To me, it's not about being anywhere, but being able to change my perceptions and experience something new.

Every single day you're the result of what you did on the days prior.

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.

Other anatomical changes associated with long-duration space flight are definitely negative: the immune system weakens, the heart shrinks because it doesn't have to strain against gravity, eyesight tends to degrade, sometimes markedly (no one's exactly sure why yet). The spine lengthens as the little sacs of fluid between the vertebrae expand, and bone mass decreases as the body sheds calcium. Without gravity, we don't need muscle and bone mass to support our own weight, which is what makes life in space so much fun but also so inherently bad for the human body, long-term.

Scientific literacy is one of the underpinnings of everything I do. It's why I work with schools. It's why I teach at university. I do a lot of outreach to try and improve general scientific literacy, but the core of all scientific literacy is just literacy.

To me, it's not about being anywhere, but being able to change my perceptions and experience something new.

If you start thinking that only your biggest and shiniest moments count, you're setting yourself up to feel like a failure most of the time.