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.

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

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.

I don't think we're going to build a 50-person spacecraft or a 100-person spacecraft.

From the distance of the moon, Earth was four times the size of a full moon seen from Earth. It was a brilliant jewel in the black velvet sky.

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.

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.