LAUNCHERS

China has developed two families of launchers – the Long March, known as the Chang Zheng (CZ), and the Feng Bao (FB, or Storm). The Long March family is divided into seven series – Long March 1, 2, 3, and 4, which have flown, with 5-7 forthcoming (these future launchers will be considered in Chapter 10). The Feng Bao launcher was used from 1971 to 1981 for the JSSW series and Shi Jian 2 (see Chapters 2 and 7), when it ended service and is not considered here; neither is the Long March 1, used for the first two launches, but not subsequently. The Chinese are visually helpful in enabling us to identify their rocket launchers, for their white – painted rockets invariably have the launcher type painted in big red letters in large English script on the side after the Chinese pictograms for “China” and “Hangtian”, the latter meaning “space” or “cosmos” in Chinese.

Although, to an outsider, all rockets, being rocket-shaped, appear to have the same means of propulsion, in fact there are many important distinctions between them. First, rockets may use either solid fuel or liquid fuel. Solid-fuel rockets operate on the same principle as fireworks. A gray sludge-like chemical is poured into a rocket container. When the nozzle is fired, the stage bums to exhaustion. Solid rockets are very powerful. Their main disadvantage is that they cannot be turned off – they simply burn out. They are less precise and less safe.

Liquid-fuel rockets are more complex. They have two tanks – a fuel tank and an oxidizer. Both are pressurized and fuel is injected, at great pressure, into a rocket engine where it is ignited. On liquid-fuel engines, the level of thrust may be varied (throttled) and the engine may be turned off and restarted. This system is complex but more versatile and, from a manned-spaceflight perspective, safer. Liquid-fuel rockets may be divided into three sub-categories, according to the type of fuel used. Most Russian and American civil rockets have used kerosene (a form of paraffin) as a fuel. These are powerful fuels, but they degrade if they are kept in a rocket for more than a few hours at a time. If a launching is missed, the fuels have to be drained and reloaded – a tedious and time-consuming process. From the 1960s, Russian and American military rockets began to use storable propellants, generally based around nitric acid or nitrogen tetroxide and UDMH (unsymetrical dimethyl hydrazine). The

advantage of storable propellants is that they can be kept at room temperature in rockets for long periods before they are fired – a necessity when military rockets must be kept in a constant state of readiness. The disadvantage is that such fuels are highly toxic, presenting hazards for launch crews and horrific consequences in an explosion. In 1960, a Soviet R-16 missile exploded at Baikonour cosmodrome. Ninety-seven engineers, supervisors, and rocket troops died in the ensuing fireball, but the level of casualties was made much worse by the toxic nature of the exploding fuel. It remains the worst rocket disaster in history. Finally, there is the use of liquid hydrogen as a fuel. Liquid hydrogen is enormously powerful, but has to be kept at extremely low temperatures. China has favored the use of storable propellants for main stages, with small solid-rocket boosters for the final kick to 24-hr orbit. The Chinese introduced a hydrogen-fuelled upper stage with the Long March 3 in 1984.

Now follows a description of each of China’s main launcher families. As with many aspects of the Chinese space program, this compilation is a hazardous exercise. Precise technical details of Chinese rockets vary slightly from one publication to another. Designators vary even more, especially when it comes to rocket engines.

Type

Successful launches

FB

4

CZ-1

2

CZ-2C

35

CZ-2D

16

CZ-2E

5

CZ-2F

10

CZ-3

13

CZ-3A

24

CZ-3B

18

CZ-3C

8

CZ-4A

2

CZ-4B

20

CZ-4C

6

Successful launches to orbit to 30 June 2012.

For example, the YF-20 engine when clustered as a first-stage engine is called the YF-21; when used as a second-stage engine, it is called the YF-22, but when linked to YF-23 vernier engines, it is called the YF-24! Table 3.3 shows launches by launcher type.

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