Russian rocket "Rokot": description, characteristics and interesting facts

The Rokot rocket is a Russian launch vehicle that can deliver light and medium payload into orbit. With the upper stage "Breeze-KM", it outputs up to 2150 kg of payload to a height of 200 km.

History of creation

What is the Rokot booster rocket? It is based on the intercontinental ballistic missile UR-100N, also known as the SS-19 Stiletto. The development of the UR-100N began in 1970 with the goal of improving the UR-100 ICBM and creating a large aircraft capable of lifting a heavier load.

Flight tests were conducted between 1973 and 1975, and the system began operating in 1974. By 1978, the total stock of 190 missiles was achieved. The improved version, called UR-100UTTX, was commissioned in 1979 and replaced the old models, reaching a maximum reserve of 360 units.

Nuclear Shield

The UR-100 rockets can carry up to six independent individual warheads with a range of 10,000 km. They can be prepared to run for 25 minutes at any time during a 22-year shelf life. Intercontinental ballistic missiles UR-100 to this day are in service.

After the end of the Cold War, the weapons were redeveloped and equipped with modern avionics and the Breeze-KM booster block, which allowed it to be used as space launch vehicles. NPO Mashinostroenie also reconstructed the UR-100 into a carrier rocket, but without significant modifications, creating a less flexible, but cheaper device for launching small payloads into a low Earth orbit. In this configuration, it is known as the "Arrow".

From Baikonur to Plesetsk

The first launch of the rocket "Rokot" was carried out on November 20, 1990 from the Baikonur cosmodrome, Kazakhstan. The first orbital flight took place on December 26, 1994. And in 1995, the company was formed Eurockot, with which the Russian carrier rocket "Rokot" was put on the market of commercial launches.

The enterprise purchased 45 spacecraft. In 2000, Astrium bought a 51% stake in Eurockot. The remaining 49% own the Khrunichev State Scientific and Technical Center. In May 2000, from the Plesetsk cosmodrome, Rokot was launched not from a mine, as was the case at Baikonur, but from a land transportation container.

Rokot: characteristics

The spacecraft is a two-stage liquid-fueled carrier rocket, usually equipped with the last stage "Breeze-KM", which is capable of delivering a payload of mass up to 2140 kg to low earth orbit and 1200 kg to the solar-synchronous one.

The characteristics of the rocket carrier Rokot are as follows:

• Height 29.15 m,
• Basic diameter of 2.5 m,
• Starting weight 107 000 kg,
• Fuel - asymmetric dimethylhydrazine (heptyl) and nitrogen tetroxide.

First stage

The first stage of the rocket of light class Rokot is 17.2 m long and 2.5 m in diameter. The tank with nitrogen tetroxide is located above the tank with asymmetric dimethylhydrazine. The two tanks are separated by a common partition. Lifting mass - 77 200 kg, inert - 5700 kg.

In the first stage three engines RD-0233 and one RD-0234 are used. Their designs are similar, but the RD-0234 has a heat exchanger supplying compressed gas to the fuel tanks in order to maintain the necessary pressure in them during the entire first phase of the flight.

All engines - with turbo-pumps of a closed cycle. Each provides 470 kilo-tonne thrust, which in total is 1,870 kN or 190,700 kg. Vacuum traction of the first stage - 2070 kN (211.100 kg), 520 kN per engine.

Control is provided by an individual cardan suspension of each of the four engines. Operating time - 121 s.

Branch is carried out in a hot mode. Vernier engine of the second stage is ignited even before the separation stage. Special hatches direct the jet of four nozzles to the outside. After the launch of the pyrotechnic mechanism, the vernier exhaust repels the spent first stage. In addition, it is equipped with four solid-propellant rocket engines, which, after separation, are ignited to remove it to a safe distance.

The second stage

The second stage is 3.9 m long and 2.5 m in diameter. Its weight is 1500 kg plus 10.700 kg of fuel. The oxidizer tank is also located above the fuel tank and is separated from it by a common partition.

The stage is equipped with engines with a turbo pump of a closed cycle: the main RD-0235 and four-chamber vernier RD-0236 for monitoring the direction of flight.

RD-0235 has a rated vacuum thrust of 240 kN (24 470 kg), providing an impulse for 320 s.

RD-0236 provides thrust of 15.76 kN (1 607 kg) and works for 293 seconds. Each of the four engine nozzles by means of a gimbal suspension can move along one axis, providing control of the rocket orientation in the second stage of the flight. It also uses a hot gas supply system to create the necessary pressure in the tanks.

Upper stage

The rocket "Rokot" is equipped with a booster block, which consists of three main compartments - a motorized, hermetically sealed cargo compartment and an intermediate compartment connected to the second stage.

