What's the best part of being an astronaut? Is it the excitement of leaving the Earth behind at the mind-boggling speed of 25,000 mph? Is it the chance to float around a shuttle in zero gravity? Or make new scientific discoveries? Or go out on a space walk? Few of us get to answer these questions for ourselves by rocketing into space. But a group of kids took the first step by going to U.S. Space Academy. For close to a week, they tried on flight...