Creepy but true space incidents, part 1. Imagine you're alone in a tiny spacecraft, it's your first time up there, all alone in endless space. Then suddenly, a knocking sound. That's what happened to Yang Liwei, China's first man in space, on his maiden flight in 2003. Astronaut Yang Liwei, was sitting in his space shuttle when he repeatedly heard a knock. According to him, it sounded like somebody hammering an iron bucket with a mallet made of wood. As sound can't travel in space, Li Wei couldn't discern if the knocking was inside the shuttle or outside. Anxious Li Wei looked out the porthole, but he didn't see anything that could explain the mysterious knocking. After returning to Earth, Li Wei tried to explain the knocking to experts, but he failed to recreate the exact sound he heard in space. The story becomes eerier, because many other Chinese astronauts claimed to hear similar sounds, on their space trips during 2005 and 2008.