China launches three astronauts to Tianhe space station

China has launched three astronauts on a three-month mission to the country's new space station, Tianhe. It’s the first of four crewed missions to build China's space station, which is due to be finished by the end of next year. Its completion will help cement China as a major space power. Victor Teo from the University of Cambridge explains what this means for China’s ambitions in space. #Tianhe