On June 15, 2017, at 03:00 the “Long March –4B” (“Changzheng-4B”) rocket-carrier was launched from the Jiuquan Satellite Launch Center in Jiuquan, Gansu Province, the northwest of China. The rocket orbited the HXMT (Hard X-ray Modulation Telescope) “Huiyan” China’s first X-ray astronomy satellite.