Cheers Aaglo, your praise means a lot.
GRM7584; The benifit of a sentry gun is that it could be carried around by non combatants, such as settlers or workers. It'd be a man portable 24 hour guard, so a design that could be folded up and carried with you would be good.
One idea would be to have a pop up gun, seated on a small crawler with a sensor pod sticking up above. When an enemy was detected the gun would pop up for deffence.
fe3333au; I think that the original landing sites would make better wonders than resources, they could give a collosus type trade advantage and then a tourism bonus later. They would be preplaced at the start of the second scenario..
Cabbit; Another set of books is the night's dawn trilogy by Peter F Hamilton. It takes place several centuries into the future when lessons have been learned form space colonisation.
The first planets to be colonised are done in a peicemeal fasion, and end up falling in to the old nation state patern. Later planets are single culture colonies, based on an ethnic and social stereotype.
In a way, the analogy between Virgin Mars and the USA is a false one. The USA was already fully ready for habitation, and inhabited. It took a similar amount of time and money to transfer goods or people from europe to America, but return goods were much more profitable. Initial colonies had lower start up costs and established colonies didn't need as much support. Also Mars is much bigger than America, Valles Marinaris (the great northern canyon system) is as large as the USA all on it's own.
Actualy there is a good analogy in America, it's Tenochlitlan the Aztec capital. When the Aztecs fist settled there it was a swampy wasteland, surounded by jungle and desert. They used their ingenuity and labour to turn it in to one of the largest cities in the world (bigger than venice at the time). They also acheived political and ideological unification of much of Meso America.
Then the Spanish arrived.
It cost enormous amounts of money to send even a small expedition to America, but it was financed on the promise of even more money from the explotation of a rich land.
The first settlers will be like the Aztecs, setting up an initial settlement, and the infastructure to support settlement. Later arivals will be more like the spanish, with no regard for any previous political arrangements, or like the french or english, settling in other regions to establish thier own expansionist utopia.
Labour on MArs would be most likley to be provided by convicts or the poor of earth, lured by the promise of high pay and trapped by the massive return fees. the cost of a trip out would likley cost something like a years indentured labour, or be free, but the cost to travel back would be your own weight in precious cargo as well as the weight of asociated life support. In the end most would stay on mars sending money back to thier family, or having them shipped out. These people would be like the black, asian or native american slaves used to build America, and they would be the driving force in political change. As they made the transition from being earthlings, tied to the homeworld by thier need for support, to independant martian citizens, the ruling class would find it hard to keep them under control.