I think the article makes the case that you do not need to import water, it is supposed to already be there. If you have a ready supply of hydrogen and oxygen (which indications are Mercury does) and an incredible amount of energy that can easily be converted you reduce your import burden substantially. This has always been my doubt about Mars, is the energy available that we need to get anything done over there? (I also agree that Nitrogen availability is a serious issue for any food production, regardless of the strategy, and this is likely a Mercury weak pont.)
Terraforming is not the goal, it is a means to an end of making a survivable planet that does not required resources from earth. Limiting your options to terraforming is not required and may not be desirable.
Terraforming is not the goal, it is a means to an end of making a survivable planet that does not required resources from earth. Limiting your options to terraforming is not required and may not be desirable.