Long March 3B
The launch of a Long March 3B carrier rocket at Xichang Satellite Launch Center.
|Function||GTO Carrier rocket|
|Country of origin||China|
|Height||3B: 54.838 metres (179.91 ft)
3B/E: 56.326 metres (184.80 ft)
|Diameter||3.35 metres (11.0 ft)|
|Mass||3B: 425,800 kilograms (938,700 lb)
3B/E: 458,970 kilograms (1,011,860 lb)
|12,000 kilograms (26,000 lb)|
|5,700 kilograms (12,600 lb)|
|3B: 5,100 kilograms (11,200 lb)
3B/E: 5,500 kilograms (12,100 lb)
|2,000 kilograms (4,400 lb)|
|3,300 kilograms (7,300 lb)|
|Derivatives||Long March 3C|
|Launch sites||LC-2, XSLC|
|Total launches||3B: 10
|Partial failures||3B: 1|
|First flight||3B: 14 February 1996
3B/E: 13 May 2007
|Specific impulse||(2556.2 N-s/kg)|
|Specific impulse||(2556.2 N-s/kg)|
|Thrust||742 KN (Main)
11.8×4 KN (Vernier)
|Specific impulse||2922.57 N-s/kg (Main)
2910.5 N-s/kg (Vernier)
|Specific impulse||(4312 N-s/kg)|
The Long March 3B (Chinese: 长征三号乙火箭, Chang Zheng 3B), also known as the CZ-3B and LM-3B, is a Chinese orbital carrier rocket. Introduced in 1996, it is launched from Launch Area 2 at the Xichang Satellite Launch Centre in Sichuan. A three-stage rocket with four strap-on liquid rocket boosters, it is currently the most powerful member of the Long March rocket family and the heaviest of the Long March 3 rocket family, and is mainly used to place communications satellites into geosynchronous orbits.
An enhanced version, the Long March 3B/E, was introduced in 2007 to increase the rocket's GTO cargo capacity and lift heavier GEO communications satellites. The Long March 3B also served as the basis for the medium-capacity Long March 3C, which was first launched in 2008. As of January 2014, the Long March 3B and 3B/E have conducted 23 successful launches, with two others ending in partial or complete failure.
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 the Intelsat 708 satellite, the rocket suffered a guidance failure two seconds into the flight and destroyed a nearby town, killing at least six people, but outside estimates suggest that anywhere between 200 to 500 people might have been killed. However, the author of  later ruled out large casualties, because evidence suggest that the crash site is evacuated before launching. 
The Long March 3B and 3B/E rockets conducted ten successful launches between 1997 and 2008.
In 1997, the Agila 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. In 2009, a Long March 3B partially failed during launch due to a third stage anomaly, which resulted in the Palapa-D satellite reaching a lower orbit than planned. 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 2014[update], having conducted a total of 23 successful launches.
In December 2013, a Long March 3B/E successfully lifted Chang'e 3, China's first Lunar lander and rover into the projected lunar-transfer orbit.
Design and variants
The Long March 3B is based on the Long March 3A as its core stage, with four liquid boosters strapped on the first stage. It has an LEO cargo capacity of 12,000 kilograms (26,000 lb) and a GTO capacity is 5,100 kilograms (11,200 lb).
Long March 3B/E
The Long March 3B/E is an enhanced variant of the Long March 3B, featuring an enlarged first stage and boosters, increasing its GTO payload capacity to 5,500 kilograms (12,100 lb). Its maiden flight took place on 13 May 2007, when it successfully launched Nigeria's NigComSat-1, the first African geosynchronous communications satellite. In 2013, it successfully launched China's first lunar lander Chang'e 3 and lunar rover Yutu.
Long March 3C
A modified version of the Long March 3B, the Long March 3C, was developed in the mid-1990s to bridge the gap in payload capacity between the Long March 3B and 3A. 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 kilograms (8,400 lb). Its maiden launch took place on 25 April 2008.
- Mark Wade. "CZ-3B". Encyclopedia Astronautica. Retrieved 26 April 2008.
- LM-3B. China Great Wall Industry Corporation. Retrieved 23 May 2012.
- Gunter Krebs. "CZ-3B (Chang Zheng-3B)". Gunter's Space Page. Retrieved 26 April 2008.
- Select Committee of the United States House of Representatives (3 January 1999). "Satellite Launches in the PRC: Loral". U.S. National Security and Military/Commercial Concerns with the People's Republic of China. Retrieved 23 May 2012.
- Lan, Chen. "Mist around the CZ-3B disaster". The Space Review. Retrieved 18 January 2014.
- Lan, Chen. "Mist around the CZ-3B disaster (part 2)". The Space Review. Retrieved 29 October 2014.
- International reference guide to space launch systems. Fourth edition. p. 243. ISBN 1-56347-591-X.
- ""帕拉帕－Ｄ"通信卫星未能进入预定轨道". Xinhua. 31 August 2009. Retrieved 31 August 2009.
- "LM-3B". China Great Wall Industry Corporation. Retrieved 31 August 2009.
- LM-3B User's Manual at GlobalSecurity.org
- Long March-3B (LM-3B) at the China Academy of Launch Vehicle Technology