There's a need for accepting responsibility - for a person's life and making choices that are not just ones for immediate short-term comfort. You need to make an investment, and the investment is in health and education.

When you're in a spacecraft, you need to know what things you can touch and what things you shouldn't touch!

You need propellants to accelerate toward Mars, then to decelerate at Mars, again to re-accelerate from Mars to Earth, and finally to decelerate back at Earth. Accordingly, the mass of these required propellants, in short, drives our need for innovative launch vehicles.

For every winner, there’s a loser. And that person didn’t really need to lose. They just didn’t understand the game plan.

One of the major problems with long-term deep space human flight is the requirement for radiation shielding.

I came to dedicate my life to opening space to the average person and crafting designs for new spaceships that could take us far from home. But since Apollo ended, such travels were only in our collective memory.