Unit attributes have changed in different eras in order to maintain game balance.
Defense units that fire from the planet's surface.
Defense units that orbit the planet at 5Mm. They form a contiguous circle and are not split into wings.
Single-use weapon used to attack enemy fleets. They are built by citadel planets and can be manually fired against enemy fleets. They will automatically fire against fleets invading planets within their 100 LY range. Jumpmissiles are the only way to damage fleets that are moving between planets.
Jumpships can move at high speed to any planet within 250LY of an owned jump_beacon|jump beacon. Explorers are an exception; they do not require jump beacons. The slowest jumpships are still 10x faster than the fastest starships or ramjets and over 200x faster than the slowest starships. The jumpfleet symbol is an isosceles triangle.
Explorers have high sensor ability, which makes them good at revealing unexplored space and detecting fleets. They do not require a jump beacon to move. They are faster than other jumpships and have higher delta V. Their weapons and armor are very weak and they have high attrition. Explorers do not require components to build.
These are just called “jumpships” by the game, which is kind of confusing. They are an inexpensive combat unit used to counter ships and planetary defenses that use missile attacks. They have point defense, which is very effective against missile-equipped units like jumpcruisers. They have weak armor and a weak, short-ranged direct attack.
Jumptransports are used to carry ground units and resources between planets. They have weak armor and will not fire their weapons (this is a bug). They can land on worlds and will be captured along with a planet. Transports carrying ground units are required to invade planets.
Jumpcruisers combine high damage with fast speed. They are ideal for waging blitzkrieg-style attacks against enemy planets within jump beacon range and for rapidly responding to enemy gunship attacks. They have medium armor and a medium-strength, medium-range missile attack.
Starships can move at low speed to any planet that is not inside or surrounded by nebula. Starships can't be built by worlds in nebula. The starship fleet symbol looks like a “T” on its side. They have lower attrition than jumpships.
Gunships are a good general-purpose attack unit. They are much faster and cheaper than the other two starship classes. They have high delta-v, medium armor, and medium-strength, medium-ranged direct attack. Gunships do not require components to build.
Starfrigates are much more expensive than gunships, but have lower attrition. They are extremely slow and are primarily used as a defensive unit to counter enemy jumpcruisers and starcruisers. They have a medium-strength, long-range directattack and medium armor, plus strong point defense.
Starcruisers are the most expensive units in the game. They have the same slow speed as starfrigates and primarily serve as a defense against gunships, but will also wreak havoc against most planetary defenses from beyond retaliation range if they are used offensively. They have a strong, long-range missile attack and ultra-strong armor.
Ramjets can move at low speed to any planet within a contiguous nebula. Ramjets must be built in nebula. The ramjet fleet symbol is an elongated hexagon. Ramjets are also called “ramships” and have the same unit roles as starships (gunship, starfrigate, and starcruiser).