You can just reload, propel it and fly again. This is extremely important for revolutionizing access to space because as long as we continue to throw away rockets and space crafts, we will never truly have access to space.

There are some important differences between me and Tony Stark, like I have five kids, so I spend more time going to Disneyland than parties.

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

Let's think beyond the normal stuff and have an environment where that sort of thinking is encouraged and rewarded and where it's okay to fail as well. Because when you try new things, you try this idea, that idea... well a large number of them are not gonna work, and that has to be okay. If every time somebody comes up with an idea it has to be successful, you're not gonna get people coming up with ideas.

Patience is a virtue, and I'm learning patience. It's a tough lesson.

It's important that we attempt to extend life beyond Earth now. It is the first time in the four billion-year history of Earth that it's been possible, and that window could be open for a long time - hopefully it is - or it could be open for a short time. We should err on the side of caution and do something now.

Biofuels such as ethanol require enormous amounts of cropland and end up displacing either food crops or natural wilderness, neither of which is good.