[chii]

> but asteroid mining's the only thing I know of with a clear ROI in space

I dont think asteroid mining at current transportation costs is a clear ROI - the same amount of resources could be used to mine the earth for a lot more.

I see ROI in micro-gravity manufacturing - stuff that is impossible to do in gravity could be the future! Things like nano particles that would not be possible to create under earth gravity, fine structures that could collapse easily could be sustained in space for example.

Also, a 2nd human habitat (moon or otherwise) as a backup isn't a bad idea, even if it doesn't generate an economic return for a while. We are one asteroid impact away from extinction!

[mym1990]

I’m not an expert in any of the following, but a couple reasons might be: 1) Living on multiple bodies would do wonders for the imagination and further space exploration. 2) reduced gravity launches for spacecraft to places other than earth 3) a test environment for developing technologies in a completely different space. The ISS serves this somewhat, but it seems like the scalability is very limited, especially manufacturing.