The dirt is part of the radiation barrier.
Everything there will probably be building blocks, panels of various lengths used to build everything. A machine that spits out building components as flat panels, tubes, I beams etc would be the way to go. So parts that assemble into other parts like erector, leggo, kinex etc...
A
3D printer would be the ideal machine for the task.
I think present concepts from NASA include using 3D printers as a possible means to construct rovers on other worlds. I think the one lunar rover they are working on was made with parts meant be easily produced via a 3D printer.
When we get the ability to smelt iron for steel and make that a viable choice for building. So when does this game take place? Do we have steel mills in the game? Have to put it into perspective, game starts at how many years after the first landing? I see a dependency here on when this takes place.
I personally like the raw gritty explorer scenario but I am only the builder..
The 'gritty explorer' thing, along with videos I saw of the old Mars Colony Online, did make me think of an idea for a sort of 'Phase 0' or 'survey mission'. (my latest overly large post over in the Gameplay thread)
One scenario pops into mind, for how things could be well established, yet still lacking in some way.
Perhaps the initial main base did have some sort of small scale steel melting and alloy producing system, but due to some sort of mishap it was damaged beyond repair (maybe someone outsourced computer components to save money and a supply lander landed in the wrong place without bothering to slow down first).
Perhaps the incident in question damaged multiple large pieces of equipment at the main base, stuff that could not initially be repaired/replaced with what was locally available (maybe they had the capability, but it got wrecked also). The main base would of course have backup systems made up of smaller and less effective equipment that was brought along for the initial colonizing efforts.
The backup (smelting) system would be in place that can operate on limited power, but with very limited capacity, and long charging periods between each batch due to the limited power available from solar, wind and basic nuclear sources.
Due to the size and weight of the equipment, replacements cannot be sent by a 'standard' supply lander.
Due to the initial excitement of colonizing Mars having wore off, Earth is not very enthusiastic and in no hurry to allocate the time and money needed to prep a 'heavy cargo lander' that would be needed to deliver replacement equipment.
That way things can be 'well established' and still have the 'gritty' feel due to basically having arrived to find out the main base has suffered a serious setback at a time when Earth is not really enthusiastic enough to put efforts into sending proper replacement equipment.
This would require some effort to be made to repair or replace the affected system(s).
Option 1: Find a way to 'convince' Earth to send a replacement (requiring a pair of heavy rockets, one to put a 'heavy cargo lander' into orbit, a second to get the 'transit stage' into orbit to actually get the heavy cargo lander to Mars. So expensive and time consuming. Could probably cram several entire resupply missions into the heavy cargo lander, to give an impression of how big and heavy the equipment is)
Option 2: Find a way to develop replacement equipment locally that won't require large amounts of energy, or perhaps can operate partly or mostly via some locally produced 'fuel'.
Option 3: Have R&D efforts to develop a new power system that can generate a sufficient amount of power, such as locally made nuclear reactor, to power the backup system consistently or to otherwise greatly reduce its down time.
Option 4: Generate sizable amounts of materials/resources needed for the main base to fabricate the components needed to get the larger and much more efficient system back online, or to otherwise rebuild it from scratch.
Option 5: Work toward having additional 'backup' systems built and sent to other bases. The other bases would use their own surplus energy to charge up small scale systems for brief periods of time. While not the most efficient option, it would likely be a more easy to reach stop gap measure, and help to decentralize production so problems do not occur should the main base's backup system break down.
They could be cumulative.
Perhaps R&D is able to locally source materials needed to make a nuclear reactor to allow the backup system to operate more consistently, while another base is able to produce materials needed to refit the original damaged system to operate on locally produced 'fuels'. So with time and effort, the player(s) can work toward having the main base actually being more productive, effective and efficient than it was in the first place.
It could also be optional.
So players can choose if they want to start.
Maybe they want to take things easy in a setting where things are well established and ready to go.
Or perhaps a bit more of a challenge and start in a setting where the Mars colony is a bit down on its luck, and in need of expanding its capabilities and rebuilding Earth's interest in the Mars colonizing efforts.
For those who really like a challenge, maybe a setting where something went horribly wrong, and the player is part of a mission to 'reactivate' a previously abandoned Mars colonization effort. A mission requiring even more time, effort and resources to get things going and get the colonizing effort on track, where initially Earth would be hesitant to deploy even a smaller supply craft based on an old rover delivery design with barely enough room for a footlocker full of supplies. An initial goal for this could be to take some leftover pre-fab materials, and get basic food, water and life support production online ASAP at an already prepared site with basics in place (sort of like the present Phase 1 and the Phase 6 based demo, but with more to do/setup/repair/replace). The supplies would be needed to help support initial efforts of the team that drew the short straw and got stuck with trying task of fixing up the run down main base itself. Then after that, the player(s) can start working on expanding their initial meager base, and working toward being able to establish a full base at another location.
Maybe the later might work as a sort setting for a tutorial. A mishap having caused a secondary base to be abandoned and fall into disrepair and then be damaged by a bad storm. The player(s) gets walked through the basics as they have to rebuild the base, getting it fully operational and made self sufficient.