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.

One Chief Astronaut used to make a point of phoning the front desk at the clinic where applicants are sent for medical testing, to find out which ones treated the staff well-and which ones stood out in a bad way. The nurses and clinic staff have seen a whole lot of astronauts over the years, and they know what the wrong stuff looks like. A person with a superiority complex might unwittingly, right there in the waiting room, quash his or her chances of ever going to space.

Our role is to develop techniques that allow us to provide emergency life-saving procedures to injured patients in an extreme, remote environment without the presence of a physician.

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.

Still, I also know that most people, including me, tend to applaud the wrong things: the showy, dramatic record-setting sprint rather than the years of dogged preparation or the unwavering grace displayed during a string of losses. Applause, then, never bore much relation to the reality of my life as an astronaut, which was not all about, or even mostly about, flying around in space.

I'm not a wealthy person and I don't think that I would be able to prioritize that much money to go for a ride to a place that I have already lived. But if the price comes down or I win a lottery or something, why not?

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