CZ-5B

The Long March 5B Payload Fairing

LM5B during rollout to LC101

Description:

• The Long March-5 is considered the basic variant of this launcher family. It is a two-stage core vehicle (5 meter diameter) with four strap-on boosters (3.35 meter diameter), capable of launching 14,000 kg to GTO. The total length is 56.97 meters, has a gross mass of 869,000 kg and a lift-off thrust of 10,573 kN.
• The Long March-5B is a one-stage core vehicle (5 meter diameter) with four strap-on boosters (3.35 meter diameter), capable of launching 22,000 kg to LEO. The total length is 53.70 meters, has a gross mass of 837,500 kg and a lift-off thrust of 10,573 kN.
• The inaugural flight was scheduled for 2013, but the China Academy of Launch Vehicle Technology (CALT) and the Shanghai Academy of Spaceflight Technology (SAST) would have to endure a hard road to the first flight. Facing enormous technical challenges, the development of the YF-100 and YF-77 engines would delay the development of the new launch vehicle family.
• The first stage length is 31.02 meters, with a 5.00 meter diameter. The first stage is equipped with two YF-77 engines consuming LOX/LH. The first stage has a gross mass of 175,800 kg with an empty mass of 17,800 kg.
• The strap-on boosters have a length of 26.28 meters and a 3.25 meter diameter. Each strap-on booster is equipped with two YF-100 engines. Gross mass is 147,000 kg with an empty mass of 12,000 kg. The YF-100 engine consumes LOX and kerosene.
• The second stage is 12.00 meters long, with a 5.00 meter diameter. It is equipped with two YF-75D engines, consuming LOX/LH. The second stage has a gross mass of 26,000 kg with an empty mass of 3,100 kg.
• The YF-77 engine, developed by the Academy of Aerospace Launch Propulsion Technology (AALPT), is a high performance and reliable booster designed for the Long March-5 family. This is the first high-thrust cryogenic engine developed in China, taking a big technological step with respect to previous Chinese cryogenic Oxygen/Hydrogen engines, such as YF-75 which powers the LM-3A/3B′s upper stage.
• The engine utilizes a gas generator cycle with cryogenic LOX/LH2 propellants. Two YF-77 engines fly on the first stage of the Long March-5, and each engine provides 700-kN in vacuum at an oxidizer-to-fuel mixture ration (O/F) of 5.5. The YF-77 develops 700 kN at vacuum and 510 kN at sea-level with an Isp of 430 seconds (vacuum) and 310.2 seconds (sea-level). Burn time is 520 seconds.
• The YF-100 development began in 2000 at the Academy of Aerospace Liquid Propulsion Technology. The engine was certified by the State Administration of Science, Technology and Industry for National Defense (SASTIND) in May 2012. It is a staged combustion cycle engine developing 1,199.19 kN at sea-level with an Isp of 300 seconds (vacuum thrust is 1,339.48 kN; vacuum Isp is 335 seconds). Burn time is 155 seconds. The YF-100 is also used on the CZ-6 launch vehicle.
• The YF-75D engine is a LOX/LH2 closed expander cycle engine that is designed to meet the requirements of second stage propulsion of the new generation LM-5 launch vehicle for its performance, reliability, development cost, schedule, etc. The YF-75D engine is capable of throttling its mixture ratio and multi-start so that it will be suited to various missions. The YF-75D engine has two turbopumps driven by gaseous hydrogen. They are designed in series and gimbaled with the whole engine. The YF-75D develops 88.26 kN at vacuum with an Isp of 442 seconds. Burn time is 780 seconds.
• The payloads orbited by the LM-5 are initially protected by a payload fairing with a 5.2 meter diameter and a 12.5 meter length.

Mission:

• The 21.6 tonne CZ-5B core stage was left in a 157 x 372 km orbit, which decayed by May 11 to 124 x 153 km. During its last orbit it flew directly over Los Angeles and New York City. The core stage began an uncontrolled reentry at 1534 UTC May 11 over 20W 20N, as it flew over the Atlantic heading towards Nouakchott, Mauritania. Some of the denser debris impacted the ground 2200 km further downtrack, in the Bocanda region of Cote d'Ivoire. 10-metre-long metal rods fell from the sky in several villages, causing minor damage to houses and equipment but no reported casualties. Infrasound measurements confirm the identification of the event as related to the reeentry. CZ-5B-Y1 was the 5th most massive object ever to make an uncontrolled reentry, after OV-102 Columbia (2003), Skylab (1979), Skylab S-II rocket (1975), and Salyut-7 (1991).