"Breeze-KM" has a length of 2.6 m, 2.5 m in diameter and a mass of 1320 kg. The tank with heptyl is located above the tank with oxidizer. The latter has a conical shape and a groove for placing the engine. "Breeze-KM" is able to contain 1 665 kg of NDMG and 3310 kg of oxidant. To maintain the necessary pressure in the tanks and to control the pneumatics, high-pressure helium is used.

The central part of the unit consists of a tank with an oxidizer located above the fuel tank. Both tanks are equipped with hydraulic and pneumatic systems, as well as internal partitions to prevent liquid impacts against the walls of the structure. They have a toroidal shape with a notch in the lower part for the main propulsion system, which made it possible to minimize the length of the stage. Below there is a compartment with the main power unit and engines of stabilization and orientation, and spherical tanks with helium and fuel for them. The equipment is covered with thermal insulation, which prevents excessive cooling of the fuel, which affects its viscosity and can lead to the freezing of pipelines and tanks.

Device compartment

In the upper part of the block in an inverted truncated cone there is an equipment compartment consisting of frames that provide the installation of various controllers, telemetry modules, batteries and communication systems. Adapters up to 2.49 m in diameter are supported.

In the lower part is a 60-cm adapter that connects the "Breeze-KM" to the second stage, and also secures the fairings.

In the overclocking unit, two fuel systems are implemented: low pressure for the engine and high pressure for the engines of stabilization and orientation. Both use asymmetrical dimethylhydrazine and nitrogen tetroxide, which ignite immediately after coming into contact with each other.

Engines of the upper stage

The orientation control motors used on the Breeze-KM are named 17D58E and provide a nominal thrust of 13.3 N. Each block has a length of 14 cm and weighs 550 g. The jet micromotor operates at a mixing ratio of 1: 1.85 and a nominal input Pressure of 14.7 bar, but it is able to withstand a large pressure range from 7.8 to 34.3 bar. To control the orientation, the power plants are used in a pulsed mode with a minimum operating time of 0.03 s, but the 17D58E is also certified to operate in a constant mode for up to 10,000 seconds. The engine can withstand 450,000 operating cycles.

The power system of the upper stage

"Breeze-KM" is equipped with its own power system, consisting of batteries and power distribution systems, which provide up to 7 hours of operation of the stage in orbit. The instrument compartment includes telemetry devices with transmitters and antennas, as well as tape recorders for storing and transmitting data. The guidance, navigation and control system is responsible for the flight at all stages. It consists of a platform with inertial guidance, including a 3-axis gyro with on-board computers. The system has a triple redundancy with majority decision making. It is completely autonomous and can not be controlled from the outside.

Cowl

The rocket "Rokot" is equipped with a fairing, which was specially designed for the commercial version of the spacecraft. It is mounted on the instrument compartment of the upper stage. It consists of two parts of 7.8 m in length, which together have an elliptical shape of 2.5 to 2.62 m in diameter. The place for the payload is 5.9 m in height.

The fairing protects the spacecraft from aerodynamic, thermal and acoustic influences exerted on it during flight in the atmosphere. When the rocket leaves it, the fairing is dropped by opening the mechanical locks securing the two half-shells along the vertical line of separation, using a pyrotechnic device located in the nose of the fairing. Then, on the horizontal line of separation, several pyro-bolts are shot, which allows the fairing to disperse laterally due to spring pushers. The loops at the base provide rotation away from the rocket and a clear separation.

Storage and startup of the system

In contrast to SS-19, which start from the mines, the launch of the Rokot launch vehicle is made from a transport and launch container at the Plesetsk, Russia cosmodrome. The missiles are stored for a long time, which requires monitoring of climatic conditions and maintenance of the nitrogen atmosphere. Transportation and installation on the launch pad are also carried out in a container. In addition, the container contains equipment for pre-start preparation and environmental protection.

Before the launch, it moves apart, and a payload, an upper stage and a fairing are installed on the launch vehicle. The container is connected with fueling interfaces, as well as power and information cables. In the vertical position, the rocket "Rokot" rests on the ring at the bottom of the container. When take-off, rupture cables are separated by mechanical systems. During the start the device is guided by two rails. The container protects the launch pad from engine emissions and is used once.

Interesting Facts

The launch of the Rokot missiles will be stopped in 2017 after the scheduled federal and commercial launches.

The name SS-19 Stiletto is the name of NATO for this type of ICBM. SS stands for "land-to-land" system, and the number 19 and the name "Stiletto" are assigned to this type of intercontinental ballistic missiles. In Russia, the official name is SS-19 - RS-18 and UR-100N.

The best thing about the Rokot space rocket is its reliability, which is confirmed by 27 successful launches from 29. And out of 150 SS-19 launches only 3 failed at the very beginning of their operation in the 1970s. The test launches of SS-19 and Rokot are conducted annually in the framework of testing the reliability of the spacecraft and the training of space troops.