The revolutionary breakthrough will come with rockets that are fully and rapidly reusable. We will never conquer Mars unless we do that. It'll be too expensive. The American colonies would never have been pioneered if the ships that crossed the ocean hadn't been reusable.

Land on Mars, a round-trip ticket - half a million dollars. It can be done.

I think there is a strong humanitarian argument for making life multi-planetary in order to safeguard the existence of humanity in the event that something catastrophic were to happen.

Your probability of dying on Mars is much higher than earth. Really, the ad for going to Mars would be like Shackleton's ad for going to the Antarctic: "It's gonna be hard. There's a good chance of death, going in a little can through deep space. You might land successfully. Once you land successfully, you'll be working nonstop to build the base."

People will visit Mars, they will settle mars, and we should because it's cool.

I know Elon, we're very like minded in many ways. We're not conceptual twins. One thing I want us to do is go to Mars, but for me it's one thing. He's singularly focused on that. I think motivation wise, for me I don't find that Plan B idea motivating. I don't want a plan B for Earth, I want Plan B to make sure Plan A works.