Some of the descriptions of shipping offworld and the offworld market refer to both Earth and the asteroids. Shipping oxygen and food to the asteroids certainly makes sense, but surely not Earth? It seems extremely hard to imagine any of these resources being economically produced on Mars and then shipped to Earth at a profit. The game doesn't have much back story, but other colonys in the asteroids is easy to imagine, and production on Mars shipping to them makes sense, why not just stick with that?
Yes, I know this is an incredibly minor point. Just amuses me whenever I see the text.