Worst case scenario, what would that actually be like? A few hundred people who gave up their lives on earth to live in habitats on an inhospitable planet one day learn that the worst fear of the 20th century came true, and there's nobody left back home. It's just them, the only remaining sentient beings in the known universe, without 99% of the technology that got them where they are now.

How could they even begin to try to rebuild civilization when they can't even go outside without an apparatus that took thousands of years of science to produce? What is the speed divisor for advancement of a society marooned on a world it didn't evolve to live on?

I'm all for Mars colonization, but as a backup plan for Homo sapiens, it kind of sucks.