China has followed last year’s secretive high-orbit satellite-to-satellite refuelling test with another in-orbit servicing mission that is aimed at advancing docking and refuelling technologies, while also testing ways to speed up the disposal of satellites at the end of their usefulness.Hukeda-2, which lifted off from the Jiuquan Satellite Launch Centre in the Gobi Desert on Monday, is China’s first commercial test satellite equipped with a flexible robotic arm to capture other spacecraft, the...