Maiden flight of Long March 5 heavy rocket started with 100 minutes of delay but finished with full success. It is already second maiden flight of Chinese rocket in 2016 performed from Wenchang Satellite Launch Center in Hainan Province and one from multiple successes of CNSA in present year.
Long March 5 is for sure important point of creating fleet of new rockets for CNSA; Long March 7 launched on June 25 was designed as medium rocket; it should be considered as launch vehicle for future Chinese spacecraft and replacement of Long March 2F (which remains in service since 1999). Also because of its modular construction it will cover most of launches conducted in China in following years. Long March 5 is heavy rocket comparable to Falcon-9 FT, Ariane 5 or Delta IV Heavy. Its usage is limited mainly for delivering heavy satellites and parts of the future modular space station planned by CNSA for 2020s. But in spite of number of differences, Long March 5 and Long March 7 are quite similar: they are using same engines and propellant and are sharing place of launch: Wenchang Satellite Launch Center (Launch Complex 101 is designated only for Long March 5, Launch Complex 201 is reserved for Long March 7).
Long March 5 have been waiting for launch since Friday October 28, when it was rolled out from assembling facility building. Today, launch was postponed for 100 minutes from 11:00 GMT to 12:40 GMT due the poor weather conditions over Wenchang Satellite Launch Center. Actually sky was covered with clouds and whole Launch Complex 101 was covered with fog. At 12:04 pressurizing of the fuel tanks started, but unfortunately live broadcast was terminated. Transmission was resumed shortly before start. Engines were ignited at 12:43 GMT and rocket finally started its maiden flight. Just after reaching safe distance from Launch Pad rocket started to fly towards East. At T+3' boosters were jettisoned and two minutes later payload fairing was released. At T+9' first stage was cut off and separated when rocket was flying on 127° East course on altitude of 196 km. At T+16' second stage was cut off and it continued ballistic flight with exposed YZ-2 upper stage. After ten minutes engine started again for six minutes and was cut off just before separation with YZ-2 at 13:14 GMT, just before separation of YZ-2 on altitude of 350 km. Upper stage started propulsion one minute later and was cut off seven minutes later. Second and last burn will be performed at T+5h53'40" and will last for 20 minutes.
Long March 5 is liquid fueled rocket designed by China Academy of Launch Vehicle Technology (CALT). Depending on configuration it can use 0, 2 or 4 boosters combined with core based on 2 or 3 stages. Rocket was designed as more environment friendly, what is present trend in designing Chinese rockets. Boosters are fueled with RP-1/LOX; first and second stages of the core of the rocket are fueled with LH/LOX. Rocket length is planned for 62 m with diameter at 5 m and total mass at 867 t. Rocket will be able to deliver 25 t of payload to LEO orbit with altitude of 200 km and 14 t to GTO. CALT also designed restartable upper stage Yuanzheng-2 (YZ-2), which can be used for Long March 5. It is long for with diameter of 5.2 m and mass of 1800 kg. Payload fairing for Long March 5 has maximal dimensions of 12.5 m (length) x 5.2 m (diameter).
Version used for maiden flight was shorter, with length of 56 m and was equipped with four strap on boosters. It weighed 869 t with boosters, two stages and YZ-2 upper stage. Each booster was long for 26.28 m with 3.25 m of diameter. Propulsion of the each booster is based on two YF-100 engines (designed by Xi'an Aerospace Propulsion Institute and utilized also by Long March 5) burning 135 t of propellant and providing thrust of 1200 kN. First stage is long for 31.02 m and is powered with two YF-77 engines (designed by Academy of Aerospace Liquid Propulsion Technology) burning 158 t of propellant. They are generating thrust of 510 kN each. Second stage is significantly shorter - it is long for 12 m with identical diameter at 5 m. It stores 22.9 t of propellant and is powered by two YF-75D engines providing thrust at 88.26 kN.
UPDATE 11/11/2016: YZ-2 upper stage delivered directly to GEO orbit Shijian-17 research satellite.