Proton-M/Briz-M – Launch Vehicle
The Proton Rocket Family is one of the most successful heavy-lift boosters in the history of space flight. Being designated UR-500, the Rocket started out as a Super Intercontinental Ballistic Missile in the 1960’s. As it was capable of launching a 100-megaton nuclear warhead, Proton was hugely over-sized and became a Space Launcher designed to lift the heaviest payloads to space.
The first Proton Launch was made in 1965. During the first five years of operation, the system experienced dozens of failures before becoming a reliable booster. Over the years, the Proton Family underwent several modifications and re-designs in order to keep the Rocket’s Systems up to date using modern technology. The early version of the Proton Family was called 8K82 and was equipped with only two stages. Proton-K was the first featuring three stages and an optional upper stage. The Proton-K Launcher was retired in 2012, leaving only the improved version of the Family, Proton-M, active.
This particular launcher configuration made its first launch in 2001. Proton-M is also a three-stage rocket with the capability to support an upper stage. Block D/DM and Briz-M (English: Breeze-M) Upper Stages are used on top of the Proton to enable the heavy-lift vehicle to deliver its payloads to a variety of orbits and trajectories. The Proton Rocket is launched from Sites 81 and 200 of the Baikonur Cosmodrome, Kazakhstan. Khrunichev State Research and Production Space Center is the manufacturer of Proton-M & Briz-M. Proton-M Launchers are operated by the Russian Government for official government mission. Also, the Rocket has been made available for commercial launches which are being operated by International Launch Services.
The Proton Family has more than 400 Launches under its belt keeping a success rate of nearly 90%. Notable payloads included modules of the Russian Salyut and Mir Space Stations as well as the Zarya and Zvezda Modules of the International Space Station. Many commercial communication satellites have been orbited using Proton-M Rockets with Briz-M Upper Stages.
|Stages||3 (+ Optional Upper Stage)|
|Mass to LEO||22,000kg|
|Mass to GTO – Briz-M||6,000kg|
|Mass to GSO – Briz-M||3,500kg|
The Proton-M Vehicle consists of three Stages each equipped with different engines that place the orbital Unit Consisting of Upper Stage and Payload to its desired trajectory in about 9 minutes. Compared to previous Proton versions, Proton-M utilizes light-weight technology as part of an effort to reduce launcher mass to maximize its capability. Also, the avionics of the Proton-M are digital, state of the art systems. Proton-M uses a simple design philosophy to increase reliability and improve flight heritage on proven components.
Overall, Proton-M/Briz-M stands 58.2 meters tall with a diameter of 7.4 meters and a launch mass of nearly 713,000 Kilograms. Proton-M can deliver payloads of up to 22,000 Kilograms to Low Earth Orbit. With Briz-M, the Proton can deliver satellites of 6 metric tons into Geostationary Transfer Orbit. Direct Geosynchronous injection capability is 3.5 tons.
|Type||Storable Propellant Stage|
|Guidance||From third Stage|
|Propulsion||6 x RD-275M|
|RD-275M Thrust SL||1,657kN|
|RD-275M Thrust Vac||1,833kN|
|Total SL Thrust||9,942kN|
|Total Vac Thrust||10,998kN|
|Engine Dry Weight||1,080kg|
|Ox. To Fuel Ratio||2.67|
The first and largest stage of the Proton-M Rocket has an inert mass of 31,000 Kilograms. It consists of the central tank containing the Oxidizer, Nitrogen Tetroxide. This large central tank is surrounded by six outboard propellant tanks containing Unsymmetrical Dimethylhydrazine which is used as fuel. The outboard tanks give the impression of strap-on rocket boosters, but are not separated during flight.
Each of the fuel tanks has a modified RD-253 Engine installed on it. Those engines are known as RD-275M or RD-276. Since 1965, the first stage engines have only been modified slightly, increasing performance to 112% of initial performance. The RD-275M operates at a higher chamber pressure as improved manufacturing techniques are available. The RD-275M uses a staged combustion cycle for oxidizer-rich generator gas.
