Passenger Ship Cost & Increasing Population Cost

Make each unit of population cost more than the previous one (like Riftborn do now), and add a cost in Food/Industry to each unit of population shipped from a Space Port.

The first element- increasing costs- will allow Food to have a solid population growth curve just like Riftborn have, but leaves us with the existing problem of being able to simply ship units of population away to reduce costs again to save time, which is a well known exploit among Riftborn players.

However, by costing the player Food or Industry to ship populations away, representing both the required and extra supplies necessary to survive a long journey, this exploit vanishes if the Food or Industry lost equals or exceeds what the player would gain from the exploit. While the next unit of Population costs 50 Food less from shipping away a pop, the player has also sacrificed 50 Food to ship the pop, cancelling out the benefit.