Space tourism and climate change

*Never be used in the atmosphere.

Probably never used at all. You'll never cut the red tape to lift a serious nuclear propulsion system off Earth, and by the time we have the facilities to build one from Lunar or asteroid materials, there will likely be something better than Newtonian rockets available (EM field drive, warp, "anti-gravity" etc. a couple oi hundred years hence)

I'd say we'll see, but I'm not sure I'll make it that long