The CZ-2 and the companion FB-1 (Feng Bao -Storm) were derived from the DF-5 ballistic missile, and consisting of two stages burning UDMH and nitrogen tetroxide. The CZ-2 was soon replaced by the currently operational CZ-2C, which featured a slightly lengthened second stage. The FB-1 was essentially a similar derivative of the DF-5 produced by the Shanghai Academy of Space Technology [SAST]. However, in practice this Shanghai product proved unsatisfactory, demonstrating poor reliability, and it was soon withdrawn from service.
During the first flight of LM-2 in 1970, the vehicle lost attitude stability after liftoff and was automatically destroyed. The failure analyses determined that the accident resulted from a severed wire connection with the pitch rate gyro signal. The control system was modified, manufacturing and assembly quality control procedures were improved, and the functional test procedures were revised. The modified Long March 2C was successfully launched in November 1975, orbiting Chinese recoverable satellite.
LM-2 / FB-1 (China)