My optimism and confidence come not from feeling I'm luckier than other mortals, and they sure don't come from visualizing victory. They're the result of a lifetime spent visualizing defeat and figuring out how to prevent it. Like most astronauts, I'm pretty sure that I can deal with what life throws at me because I've thought about what to do if things go wrong, as well as right. That's the power of negative thinking.

Scientific literacy is one of the underpinnings of everything I do. It's why I work with schools. It's why I teach at university. I do a lot of outreach to try and improve general scientific literacy, but the core of all scientific literacy is just literacy.

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.

Decide in your heart of hearts what really excites and challenges you, and start moving your life in that direction. 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. Look at who you want to be, and start sculpting yourself into that person. You may not get exactly where you thought you'd be, but you will be doing things that suit you in a profession you believe in. Don't let life randomly kick you into the adult you don't want to become.

I guarantee if you walk into 100 spider webs, you will have changed your fundamental human behavior. And you can apply this to anything, And figure out a way to reprogram yourself, to change your primal fear.

There is no problem so bad that you cannot make it worse

In all of the movie portrayals, a spacewalking suit seems sort of insignificant, like a pair of shorts and a T-shirt. No one thinks much about it. But it's a spaceship, not a spacesuit, an entire life-support mechanism that's incredibly complex and cumbersome. It's very difficult to put on and off. You have to run it the whole time you are wearing it, and it redefines how you move. It's like if you put on a wetsuit and a snowmobile suit and froze yourself solid and then tried to go and do work.