About the comet.

[grrrz]

I belive that is the case. Since the earth is inhabitable, a lot of people probably died.
Maybe Pathos II already existed before the comet hit the earth though.

It's made pretty clear in the com center that it was the end of the world for pretty much everybody on earth, and at various points that the station was the only inhabitable place left on the planet (and at the end you know, the earth in on fire). Pathos 2 of course existed before the comet (who would have built it otherwise?), as a geothermal energy station, launch pad, and probably underwater scientific research facility.