, completely stable at ordinary pressures. Flakes of metallic hydrogen are used as solid fuel for thrusters, particularly main thrusters of Concordian ships, as a backup fuel for Collective ships, and as fuel for reaction control thrusters of Collective ships.