I find it useful to acknowledge that Elon Musk is first and foremost a businessman. We should take what he has with a grain of salt. He has a financial incentive to build hype around the possibility of interplanetary space travel, specifically using SpaceX spaceships. It would be foolish of him to acknowledge any kinks they have yet to work out or problems they have yet to tackle because there just isn't any incentive to do so. Also take note that we don't have much in the way of technical specs on how he plans to do it. All we have are some rendered mock ups, animations, and an optimistic outlook from someone with a monetary conflict of interest of how the public perceives the viability of future space exploration.