It's really not. It's not a far leap from "aluminium tube in space" to "slightly larger radius aluminium tube in space rotating along its axis surrounded by liquid hydrogen".
We don't need some magic force field to shield against radiation - water has already proven it can do this. Liquid hydrogen is an even better shield and it's something we currently have the technology to use.
The combination of much cheaper launch costs of SpaceX's Starship, zero to negative interest rates, and a bunch of space-interested billionaires, might just get some rotating space hotels up and running sooner than you might think.
I count three, the latter two of which are already doing more for less than most were expecting.
And this has all been clearly chosen as a development sequence that leads to them being a space trucking company, so those “decades” plural have already start.
But if it takes two more decades, so what? The points, pro and con, still stand. Technologically achievable, but no clear economic reason as yet.
I consider 30 years timeline as an optimistic scenario because we will have Super-Heavy rockets in operation in later half of 2020's, and from there onward the priorities for most major space agencies for manned spaceflight is return to the moon and in-situ resources. Which I believe should have been the focus for a while.
Most of innovation and commercial activity will be focused around lunar habitation and infrastructure, by the looks of it.
Just a nit-pick: i think it’s a political problem, not an economic problem. Humankind as a whole has the money/resources to do it, perhaps unprofitably. There is just no political will to prioritize it and make it happen.
Yeah and that might be because there are lots of problems down on earth right now, like climate change, requiring more effort and are maybe more important than space advance. And sadly I would agree, you don't?
> Liquid hydrogen is an even better shield and it's something we currently have the technology to use.
First get your liquid hydrogen (and any other similar solutions) into orbit.
I used to be (in the 70s) gung-ho for space colonies, but really the economics simply don't make sense with anything like current drive technologies, or indeed any in the foreseeable future. In my opinion, the answer to the Fermi Paradox is that putting intelligent living organisms into space for their lifetimes is simply far, far too difficult.
It's really not. It's not a far leap from "aluminium tube in space" to "slightly larger radius aluminium tube in space rotating along its axis surrounded by liquid hydrogen".
We don't need some magic force field to shield against radiation - water has already proven it can do this. Liquid hydrogen is an even better shield and it's something we currently have the technology to use.