The pilgrims on the Mayflower landed at Plymouth Rock. To my knowledge, they didn't wait around for a return trip to Europe. You settle some place with a purpose. If you don't want to do that, stay home. You avoid an awful lot of risks by not venturing outward.

Exploring and colonizing Mars can bring us new scientific understanding of climate change, of how planet-wide processes can make a warm and wet world into a barren landscape. By exploring and understanding Mars, we may gain key insights into the past and future of our own world.

Look at what Silicon Valley has done - the advance of computers.

Space tourism is a logical outgrowth of the adventure tourist market.

During the divorce process, I lived alone and tended to get extremely down on myself.

Fighter pilots have ice in their veins. They don't have emotions. They think, anticipate. They know that fear and other concerns cloud your mind from what's going on and what you should be involved in.

Going back to the moon is not visionary in restoring space leadership for America. Like its Apollo predecessor, it will prove to be a dead end littered with broken spacecraft, broken dreams and broken policies.

I think the American Dream used to be achieving one's goals in your field of choice - and from that, all other things would follow. Now, I think the dream has morphed into the pursuit of money: Accumulate enough of it, and the rest will follow.

Globalisation means many other countries are asserting themselves and trying to take over leadership. Please don't ask Americans to let others assume the leadership of human exploration. We can do wonderful science on the Moon, and wonderful commercial things. Then we can pack up and move on to Mars.

I want people to go into space, to orbit around the world a few times, even to stay there for 24 hours and then come back to where they took off. And I also want people with a low income to be able to do that, not only rich people.

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.

By refocusing our space program on Mars for America's future, we can restore the sense of wonder and adventure in space exploration that we knew in the summer of 1969. We won the moon race; now it's time for us to live and work on Mars, first on its moons and then on its surface.

We could have human intelligence in orbit around Mars, building things there.

The beauty of Hawaii probably surpasses other places. I like the Big Island and the two mountains, Mauna Loa and Mauna Kea, where you can look out at the stars.

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.

Space is not just going up and coming back down again. Space is getting into orbit and being there, living there, establishing a presence, a permanence.

Absolutely the United States should lead in space, for the survival of the United States. It's inspiring for the next generation. If we lose leadership, then we'll be using Chinese capability to inspire Americans.

Whenever I gaze up at the moon, I feel like I'm on a time machine. I am back to that precious pinpoint of time, standing on the foreboding - yet beautiful - Sea of Tranquility. I could see our shining blue planet Earth poised in the darkness of space.

The way I see it, what is going to come out of the moon activities is a respect for U.S. leadership.

Whenever I gaze up at the moon, I feel like I'm on a time machine. I am back to that precious pinpoint of time, standing on the foreboding - yet beautiful - Sea of Tranquility. I could see our shining blue planet Earth poised in the darkness of space.

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

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.