Long March 3B

Rendering of Long March 3B
Function	Launch vehicle
Manufacturer	China Academy of Launch Vehicle Technology (CALT)
Country of origin	China
Cost per launch	US$50-70 million[1][2][3]
Size
Height	3B: 54.8 m (180 ft)[4] 3B/E: 56.3 m (185 ft)[5]
Diameter	3.35 m (11.0 ft)[4]
Mass	3B: 425,800 kg (938,700 lb) 3B/E: 458,970 kg (1,011,860 lb)[5]
Stages	3 / 4
Capacity
Payload toLEO
Mass	11,500 kg (25,400 lb)[6][7]
Payload toSSO
Mass	7,100 kg (15,700 lb)[6][7]
Payload toGTO
Mass	3B: 5,100 kg (11,200 lb)[6][7] 3B/E: 5,500 kg (12,100 lb)[5]
Payload toGEO
Mass	2,000 kg (4,400 lb)[7]
Payload toHCO
Mass	3,300 kg (7,300 lb)[6][7]
Associated rockets
Family	Long March
Derivative work	Long March 3C
Comparable	Atlas V Delta IV Falcon 9 (reusable) GSLV Mk III H-IIA Zenit-3F
Launch history
Status	3B: Retired 3B/E: Active
Launch sites	Xichang LC-2, LC-3
Total launches	112 3B: 12 3B/E: 100
Success(es)	108 3B: 10 3B/E: 98
Failures	2 3B: 1 (Intelsat 708) 3B/E: 1 (Palapa-N1)
Partial failures	2 3B: 1 (Palapa-D) 3B/E: 1 (ChinaSat 9A)
First flight	3B: 14 February 1996 (Intelsat 708) 3B/E: 13 May 2007 (NigComSat-1)
Last flight	3B: 18 September 2012 (Compass M5, M6) 3B/E: 21 November 2025 (TJS-21)
Carries passengers or cargo	Chang'e 3,Chang'e 4,BeiDou,ChinaSat,Tianwen-2
Boosters (3B)
No. boosters	4
Height	15.33 m (50.3 ft)
Diameter	2.25 m (7 ft 5 in)
Propellant mass	37,700 kg (83,100 lb)
Powered by	1 ×YF-25
Maximum thrust	740.4 kN (166,400 lbf)
Specific impulse	2,556.2 m/s (260.66 s)
Burn time	127 seconds
Propellant	N2O4 /UDMH
Boosters (3B/E)
No. boosters	4
Height	16.1 m (53 ft)
Diameter	2.25 m (7 ft 5 in)
Propellant mass	41,100 kg (90,600 lb)
Powered by	1 ×YF-25
Maximum thrust	740.4 kN (166,400 lbf)
Specific impulse	2,556.2 m/s (260.66 s)
Burn time	140 seconds
Propellant	N2O4 /UDMH
First stage (3B)
Height	23.27 m (76.3 ft)
Diameter	3.35 m (11.0 ft)
Propellant mass	171,800 kg (378,800 lb)
Powered by	4 ×YF-21C
Maximum thrust	2,961.6 kN (665,800 lbf)
Specific impulse	2,556.5 m/s (260.69 s)
Burn time	145 seconds
Propellant	N2O4 /UDMH
First stage (3B/E)
Height	24.76 m (81.2 ft)
Diameter	3.35 m (11.0 ft)
Propellant mass	186,200 kg (410,500 lb)
Powered by	4 ×YF-21C
Maximum thrust	2,961.6 kN (665,800 lbf)
Specific impulse	2,556.5 m/s (260.69 s)
Burn time	158 seconds
Propellant	N2O4 /UDMH
Second stage
Height	12.92 m (42.4 ft)
Diameter	3.35 m (11.0 ft)
Propellant mass	49,400 kg (108,900 lb)
Powered by	1 ×YF-24E YF-22E (Main) YF-23F (Vernier)
Maximum thrust	742 kN (167,000 lbf) (Main) 47.1 kN (10,600 lbf) (Vernier)
Specific impulse	2,922.57 m/s (9,588.5 ft/s) (Main) 2,910.5 m/s (9,549 ft/s) (Vernier)
Burn time	185 seconds
Propellant	N2O4 /UDMH
Third stage
Height	12.38 m (40.6 ft)
Diameter	3.0 m (9.8 ft)
Propellant mass	18,200 kg (40,100 lb)
Powered by	2 ×YF-75
Maximum thrust	167.17 kN (37,580 lbf)
Specific impulse	4,295 m/s (438.0 s)
Burn time	478 seconds
Propellant	LH2 /LOX
Fourth stage (optional) –YZ-1
Powered by	1 ×YF-50D
Maximum thrust	6.5 kN (1,500 lbf)
Specific impulse	315.5 s (3.094 km/s)
Propellant	N2O4 /UDMH
[edit on Wikidata]

