It feels to me terraforming small bodies might be a little too easy, if they're running around colonizing asteroids with the plan to quickly terraform them. Lack of gravity to hold an atmosphere would become an issue at some point. Even if, on re-reading, it was an absolutely gigantic asteroid (that's more than half the diameter of the moon).
I am still playing around with balancing Terraforming as it has changed so much. There are several new factors.
1) You need 0.5 atm of water vapour to go from zero water to 20% (minimum for no water-based colony cost) and that water vapour will take five years to condense (0.1 atm per year). So even if you add the water vapour quickly, you still can't make a water-less world completely habitable in less than five years. A large world with water is still a better option than a mid-sized world without and larger worlds are more likely to have water.
2) Population capacity is a new consideration. This body is very large for an asteroid, but it is barely above minimum gravity and has a maximum population capacity of fifty million. Small worlds can be colonized more quickly but have limited population. You can't terraform any world with less than 0.1 gravity.
3) Many more worlds are available to be colonised due to the higher speed of terraforming small bodies. In VB6 Aurora, this asteroid would never be considered as a realistic terraforming prospect because it lacked atmosphere. Faster terraforming for small worlds means you have a choice on using your terraforming resources on many small colonies or fewer larger colonies. More choice and more decisions.
4) You can create terraforming stations and build them using construction factories. In VB6, you would need an orbital habitat for that, which is much less practical. This means you can put a lot of terraforming modules into space if that is your priority.
I need to see how this works out in practice, but when the aliens were discovered the terraformers were working on two worlds larger than Earth. Large worlds are slow to terraform but they are also a lot more likely to have existing water and atmospheres and larger mineral deposits. Even this asteroid would probably not be considered for terraforming except for the nearby aliens.
