The Alliance Combat System (abbreviated ACS) allows for friends and alliance members to temporarily combine their fleets to attack or defend a target that either might not have been able to attack or defend alone. An Alliance Depot is not required to attack or defend a planet. OGame currently only has this feature implemented in Universes 1 GR, 5 and 18+. All universes starting after 18 WILL have the ACS enabled. It has not been decided whether or not the remaining universes will have the ACS switched on at a later date. (The redesign universes (U42, Andromeda/U44/ Barym/U45 & Electra) all have ACS, except for the newly opened universe Fornax.)