The colonial structure of mars depends upon the economic growth model of mars and the Solar system as a whole. Mining on mars is often used as the basis in science fiction, but reality is there is nothing we know of on mars we can't get here on terra. The most likely money maker of mars is as a processing refining and shipping hub for resource mining operations from the outer solar system. Helium 3 from the outer gas giants, raw materials from the asteroid belt. These industries will demand positions closest to your space ports.
Second to this is Mars own needs. Power can be established via wind turbines, Helium3 imported from the Gas Giants of the outer solar system, solar power via collectors mounted atop the habitats. Shelter can be built both in and on mars using materials from the outer solar system and the planet its self. Water can be taken from the poles and under the surface. Filtered and treated by the colonies in plants built into the very earliest stages of development. And finally food. This is the most likely to be imported by mars from earth but here is the issue how much can be imported economically? I mean assume Mars and earth have decided on a uniform exchange rate for Martian currency, (lets call it the Marvin
) now assume that one Marvin is equal to one dollar. Now on earth I can get a slice of pizza from a restaurant for about three dollars. Now take the ingredients for that same pizza and send them to mars. That going to be three billion Marvins for a slice. The cost of processing that ingredients is negligible and done all the time but the fuel for sending them makes it astronomic. Now we need to consider ways of reducing the price, assume ultra light weight packaging, that might shave a few thousand Dollars, assume dehydration, there is maybe a billion dollars. Now assume that instead of rocket fuel we use some other means to orbit the ingredients and then ship them to mars like say using a startram then docking with a ship using extremely efficient ion drive. Down to a mere 800million Marvin per slice... What a bargain. So Mars needs agriculture. Lets assume then the the wheat, the tomatoes, the peppers most of the ingredients are in fact not imported but grown in agro domes on mars using Hydroponics and and climate controlled greenhouses . That cuts our slice down to imported Oil, eggs, cheese, pepperoni and meats. So may be it would be 100 Marvin a pizza. Obviously dominos would make a killing. Cheap things on earth would be pretty pricey to import on Mars. Even with regular trips back and forth. Now 100 Marvin a slice is pretty steep but if you are processing materials from the ore cloud working on Mars your probably making enough Marvin to afford it.
* Note prices are not actual,
the water plants the power plants the habits and Green houses are likely to be farther from the space port. Additionally the its likely that there would not be one single unified colony. You might have a main colony operated by a government like the US or PRC or Russia or even the EU then off of this there could be smaller corporate colonies. These might be somewhat self sufficient operating purely for the corporation that owns them. They could have there own small space port for shipping product and receiving raw materials. So there could be the EU dome with residences and its governance the off of that you have the BP dome processing Helium 3 for commercial purposes. Now between them there would likely be established some form of transport like a vacuums monorail with a climate controlled car for personal transport. Workers coming in from earth working at the BP refinery dome could arrive at the EU dome then transit to the BP dome for work.
But what happens if a hostile force takes the BP dome? What if. They cut the rail way between it and the main EU colony? Then do you suit up and start walking? Sure there will have to be EVA gear on mars but with at a absolute stretch 25 hours of O2 how long will it last and how much can you get done in that time. A vehicle can close the distance between colonies faster and would slow support for your power Eva suits charging there batteries, and O2 it would alow the troops to rest, breif, eat and whatever else they need before suiting up and operating. The issues for operations though suggest that fighting is more likely indoors then out in the sands of mars.
