As you can see a research tech will take some CP / Turns / Credits, however this is taken once to gain this tech.
The fact that it takes more resources is not important, they are calculated in a way that will make them available as you progress, as they only need to be gathered once, and will get you an advantage over the other commanders once you have them.
When you have the tech to build the space station, and also gather all the minerals to build it, you also need help from the alliance members to defend it, as alliance fleets stationed in the system will defend the space spation.
You may ask what is the profit in building them?
Well, the colonization of the system is as an investment, with the space station as the guard, and the other structures as profit makers. For example, the second structure you would want to build after the system is secure is the mining post.
This will enable automatic harvesting of asteroids in the system, whitout the need to use turns as you had to build the first space station. However, here is another interesting thing, there are different degrees of profitability for each system, for example a system will have 5 belts of the best asteroids, that is the system you would want to find out, because the mining post will extract a fixed number of resources from EVERY belt in the system, and as you know some are way better then others. Then comes the replication and energy / matter theory, that will bascally enable you to transform resources from one to the other depending on your tech levels and the resources and eventually credits, a complicated but very interesting process
So after you get resources from the mining post, this will then be used to build and upgrade the modules for all your structure and mothership needs, making your ascension dependant only on your number of active mining posts and the profitability of the systems they are in.
It's a lot of work, but it will make for some VERY interesting combat for the rich systems...
P.S.: Of course you know that there are infinite tech levels to get better, so there is always room for improvement to get the upper hand on the others
witch is very very nice