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.
TH 1 (Tianhui-1 = "Sky drawing") is a Chinese stereo-topographic mapping satellite operated by the People’s Liberation Army (PLA). The satellites are built by the Hangtian Dongfanghong Weixing Corporation and the China Aerospace Science and Technology Corporation and the Chinese Academy of Space Technology (CAST). The satellites operate on a 500 km circular sun synchronous orbit. Electrical power is provided by two deployable solar panels that is stored on onboard batteries. They are equipped with a three-dimensional survey camera and a CCD camera with a ground resolution of 5 meters, spectral region of 0.51 µm to 0.69 µm and with a camera angle of 25 degrees. Also on board is a multi-spectral camera with a ground resolution of 10 meters operating in four spectral bands of 0.43 µm to 0.52 µm, 0.52 µm to 0.61 µm, 0.61 µm to 0.69 µm, and 0.76 µm to 0.90 µm. The swath width of the cameras is 60 kilometers wide.