Inter-satellite communications satellites

decommissioned ESA communication satellite

network of communication satellites and ground stations

series of geosynchronous Russian radio relay satellites

Tianlian (Simplified Chinese: 天链, Traditional Chinese: 天鏈, English: Sky Link) also known as CTDRS, is a Chinese data relay communication satellite constellation. The constellation serves to relay data from ground stations to spacecraft and rockets, most significantly China's crewed spaceflight program. The system currently consists of ten satellites in two generations, with the first satellite being launched in 2008.