I suggest that going to Mars means permanence on the planet - a mission by which we are building up a confidence level to become a two-planet species.

I was motivated to improve the U.S. strategy of going back to the moon in 1985. That's a long time ago. Going back to the moon would be a great achievement for tourism adventure flights.

I was given permission to serve myself Communion, with wine and a wafer, on the surface on the Moon. But I was advised not to say anything about it at the time. Someone had strongly objected to the Apollo 8 crew reading from the Bible. We didn't want to get into any further trouble with the religious critics.

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.

To send humans back to the moon would not be advancing. It would be more than 50 years after the first moon landing when we got there, and we'd probably be welcomed by the Chinese. But we should return to the moon without astronauts and build, with robots, an international lunar base, so that we know how to build a base on Mars robotically.

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 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.