Tianlian 1, also known as Tian Lian 1, TL-1, and CTDRS-1 is a Chinese data tracking and relay communications satellite series. Based on the DFH-3 satellite bus, it will provide communication coverage for manned Shenzhou missions, from Shenzhou 7 onwards. Functionally, it is similar to the United States Tracking and Data Relay Satellite System.