We Need to Start Building in Space

 Literally.

Gateway, the proposed space habitat for moon exploration will be so small astronauts will have to do the equivalent of backing up to the nearest passing space. It's going to be extremely claustrophobic.

And the reason is that every bit of it has to be hauled out of the gravity well and it's harder to get stuff up there.

In the long term, the only way we're going to get livable space habitats outside low Earth orbit is to build them in situ.

Science fiction authors have known this for decades, but now we really have to start thinking about how we make it practical.

One step is the DART test. In addition to planetary defense, DART could be used to point a metal-rich asteroid at a Lagrange point, where it could be captured and mined for raw materials.