If you go on a journey to Mars and get into deep space, there is several hundred times, maybe 300 times the radiation.

People do really well on space missions, but it's the physiological, the medical stuff, the stuff like radiation, loss of bone mass and muscle mass and density. It's those things that we need to figure out.

I personally think going to Mars, if it takes two years or two and a half years, that's doable. Certainly, the first people who go there, that's going to be a big motivator, being first getting to Mars.

The Earth is a beautiful planet. The space station is a great vantage point to observe it and share our planet in pictures. It makes you more of an environmentalist.

During my time in orbit, I lost bone mass, my muscles atrophied, and my blood redistributed itself in my body, which strained my heart. Every day, I was exposed to ten times the radiation of a person on Earth, which will increase my risk of a fatal cancer for the rest of my life.

I fell in love, not deep, but I fell several times and then fell out.