I would've said that the mission for defending the orbital stations is OP, seeing that it can pop up on heavily defended stations with maxxed defender ships, so it ends up being a free $200k to $300k, and you mostly watching the fireworks with your few little ships.
But then again, smuggling in this game exists, where you can buy supplies for dirt cheap and sell them in the same system for more than double the price (looking at you, Hybrasil).