Re: 600,000
Yes. This figure in the order of 1,000 is a lot more realistic. It would probably be sensible to have around 3 semi-autonomous communities of this size in case of some form of infection / natural disaster / depressurisation / fire wiping out a community altogether.
And to be practical, rather than fashionable, we should, of course, start on the moon for fairly obvious reasons.
Biting the hand that feeds IT
