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 wasn't lonely. Loneliness, I think, has very little to do with location. It's a state of mind. In the centre of every city are some of the loneliest people in the world. If anything, because our whole planet was just outside the window, I felt even more aware of and connected to the seven billion other people who call it home.
Early success is a terrible teacher. You're essentially being rewarded for a lack of preparation, so when you find yourself in a situation where you must prepare, you can't do it. You don't know how.
Life off Earth is in two important respects not at all unworldly: you can choose to focus on the surprises and pleasures, or the frustrations. And you can choose to appreciate the smallest scraps of experience, the everyday moments, or to value only the grandest, most stirring ones.
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.
My father was an airline pilot, so we travelled more spontaneously than a lot of families. On a Thursday, we could decide to go somewhere like Barbados the next day for a long weekend.
If you don't like airline food, you'll probably have the same impression of space station food. I would not fly to space for the food.
Airline food is cooked in an oven and then kept warm. Space station food is often cooked in an oven and then thermo-stabilised, irradiated or dehydrated and then stored for a year or two before you even get to it.
One place that I looked at a lot from space and which looks alluring is New Zealand, especially the North Island. It's a big broad valley with a river flowing through it, and you can see the wine-making dryness of the land.
Almost everything worthwhile carries with it some sort of risk, whether it's starting a new business, whether it's leaving home, whether it's getting married, or whether it's flying in space.
You could look at something a hundred times from space, but the next time you come around the world, suddenly it's very different and gorgeous-looking, just because of the change of weather or the angle of the sun.
And now for Return to Flight, I'm chief of robotics working in the astronaut office in Houston, as a Canadian.
We have never lost a crew member on the space station, but of course, the Columbia accident. I was - I'd already been an astronaut for a decade when the crew of Columbia was killed. And I went through test pilot school. Rick Husband and I were out at Edwards at test pilot school together. He was the commander of Columbia.
To be one of the world's top space robotic arm operators is a necessary skill for an astronaut, but it doesn't have much carry-over.
In the astronaut business - the shuttle is a very complicated vehicle; it's the most complicated flying machine ever built. And in the astronaut business, we have a saying, which is, 'There is no problem so bad that you can't make it worse.'
Now, as an astronaut, I have to bring a Sharpie with me everywhere - so I have a pen to sign autographs.
There are no wishy-washy astronauts. You don't get up there by being uncaring and blase. And whatever gave you the sense of tenacity and purpose to get that far in life is absolutely reaffirmed and deepened by the experience itself.
Nothing focuses your mind quite like flying a jet. That's one reason NASA requires that astronauts fly T-38s: it forces us to concentrate and prioritize in some of the same ways we need to in a rocket ship.
The International Space Station is a phenomenal laboratory, an unparalleled test bed for new invention and discovery. Yet I often thought, while silently gazing out the window at Earth, that the actual legacy of humanity's attempts to step into space will be a better understanding of our current planet and how to take care of it.
In the Soyuz, the little Russian capsule, you can actually hear the banging of the big shield, the big heat shield on the bottom, as it slowly erodes away from the heat and pieces of it fly off like sparks across your window, and it's an interesting thing to ride through, you know.