I just had an idea to look in components.txt to see what abilities are listed for all of this stuff. Here is what I found out:
Combat Sensors (first 3 levels of the Sensors research path) add to your attack probability. None of the other sensors have this ability, so you always need to have your best combat sensors on board to get the best attack bonus.
Tachyon Sensors give Active EM scanning ability (3 levels).
Hyper-Optics give Passive EM scanning ability (3 levels).
Gravitic Sensors, Psychic Receptors, and Temporal Sensors all give the respective scanning abilities, 3 levels each.
Cloaking Devices prevent scanning by all of the above, at 3 ability levels.
So, bottom line is that Tachyon, Hyper-Optic, Gravitic, Psychic and Temporal Sensors are all redundant to each other - if you have one kind, you don't need the others. Just research whichever of these kinds has the cheapest research path for your race and the other techs you have researched.
What really bugs me is that Gravitic Sensors are in the same research path as Tachyon, at a higher level, so you need to research Tachyon first. Since the level 1 Gravitic Sensor is actually not as good as the level 3 Tachyon Sensor that comes right before it on the path, it is actually an expensive step down, not up.
Unless there is some tech that will block Tachyon sensors but not block Gravitic, I cannot see why anyone would ever want to waste the extra research points getting Gravitic when they have to get Tachyon first on that same path.
This all refers to the unmodded game, of course. Imperator Fyron mentioned that some mods change these, but I haven't tried any yet. Still trying to figure out the basics.
SpaceBadger
Re: different types of sensors
Linear Mode
