The China Aerospace Science and Technology Corporation (CASC) is the main contractor for the Chinese space program. It is state-owned and has a number of subordinate entities which design, develop and manufacture a range of spacecraft, launch vehicles, strategic and tactical missile systems, and ground equipment. It was officially established in July 1999 as part of a Chinese government reform drive, having previously been one part of the former China Aerospace Corporation. Various incarnations of the program date back to 1956.
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.