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

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.

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.

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.

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

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.