RD-275M provides a sea level thrust of 1,657 Kilonewtons – giving the Proton a liftoff thrust of 9,942 Kilonewtons – 1.014 Million Kilograms creating an initial thrust-to-weight ratio of 1.42. The engine operates at a chamber pressure of 16.9MPa with an expansion ratio of 241. Overall, the engine is 2.72 meters long, 1.5m in diameter with a dry mass of 1,080kg and a filled mass of 1,260kg. RD-253/275 has a reliability coefficient of .998.
Proton uses a one-degree of freedom thrust vector control system on its first stage. Each of the six engines can only move +/-7 degrees in one direction, tangentially to the circular engine cluster.
The first stage is separated from the launch vehicle after 120 seconds into the mission. Modifications allowed reduced propellant residuals in the Proton’s stages in order to improve launcher performance and avoid environmental hazards as the Propellants are highly toxic. Guidance data is provided by the Navigation System that is installed on the third stage.
|Type||Storable Propellant Stage|
|Guidance||From third Stage|
|Propulsion||3 x RD-0210 & 1 x RD-0211|
|Engine Dry Weight||566kg|
|Chamber Pressure||14.7 MPa|
|Tank Pressurization||Via RD-0211|
Unlike the first stage, the second stage of the Proton-M uses the conventional cylindrical stage design with Fuel and Oxidizer Tanks mounted in a stacked manner.
The second stage also uses Nitrogen Tetroxide and Unsymmetrical Dimethylhydrazine as propellants.
With an empty weight of 11,700 Kilograms, the stage holds up to 156,100 Kilograms of propellants that are used during 206 seconds of powered flight before the stage is separated from the third stage of the vehicle.
Stage is powered by four engines, three RD-0210 engines and one RD-0211 engine which is a slightly modified RD-0210 engine that accommodates a gas generator heat exchanger that supplies pressurant gas to the propellant tanks to keep them at proper flight pressure levels.
In total, all engines provide approximately 2.4 Meganewtons of thrust – 244,600 Kilograms. The RD-0210 engine is also a staged combustion cycle engine. Each of the four engines is 2.33 meters long, 1.47 meters in diameter and weighs 566 Kilograms operating at a chamber pressure of 14.7 MPa.
|Type||Storable Propellant Stage|
|Propulsion||RD-0213 Engine + RD-0214 Vernier|
|RD-0213 Thrust Vac||583kN|
|Chamber Pressure||14.7 MPa|
|Chamber Pressure||5.3 MPa|
The third stage of the Proton-M Rocket is the final stage of the actual launch vehicle that delivers the orbital unit to a preliminary orbit or a suborbital trajectory, depending on the mission profile.
This stage also utilizes a conventional design and consumes Nitrogen Tetroxide and Unsymmetrical Dimethylhydrazine a propellants. An RD-0213 engine powers the vehicle providing 583 Kilonewtons of thrust.
This engine is a non-gimbaled version of the RD-0210 engine that is used on the second stage. For vehicle control and additional thrust, an RD-0214 Engine with four gimbaled nozzles is installed on the third stage.
The RD-0214 provides 31 Kilonewtons of thrust for a total 3rd stage thrust 62,600 Kilograms.
The third stage houses the vehicle’s Navigation, Guidance and Control System that operated the vehicle during all aspects of powered flight which is fully automated and does not require commands from ground stations. A triple redundant digital guidance system is used to control the vehicle.
The Control System has been upgraded several times since the Proton-M started operations in 2001. The guidance mode used is cosed-loop. A high-precision three-axis gyro stabilizer provides exact attitude data to the digital flight computer. The avionics system also provides flight termination in case of a major anomaly during ascent.
