MOSCOW, September 7 (RIA Novosti) - An American software billionaire has become the latest potential space tourist to start training outside Moscow, the Space Training Center said Thursday. Charles Simonyi, 58, a U.S. citizen of Hungarian descent and a key figure in developing Microsoft's Word and Excel applications, has signed a contract with Virginia-based orbital tourism firm Space Adventures this year for a 10-day science mission to the International Space Station in 2007. "Simonyi is seriously determined for the flight and he is ready for thorough and gradual preparations," a training center spokesperson said, adding that the first stage of...