When a colony is attacked the colonists will try to defend themselves as Civil Defense batteries. Civil Defense batteries are weak, but mean that even otherwise undefended colonies will provide at least a token of resistance to invaders. These weapons are created by the colonists themselves at the start of every battle; you cannot build or improve on them and enemies cannot wear them down by attrition.

Civil Defense will not protect a colony against a strong attack, additional Ground Defense and defensive fleets should be built to ward off enemies.

The number of civil defense batteries at a colony is affected by:

• Population
  
• Military Index

The damage of the batteries is affected by:

• The logarithm of the population

The firerate of the batteries is affected by:

• Military Index

The mass of the batteries is affected by:

• Military Index

Note: If fratricide protection is active, then the number of batteries and their mass, damage, and fire rate will increase.