I agree with Torgard.

I agree, an excellent idea Torgard. The costs, as someone has previously stated, this could be tweaked, we wouldn't want players with 200 worlds. lol. Other than that, if the costs increases exponentially, then it would put a natural block on over expansion. Also, you wouldn't want players with four maybe five system full of their own worlds all together. Perhaps a maximum number of worlds allowed to be colonised per system, or not allowing two consecutive systems to be colonised?

like the idea, indeed with a natural occuring cap, like the exponential cost increase as proposed...