Tianlian is a Chinese data tracking and relay communications geostationary satellite series. The TL-3 (Tian Lian 3) satellites are the 3rd generation of China's geostationary orbit data relay satellites, based on the DFH-4E geostationary satellite bus. They will be used to support real-time communications between orbiting satellites/rockets in-flight and ground control stations. This system replaces/supplements the current network of ground-based space tracking and telemetry stations and space tracking ships.