"Zenith", a rocket. Launch vehicle 11K77 ("Zenith")

РН 11K77 "Zenith" is a medium-range missile intended for launching civil and military satellites, as well as manned vehicles, into the near-Earth orbit in an automatic mode. There are two- and three-step modifications. As fuel used kerosene grade RG-1 and liquid oxygen.

An example of mutually beneficial cooperation

On the question, the missile "Zenith" Russian or Ukrainian, it is not easy to answer. The main structural elements were developed in Dnipropetrovsk in the Yuzhnoye Design Bureau by the efforts of Soviet engineers and scientists. After the collapse of the Secular Union, the design bureau passed under the jurisdiction of Ukraine, retaining its profile of activity and continuing the development of the Zenit series. Assembling of missiles was also carried out at the Dnipropetrovsk enterprise "Yuzhmash".

Meanwhile, important design elements were designed and manufactured at Russian enterprises. In particular, RKK Energia boomed off the DM booster blocks, and RD-171 and RD-171M liquid rocket engines - at Energomash NPO. In general, the enterprises of the Russian Federation supplied 70% of the components. We can say that Zenit is a Ukrainian missile, and its stuffing is Russian.

History of creation

The Yuzhnoye Design Bureau initially developed a two-stage Zenit LV with an index of 11K77 in the late 1970s and early 1980s, in accordance with the task of the USSR Ministry of Defense, to have such a withdrawal facility that would quickly and effectively make up the military satellite satellites.

Accordingly, when designing it, special attention was paid to reliability, ease of operation and speed of preparation for launch, which was achieved on the basis of wide application of standardization and automation. Heavy-duty rockets by definition can not be mobile, so designers focused on the design of medium-range LV.

Unlike the systems developed in previous years, this design uses the most advanced training and start-up technologies developed by the Research Institute of SK, a partner of SE "Yuzhnoye" for many projects.

Flight Operations

The debut launch of the carrier rocket took place in April 1985, and went out abnormally, as well as the second one. The successful launch was carried out in October 1985. Initially, the complex was focused on the operational withdrawal of military satellites and dual-purpose systems, but later there was a reorientation to launch commercial satellites.

The second area of application of the original version of the Zenit-2 LV 11K77 was to provide flights to Mir orbital station with the crew on board. In order to meet all the requirements for manned spacecraft launching facilities , the Zenit launch vehicle has a significant internal backup and many other measures to improve reliability.

Basic construction parameters

"Zenith" is a booster rocket, whose technical characteristics and design parameters correspond to the best world standards. It deserves special attention that more than 90% of the total mass of the stages is fuel. Thus, the design of both stages is one of the most effective in modern space exploration.

With respect to the 1 st stage, this is largely due to the high performance of the RD171M engine, as well as the lack of side accelerators. The lack of side accelerators further simplifies the 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 proves to be more efficient, the number of pyrotechnic means is reduced, and the overall reliability increases, since there is no need for mechanisms for separating the lateral accelerators. In addition, a wide range of controllability at all stages of the flight makes it possible to launch "Zenith" at different wind speeds and in different weather conditions, which also contributes to the timely and accurate removal of the payload.

Basic Systems

On the LV there is a complete set of on-board radio-electronic equipment for the operation of the telemetry system. The onboard telemetry system "Sirius" provides the transmission of TMI over two separate radio channels to existing NPCs located on the territory of Russia.

Separation of stages - "warm": it is carried out by starting the 2nd stage steering motor, undermining interstage mechanical connections and braking with the help of four solid propellant rockets of the separating part of the first stage. After its removal, a 2-st march engine is launched to the safe distance.

The following systems are installed on LV, ensuring its operation and functioning in flight:

• control system;
• System of measurements;
• Pneumohydraulic system for supplying fuel components;
• Fuel consumption management system;
• Fueling control system;
• Flight safety system;
• High-pressure air -conditioning system ;
• Elements of the temperature control system;
• Elements of the thermostating system;
• Hydraulic drive systems;
• Fire alarm system.

Modernization

The Zenit-2 launch vehicle did not disappear into oblivion after the collapse of the USSR . The Ukrainian enterprise "Yuzhmash" continued close cooperation with Russian and foreign partners in 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 offshore platforms (Zenit-3SL). Almost all launches of ground-based missile systems were carried out at Baikonur.

The international project "Sea Launch" was organized in 1995 by the efforts of the American company Boeing Commercial Space (40% of the capital), the Russian RKK Energia (25%), Ukrainian Yuzhmash and Yuzhnoye (15% Norwegian shipbuilders Aker Solutions (20%). The purpose of the consortium was more convenient and economical launches from the offshore platform Odyssey, located in the equator zone. Demonstrative testing of the missile was successful. Since 1999, 32 successful commercial launches with Zenit-3SL LV and 4 unsuccessful launches have been carried out. At the moment due to the negative events in Ukraine, the Ukrainian side in the project has suspended its participation.

First stage

The design of the first stage of the Zenit launch vehicle includes:

• Interstage frame;
• Engine RD171 (RD171M);
• Tail section;
• Fuel and oxidizer tanks.

The interstage frame is a transitional compartment of a welded truss structure. On it is mounted the side plate of the electro-pneumatic connectors, which provides the communication of the LV and spacecraft systems with the corresponding ground systems prior to the launch of the ILV.

In the fuel tanks there are automatic PGSP control units, VHF sensors, SURT, in the oxidizer tank, in addition, cylinders of the boost system are installed. In the tail section there is a four-chamber engine RD171M, which is mounted on the lower end frame by means of a rod frame.

Engine RD171

The power plant is designed to create traction and control forces on all channels of ILV stabilization. This engine was installed at the first stages of all modifications of the Zenit launch vehicle. The missile is currently being equipped with an upgraded version of the RD171M. The design of the engine introduced changes aimed at increasing its reliability and performance.

In RD171, the most advanced technologies for manufacturing liquid rocket engines, developed by Russian enterprises in the field of engine building, have found application. At the moment, the modification of the RD171M is the most powerful LRE in the world, its thrust at the time of launch (near the Earth) is 740 tons.

The second stage

The design of the second stage of the Zenit launch vehicle includes:

• The instrument module;
• Marching engine RD120;
• Steering engine RD8.
• Oxidizer and fuel tanks;
• Tail section.

In the instrument module, the main part of the radio-electronic on-board equipment of the control system and the measurement system is located. In fuel tanks, as well as in the first stage, sensors SURT, VCS, automatic control units of PGSP are placed, in the tank of oxidizer - cylinders of the pressurization system.

The tail section with a cylindrical riveted power envelope is intended for locating the motor block consisting of a single-chamber marching engine RD120 and a four-chamber steering motor RD8.

"Zenith": rocket and its technical characteristics

During the operation of the Zenit carrier rockets of all types 82 launches were made, most of it was absolutely successful (69 launches), 4 - partially unsuccessful, the rest are non-standard.

• The length of the rocket: 57-59.6 m.
• Number of steps: 2 or 3.
• The maximum diameter: 3.9 m.
• Payload: 15 tons for sea launch systems, 13.7 tons for ground systems.
• Starting mass: 445-462 t.

Despite the example of successful cooperation under the international program "Zenith", the missile is not being produced at the moment due to the unstable situation in Ukraine.