Long March 3 Launch Vehiclel“長征三號”運載火箭Long March 3 (LM-3) is a three-stage launch vehicle, primarily intended for sending spacecraft into Geosynchronous Transfer Orbit with the GTO capacity of l. 5 metric tons and the length of 44. 56m. The diameters of the first and second stages of LM-3 are the same, 3. 35m and the third stage, 2.25m. The development of the first and second stages is based on the first and second stages of LM-2C. The first two stages burn UDMH/N204 as propellants, while the third stage of LM-3 is powered by a cryogenic engine, using liquid oxygen ( LOX) and liquid hydrogen( LH2 ) as propellants .The launch site is Xichang Space Launch Center. The C2-3 launch vehicle won a perfect success in April, 1984. The vehicle also marked the first use of a high technology upper stage. On April 7, 1990, LM-3 delivered the first foreign communication satellite, Asia Sat l, made by the U. S. Hughes Corporation, into a predetermined GTO. It was a total success and marked the real entrance of Long March launch vehicles for China into the international commercial launch service market.“長征三號”運載火箭是三級火箭，主要用于發射地球同步軌道有效載荷，運載能力為1.5噸。全長44. 56米，一、二子級直徑3.35米、三子級直徑2. 25米。其一、二級是在“長征二號丙”運載火箭的一、二子級的基礎上研制的，使用偏二甲肼( UDMH)和四氧化二氮(N204)作為推進劑，其三子級采用了低溫高能液氫( LH2)液氧(LOX)發動機。“長征三號”火箭在西昌衛星發射中心(XSLC)進行發射。“長征三號”運載火箭在1984年4月進行首次飛行，成功地將“東方紅二號”試驗通信衛星送入預定地球同步轉移軌道，標志著中國運載火箭技術跨人世界先進行列。該火箭曾于1990年4月7日成功地將美國休斯公司制造的“亞洲1號”衛星送人地球同步轉移軌道，是中國運載火箭發展上的一個重要里程碑。在此之后，“長征三號”運載火箭成功地發射了包括“亞太一號衛星”、“亞太一號甲衛星”、“風云二號衛星”等在內多顆國內外衛星。