"Astrophysicist Stephen Hawking, who has been confined to a wheelchair for most of his adult life, expects weightlessness to feel like 'bliss' when he goes on a 'zero-gravity' flight Thursday aboard a refitted jet. . ."
This man has been living with ALS for over 40 years - many times over past the longest reasonable life expectancy he could have been given when diagnosed at age 21. He's now 65, and, oh yeah, during those intervening years he managed to compute many features of the space-time continuum and develop human understanding of our place in the universe. This guy is made of tougher stuff than the Iron Horse himself.
I think I'm going to re-read A Brief History of Time for my next book.