British physicist Stephen Hawking, who is world-famous for his intellectual prowess as well as his physical frailty, has made a firm date with weightlessness on April 26, aboard a jet flying out of NASA's Kennedy Space Center in Florida. Hawking's excellent adventure, provided by California-based Zero Gravity Corp., would represent one small step toward the 65-year-old scientist's goal of flying in space as early as 2009 — as well as one giant leap for people with disabilities. "As someone who has studied gravity and black holes all of my life, I am excited to experience, firsthand, weightlessness and a zero-gravity...