I've been wondering for a while, will terraforming Mars be a goal in the game? Or will the game just stick to enclosed cities?
They mentioned in their gameplay video that terraforming is out of the scope of the game. The game spans decades. Terraforming would be a couple centuries away. So no.
However, the early stages of a terraforming process could be implemented in the early stages of colonization, so I can easily see the implementation of a terraforming process as a mid-endgame goal.
Mmmh, you want long-term terraforming (i.e. retaining the atmosphere) you need at minimum raising the planetary mass to about 1/4 of Earth's. Could make for a fun end-game story line, but would be pretty apocalyptic for anyone already on the surface.
I suppose the goal would mostly be to reduce the harsh conditions on the surface, thereby reducing the protective measures required to travel on the surface.
The quantity of matter you'd need to drop to make Mars habitable is more than you could extract from the asteroid belt, let alone questions of how you'd deliver that to the surface without rapidly wiping out all life on the surface.