I haven't built any mining starbases yet, so my advise will be limited to economy in general. One point though, did you research the necessary tech to be able to build mining starbases?

As for economy:
1) Morale only needs to be high enough to have a good population growth early on. In the late game, you can have morale just above the point where you'd lose population on your least happy planet (mid 20% if I remember well), except just before the election, then 60-70% is a safe choice. Just increase taxes according to the minimum morale needed in the late game.
2) Research economy & morale techs, more advanced government types.
3) On your homeworld, at least 1 morale building will be necessary - or a political capital. Otherwise you'll need extremely low taxes to keep your population happy. On any planets with farms, additional morale buildings will be needed.
4) Consider changing some lower quality planets to economy only. Specializing them in research or production won't make such a vast difference if you already have higher quality planets doing that.
5) Improve any starbases you have on resources (the crystal-like resources, not the mining ones) to their maximum, except for influence unless that has some use for you. But improved research, morale, economy all help to maintain a better economy.
6) Trade routes don't do much anymore in TA but having up to 10 trade routes helps a little.
7) Economic alliances, especially with AI's who have an average or strong economy.
8) Selling non-diplomacy techs to AI's, even weak military techs. This doesn't solve the economic problem but at least gives a cash boost.

Also, check where your biggest expenses are, why are you still struggling with the economy in the late game? Can you improve things by changing the slider settings?
Check your spending on espionage, any chances of reducing that a little?

ok this is all sound advice. yet.... my original question was not answered in the slightest .

as for going in red late game. perhaps we are not agreeing what "late game is"
I usually try to end A game As quickly as possible. so I may build A large army of transports and position them to make one big sweep and take over like 25 planets on the same few turns.

sure this ruins me economywise . thats probably due to me not going about it peicemeal and letting a group of conquered planets stabilize first, before moving on to the next group.

all of this is purely playstyle and is off topic of what I need to know.

what i need to know. is why the AI is putting ECONOMY starbases on its asteroid mining paths .

.

Maybe a frighter route was going across the mining starbase rails?