Starbases questions

1a) They upgrade ships only in the starbase radius. According to economic starbases should affect a planet if any part of the planet's square is touched by the starbase radius. I'd assume that applies to military starbases and ships as well.
1b) They *should* affect ships defending planets. However, I have read reports of some ships not gaining the bonuses properly while in orbit.

2a) As long as the planets are all within the starbase's radius, all of the planets will gain the upgrades.
2b) Trade improvements affect any trade routes that you own that pass through the radius. You do not have to have the originating planet inside the radius, just the trade route line.
2c) Yes, the bonuses from multiple starbases stack.

3a) They affect both your planets as well as enemy planets.
3b) It makes perfect sense, especially if your planet is under the sway of enemy influence.

4) The only way you can gain access to a resource is to build a mining starbase on it. A mining starbase doesn't have the radius effect abilities that the other starbases have. However, it can be upgraded to defend itself, and does a heck of a job mining the resource. The bonuses from mining resources are applied accross your *entire* civ.

EDIT: Apparently I was typing as curttasker was replying with the same info, but I'll leave it rather than obliterate it...

1. Only help ships in the radius and usually the ships must have something that can be assisted. For ex, if your starbase gives +1 beam assist a ship needs at least 1 beam attack to benefit - starbases do not magically empower weaponless ships. I'm not entirely sure about ships in orbit but I would think they get the effects too (I rarely build military starbases at this point so...)

2. Econ starbases jack up the production of all planets in their radius and these effects stack if you have multiple econ starbases overlapping multiple planets. One of the subwindows of the planet/tile window shows you the bonuses a planet is getting from starbases. Trade modules only bump your trade revenue when freighters are passing within the radius of the starbase - view your trade routes sometimes and you'll notice wildly fluctuating values on the routes.

Personally I build a lot of econ bases and go for a lot of overlap. For ex, if I have a corner planet/sun and some bordering planets I might have all my trade routes start from the cornermost (if that's a word) planet, so that they'll spend a lot of time in "my space" - and "my space" will have quite a few econ starbases, maximizing the amount of time my freighters spend in boosted space.

I tend to conquer so relying on trade income isn't a great idea. I like econ bases the most for the production boosts.

3. Influence starbases have no affect on planets - they are seperate "influence projectors" - some uses for them are to prevent another civ's influence from overtaking your planets/influence, to peacefully assimilate other civ's planets, or to project your influence into remote and empty parts of the map to increase your overall influence.

4. You get global benefits from the resource starbases regardless of where they're located and you can't build modules on them that have any radius types of benefits. All of their "mining" modules increase the value of that resource only and other than that all you can build is defense/attack modules for them (which is a good idea especially on a remote starbase). In theory, you want to control as many resources as you possibly can as they can have a significant effect on your entire empire. For example, a morale resource with mining improvements gives your entire empire a morale boost, which is huge - and all the other resource types have equally huge impact.