On May 20, 2018 at 21:28 UTC (on May 21 at 05:28 Beijing time) the Chang Zheng-4 (Long March-4) rocket-carrier was launched from Xichang Cosmodrome, Sichuan province, southwestern China. The rocket orbited the “Queqiao” relay satellite, which will serve as a communication relay satellite between Earth and the lunar farside.