Briz-M Upper Stage
|Propellant Tanks||Aluminum Alloy|
|Engine Type||Gas Generator, Open Cycle|
|Thrust – Vacuum||19.62kN|
|Specific Impulse Vac||328.6s|
|Mixture Ratio||2.00 (+/-0.04)|
|Burn Time||Total: 3,200s, Single Burn: 2,000s|
|Restart Capability||Up to 8|
|Settling Thrusters||4 x 11D458M|
|Min Impulse Bit||13.7Ns|
|Burn Time||0.05 to 1,000s|
|Reaction Control||12 x 17D58E|
|Inlet Pressure||7.8 to 34.4bar|
|Burn Time||0.03 to 10,000s|
Briz-M is a hypergolic upper stage developed for the Proton Rocket allowing access to a variety of orbits including Geostationary Transfer Orbit, Geosynchronous Orbit, escape trajectories and all types of lower orbits. Due to its propellant combination and low-performance engine, the payload capacity of Angara with Briz-M are much smaller than with the cryogenic upper stage.
Briz was developed on the basis of an anti-satellite propulsion system studied in the 1980s and first flew as Briz-K before being developed into the smaller Briz-KM for the Rockot launcher and its larger sister, the Briz-M, for Proton missions. Briz-M first flew in 1999 and the KM version made its debut in 2000.
Briz-M is 4.0 meters in diameter and 2.61 meters in length consisting of a central block that houses propellant tanks, the engine compartment, pressurization systems and the flight control system. The Core Section is 2.49 meters in diameter. A toroidal tank section installed around the core vehicle carries additional propellants and is jettisoned after being emptied. In total, Briz-M weighs around 22,300 Kilograms including 5.2 metric tons of propellants stored in the core module and 14.6 tons of propellants carried in the Auxiliary Propellant Tank.
The Central block consists of an oxidizer tank on top of the fuel tank, both are separated by a common bulkhead. The tanks include hydraulic and pneumatic systems as well as internal baffles to prevent propellant sloshing inside the tanks. Structurally, the tanks are toroidal in shape, leaving a cavity at the bottom to provide space for the main propulsion system in order to minimize the length of the stage. Below the tanks, the engine compartment features the main propulsion system, settling and attitude control thrusters, spherical helium pressurant tanks and spherical high-pressure propellant tanks for the settling and attitude control systems. The tanks are coated with screen vacuum thermal insulation to avoid excessive cooling of the propellants that affects viscosity and can lead to freezing the lines and tanks.
On top of the Central Block is the equipment section of the Briz-M that is housed in an inverted truncated cone that features sub-frames to provide installation surfaces for the various controllers, telemetry modules, batteries and communications systems. Installed on the top frame of the Central Block is the payload adapter that provides the structural attachment point of the spacecraft and also includes communication interfaces. Payload adapters up to 2.49 meters in diameter can be supported.
At the bottom of the Central Block is a 60-centimeter long adapter section that builds the structural interface between the Briz-M and the second stage of the launch vehicle and also provides attachment points for the payload fairing to transfer loads from the fairing and house separation equipment. This interstage section is separated with the second stage. Briz-M is encapsulated in the payload fairing of the launcher and reduces the available payload envelope.
The Auxiliary Propellant Tank is mounted to the Central Block via a number of structural struts. Umbilical Interfaces are used to transfer propellants, power, and data between the two components. The toroidal compartment with cylindrical shells is divided into two separate tanks by an intermediate bulkhead creating an oxidizer tank (top) and fuel tank (bottom). Loads from the vehicle are transferred to the APT via the load-bearing cone inside the oxidizer tank and the outer cylindrical shell of the fuel tank. The tanks also include baffles to dampen propellant sloshing.
Once the 14.6 metric tons of hypergolics inside the APT are consumed, the tank section is jettisoned by initiating pyrotechnic bolts that cut the structural attachment points of the APT. Electrical and fluid connectors automatically disconnect at separation and spring pushers initiate the clean separation of the APT that is ensured by guide rails and roller supports on the tank and Central Block.
