On Saturday we mark a giant leap in history - the first time humans walked on the Moon. NASA's Apollo 11 flight was a stunning achievement. And it also inspired a generation of men and women to reach for the stars. One of them was Helen Sharman. In the 1990s she was selected from 13,000 applicants for the privately-funded Project Juno...spending eight days with a Soviet mission to the Mir Space Station. Derek Johnson spoke to Britain's first astronaut about space flight then and now.