Square astronaut, round hole. But somehow, I'd managed to push myself through it, and here was the truly amazing part: along the way, I'd become a good fit. It had only taken 21 years.

Spaceflight isn't just about doing experiments, it's about an extension of human culture.

Our role is to develop techniques that allow us to provide emergency life-saving procedures to injured patients in an extreme, remote environment without the presence of a physician.

Don't let life randomly kick you into the adult you don't want to become

Almost everything worthwhile carries with it some sort of risk.

Decide in your heart of hearts what really excites and challenges you, and start moving your life in that direction

Every single day you're the result of what you did on the days prior.

Focus on the journey, not on arriving at a certain destination.

Remember, nobody changes the world on their own.

Every decision you make, from what you eat to what you do with your time tonight, turns you into who you are tomorrow and the day after that.

The cool things about space is when you put your pants on here, you can put them on two legs at a time.

Even as I think them, the words lose their context, dissolve into grains of absurdity in the vast ocean of day-to-day hunger.

God's glory in our lives has little to do with our sacrifice and everything to do with our surrender.

I'm not afraid of heights, I actually want to go higher.

I explained it loudand clear. What part of "meow"don't you understand?

Open markets offer the only realistic hope of pulling billions of people in developing countries out of abject poverty, while sustaining prosperity in the industrialized world.

Two paradoxes are better than one they may even suggest a solution.

What is greatness? Greatness is when you have found out that you are not great, but everything else is.

I never found much comfort in overly organized religion of any sort.

God's commandments not only reflect His holiness, they promote our happiness.

There's a flip side to having prominent public intellectuals, which is that they start meddling in politics and often with quite disastrous results.