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.

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.

We need the next generation to be motivated and to push technological boundaries, to seek out new innovations.

Let's not spend resources that we don't need to be sending astronauts back to the moon. Let's not spend expensive resources on bringing people who have reached Mars back again. Prepare them to become a growing colony.

Not everyone will understand this need for America to lead the world in space.

The big companies are the private industry. But they're faced with a short-term need to show a profit in short-term.

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

Having walked on the Moon, I know something about what we need to explore, really explore, in space.