Its true that active search sensors on ships paint targets for any FC's in range. But what I'm not sure of is whether or not the active sensor on missiles is a search sensor or a fire control.
these is going to take some experimentation to find out if it works that way. if not I'm going to have to develop a FAC sized fighter carrier to launch scout fighters
In any case, at this early stage of the game, a new missile launcher should be really cheap. I'd design a missile with a big thermal sensor, lots of fuel, and a few thousand km/s faster than your fleet. Size isn't important since you're not really in a hurry to launch tons of these, and they'll only be weighing down your sensor ship. The thermal sensor will help you find any ships, which you can then head towards and paint with your on-board active sensors.
I generally want to launch my missiles at max effective range before i'm detected on Actives I.E they see my thermal and are approaching to investigate and blam runs into a cloud of missiles and bracketed by active sensors so i know which way they are going to move or if they have reinforcements on the way
