I applied to be an astronaut four times. I was rejected three times before I was accepted. So, it's about that, not - following your dream and not giving up.

Astronauts cannot pick their nicknames and can only get their nicknames from other astronauts. Any astronaut who tries to give himself a cool nickname will regret it by getting just the opposite from his astronaut friends.

The reason we have the stars twinkle at night is because the light is being kind of blurred by the atmosphere around the Earth. That is why the Hubble Space Telescope is so good, because it is above the atmosphere. So it is kind of like looking at the sun from the bottom of a swimming pool, versus looking at the sun above the swimming pool.

I think most astronauts are not risk takers. We take calculated risks for something that we think is worthwhile.

At every step of the way, when I had trouble, there were people that came in, in my life that helped me. It's important to go seek help when you need it, and to give help when other people need it. And that is really more important than coming in with a gigantic brain into the astronaut program.

The hardest thing for me as an astronaut was to improve my swimming skills.

I applied to be an astronaut four times. I was rejected three times before I was accepted. So, it's about that, not - following your dream and not giving up.