IMAGE SOURCE SPACEX image caption Starship prototype SN9 during its flight test at Boca Chica, Texas, in January 2021 Elon Musk is developing a vehicle that could be a game-changer for space travel. Starship, as it's known, will be a fully reusable transport system capable of carrying up to 100 people to the Red Planet. The founding ethos of Elon Musk's private spaceflight company SpaceX was to make life multi-planetary. This is partly motivated by existential threats such as an asteroid strike big enough to wipe out humanity. Settling other planets would place some of the eggs in other baskets, sparing human civilisation if one of them were to experience a cataclysm. In 2016, the entrepreneur outlined his rationale at an international conference in Mexico: "History is going to bifurcate along two directions. One path is we stay on Earth forever, and then there will be some eventual extinction event," he said. "The alternative is to become a spacefaring civil...