If anyone thinks they'd rather be in a different part of history, they're probably not a very good student of history. Life sucked in the old days. People knew very little, and you were likely to die at a young age of some horrible disease. You'd probably have no teeth by now. It would be particularly awful if you were a woman.

I think it's very important to have a feedback loop, where you're constantly thinking about what you've done and how you could be doing it better.

Focus on something that has high value to someone else, be really rigorous in making that assessment, because natural human tendency is wishful thinking, so the challenge to entrepreneurs is telling what's the difference between really believing in your ideals and sticking to them as opposed to pursuing some unrealistic dream that doesn't actually have merit, be very rigorous in your self analysis, certainly being extremely tenacious, and just work like hell. Put in 80-100 hours every week. All these things improves the odds of success

People often mistake technology for a static picture. It's less like a picture and more like a movie. It's the velocity of technology innovation that matters. It's the acceleration.

It would take six months to get to Mars if you go there slowly, with optimal energy cost. Then it would take eighteen months for the planets to realign. Then it would take six months to get back, though I can see getting the travel time down to three months pretty quickly if America has the will.

I realized that a methane-oxygen rocket engine could achieve a specific impulse greater than 380.

I read books and talked to people. I mean that's kind of how one learns anything. There's lots of great books out there & lots of smart people.