Communication and relay satellite were developed to provide communication support for space exploration missions. With China’s lunar exploration program, we developed the CE-4 Relay satellite, which will support the communication between spacecraft. The satellite is the first spacecraft operating on Earth-Moon L2 Halo orbit to provide communication relay support for the lander and the rover Chinese Chang’e 4 lunar far side landing exploration mission. There are other communication and relay satellites in the demonstration phase. It was launched in May 2018.