My game has been going on for about a decade now, but there is only one commercial ship (a luxury liner). I've colonized Mars up to 10m population with my own ships (though it doesn't have any minerals), and I have 3 other mining colonies. There is one civilian mining complex, but that's it. What am I supposed to do to encourage commercial ships to appear?
Is the shipping line making money? Does it have enough cash on hand to buy a new ship? The cost of the new ship is the number of build points, IIRC, so if you've got super-mongo-huge (that's a technical term
) civie designs then it might not be able to buy any. The typical freighter has 5 cargo holds (so it can hold a single factory/mine/automine/...). The typical colony ship has 4-6 cryo-bays. Also, you should check the F5 screen to make sure that your freighter and colony designs really are classified as commercial - you can mess this up by putting sensors of size>1 or military engines on the class.
Note that there's a "subsidize" button on the civie shipping line screen that allows you to transfer some cash from your empire to the civie line. I wouldn't use this, however, unless the line doesn't have enough money to buy new ships.
John