> Humans are going to need many thousands of rockets like that one if we are to survive.
There is no chance in the next hundred years (I would bet more like 200-500) of a self-sufficient colony anywhere away from the earth. If humanity can't survive without rockets, it can't survive at all.
Not to mention that it is basically impossible to imagine that any technology that could allow a self-sufficient colony on another planet couldn't much more easily allow humans to live on earth after any catastrophe you could imagine short of cosmic ray events. It's much, much harder to live on Mars than on a post-apocalyptic earth, regardless of which apocalypse you care to choose (nuclear war, nuclear meltdowns in all nuclear power plants, catastrophic global warming, super volcanoes, meteor impact the size of the Cambrian event, you name it).
Sure, in the enormously long term there may be a need to leave the earth before the sun ages too much, or to try to have a chance against planetary collisions or gamma ray bursts.
There is no chance in the next hundred years (I would bet more like 200-500) of a self-sufficient colony anywhere away from the earth. If humanity can't survive without rockets, it can't survive at all.
Not to mention that it is basically impossible to imagine that any technology that could allow a self-sufficient colony on another planet couldn't much more easily allow humans to live on earth after any catastrophe you could imagine short of cosmic ray events. It's much, much harder to live on Mars than on a post-apocalyptic earth, regardless of which apocalypse you care to choose (nuclear war, nuclear meltdowns in all nuclear power plants, catastrophic global warming, super volcanoes, meteor impact the size of the Cambrian event, you name it).
Sure, in the enormously long term there may be a need to leave the earth before the sun ages too much, or to try to have a chance against planetary collisions or gamma ray bursts.