Seems like a conflict stretch to me.
If you've seen the infamous movie 2012 you can recognise same settings. I understand that to many people this sort of governmental manipulation seems pretty thin. They would tell us, right? I don't believe so. I think the elite would try to wash their hands from us with those sort of event. It's just I don't think they would survive in the nuclear bunkers four years for the skies to clear up. Or have enough of resources once the nuclear winters goes away to restart the civilisation.
How they got into this was thin and you could throw whole kitchen into that plot hole, but now that it's established that doom pr0n in on the menu, why to hide it. This series is going to be much more about the colonisation effort than the apocalyptic event, because 186 days is a fixed period and if they're going to keep up with the pace, major time jumps has to happen.
They could also slow it down and throw in the politics around the salvation project. Or show how they're building the arc vessels. I strongly believe there's going to be a limited number of them that get off the rock before the Samson hits Earth's atmosphere.