TheLong March 3B (Chinese:长征三号乙;pinyin:Chángzhēng sānhàoyǐ), also known as theCZ-3B andLM-3B, is a Chineseorbitallaunch vehicle. Introduced in 1996, it is launched from Launch Area 2 and 3 at theXichang Satellite Launch Center inSichuan. A three-stage rocket with four strap-onliquid rocket boosters, it is the heaviest variant of the Long March 3 rocket family, and is mainly used to placecommunications satellites andnavigation satellites intogeosynchronous orbits.

An enhanced version, the Long March 3B/E or G2, was introduced in 2007 to increase the rocket'sgeostationary transfer orbit (GTO) cargo capacity and lift heaviergeosynchronous orbit (GEO) communications satellites. The Long March 3B also served as the basis for the medium-capacityLong March 3C, which was first launched in 2008.

As of 21 November 2025^[update], the Long March 3B, 3B/E and 3B/G5 have conducted 108 successful launches, plus 2 failures and 2 partial failures, accumulating a success rate of96.4%. It is the firstLong March series rocket to accumulate 100 orbital launches.

The development of the Long March 3B began in 1986 to meet the needs of the international GEO communications satellite market. During its maiden flight, on 14 February 1996 carrying theIntelsat 708 satellite, the rocket suffered a guidance failure two seconds into the flight and destroyed a nearby town, killing at least six people,^[8] but outside estimates suggest that anywhere between 200 and 500 people might have been killed.^[9] However, the author of the report^[9] later ruled out large casualties, because evidence suggest that the crash site was evacuated before the launch.^[10]

The Long March 3B and 3B/E rockets conducted ten successful launches between 1997 and 2008.^[5]

In 1997, theAgila 2 satellite was forced to use onboard propellant to reach its correct orbit because of poor injection accuracy on the part of its Long March 3B launch vehicle.^[11] In 2009, a Long March 3B partially failed during launch due to a third stage anomaly, which resulted in thePalapa-D satellite reaching a lower orbit than planned.^[12] Nonetheless, the satellite was able to maneuver itself into the planned orbit. The Long March 3B and its variants remain in active use as of January 2021^[update], having conducted a total of 26 consecutive successful launches, since 19 June 2017 until 9 March 2020.

In December 2013, a Long March 3B/E successfully liftedChang'e 3, China's first Lunar lander and rover into the projected lunar-transfer orbit.

In April 2020, the third stage of the Long March 3B/E failed during a Palapa-N1 communications satellite mission; this was the first total failure of the Long March 3B/E.^[13]

The Long March 3B is based on the Long March 3A as its core stage, with fourliquid boosters strapped on the first stage. It has alow Earth orbit (LEO) cargo capacity of 11,200 kg (24,700 lb) and a GTO capacity is 5,100 kg (11,200 lb).

The Long March 3B/E, also known as 3B/G2, is an enhanced variant of the Long March 3B, featuring an enlarged first stage and boosters, increasing its GTO payload capacity to 5,500 kg (12,100 lb).^[14] Its maiden flight took place on 13 May 2007, when it successfully launchedNigeria'sNigComSat-1, the firstAfricangeosynchronouscommunications satellite. In 2013, it successfully launched China's first lunar landerChang'e 3 and lunar roverYutu.

Since 2015, the Long March 3B and 3C can optionally accommodate aYZ-1 upper stage, which has been used to carry dual launches orBeiDou navigation satellites intomedium Earth orbit (MEO).

A modified version of the Long March 3B, theLong March 3C, was developed in the mid-1990s to bridge the gap in payload capacity between the Long March 3B and3A. It is almost identical to the Long March 3B, but has two boosters instead of four, giving it a reduced GTO payload capacity of 3,800 kg (8,400 lb). Its maiden launch took place on 25 April 2008.

• Intelsat 708
• Beidou
• Chang'e 3
• Chang'e 4
• Tianwen-2
• Eutelsat W3C
• TJS-5
• Apstar 6C
• Chinasat 9A
• Chinasat 6C
• Palapa-D
• Fengyun 4B
• NigComSat-1
• Tiantong 1-03
• Gaofen 14

On 14 February 1996, the launch of the first Long March 3B withIntelsat 708 failed just after liftoff when the launch vehicle veered off course and exploded when it hit the ground at T+23 seconds.

