My odyssey to become an astronaut kind of started in grad school, and I was working, up at MIT, in space robotics-related work human and robot working together.

To become an astronaut is not a question of being the best at something or things coming easy to you, but it's being a person that can work with others and not give up. And, for me, that was part of it too.

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.

Viewing our planet was so compelling. Words like beautiful and awesome just don't do it justice. I felt that I was looking at a paradise. I was looking at heaven. I can't imagine any place being more beautiful than our planet and how lucky we are to be able to live here.

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 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.

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