Mars, we know, was once wet and warm. Was it home to life? And what can living and learning to work on its rust-colored surface teach us about the future of our own planet, Earth? Answering those mysteries may hold the key to our future.

Unless we are able to commit to a permanent growing settlement [on Mars], then I don't think just going there with humans and coming back is worth doing. The expense of planning to come back is like the people who left Europe to come to America and then to turn around and go back to Europe, it really doesn't make any sense at all.

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

Apollo 11 will probably go down in history as one of the major responses of two nations facing each other with threatening technologies - sometimes called mutually assured destruction. It was also the America's response to the apparent superiority of the Russians in putting objects into space before USA could.

I was saddened to learn of the passing of Leonard Nimoy, a fellow space traveler because he helped make the journey into the final frontier accessible to us all.... Indeed, there are strange new worlds to explore -- to seek out new life and start new civilizations. It is time to boldly go where no man -- or woman -- has gone before. Thanks to Leonard Nimoy and his beloved Mr. Spock, the bar has been set high for us to continue humanity's quest to probe outward in the universe.

Knowledge of the past and an optimistic view of the present give you great opportunities.

There are a lot of reasons for not doing something. And if humanity had come up with all the reasons for not doing something we wouldn't have spread across the Earth the way we have. There's a curiosity, and I would submit that that curiosity will put human beings on the surface of Mars.