The Danger Is Different From

When I Stand On The Edge Of A Cliff Or Right At The Edge Of A Building Or Something, It's One Of The Few Things That Gives Me Kind Of A Deep, Overwhelming, Irrational Fear Where It Affects My Physiology.

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.

I've Had A Chance To Fly A Lot Of Different Airplanes, But It Was Nothing Like The Shuttle Ride.

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.

My Optimism And Confidence Come Not From Feeling I'm Luckier Than Other Mortals, And They Sure Don't Come From Visualizing Victory. They're The Result Of A Lifetime Spent Visualizing Defeat And Figuring Out How To Prevent It. Like Most Astronauts, I'm Pretty Sure That I Can Deal With What Life Throws At Me Because I've Thought About What To Do If Things Go Wrong, As Well As Right. That's The Power Of Negative Thinking.