Thermic shelter

Thermic shelters were a type of protective structure which the citizens of Earth were evacuated to before the start of a period of five thousand years of solar flare activity.

However, they were apparently not expected to be capable of sustaining a human population for the whole period, as the government relied on the Ark instead to repopulate the human race. Still, Rogin, upon witnessing the situation that existed at the time of his awakening, damned himself for not taking his chances with the shelters, saying he could be "happily dead by now". (TV: The Ark in Space)