The emotional build-up and anticipation if you travel at Christmas can make it harder to enjoy a trip. I think sometimes it is better to travel outside of conventional holiday times for that reason.

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

Imbibe three or four times as much water as you think you need and skip at least one, if not two meals, when you are travelling. You should arrive at your destination feeling slightly hungry and your digestive system reset.

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

Do your homework in advance about the actual travel details so transportation issues do not define your holiday.

Ultimately, leadership is not about glorious crowning acts. It's about keeping your team focused on a goal and motivated to do their best to achieve it, especially when the stakes are high and the consequences really matter. It is about laying the groundwork for others' success, and then standing back and letting them shine.

Our three big emergencies are fire, loss of pressurization or contaminated atmosphere. Any of those things in a spaceship are very deadly and time critical. Everybody's trained, but I'm the commander of the ship, and it's up to me to decide.