Scott Kelly

The ride to orbit was impressive, as it always is. But once I got on board the space station, it really felt like I was visiting an old home; it felt very comfortable.

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.

If we're going to go farther from Earth, to Mars or somewhere else someday, we have to have a good understanding of the psychological impact on people. And not only psychologically, but how it affects their cognition. We're doing a lot of research on my cognitive abilities.