China's aeronautics and astronautics industry was established in the 1950s. At Xi'an, Shanghai, Shenyang and Chengdu, respectively, there are four large airplane manufacturing bases, capable of producing civilian and military aircraft. The "Yun 7" airliner produced by the Xi'an Aircraft Corporation has become the major type used for medium and short domestic flights. Since 1979, the China Aerospace Corporation has established trade, economic and technical cooperation relationships with more than 70 countries and regions, one after another, in various forms. It has exported airplanes, engines and airborne installations to several countries, and manufactured airplanes and engine components for foreign factories and business people. With a complete system encompassing research, design, trial manufacture, testing and production, China's astronautics industry is capable of developing various types of carrier rockets, and developing and launching all kinds of satellites. Moreover, an aerospace instrumentation and command system has been established. Now among the world's leaders insatellite research and launching, China has mastered all kinds of technologies, including satellite recovery, the launching of satellites with single carrier rockets, satellite survey and control, and strong-propulsion carrier rocket trussing. China is capable of launching remote-sensing satellites into near-earth orbit and earth-synchronous orbit, and meteorological satellites into sun- synchronous or.bit. It is also capable of providing satellite launching and monitoring and control services for foreign countries. On November 20, 1999 the first spacecraft, named "Shenzhou," developed by China was launched by a China-made carrier rocket, and returned to earth after fulfilling space science experiments. According to statistics, between 1970 and 1999, China's Long March series carrier rockets successfully launched 51 satellites (excluding those lanched by China for foreign countries).