SpaceX wants to be the railroad of the future

SpaceX's plans for getting people to Mars are big and still a bit vague. Its plan for helping colonists actually live there for long periods of time is even more nebulous. But company founder Elon Musk suggests the latter part is by design — because SpaceX's job is to be the railroad of the space age, opening up the Martian frontier to people who will make the most of living there. "The goal of SpaceX is really to build the transport system. It's like building the Union-Pacific Railroad," said Musk during today's event. "And once that transport system is built, then there's a tremendous opportunity for anyone who wants to go to Mars and create something new, or build the foundations of a new planet."

"That's really where a tremendous...