Ground combat happens at the beginning of the turn, before movement, in the CargoDump stage of host processing. Ground combat happens whenever a ship unloads colonists onto a hostile planet.
Preconditions for Ground Combat:
- The ship must be in orbit of a hostile planet. If the planet is friendly, the unloaded colonists will become part of the existing colony. If the planet is unowned, it will be colonized peacefully.
- The ship must have fuel. Fuelless ships cannot use their cargo transporter.
- The ship may have any mission, including cloak.
In ground combat, attacking colonists will fight the planet's inhabitants. Depending on their strength, one party will survive. Whereas attackers have only their GroundKillFactor, defenders have GroundDefenseFactor as well as a bonus from their defense posts. See Ground Combat formulas for details. If all parameters are known, ground combat is 100% deterministic.
Effects of Ground Combat:
- Ground combat does not destroy planetary infrastructure. All defense posts and the starbase will remain intact.
- If the planet (and thus, the starbase) changes ownership, the base's build order will be canceled, hulls in storage will be recycled, and the base's fix/recycle order will be cleared.
- If the planet changes ownership, all its experience will be lost.
- Other planetary properties, such as tax rates, happiness, and friendly code, do not change.
Imperial Assault is a special case of ground combat.
