"The key to making life multi-planetary is full and rapid reusability. For building a city on Mars, you need thousands of Starships because you can only go to Mars every 26 mos."Elon Muskhttps://t.co/idkyPCzBWl ...

Elon Musk: “I couldn't think of anything more exciting, fun, and inspiring for the future than to have a base on Mars"At The Mars Society, August 2012https://t.co/lyRguqETM7 ...