I want to know: How does a space suit on Mars work? Show me how it is pressurized, and how it is cooled. What's the glove design? None of that stuff can be bought off the rack. It does not exist. You can't just go to SpaceMart and buy those things.

Remember, nobody changes the world on their own.

"What's the next thing that's going to kill me?" is a mantra for pilots and astronauts.

You can't just ignore spacewalking suit; it partially defines the experience. So maybe the most difficult thing is becoming completely attuned to efficiently wearing a garment that is so inhibiting to motion, and making it look effortless, as if it's the most natural thing to be out there on a spacewalk.

The danger is different from the fear. ... [practice] what to do if things go wrong, as well as right.

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.

Doing a space walk. It is one of the most rare human experiences. To leave your spaceship and go outside, so that you are alone in the universe with Earth distant and the universe around you. That is amazing.