That's my lesson for taking a vacation: vacation will kill you.

I feel very strongly that SpaceX would not have been able to get started, nor would we have made the progress that we have, without the help of NASA.

I think it's important to reason from first principles rather than by analogy. The normal way we conduct our lives is we reason by analogy. [With analogy] we are doing this because it's like something else that was done, or it is like what other people are doing. [With first principles] you boil things down to the most fundamental truths…and then reason up from there.

If you're co-founder or CEO, you have to do all kinds of tasks you might not want to do. If you don't do your chores, the company won't succeed. No task is too menial.

I started SpaceX with the expectation of failure.

A Prius is not a true hybrid, really. The current Prius is, like, 2 percent electric. It's a gasoline car with slightly better mileage.

If humanity doesn't land on Mars in my lifetime, I would be very disappointed.