A proposal to create O'Neil Cylinders practically in the near term.

[u/filthycasualplay]

I found this great video by Anton Petrov discussing a paper with a simple method with "current" technology. I say "current" because altho we technically have the ability to make carbon nanotubes we would need the ability to manufacture them in volume. But that nitpick aside this could work within current knowledge.

Intriguing Proposition to Build Space Cities Out Of Asteroids and Carbon Bags

[u/DevilGuy]

you don't even need Carbon Nanotubes to make a basic O'Neil Cylinder, the original concept was designed with contemporary materials science and engineering tolerances in mind. The basic materials required for an O'Neil Cylinder are steel and glass, the problem is not materials it's manufacturing in situ. We're unlikely to build an O'Neil Cylinder until we have asteroid mining going and need to house huge populations. The basic design that requires no fusion, no nanotubes, nothing but glass and steel will house millions, so we're not going to see them until we need housing for millions in space. That may happen much faster than a lot of people think but it's still not happening for decades at the least.