Say you stumbled across a system while flying in deep space, and wanted to slab a planet. You are not in a faction so in order to "control" the planet you would have slab the whole thing. Planets can be up to 20x20, which is 400 squares = 400 hours. If you spent the whole 7 days slabbing every hour, you would still have 232 squares to go before everyone else can see it. My question is this, do you lose out on those terrains to others because your not in a faction to claim the planet with just one city? Or could you have a friend/friends (also not in a faction/s) come help you slab it then turn those cities over to you? Cheers.
The game is designed around factions, so yes as a singular player it would be hard to control a planet. For those time, that is not including the travel time on the terrain/slab and crossterrain, which will probably be an additional hour between each city creation.
But, yes, you could get friends to help you if you want - nothing in the rules against it. However some of those people ask their faction (or a friendly faction if they are not in one) if they would mind owning the flats to control the planet for you and allow you to build.