Chang Zheng    CZ-3A /-3B /-3C

China National Space Administration * China Academy of Launch Vehicle Technology (CALT)*  Shanghai Academy of Spaceflight Technology
China Academy of Space Technology

CZ-3A Launch Vehicle
is a large-scale three-stage liquid launch vehicle. A powerful cryogenic third stage has been developed to enable CZ-3A to present greater GTO capability. The typical GTO launch capability of CZ-3A is 2.65 tons. By adopting flexible and advanced control system, CZ-3A can provide large attitude-adjustment and orientation before SC/LV separation, and adjustable SC spin-up rate at the separation. Therefore CZ-3A is of great adaptability. CZ-3A has paved the way for the development of CZ-3B and CZ-3C, and has become the basic type of Chinese GTO launchers.
CZ-3A is mainly used for GTO missions, but also can be used for LEO, SSO and polar orbit missions, or dual-launch and multiple-launch missions.

The first stage is 26.972 meters long. It employs storable propellants, i.e. N2O4 (stored in the oxidizer tank) and UDMH (stored in the fuel tank). The first stage is equipped with DaFY6-2 engine, which is composed of four engines in parallel attached to the first stage. The thrust of each engine is 75t. With the help of servo-mechanism, the four engines can swing in tangential directions for attitude-adjustment with maximum deflection angle of 10 deg.
The second stage is 7.826 meters long. It employs storable propellants, i.e. N2O4 (in the oxidizer tank) and UDMH ( in the fuel tank). There are one main engine (DaFY20-1) and four vernier engines (DaFY21-1) on the second stage. The thrust of the main engine is 75t, and the thrust of each vernier engine is 4.8t. The nozzle of the main engine is fixed, and the nozzles of four vernier engines can swing in tangential directions for attitude-adjustment with maximum deflection angle of 60 deg.
The third stage is 8.835 meters long. It employs cryogenic propellants, i.e. LOX (in the oxidizer tank) and LH2 (in the fuel tank.) The third stage uses YF-75 as its engine, which is capable of restarting in the vacuum. YF-75 is composed of two independent single-nozzle engine in parallel, the thrust of each engine is 8 tons. The nozzles of YF-75 can swing in two-directions for attitude adjustment with maximum deflection angle of 4 deg.

The payload fairing consists of dome, forward cone section, cylindrical section and reverse cone section. The dome shell and forward cone section are made of fiberglass structure. The cylindrical section is made of aluminum honeycomb sandwich structure. The reverse cone section is made of chemical-milled aluminum structure. The typical CZ-3A fairing is 3.35m in diameter, and 8.887m in length. The maximum fairing static envelope is 3.0 m in diameter.

CZ-3A can send the SC into the Geo-synchronous Orbit (GTO). For a typical GTO mission, the first and second stages of CZ-3A firstly send the SC/Stage-3 stack into a circular parking orbit. Then, the Stage-3 performs a coast phase flight for about 600 seconds. After the re-orientation, the Stage-3 engine re-starts and puts the SC/Stage-3 stack into the target GTO. Finally, the SC separates from the Stage-3.
 

CZ-3B Launch Vehicle
is a large-scale three-stage liquid launch vehicle. It takes enhanced CZ-3A as its core stage with 4 CZ-2E strap-on boosters. The GTO launch capability of CZ-3B can reach up to 5200 kg. With many advantages, such as great launch capability, flexible adaptability, good heritages, CZ-3B is the most powerful, most advanced, and most complicated launch vehicle in current China. It represents the highest level of launch vehicle technology in China, and also stands on the frontier of the world aerospace industry.

The first stage is 23.272 meters long. It employs storable propellants, i.e. N2O4 (stored in the oxidizer tank) and UDMH (stored in the fuel tank). The first stage is equipped with DaFY6-2 engine, which is composed of four engines in parallel attached to the first stage. The thrust of each engine is 75t. With the help of servo-mechanism, the four engines can swing in tangential directions for attitude-adjustment with maximum deflection angle of 10 deg.
There are 4 boosters strapped on the Stage-1. Each booster is 15.326 meters long. It employs storable propellants, i.e. N2O4 (stored in the oxidizer tank) and UDMH (stored in the fuel tank). There is a tail fin installed on each booster. And each booster is equiped with DaFY5-1 engine, whose thrust is 75t. The nozzle of the engine is fixed.
The second stage is 9.943 meters long. It employs storable propellants, i.e. N2O4 (in the oxidizer tank) and UDMH ( in the fuel tank). There are one main engine (DaFY20-1) and four vernier engines (DaFY21-1) on the second stage. The thrust of the main engine is 75t, and the thrust of each vernier engine is 4.8t. The nozzle of the main engine is fixed, and the nozzles of four vernier engines can swing in tangential directions for attitude-adjustment with maximum deflection angle of 60 deg.
The third stage is 12.375 meters long. It employs cryogenic propellants, i.e. LOX (in the oxidizer tank) and LH2 (in the fuel tank.) The third stage uses YF-75 as its engine, which is capable of restarting in the vacuum. YF-75 is composed of two independent single-nozzle engine in parallel, the thrust of each engine is 8 tons. The nozzles of YF-75 can swing in two-directions for attitude adjustment with maximum deflection angle of 4 deg.

The payload fairing consists of dome, Bi-conic section, cylindrical section and reverse cone section. The dome shell and forward cone section are made of fiberglass structure. The cylindrical section is made of aluminum honeycomb sandwich structure. The reverse cone section is made of chemical-milled aluminum structure. The typical CZ-3B fairing is 4.0 m in diameter, and 9.56m in length. The maximum fairing static is 3.65m in diameter.

CZ-3B can send the SC into the Geo-synchronous Orbit (GTO). For a typical GTO mission, the first and second stages of CZ-3B firstly send the SC/Stage-3 stack into a circular parking orbit. Then, the Stage-3 performs a coast phase flight for about 600 seconds. After the re-orientation, the Stage-3 engine re-starts and puts the SC/Stage-3 stack into the target GTO. Finally, the SC separates from the Stage-3.