China has launched twin BeiDou-3 navigation satellites, on a single carrier rocket. This brings the number of satellites in its domestic BeiDou Navigation System to 31. BeiDou is the Chinese word for Big Dipper. The Long March-3B carrier rocket lifted off from Xichang Satellite Launch Center in southwest China's Sichuan Province at 1:56 AM today. The two satellites entered orbit more than three hours later. They will work together with six previously launched BeiDou-3 satellites once they pass a series of tests. The BeiDou System started providing independent services over China in 2000. It will serve countries along the Belt and Road route by the end of this year.