TheXinhua news agency reported that six people were killed and 57 injured. However, the Americans on hand for the launch have testified that "dozens, if not hundreds", of people were seen to gather outside the centre's main gate near the crash site the night before launch.^[21] When reporters were being taken away from the site, they found that most buildings had sustained serious damage or had been flattened completely.^[21] Other eyewitnesses were noted as having seen dozens of ambulances and many flatbed trucks, loaded with what could have been human remains, being taken to the local hospital.^[21]

The cause of the accident was traced to short-circuiting of the vehicle's guidance platform at liftoff.^[22]

The participation ofSpace Systems/Loral in the accident investigation caused great political controversy in theUnited States. In 1997, the U.S. Defense Technology Security Administration found that China had obtained "significant benefit" from the Review Committee, results of which would improve their "launch vehicles ... ballistic missiles and in particular their guidance systems".

As a result, theU.S. Congress reclassified satellite technology as amunition and placed it back under the restrictiveInternational Traffic in Arms Regulations in 1998.^[23] No license to launch United States spacecraft on Chinese rockets has been approved by theU.S. State Department since then, and an official at theBureau of Industry and Security emphasized in 2016 that "no U.S.-origin content, regardless of significance, regardless of whether it's incorporated into a foreign-made item, can go to China".^[24]

On 31 August 2009, during the launch ofPalapa-D, the third stage engine under-performed and placed the satellite into a lower than planned orbit. The satellite was able to make up the performance shortfall using its own engine and reach geosynchronous orbit, but with its lifetime shortened to 10.5 years from the originally projected 15–16 years. The investigation found that the failure was due to burn-through of the engine's gas generator, and that "the most likely cause of the burn-through was a foreign matter or humidity-caused icing in the engine's liquid-hydrogen injectors".^[25]

On 19 June 2017, a Long March 3B/E mission carryingChinaSat-9A ended in partial failure. Officials did not release details regarding the status of the mission for at least 4 hours after liftoff.^[26] Two weeks later, on 7 July 2017, officials confirmed that the mission had been anomalous, with Space Daily reporting that "an anomaly was found on the carrier rocket's rolling control thruster, part of the attitude control engine, during the third gliding phase". The failure in the rocket's third stage left the payload in a lower than intended orbit, and the payload was forced to spend two weeks reaching its intended orbit under its own power.^[27]

On 9 April 2020, a Long March 3B launcher failed after lifting off from theXichang Satellite Launch Center in the southwesternSichuan province at 11:46 UTC during the launch of an Indonesian communications satellite,Palapa-N1 (Nusantara Dua) of a mass of 5500 kg and was expected to enter service in geostationary orbit at 113.0° East, replacing thePalapa-D satellite. But one of the twoYF-75 third stage engines failed to ignite, preventing the Palapa-N1 (Nusantara Dua) satellite from reaching orbit.^[28] Wreckage from the third stage and the Palapa-N1 spacecraft re-entered the atmosphere, leading to sightings of fiery debris in the skies over Guam. With the Long March 3B failure, Chinese rockets have faltered on two missions in less than a month. ALong March 7A rocket failed to place a satellite in orbit on 16 March 2020 after taking off from theWenchang Spacecraft Launch Site onHainan Island, located in southern China.^[29] After two Chinese launch failures in less than a month, further Chinese launches will be likely delayed until it is sure that the quality control is satisfactory.^[30]

Debris from Long March 3B launches have fallen on nearby villages due to the inland location of China's launch sites. Grid fins for guiding boosters down to Earth more accurately have been tested onLong March 2C and4B, but not yet on 3B.^[31]

• List of Long March launches (2025-2029)

• LM-3B User's Manual at GlobalSecurity.org
• Long March-3B (LM-3B)Archived 8 July 2011 at theWayback Machine at the China Academy of Launch Vehicle Technology

• Long March (rocket family)
• Vehicles introduced in 1996

• Source attribution
• CS1 maint: multiple names: authors list
• Articles with short description
• Short description matches Wikidata
• Use British English from March 2020
• All Wikipedia articles written in British English
• Use dmy dates from March 2020
• Articles containing Chinese-language text
• Articles containing potentially dated statements from November 2025
• All articles containing potentially dated statements
• Articles containing potentially dated statements from January 2021
• Webarchive template wayback links