According to Space.com, the billionaire founder and CEO of the private spaceflight company SpaceX spilled details about his hopes for a future Mars colony during a talk at the Royal Aeronautical Society in London on Nov. 16.

Earlier this year, SpaceX became the first private U.S. company to deliver cargo to the International Space Station. Musk has never been shy about his ambitions to take human colonists to another planet, mentioning in the past that he wants to provide flights to Mars for about $500,000 a person. But now he’s talking about building a small-city-sized settlement on the Red Planet, starting with a 10-person crew in the coming decades to begin establishing and building infrastructure.