None of the other planets of the solar system is sufficiently similar to Earth to be interesting as a colony, so that once the technology for inter-stellar colonization had been developed, exploration of the Sun's planets rather lagged. By 2060, when inter-stellar exploration really took off, however, there were already quite substantial bases on the moon, Mars and Venus, largely robotic in nature, and they have continued to expand. Mars and Venus are useful sources of minerals, while the moon is the main launching-pad for inter-stellar missions with its orbital platforms, which have close to zero gravity. Each planet also contains fully backed-up copies (eclones) of most existing humans as an insurance policy against any terminal event on earth itself. The active human population of the three bodies – all in the form of RCRs with human 'fathers' – is less than 100,000. Since 2070, no 'original' humans have left earth. There is no point, since they are extremely expensive to maintain in extra-terrestrial environments, and can inhabit RCRs with full sensory equivalence. At first it was a specialist activity, requiring a significant amount of initial training, for an individual to 'inhabit' fully their equivalent RCR partner, let alone multiple partners; but as the software protocols for inhabiting became more sophisticated, and re-organization of human neural structures made it more 'natural' for humans to work with remote sensory and cognitive input, inhabiting an RCR or an RCC became as easy as using your own hand.
There is still controversy over the validity of such 'inhabiting' – why, say the antis, patronize the RCRs by inhabiting them when they are fully capable of being independent. What, they ask, is the difference between a human that happens to be made of titanium and one that is made of mush? But they provide an escape route from Earth for a large number of people who couldn't otherwise find anything interesting to do there. Perhaps one day people and RCRs will stop seeing each other as different – given the high percentage of bionic components in people, and the equally high percentage of biochemical tissues employed in RCRs, it is of course increasingly specious to distinguish between them. And in RCCs, which almost monopolize communal activities such as governance, management and socializing on the planets, as they do on earth, original humans mingle happily with 'human' RCRs and non-human RCRs.