| Manufacturer | China Academy of Space Technology (CAST) |
|---|---|
| Country of origin | China |
| Operator | China Aerospace Science and Technology Corporation (CASC) |
| Applications | Tracking and Data Relay Satellite System |
| Specifications | |
| Bus | |
| Regime | Geostationary |
| Production | |
| Status | In service |
| Launched | 8 |
| Operational | 8 |
| Maiden launch | Tianlian I-01 25 April 2008 |
| Last launch | Tianlian II-03 12 July 2022 |
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 seven satellites in two generations, with the first satellite being launched in 2008.