You can picture pretty easily if there were a paying passenger aboard a rocket that failed, like Challenger failed. Certainly it would be a tragedy, and a tragedy for the company. They would have a hard time recovering from it.

The view of earth is spectacular from space. Most people imagine that when astronauts look out the window of the shuttle they see the whole earth like that big blue marble that was made famous by the flights that went to the moon. But the shuttle is much, much closer than those astronauts were. So we don't see the whole planet, the whole ball at once, we just see parts of it.

Ever been to Disneyland? That was definitely an E ticket!

So most astronauts getting ready to lift off are excited and very anxious and worried about that explosion - because if something goes wrong in the first seconds of launch, there's not very much you can do.

Astronauts will remain the explorers, the pioneers-the first to go back to moon and on to Mars. But I think it's really important to make space space available to as many people as we can. It's going to be a while before we can launch people for less than $20 million a ticket. But that day is coming.

On both of my flights, everything went very well.

The experience of being in space didn't change my perspective of myself or of the planet or of life. I had no spiritual experience.