The recent impactor discussions brought up about the comet that may hit Mars brought to mind some vaguely remembered ideas about terraforming Mars. Volatile rich bodies are directed at Mars to give it an atmosphere of the resulting gasses. If my BOTE numbers are right, the estimated 30km diameter comet would roughly double the atmospheric pressure if it hit and converted all of its’ material to gas that didn’t escape. If that were the case, then 40-50 comets would give Mars an atmospheric pressure of roughly half Earth sea level. With the quantity of volatiles that either escaped Martian gravity, condensed to liquid, or just weren’t there in the first place, it would take 100-200 comets at least to get the job done.
That would give enough atmosphere for radiation protection, exploration with tanked air instead of spacesuits, and sealed but unpressurized living, working, and farming buildings. Compared to the advances of the last fifty years in space travel, this might seem a very long way off. Compared to the advances of the last century though, it might be much closer than any of us currently would think.
I know this concept has been kicked around for decades. My question is, “What is the recent credible work on it?”