When I stand on the edge of a cliff or right at the edge of a building or something, it's one of the few things that gives me kind of a deep, overwhelming, irrational fear where it affects my physiology.

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.

The Bahamas are gorgeous. The deep trench in the ocean floor called the Tongue of the Ocean, which comes between the islands, is the most beautiful deep indigo colour.

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.

The rough and ready improvisational quality to life on board the International Space Station is reminiscent of a long trip in a sailboat: privacy and fresh produce are in short supply, hygiene is basic, and a fair amount of the crew's time is spent just on maintaining and repairing the craft.

In my experience, fear comes from not knowing what to expect and not feeling you have any control over what’s about to happen. When you feel helpless, you’re far more afraid than you would be if you knew the facts.