In Starpires will need a military to both defend your empire and attack other empires. Each type of military unit has different strengths and weaknesses so you will need an appropriate mix to defeat an opponent. Each turn there is an upkeep cost to maintain your military in optimal condition.

Troops - Basic ground forces. You will need them to both defend and capture planets during an attack and they require generals to lead them into battle.  Very ineffective at attacking space based military units such as cruisers, carriers and command ships.  They are also prone to deserting your military if your military moral becomes to low.

Weaknesses: Chemical strikes, low military moral

Upkeep: 5 credits + food

Generals - Command your troops and make them more effective fighting force. You will need 1 general per 50 troops to lead them on attacks. If you have too few generals your troops moral maybe effected. Generals have very little fighting capability themselves.

Upkeep: 50 credits + food

Fighters - Equally effective against almost all forces but are primarily an offensive weapon with very weak defensive capabilities.. You will need 1 carrier per 100 fighters to transport them on attack missions.

Weaknesses: Defense stations

Upkeep: 12 credits

Heavy Cruisers - Very effective at taking out defense stations.

Weaknesses: Command ships

Upkeep: 80 credits

Defense Station - Defense stations are only defensive and can not be sent out on attacks.  They are heavily armored and very effective against many types of military units. Your best bet for defending your empire.

Weaknesses: Heavy cruisers

Upkeep: 12 credits

Carriers

You need one for every 100 fighters to be able to take them into combat, but don’t have much firepower themselves.

Weaknesses: Heavy cruisers, command ships

Upkeep: 100 credits

Command Ships - This heavily armored capital ship is extremely effective at taking on heavy cruiser and other command ships. It has the added benefit of significantly increasing the effectiveness of heavy cruisers under it’s command. Has almost no ground attack capabilities and is vulnerable to fighters.

Weaknesses: Fighters

Upkeep: 400 credits

Covert Agents - Allow you to take covert actions against other empires. The more you have the higher the chance of success in both completing operations and countering operations against you.

Upkeep: 100 credits