Space colonization will never happen and can never happen. People mistakenly believe it's possible for the same reason we're killing our environment: we egotistically imagine that we are separable from the ecosystemic context in which we evolved.
The closest we've ever come is glorified scuba expeditions, where supplies are brought in from the ecosystemic context from which we evolved. And this is as close as we'll get (with perhaps some relative advancement), because the human organism will never be a separate entity.
The closest we'll ever come is extending our ecosystem a bit beyond its natural boundaries, and the difference between this and space colonization is the difference between jumping and flying. Meanwhile we're destroying our home while looking to the stars like a bunch of morons.
The unspoken assumption behind the infinite growth required by capitalism is that we can expand into space and explore the stars, and we just can't. That's a delusion arising from a fundamental misperception of what a human organism is.
Believing you can extract a human organism and send it to a separate space colony with its own artificial ecosystem is like believing you can extract a ripple from the pond in which it's appearing. We are just not nearly as separate and separable as conventional minds imagine.
It's got nothing to do with limitations of technological innovation, it's to do with a misperception of what's actually happening. People believe space colonization is possible because they believe, erroneously, that we're separate from earth in some way.
