"What are you going to do with astronauts who first reach the surface of Mars and then turn around and rocket back home-ward? What are they going to do, write their memoirs? Would they go again? Having them repeat the voyage, in my view, is dim-witted. Why don't they stay there on Mars?"

"NASA's been one of the most successful public investments in motivating students to do well and achieve all they can achieve, and it's sad that we are turning the program in a direction where it will reduce the amount of motivation it provides to young people."

"There's no doubt who was a leader in space after the Apollo Program. Nobody came close to us. And our education system, in science, technology, engineering and math, was at the top of the world. It's no longer there. We're descending rather rapidly."

"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."

"Bringing an asteroid back to Earth? What's that have to do with space exploration? If we were moving outward from there, and an asteroid is a good stopping point, then fine. But now it's turned into a whole planetary defense exercise at the cost of our outward exploration."

"If we go back to the moon, we're guaranteed second, maybe third place because while we are spending all that money, Russia has its eye on Mars. Landing people on the moon will be terribly consuming of resources we don't have. It sounds great - 'Let's go back. This time we're going to stay.' I don't know why you would want to stay on the moon."

"Computers allow us to squeeze the most out of everything, whether it's Google looking up things, so I guess that tends to make us a little lazy about reading books and doing things the hard way to understand how those things work."

"There may be aliens in our Milky Way galaxy, and there are billions of other galaxies. The probability is almost certain that there is life somewhere in space."

"If we can conquer space, we can conquer childhood hunger."

"I didn't start skiing until I was 50. My wife Lois taught me how to ski. I'm proficiently conservative."

"When I was a little kid, we only knew about our nine planets. Since then, we've downgraded Pluto but have discovered that other solar systems and stars are common. So life is probably quite prevalent."

"We must still think of ourselves as pioneers to understand the importance of space."

"The much-hyped Ares 1-X was much ado about nothing."

"Being first outside the spacecraft would bring much more responsibility, and I really wasn't looking for that."

"I want to reach a new generation. That's why I am Twittering now. I have a BlackBerry, an iPhone and a Mac."

"Before deciding what to do about national space policy, Obama set up an outside review panel of space experts, headed up by my friend Norm Augustine, former head of Lockheed Martin and a former government official."

"I think there would be no shortage of applicants to the government astronaut corps to be settlers on the planet Mars. And I think this would be very inspiring."

"Some things just can't be described. And stepping onto the moon was one of them."

"The guys who walk on Mars are going to be historic."

"Instead of planning the retirement of the Space Shuttle program, America should be preparing the shuttles for their next step in space: evolving, not shutting them down and laying off thousands of people."

"Space travel for everyone is the next frontier in the human experience."

"The first footfalls on Mars will mark a historic milestone, an enterprise that requires human tenacity matched with technology to anchor ourselves on another world."

"Every couple of years, we could dispatch people from Earth to Mars."

"I wrote 'Reaching for the Moon' because I wanted to tell kids that all of us have a moon, a dream, that we can strive for. Even if you don't attain it, you can at least reach for it."