Long March 4B

Long March 4B

The Long March 4B (also written as CZ-4B) is a Chinese expendable orbital launch vehicle developed and operated by the Shanghai Academy of Spaceflight Technology (SAST), a subsidiary of the China Aerospace Science and Technology Corporation (CASC). It serves as one of China's workhorse medium-lift rockets, fulfilling a dedicated role in the deployment of Earth observation, remote sensing, and scientific satellites into sun-synchronous and polar orbits.

Development and Design

The Long March 4B is an evolution of the earlier Long March 4A, sharing the same three-stage, storable-propellant architecture that uses nitrogen tetroxide and unsymmetrical dimethylhydrazine (UDMH) as propellants. Standing 44.1 metres tall with a core diameter of 3.35 metres, the vehicle is sized for medium-class payloads. It is capable of delivering 4,200 kg to low Earth orbit (LEO) and 1,500 kg to geostationary transfer orbit (GTO), making it well suited to the reconnaissance and civil remote sensing satellites that constitute its primary manifest. The rocket launches predominantly from the Taiyuan Satellite Launch Center in Shanxi Province, a facility specifically oriented toward polar and sun-synchronous missions.

Operational History

Our flight record documents 56 launches of the Long March 4B between 1999 and 2025, of which 55 were fully successful and one resulted in a failure or partial failure — a reliability record that reflects the vehicle's mature, well-understood design. That record places it among the more dependable members of the Long March family and of the global medium-lift launcher class more broadly.

The rocket's customer base is concentrated within the Chinese state space sector. China Aerospace Science and Technology Corporation and China Aerospace Corporation account for the majority of its payload manifest, consistent with the vehicle's role as an institutional workhorse rather than a commercial competitor on the open market.

Recent Missions

Recent launches have demonstrated the continued demand for the Long March 4B across multiple mission types. The Haiyang 4-01 mission extended China's ocean observation constellation, while the Ziyuan-3-04 and Tianhui 7 launches supported land surveying and mapping capabilities. The Yaogan 43 Group 02, Yaogan 47, and Shijian 26 missions reflect the rocket's persistent use for reconnaissance and experimental spacecraft — categories that have defined much of its career since the late 1990s. This diversity of recent payloads underscores the vehicle's flexibility across civil, scientific, and military-adjacent remote sensing applications.

Role and Legacy

Over more than two decades of operation, the Long March 4B has quietly established itself as a reliable, unpretentious tool of China's space programme. While newer vehicles in the Long March family attract attention for their scale or advanced technology, the 4B's consistency and specialisation have kept it in regular rotation. Its longevity from 1999 through to at least 2025 — spanning China's emergence as a major spacefaring nation — makes it a vehicle of genuine historical significance within the broader story of Chinese spaceflight.