The Long March 2F (Chinese: 长征二号F火箭 Changzheng 2F), also known as the CZ-2F, LM-2F and Shenjian, is a Chinese orbital carrier rocket, part of the Long March 2 rocket family. Designed to launch crewed Shenzhou spacecraft, the Long March 2F is a human-rated two-stage version of the Long March 2E rocket, which in turn was based on the Long March 2C launch vehicle. It is launched from complex SLS at the Jiuquan Satellite Launch Centre. The Long March 2F made its maiden flight on 19 November 1999, with the Shenzhou 1 spacecraft. After the flight of Shenzhou 3, CPC General Secretary and President Jiang Zemin named the rocket 'Shenjian' meaning 'Divine Arrow'.
On 15 October 2003, a Long March 2F launched Shenzhou 5, China's first human spaceflight. It has since launched the Shenzhou 6, Shenzhou 7, Shenzhou 9, Shenzhou 10 and Shenzhou 11 missions into orbit.
Externally, the rocket is similar to the Long March 2E from which it was derived. Most of the changes involve the addition of redundant systems to improve safety, although there are some structural modifications that allow the rocket to support the heavier fairing required by the Shenzhou capsule. The rocket is also capable of lifting heavier payloads with the addition of extra boosters to the first stage.
The rocket also has an "advanced fault monitoring and diagnosis system to help the astronauts escape in time of emergency" (in other words, a launch escape system), and is the first Chinese made rocket to be assembled and rolled out to its launch site vertically.
A derivative called Long March 2F/G, first launched in 2011, was designed to launch space laboratories such as Tiangong-1 and Tiangong-2. It dispenses with the launch escape system and sports a larger fairing to accommodate the bulkier payloads.
During the Shenzhou 5 flight, Yang Liwei became unwell due to heavy vibrations from the rocket. Although the problem was reduced somewhat by modifications to the rocket, vibrations were reported again in Shenzhou 6 necessitating further changes. According to Jing Muchun, chief designer of the Long March 2F "We made changes to the pipelines of the rocket engine, adjusting its frequency. A new design for the pressure accumulator produced evident results. The vibration has now been reduced by more than 50 percent." 
The predecessor Long March 2E had also been known for vibration. During two launches, excessive vibration caused the collapse of the payload fairing, destroying the Optus B2 and Apstar 2 satellites. After the payload fairing was redesigned, excessive vibration also damaged the AsiaSat 2 satellite during launch. The Long March 2E was withdrawn from the geostationary launch market a year later.
|Flight number||Date (UTC)||Launch site||Payload||Orbit||Result||Remarks|
|1||November 19, 1999
|LA-4/SLS-1, JSLC||Shenzhou 1||LEO||Success||First unmanned test of the Shenzhou spacecraft|
|2||January 9, 2001
|LA-4/SLS-1, JSLC||Shenzhou 2||LEO||Success||Second unmanned test of the Shenzhou spacecraft, carried live animals|
|3||March 25, 2002
|LA-4/SLS-1, JSLC||Shenzhou 3||LEO||Success||Third unmanned test of the Shenzhou spacecraft|
|4||December 29, 2002
|LA-4/SLS-1, JSLC||Shenzhou 4||LEO||Success||Final unmanned test of the Shenzhou spacecraft|
|5||October 15, 2003
|LA-4/SLS-1, JSLC||Shenzhou 5||LEO||Success||China's first crewed spaceflight|
|6||October 12, 2005
|LA-4/SLS-1, JSLC||Shenzhou 6||LEO||Success||Second crewed spaceflight, first with two astronauts|
|7||September 25, 2008
|LA-4/SLS-1, JSLC||Shenzhou 7||LEO||Success||First flight with three crew members, first to feature extra-vehicular activity|
|8||September 29, 2011
|LA-4/SLS-1, JSLC||Tiangong 1||LEO||Success||The first Chinese space station. Modified version Long March 2F/G with larger payload fairing|
|9||October 31, 2011
|LA-4/SLS-1, JSLC||Shenzhou 8||LEO||Success||Unmanned spaceflight to test automatic rendezvous and docking with Tiangong-1|
|10||June 16, 2012
|LA-4/SLS-1, JSLC||Shenzhou 9||LEO||Success||Three crew members, to test rendezvous and docking with Tiangong-1|
|11||June 11, 2013
|LA-4/SLS-1, JSLC||Shenzhou 10||LEO||Success||Three crew members; rendezvous and docking with Tiangong-1|
|12||September 15, 2016
|LA-4/SLS-1, JSLC||Tiangong 2||LEO||Success||Second Chinese space laboratory Tiangong-2, launched by 2F/G variant|
|13||October 16, 2016
|LA-4/SLS-1, JSLC||Shenzhou 11||LEO||Success||Two crew members; rendezvous and docking with Tiangong-2 for a 30-day mission.|
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The principal difference between the Shenzhou-launching Long March 2F and its 2F/G cousin is easy to spot. The 2F/G carries a very different payload fairing at its top. This accounts. for the larger dimensions of the Tiangong laboratory, which wouldn't fit inside the standard payload fairing for the 2F.
It also lacks an emergency escape system. With no astronauts on board, the escape rocket and stabilizer panels that help Shenzhou spacecraft to separate from their rocket in a launch failure are not needed. This simplifies the design and also reduces the weight of the rocket. That's critical. Tiangong modules weigh more than Shenzhou spacecraft, so this helps to keep the overall launch mass within performance limits.