Briz-M includes two propellant systems – one low-pressure system for the main engine and a high-pressure system for the settling thrusters and the attitude control system. Both use Unsymmetrical Dimethylhydrazine as fuel and Nitrogen Tetroxide as oxidizer. These hypergolic propellants ignite immediately when coming into contact.
Briz Propulsion Section (Photo: Briz-KM, similar to Briz-M)
Briz-M uses a single S5.98 main engine that delivers 19.62 Kilonewtons of thrust (2,000kgf) and is based on an open cycle design. In this propulsion scheme, a small amount of oxidizer and fuel are injected into a gas generator that creates a high-pressure hot gas consisting of combustion products. This high-pressure gas feed is used to drive the turbines of the turbopumps of the fuel and oxidizer to deliver high-pressure propellant components into the combustion chamber. Regenerative cooling is accomplished by flowing propellant through the engine heat exchangers that cool the combustion chamber and warm up the propellants to temperatures where they have favorable physical properties.
S5.98 operates at a chamber pressure of 95 to 98 bar and uses a propellant mixture ratio of 1.96 to 2.04. It generates a specific impulse of 328.6 seconds. Overall, the engine is 115 centimeters long and 94.8 centimeters in diameter weighing 95 Kilograms. S5.98 can support up to eight re-starts in flight.
S5.98 is protected by a cover that is opened for main engine burns and protects the engine during coast phases using a hinged opening mechanism.
The propellant settling system is comprised of four 11D458M thrusters installed on four thruster pods located on the aft end of the Central Block. These pods include one settling thruster and three attitude control engines connected to the same propellant supply. Also consuming hypergolic propellants, the settling and attitude thrusters use propellants supplied by the high-pressure system.
Each settling thruster delivers 392 Newtons of thrust being 46.9 centimeters long and 19.2 centimeters in diameter with a mass of about 3 Kilograms. 11D458M operates at a mixture ratio of 1.85 and a propellant inlet pressure of 14.7 bar. It can be fired in pulse mode or make long steady-state burns and is certified for firings of up to 1,000 seconds and 10,000 duty cycles. For propellant settling, all four thrusters are activated 15 seconds before the main engine start to provide a forward acceleration for propellant settling inside the large tanks.
The attitude control thrusters used on Briz-M are known as 17D58E providing a nominal thrust of 13.3 Newtons. Each unit is 14 centimeters long and weighs 550 grams. The thruster also operates at a mixture ratio of 1.85 and a nominal inlet pressure of 14.7 bar, but it can tolerate a large pressure range from 7.8 to 34.3 bar. For attitude control, the thrusters are used in pulse mode with a minimum on-time of 0.03 seconds, but 17D58E is also certified for burns in steady-state mode up to 10,000 seconds. The engine is certified for 450,000 duty cycles.
Briz-M is outfitted with an inertial guidance platform, a digital flight computer and batteries that allow the stage to operate for up to 24 hours.
|Separation||During 3rd Stage Burn|
The Payload Fairing is positioned on top of the stacked vehicle and its integrated Payload. It protects the spacecraft against aerodynamic, thermal and acoustic environments that the vehicle experiences during atmospheric flight. When the launcher has left the atmosphere, the fairing is jettisoned by pyrotechnically initiated systems. The fairing is attached to the third stage and the Briz-M Upper Stage.
Proton-M can be equipped with two different fairing designs. Both are cylindrical in shape, but their overall length and weight varies. Both types of fairing have an inner diameter of 4.35m. The shorter version is 13.31m in length while the large fairing is 15.26m long.
Payload Adapters interface with the vehicle and the payload and are the only attachment point of the payload on the Launcher. They provide equipment needed for spacecraft separation and connections for communication between the Upper Stage and the Payload. The separation system can be based on either the traditional pair of pyrotechnically-initiated bolt cutters or a low-shock Clamp Band Opening Device (CBOD). Four off-the-shelf Payload Adapters are currently available for Proton Flights, however custom designs based on Spacecraft requirements are also provided by Khrunichev, the manufacturer of Proton Adapters.