[Puke]

what, you are going to make the starting facilities a mix of first world and third world nations that produce various resources and adversely impact the planet in some way?

and then you cant build anything real until you spend a few (tens of) decades researching "world government" and "practical space program"

that sounds irritating. and it ruins the suspension of disbelief if you have to pay attention to how those things happen. just roll the clock ahead 400 years, and hand-waive away the reasons your planetary government formed and developed spaceflight.

i mean seriously, if we have to imagine an entire humanlike species forming a common collective for government, directed towards a single purpose, its not really a sci-fi game anymore. its totally fantasy.