RN 11K77 Zenit is a middle-class rocket designed to launch civilian and military satellites, as well as manned vehicles, into near-Earth orbit in automatic mode. There are two- and three-stage modifications. RG-1 brand kerosene and liquid oxygen are used as fuel.
An example of mutually beneficial cooperation
It is not easy to answer the question whether the Zenit rocket is Russian or Ukrainian. The main structural elements were developed in Dnepropetrovsk at the Yuzhnoye Design Bureau by the efforts of Soviet engineers and scientists. After the collapse of the Secular Union, the design bureau came under the jurisdiction of Ukraine, retaining its profile and continuing the development of the Zenit series. Missiles were also assembled at the Yuzhmash Dnepropetrovsk enterprise.
Meanwhile, important structural elements were developed and produced at Russian enterprises. In particular, DM boosters were produced by RSC Energia, and RD-171 and RD-171M liquid - propellant rocket engines were produced by Energomash NPO. In general, Russian enterprises supplied 70% of components. We can say that the Zenith is a Ukrainian rocket, and its filling is Russian.
History of creation
Yuzhnoye Design Bureau initially developed a two-stage Zenit rocket with an index of 11K77 in the late 1970s and early 1980s, in accordance with the instructions of the USSR Ministry of Defense, to have such a launch vehicle that would quickly and efficiently replenish military-oriented satellite groups.
Accordingly, during its design, special attention was paid to reliability, ease of use and speed of preparation for launch, which was achieved through the widespread use of standardization and automation. Heavy class launch vehicles, by definition, cannot be mobile, so designers focused on designing a medium-class launch vehicle.
Unlike systems developed in previous years, this design uses the most advanced preparation and start-up technologies developed by the SRI SK, a partner of SE Yuzhnoye in many projects.
Flying
The debut launch of the launch vehicle took place in April 1985, and went abnormally, as well as re -launch . A successful launch was carried out in October 1985. Initially, the complex focused on the operational output of military satellites and dual-use systems, but later there was a reorientation to launch commercial satellites.
The second area of application of the initial Zenit-2 11K77 launch vehicle was the provision of flights to the Mir orbital station with a crew on board. In order to meet all the requirements for launch vehicles for manned spacecraft, the Zenit rocket was designed with significant internal redundancy and many other measures were taken to increase reliability.
Key design parameters
Zenit is a launch vehicle whose technical specifications and design parameters comply with the best international standards. Of particular note is the fact that more than 90% of the total mass of the steps falls on the share of fuel. Thus, the design of both stages is one of the most effective in modern astronautics.
In relation to the 1st stage, this is largely due to the high characteristics of the RD171M engine, as well as the lack of side accelerators. The absence of side boosters further simplifies preparation for launch, being one of the main differences between the Zenit launch vehicle and other launch vehicles. In addition, the design of the stage is more effective, the number of pyrotechnic means is reduced, and the overall reliability also increases, since there is no need for separation mechanisms for side accelerators. In addition, a wide range of controllability at all stages of flight allows Zenit launches at various wind speeds and in different weather conditions, which also contributes to the timely and accurate removal of the payload.
Core systems
On the LV there is a complete set of on-board electronic equipment to ensure the operation of the telemetry system. The Sirius airborne telemetry system provides TMI transmission via two separate radio channels to existing NPCs located in Russia.
The separation of the steps is “warm”: it is carried out by starting the steering engine of the 2nd stage, undermining the interstage mechanical connections and braking with the help of four solid propellant motors of the separating part of the first stage. After removing it to a safe distance, the 2nd stage mid-flight engine starts.
The following systems are installed on the launch vehicle to ensure its operation and operation in flight:
- control system;
- measurement system;
- pneumohydraulic system for supplying fuel components;
- fuel management system;
- refueling control system;
- flight safety system;
- temperature control system with high pressure air;
- elements of a temperature control system;
- elements of a temperature control system;
- hydraulic drive systems;
- fire warning system.
Modernization
The Zenit-2 LV after the collapse of the USSR did not sink into oblivion. The Ukrainian enterprise Yuzhmash, in close cooperation with Russian and foreign partners, continued the development of the Zenit project. Missile systems were developed that allow launching from the ground (Zenit-2SL B, Zenit-3SL B, Zenit-3SL BF) and from offshore platforms (Zenit-3SL). Almost all launches of ground-based missile systems were carried out at Baikonur.
The International Sea Launch project was organized in 1995 by the efforts of the American company Boeing Commercial Space (40% of the capital), the Russian RSC Energia (25%), the Ukrainian PO Yuzhmash and CB Yuzhnoye (a total share of 15%) and Norwegian shipbuilders Aker Solutions (20%). The consortium aimed at more convenient and economical launches from the Odyssey offshore platform, located in the equator zone. A demonstration test of the rocket was successful. Since 1999, 32 successful commercial launches using the Zenit-3SL LV have been carried out, and 4 unsuccessful ones. At the moment, due to negative events in Ukraine, the Ukrainian side has suspended its participation in the project.
First stage
The design of the first stage of the Zenit LV includes:
- interstage frame;
- engine RD171 (RD171M);
- tail compartment
- fuel and oxidizer tanks.
The interstage frame is a transition compartment of a welded truss structure. It mounted a side board of electric pneumatic connectors, which provides communication between the LV and spacecraft systems with the corresponding ground systems before the launch of the rocket launcher.
In the fuel tanks there are automatic control units for gas-turbine power plants, SKZ, SURT sensors, and in the oxidizer tank, in addition, pressurization system cylinders are installed. In the tail compartment there is a four-chamber RD171M engine, which is installed on the lower end frame with the help of a rod frame.
RD171 engine
The power plant is designed to create traction and control efforts across all ILV stabilization channels. This engine was installed in the first steps of all modifications of the Zenit launch vehicle. The missile and is currently equipped with an improved modification of the RD171M. The design of the engine introduced changes aimed at improving its reliability and performance.
In RD171, the most advanced technologies for manufacturing liquid-propellant rocket engines developed by Russian enterprises in the field of engine building were used. At the moment, the modification of the RD171M is the most powerful rocket engine in the world, its thrust at the time of launch (near the Earth) is 740 tf.
Second stage
The design of the second stage of the Zenit LV includes:
- instrument module;
- mid-flight engine RD120;
- steering engine RD8.
- oxidizer and fuel tanks;
- tail compartment.
The instrument module houses the bulk of the electronic equipment on-board the control system and the measurement system. In the fuel tanks, as well as in the first stage, SURT, SKZ sensors, automatic control units of the automatic control system are located, in the oxidizer tank - boost system cylinders.
The tail compartment with a cylindrical riveted power shell is designed to accommodate the propulsion unit, consisting of a single-chamber marching engine RD120 and a four-chamber steering engine RD8.
Zenit: the rocket and its technical characteristics
During the operation of Zenit launch vehicles of all types, 82 launches were carried out, the majority were absolutely successful (69 launches), 4 partially failed, the rest abnormally.
- Missile length: 57-59.6 m.
- Number of steps: 2 or 3.
- Maximum diameter: 3.9 m.
- Payload: 15 tons for sea launch systems, 13.7 tons for ground systems.
- Starting weight: 445-462 t.
Despite the example of successful cooperation under the Zenit international program, the rocket is currently not being launched due to the unstable situation in Ukraine.