No one, without a time machine. Having not one copy of such a device on my wrist or in my storage space, it is all speculation.Realistic for contemporary fiction, certainly. Internally realistic for science fiction, set centuries from now? Who is to say?
Speculation of what is possible is the point, but "realism" (as I see it, what is real, right now, today's world) rules that out.
My Traveller campaign is firmly is the camp of space opera, not "realism".
Thus, I am free to do whatever I want for the story, and not worry about the exact details of how something that might be possible 1000 years in the future might work.
Thus I have a planet, a crew, a starship, a challenge, some enemeis, some conflict, drama, and a whole bunch of fun.
I once, long ago designed as "realistic" a planet as I thought possible. I ran a scout initial survey mission, where the players discovered all these little details of the animals, the climate, the lost ruins, the temperature of different areas based on albedo, latitude, proximity to a local sea.
After we were done, the whole player group said:
"Man, we never want another survey mission again." "Just gloss it over, give us the big picture."
"If I wanted gaming by spreadsheet, I'd go to work, after hours."
"No offense, but I'd rather chew rocks."
We went back to:
- Giant asteroids tumbling in space, a la Return of the Jedi (even though "real" belt density is much lower, I'm told).
- Cloud cities floating lazily over a gas giant (even though winds would rip one apart, i guess.)
- Planets with moons in close orbit inside Roche's limit, causing massive tides.
- Colonies on planets with no microbial life in the native soil.
Fun was had, because it was all about STORY, not scientific accuracy that was not worth the effort to track down to the Nth degree.