We can continue to try and clean up the gutters all over the world and spend all of our resources looking at just the dirty spots and trying to make them clean. Or we can lift our eyes up and look into the skies and move forward in an evolutionary way.

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.

I think humans will reach Mars, and I would like to see it happen in my lifetime.

We can continue to try and clean up the gutters all over the world and spend all of our resources looking at just the dirty spots and trying to make them clean. Or we can lift our eyes up and look into the skies and move forward in an evolutionary way.

Mars is there, waiting to be reached.

'Anthony and the Magic Picture Frame' tells it like it really was in America's early space program - the adventure, the risks, and the rewards.

A family needs to work as a team, supporting each other's individual aims and aspirations.

A mind concerned about danger is a clouded mind. It's paralyzing.

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.

All the Chinese have to do is fly around the Moon and back, and they'll appear to have won the return to the Moon with humans. They could put one person on the surface of the Moon for one day and he'd be a national hero.

America can take man to the moon, and America can take men to Mars - and beyond.

America's can-do spirit cast a warm glow across nations and cultures, generating more goodwill and support for our country's ideals and causes than had otherwise been possible.

American greatness was elevated significantly after Sputnik.

Any observations from the Moon or a sense of realising this or that about the greater meaning of things wasn't as influential for me as the experience of coming back and dealing with being a person who's been to the Moon.

Anything we can do in the near future that begins to stimulate the interest of people - seeing somebody down the street have an opportunity to go into space - buoys up the whole neighborhood.

Armstrong described the lunar surface as 'beautiful.' I thought to myself, 'It's not really beautiful. It's magnificent that we're here, but what a desolate place we are visiting.'

As a student, I wrote English reports on science fiction.

As someone who flew two space capsules and twice landed in the ocean, I can attest from personal experience how much logistics work is needed to get you home.

As we begin to have landings on the moon, we can alternate those with vertical launch of similar crew modules on similar launch vehicles for vertical-launch tourism in space, if you want to call it that... adventure travel.

As we reflect back upon the tragic loss of Challenger and her brave crew of heroes who were aboard that fateful day, I am reminded that they truly represented the best of us, as they climbed aloft on a plume of propellant gasses, reaching for the stars, to inspire us who were Earthbound.

Astronauts are not superhuman. They lead ordinary lives and have varied personalities.

Astronauts working for the government will always need to be either pilots or mission specialists. Those who want to be pilots should have military experience - ideally, a test pilot background.

Because of his military service, Dad was buried in Arlington National Cemetery.

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.

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

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.

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.

By venturing into space, we improve life for everyone here on Earth - scientific advances and innovations that come from this kind of research create products we use in our daily lives.

Can you imagine, in 2030, taking a space cruise on the very ship that carried the first human beings to Mars? I can't believe that people wouldn't line up for that possibility.

Certainly, I've never wanted to live on past achievements.

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.

Do we really need these big, gigantic, heavy rockets? What if we launch a rocket that's empty, and its sole purpose is to act as a source of fuel on the Moon? Who should build that? Well, I think the U.S. should build that.

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

Everyone should take their hats off to Neil Armstrong. He is a humble guy who doesn't wave his own flag.

Everyone who's been in space would, I'm sure, welcome the opportunity for a return to the exhilarating experiences there.

Exploring Mars is a far different venture from Apollo expeditions to the moon; it necessitates leaving our home planet on lengthy missions with a constrained return capability.

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.

Extraordinary observations require extraordinary evidence.

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.

For the future, primarily, we must educate people in science, engineering, technology and math.

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.

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.

Going to Mars would evolve humankind into a two-planet species.

Growing up, I was fascinated with Buck Rogers' airplanes. As I began to mature in World War II, it became jets and rocket planes. But it was always in the air.

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

Heavy lifting doesn't need to be heavy spending if we do the job right.

I am Buzz Lightyear!

I am excited to think that the development of commercial capabilities to send humans into low Earth orbit will likely result in so many more Earthlings being able to experience the transformative power of space flight.

I am not sure about Bill Nelson. I haven't heard him say, 'Let's junk the NASA plan to send humans to the moon.' He's not about to say that. That would not be very popular.