It's always too early to quit.
Expect problems and eat them for breakfast.
Wherever you are - be all there.
If you've got a talent, protect it.
Quality is not an act, it is a habit.
Never complain and never explain.
Be gentle to all and stern with yourself.
Things do not happen. Things are made to happen.
Problems are not stop signs, they are guidelines.
Know or listen to those who know.
There's a lot of interest from the medical community on how things develop in microgravity, and the hope, later, that is expected to apply to what the changes are in humans as well.