Technical Information - Cyclone-4 Launch Vehicle

The main components of the Cyclone-4 launch vehicle are the first, second and third stages and the payload unit. Two types of payload units can be used in the Cyclone-4 rocket: 

- Type 00 Payload unit, 8.590 meters long
 

- Type 01 Payload unit, 9.590 meters long 

Cyclone 4

The Cyclone-4 has a nominal length of 40.190 meters with a type 00 payload unit, and a diameter of 3 meters for the first two stages. The table below shows the technical specifications of the Cyclone-4 for GTO and LEO orbits. 

The Cyclone-4 first stage consists of an interstage section, oxidizer and fuel tanks, equipment and aft bays, main engine and steering engine. The Guidance, Navigation and Control (GNC) system, the measurement system and the avionics system are accommodated in the equipment and aft bays. 
 

 

The propellant tanks are cylindrical vessels with hemispherical ends. The oxidizer feed pipeline reaches the main engine through a tunnel in the fuel tank. The main engine, steering engines, and solid retrorockets are located in the aft bay. The retrorockets break the first stage at separation from the second stage. The bulkhead rigidly fixes the main engine to the lower end frame of the fuel tank.

The main engine consists of three two-chamber liquid rocket engines. The main engine is designed as three identical two-chamber engines attached to a common frame. The steering engine is a four-chamber liquid rocket engine with a turbo-pump feed system. The pneumo-hydraulic system supplies propellants to the main and steering engines. Pivoting the steering engine combustion chambers within ± 41° controls the first stage flight.
 

The second stage consists of an interstage section, propellant tank and aft bay, main engine and steering engine. The GNC, Measurement System and Safety System instrumentation (avionics system) is accommodated in the equipment and aft bays. 

The propellant tank is an all-welded cylindrical vessel with spherical ends, divided into an upper oxidizer compartment and a lower fuel compartment with an intermediate bulkhead. The oxidizer feed pipeline is located inside the fuel tank.

The main and steering engines and solid retrorockets are located in the aft bay. The retrorockets break the second stage at separation from the third stage. The bulkhead rigidly fixes the main engine to the lower end frame of the propellant tank.

The main engine is a two-chamber liquid rocket engine. The steering engine is a four-chamber liquid rocket engine with a turbo-pump feed system. The pneumo-hydraulic system supplies propellants to the main and steering engines. Pivoting the steering engine combustion chambers within ± 30° controls the second stage flight.
 

The third stage consists of a propellant tank, main engine, liquid jet system (LJS), pneudraulic system, and GNC, Measurement and Safety System instrumentation (avionics system). The main component of the third stage is the propellant tank.  

The propellant tank is an all-welded sphere-cone tight vessel consisting of two compartments: 

– spherical oxidizer compartment, and
– conical fuel compartment.

The main engine is aligned with the third stage longitudinal axis and fixed to the lower frame of the propellant tank by the bulkhead. The main engine is a liquid rocket engine with a turbo-pump feed system. The pressure vessels and LJS propellant tanks are located on the upper side of the propellant tank. The units for separation of the pneudraulic pipelines between the third stage and the interstage are mounted on the spacer ring of the conical fuel compartment.

The equipment bay is a conical compartment accommodating the GNC, Measurement and Safety System instrumentation. Quick disconnect boards of the third stage and interstage, and the thermal conditioning system inlets and outlets are placed on the outside of the equipment bay. Pivoting the main engine combustion chamber and LJS operation control the third stage flight.

The liquid jet system serves for: 

– the generation of control forces to provide angular attitude control during coast flight;

After the engine shutdown, the third stage continues coasting, and the LJS provides stabilization. Before the main engine re-ignitions, the LJS generates a preburning axial acceleration. Duration of the acceleration is selected to ensure propellant transfer to the capillary intaker, damping of the propellant sloshing, and extraction of the gas inclusions from the propellant. After termination of the main engine operation, when the third
stage approaches the target point, the LJS provides the required accuracy of spacecraft injection. Then the stage performs a collision and contamination avoidance maneuver.

The LJS uses the same propellant components as the third stage main engine (NTO and UDMH). The LJS thruster has a nominal thrust of 3 kgf, and the system has an operating life of 6 hours. The LJS starts functioning after the second and third stage separation. 

During operation of the third stage main engine, the LJS is responsible for controlling the third stage roll movement. After the third stage main engine shutdown, the LJS is responsible for the stabilization and angular attitude control during coast flight. Before re-ignition of the third stage main engine, the LJS generates axial accelerations to ensure propellant continuity at the main engine inlet by damping the propellant sloshing and reducing gas inclusions in the propellant. 

After the end of the third stage main engine operation, close to the satellite orbit insertion point, the LJS is responsible for controlling the third stage attitude, for guaranteeing the precise orbit insertion, and for performing a maneuver to avoid collision with the satellite and to avoid satellite contamination. The LJS is also responsible for controlling the third stage reentry.  

The payload unit (PLU) is the launch vehicle compartment designed for transporting and protecting the spacecraft. The payload unit consists of a payload fairing, spacecraft adapter, and payload unit adapter. The payload fairing and the payload unit adapter form an isolated environment in which the thermal, humidity and cleanness conditions are controlled according to international ISO 14644-1 standards. The controlled characteristics air supply to the PLU is performed by an air-conditioning system on the ground or by a compressed air system.  

The payload unit adapter is a conic structure of aluminum alloys with thermal insulation on its exterior. The adapter is bolted to the third stage. The adapter is 725 mm high and the upper radius is 2,660 mm. A spacecraft adapter for one satellite or a dispenser for multiple satellites can be attached to the upper radius.

The spacecraft adapters and dispensers connect satellites to the launch vehicle and perform the satellite separation with the required parameters after reaching the desired orbit. The spacecraft adapters and dispensers can be designed by Yuzhnoye or by the launch service client. The user manual provides more details and dimensions of some of the available standard dispensers.

The payload fairing protects the satellite from aerodynamic and thermal loads during liftoff and atmospheric flight of the launch vehicle. Together with the payload unit adapter, it isolates the satellite in a controlled temperature, humidity and cleanness environment. There are two types of fairing. Type 00 which is 8.59 meters long, and Type 01 which is 9.59 meters long. The user manual has more details and dimensions on the fairings. 

The PLF is jettisoned during the second stage flight after the dynamic pressure is safe for the satellite. The PLF structure consists of two half shells which are linked together by locking mechanisms. The GNC system commands the split of the vertical interface between the two PLF shells. Then, pneumopushers force the half shells to hinge until the center of gravity of each shell passes its neutral axis. From then on, the half shells rotate under g-load approximately 60° when the hinges break up and the shells continue in free fall. It is guaranteed that the fairing will not come into contact with payloads whose dimensions are within the specifications required by Yuzhnoye.