Salvation is a surprisingly good show. I was hooked from the pilot. An asteroid coming to obliterate the planet is the most realistic threat that we have to deal with today. All those other threats that Hollywood likes to push, like zombies, are completely unrealistic.
I have to say, however, there are several unrealistic scenes in the show from what I've seen so far. I mean cmon Darius Tanz, the world is ending and you're the only one who can save it, but instead you go have tacos from a food truck and flirt with your protege's girlfriend while sitting riverside?