Troops in Space Empires IV are units which can either be placed on planets or carried as cargo. Their main purspose is to take over planets but there are many other uses for them. There are 3 tech levels of troops, each one granting a new size, Small (10kT), Medium (15kT), or Large (20kT). Because they are so small, troops carry miniaturized versions of components, much like fighters and mines. Weapons on a troop are not fired like in space battles, instead they are calculated into an equation that shows what happened. Troop weapon range is not useless, it is calculated into an algorithm to increase total damage result.
The primary function of troops is ground combat. To attack another planet in this way, load troops onto a transport and move the transport to the same sector as the planet. Then, the troop ship must be moved to a square adjacent to the planet.
You can do this manually in tactical combat. Just move the ship next to the planet and select "drop troops" from the menu. Note that in tactical combat it is also possible to use a planet as a troop transport! If you and your enemy own differnt worlds in the same sector (ie a planet and its moon) and the combat map puts them immediately adjacent to one-another, then you can issue the "drop troops" order to your planet!
Alternatively, allow the game to invade on your behalf in strategic combat. Set the ship's strategy to "drop troops" The "drop troops" strategy works just fine, but be aware that if the the troop transport is part of an armed fleet, it won't attempt to close on the planet until the rest of the fleet has wiped out any armed weapon platforms. (IE: when the planet cannot shoot back) Troop transports will make an attempt to drop their troops despite the weapon platforms if all of the allied warship have been destroyed.
Once troops are dropped, there is a series of turns (10 by default) in which you and the planetary defense (ie enemy troops already present on the planet) battle it out. When all of the enemy's forces have been destroyed, the planet is yours! Any population, facilities and units that survived combat are now controlled by you. Keep in mind that while you can conquer planets with troops, you can also place them on your own planet to reinforce against enemy invasions.
Troops dropped on your own planet not only defend against enemy troops, they also increase your planets happiness! Having a troop on your planet increases your happiness by a certain amount specified in happiness.txt (the default is -2 anger per turn). This ability stacks, so 100 troops on a planet will decrease anger by 200 every turn (happy no matter what, basically). Often this is abused in games where the player can do things that go against their happiness type and still keep everyone jubilant. Most of the time the troops will only have a cockpit so they can be constructed quickly. These 'Police' Troops can keep your population happy in all but the most horrible situations.
Troops are not the only planetary defenders. When you attack a planet, it will defend with militia. Although these militia are very weak compared to your troops, they are strong in numbers, so taking a homeworld with 4000M+ people can be difficult without many troops or advanced weapons. Oftentimes ships in orbit will soften the planet up for the troops, bombarding it until only a few population is left. This has the side-effect of reducing the amount of their race you will get, unfortunately.
| Manual (SEIV)