As Bezos mentioned, it's up to future generations to make the science and engineering work. All off planet habitation and life will be a massive multi-generational endeavor. Personally, I like O-Neil colonies too. If they work, then they can be constantly expanded.
I’ve now watched Bezos’s presentation twice. His vision is vast, but familiar to those who have read the many works of fiction that incorporated O-Neil cylinders or something similar (my favorite
Ringworld series - Wikipedia ).
However, the technology required to construct and maintain even a modestly-sized O’Neil cylinder is so far beyond what we are currently capable of that it makes creating a self-sustaining colony on Mars look like child’s play. The size of such a habitat dwarfs any structure humans have ever constructed. Add to that the fact that it has to be built in space using primarily non-terrestrial resources, and the challenge is immense.
But that still isn’t the hardest part. Creating a functioning, balanced, closed ecosystem on that scale is likely even more difficult. It’s hard enough to do that on the scale of about 1 hectare (see
Biosphere 2 - Wikipedia ) and
on Earth. Bezos wants to do it in space where environmental controls will be much more difficult to maintain.
While I admire Bezos’s vision and enthusiasm, I continue to believe that what SpaceX is doing is both logical and necessary and is far more likely to come to fruition even on a timescale of millennia.
I confess to being annoyed by Bezos completely ignoring what SpaceX has accomplished to date. It seems to be personal with him. Obviously SpaceX has paved the way with reusable orbital-class rockets and been doing it for years now. Blue Glenn, which has yet to fly, is not completely reusable, the second stage is discarded. Starship will be 100% reusable. BO is lagging in that area.
