Umm..think you've lost me a bit. You colonise a new world, which starts with just a colony hub. You then build a spaceport, which gives you ship production abilities. You seem to be saying that you somehow 'lose' the spaceport? I really don't follow.

War Can Destroy the starport so they can loose the port and loose ship production cability for a while and has a good influence on range and economy. also it prevents new colonies from buliding military or Civilian (I mean unarmed) vessels another pacing feature that is interesting to deal with. and better starports give a special military production bonus if their better Factories will always do Soc and Mil together but starports give mil bonuses and it gives a incentive for the capital and Modern Planets to be kept safe and used as military bulid-up stations...