Long March 2F

The Long March 2F (Chinese: 长征二号F火箭 Chang Zheng 2F), also known as the CZ-2F, LM-2F and Shenjian,^[1] is a Chinese manned orbital carrier rocket, part of the Long March rocket family. Designed to launch manned Shenzhou spacecraft, the Long March 2F is a man-rated two-stage version of the Long March 2E rocket, which in turn was based on the Long March 2C launch vehicle.^[2] 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'.^[3]

On 15 October 2003, a Long March 2F launched Shenzhou 5, China's first manned spaceflight. It has since launched the Shenzhou 6 mission and the Shenzhou 7 mission into orbit.^[4]

Differences from the Long March 2E

Externally, the rocket is little different from the Long March 2E from which it was derived. Most of the changes are redundant systems to improve safety, although there are some structural modifications which 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.^[5]

The rocket also has an "advanced fault monitoring and diagnosis system to help the astronauts escape in time of emergency", and is the first Chinese made rocket to be assembled and rolled out to its launch site vertically.^[6]

Vibration issues

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." ^[7]

Launch history

Specifications

• Stage number: 0 - Strap-on boosters x 4
  • Gross mass: 41,000 kg
  • Empty mass: 3,200 kg
  • Thrust (vac): 4 x 814 kN
  • Isp: 291 seconds (2.9 kN·s/kg)
  • Burn time: 128 seconds
  • Diameter: 2.3 m
  • Span: 8.0 m
  • Length: 15.3 m
  • Propellants: N2O4 / UDMH
  • Engines: 1 x YF - 20B per booster = 4

• Stage number: 1 - Core stage
  • Gross mass: 196,500 kg
  • Empty mass: 9,500 kg
  • Thrust (vac): 3,256 kN
  • Isp: 289 seconds (2.8 kN·s/kg)
  • Burn time: 166 seconds
  • Diameter: 3.4 m
  • Length: 23.7 m
  • Propellants: N2O4 / UDMH
  • Engine: 4 x YF - 20B

• Stage number: 2 - Final stage
  • Gross mass: 91,500 kg
  • Empty mass: 5,500 kg
  • Thrust (vac): 831 kN
  • Isp: 289 seconds (2.8 kN·s/kg)
  • Burn time: 300 seconds
  • Diameter: 3.4 m
  • Length: 15.5 m
  • Propellants: N2O4 / UDMH
  • Engine: 1 x YF - 25/23

References