I'm not far into this book but I think I'm done. So far the premise seems to be, we must preserve humanity by selecting those most representative of human variety and best able to survive, send them into low earth orbit where they will procreate and live for generations inside cans. The rest of us remain on Earth where we can look forward to being scorched alive in a couple of years. But we will somehow be motivated to build the rockets and infrastructure necessary to blast the lucky few into orbit. It's vital that we preserve the likes of Neil degrasse Tyson because we're going to be in space after all, but the folks machining the rockets, mining the ore, wiring up the gadgetry, growing the food? Not so much.
No disrespect intended towards Dr. Neil, a person very much worth preserving IMHO.