Battle fleet: costs 29
6 HP, fast attack. (we'll call this attack speed 10)
Extremely resource and shipyard efficient. It would cost far more resource and far more time to generate this much HP and attackspeed out of the other fleets. Plus at 6HP it's much easier to repair them and keep veterancy.

Battle station: costs 53
15 HP, 3-4x the attack speed of the battle fleet (35+ attack speed). Can't move. HP restored to full at the end of combat.
Even more resource efficient than the battlefleet, but not being able to move is a big downside. Useful if there are transports going through that planet to kill the enemies quickly, ending the battle and restoring the trade route, but otherwise these can probably get bypassed and end up becoming worthless.

Invasion Fleet costs 20
3 HP, slow attack. (~3 attack speed)
3 Ground HP also.
Can invade planets -- you have to press the button for this manually once the fleet arrives (Hotkey Q). All consequences from ground combat affect space combat; If they take damage from ground combat this will affect their space strength too, if they rank up from destroying ground armies, the fleet will get ranks too.

Defense army costs 15
3 Ground HP. Otherwise the same as a landed Invasion army, but cheaper. It's much harder to give these troops veterancy. You don't need these to control a planet, especially not if the enemy isn't actually invading.

Siege Fleet costs 43
2 HP, medium attack (about 4 attack speed)
Can bombard the planet to eventually make it a Red No Man's Planet (about 6 shots?) that can't be owned.
Their main advantage is that they don't take damage from the surface when they invade (and fleets in combat don't take attrition either), so you can just keep killing planets without repairing if that's what you really need to do.

Kinetic Shields costs 43
20 HP, prevents all other friendlies from taking damage. No attack!!
Can't move. HP restored to full at the end of combat. Can be built alongside the Battle Station (ie yes, they combine). Note they count as a fleet for space combat that will block enemy fleets from arriving.
Somewhat useful for parking your Invasion Fleets so they don't take damage, but lets these fragile fleets fire back at attackers. Also useful at frontline repairyards so your repairing ships don't just get sniped into combat as they arrive for repairs.

Transport Fleet n/a cost
Automatically deploys between resource planets (asteroid or shield-like crystal/rock shape on planets on the map) and towards planets where production is ongoing. Obviously this means these planets are priority invasion targets.

Building fleets and infrastructure on planets takes resources. Any planet can make infrastructure but only shipyards with the cog icon can build fleets.

Resources take some time to extract before the Transport fleet is sent, so there is a slight delay between building and starting. They can path through white planets but they seem to prefer blue ones (remember, warping through blue-to-blue planets with the blue lanes is faster) and may even have range/time flight restrictions (visible on the campaign mission with the whole pocket of mines in the corner).

Transport fleets can be "destroyed". As a general rule, if an enemy fleet is in the area they will be killed. The transport flashes red if it approaches a planet in the middle of combat (red circle background), including the "wrapping up phase" at the end, that still counts as a planet in combat. Gets "destroyed" if it actually hits the planet during combat, counting the enemy fleet as still existing until combat finishes. (Obviously, you can use this to your advantage by blockading the enemy resource planets or trade routes. Technical sidenote: it is not clear yet whether parking a fleet over a resource planet counts as "killing" the transports or whether they just don't spawn at all, I haven't tested this. Either way, parking a fleet ontop of a resource mine will stop resources going out.)
If the build target is invalid or cancelled they will automatically attempt to redeploy to a current production project.

A construction project will first fill up with resources (orange bar) and then complete it. Shipyards seem to only need about 2 resource planets to get going, so you'll eventually need multiple shipyards to spend all your resources/ore.

Whenever any enemy fleets are at the same planet as a friendly group of fleets, space combat starts. Whenever the player clicks the invade or destroy (I may call this bombardment) buttons, combat will start too. You can join combat mid-fight with other fleets in the same ways. The new units will simply start their firing timers late once they arrive.

When combat starts each army or ship will "wind up," shown in the little bar beneath its icon, and then shoot 1dmg at a random enemy target. You can't choose the targets or their priority.

Veterancy means they will shoot faster (shown by the shortened yellow padding on the left side of the firing bar). This also means they shoot first which is great. You get veterancy from kills (any of fleet kills, invasion kills or city kills will do) and you can rank up to 5 (yellow square with star); the ranks are chevrons 1-3, star, square with star.

All fleets can retreat jump away from combat, but you can't fire while escaping and this takes 12s (about the length of a siege fleet shot) so you might get blown up before it goes through. The whole group has to retreat, individual fleets can't be chosen to retreat.
Fleets cannot fight within transport lanes, or cancel transport once they start moving, so be careful before moving them. Because you can't fight while moving, if you need to intercept something, leave a fleet at the target planet, at least something like 1-2 ships to start a fight and lock them down, don't try and use your whole group to chase them around too much.
However for invasions and bombardments, there is definitely a defender's advantage, as ground invasions get cancelled if they get engaged in space combat. If the intercepting fleet is one jump away, you might have about 2 rounds of ground combat to deal damage and kill enemy armies before you will get kicked back out to space combat. When attacking beware that this seems to completely reset the fight, so also be careful (this is where the instant kill technique is useful)

If you can instantly kill the unit in one shot you will have minimal losses and in the fastest time possible.

A planetary army has 3 HP, so bringing 3 invader transports will oneshot it. The fleets/armies still need to wind up first but combat will end as soon as the first round fires and ends.

Once you have a veterancy advantage over the AI, your army will shoot first and their defending ground armies can't even shoot back. If damage would be dealt simultaneously, but the enemy army dies first then they can't shoot back.

The same applies to multiple defending armies (2x3HP), or enemy fighter fleets, 6 HP. Outnumbering them 6:2 armies or 6:1 fighters will oneshot them, but this is obviously much harder. You don't have to oneshot fighters because your own fighters are pretty tanky and can take 6 shots back, but this will still let you estimate how long a fight will take. For example fighting a battle station, it's advantageous to get factors of 15HP against it to try and get a kill time advantage.

• 4 fighters will kill a station in 4 rounds (of fighter firing)
  
• 5 fighters will kill it in 3 rounds
  
• but 6 fighters doesn't necessarily kill it faster (15/6 = 2.5, rounding up to 3 rounds) unless there are stray fleets around to soak up the rest of the damage.

6 March: You can use siege fleets to kill extra cities, reducing the enemy planet to 1 city/1 army to finish them off. This applies to neutral planets too, you can just make them easier to capture. Of course this will limit the defensive army cap and make it harder to defend any counterattacks, but hopefully you will have moved the front line by then.

In most campaign defensive missions, the enemy will beeline for pre-scripted planets you defend. They will not attempt to take systems that you invade so you can steal some of their 1-city planets and get free intel on neighbouring systems. However, Battle of Samoa (#10) the AI is smart and if you have 0 defending armies, their invasion fleets will instantly steal the planet, and without defenders they don't even have to go to battle phase. So you will actually need to build a couple defending armies.

First drafted 1 March 2024. More added 2-3 March 2024. Created by Techwitch for Steam Community Guides. Not intended to be published off Steam.