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Above: A 1-to-10 scale models of Briz-KM (left) and Briz-M upper stages.



A scale model of the Briz-K upper stage. Copyright © 2010 Anatoly Zak


Briz-K and Briz-KM stages. Credit: Eurockot


A Briz upper stage (apparently shown in "upside down" position). A special niche for the main engine, designed to reduce the height of the stage, is visible in the center. Credit: Eurockot


The KOMPSAT-2 satellite attached to the Briz-KM upper stage during the launch in July 2006. Credit: Eurockot


Briz-M upper stage with an external propellant tank. Red protective boxes cover correction engines before launch. Credit: GKNPTs Khrunichev


Scale models of Briz-M's 14D30 engine (S5.98) (left) and its predecessor S5.92. Copyright © 2011 Anatoly Zak



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The Briz (Breeze) rocket stage apparently originated in the 1980s within a Soviet anti-satellite weapons program designed to carry a "killer" vehicle toward its target in orbit. After the end of the Cold War, the propulsion section of the "killer" satellite was converted to a pair of upper stages, which were designated Briz-K (a.k.a. 14S19) and Briz-KM (a.k.a 14S45). Both were designed to fit on top of the Rockot launcher, which itself derived from the two-stage UR-100NU ballistic missile.

Following three launches of Briz-K from 1990 to 1994, the technical project for Briz-KM was officially approved in 1995 with the initial goal of carrying Iridium satellites, whose launch was ordered by the Motorola company.

The Briz-KM stage with a reported mass of 6.77 tons would enable Rockot to deliver 1.95 tons of payload into a 200-kilometer circular orbit with an inclination 63 degrees toward the Equator following its launch from Plesetsk. Powered by internal batteries, Briz-KM could function up to seven hours in orbit.

Briz-KM was first launched during the maiden Rockot mission on May 16, 2000.


In the next phase of upgrades, Briz-KM was to be upgraded with an external propellant tank to form a 22.9-ton Briz-M (14S43) stage, which would serve as the fourth stage of the Proton-K and Proton-M rockets. In this role, it would replace the veteran Block D upper stage. Officially, Briz-M won the federal tender for the upgraded upper stage of the Proton rocket, which was conducted from 1993 to 1994. The program was funded by the Ministry of Defense for prospective military missions. GKNPTs Khrunichev's design arm -- KB Salyut -- completed a preliminary design of the Briz-M stage in 1996. A year later, a set of blueprints for the first flight vehicle and for as many as 10 development prototypes of the stage was issued.

GKNPTs Khrunichev advertised such advantages of the vehicle as record-breaking compact size and the capability to function in space for prolonged periods of time. Briz-M stood just 2.6 meters high, comparing to Block D's 6.5 meters. As a result, it left much more volume available for potential payloads onboard the launch vehicle. Briz-M's main engine was claimed to be able to fire up to eight times during its mission and survive in orbit up to 24 hours. In combination with a cluster of smaller engines onboard, the stage could perform carefully choreographed maneuvers when delivering single or multiple payloads.

The introduction of Briz-M enabled Proton to carry 3.2-3.5 tons of payload directly into the geostationary orbit (instead of previous 2.5 tons with Block D) or to deliver from 5.5 to more than six tons in the geostationary transfer orbit. Proton/Briz-M combination could place around 15 tons into the low Earth orbit.

Briz-M was also designed to be compatible with the next-generation Angara family of launch vehicles including Angara-A3 and Angara-A5. During the 1990s, the stage was also proposed for the European Ariane-5 rocket, the Ukrainian-built Zenit and, possibly, for Russian Soyuz-2 launcher.

The stage flew for the first time on June 5, 1999, but never had a chance to fire due to the failure of its Proton-K rocket. It worked normally during another launch of Proton-K in 2000 delivering a Gorizont-45 satellite into its planned orbit. On April 7, 2001, the Briz-M flew for the first time on Proton-M.


Yet another version of the stage (without the propellant tanks and designated Briz-KS) would be customized for light-weight Rockot, Angara-1.1 and Angara-1.2 vehicles. Briz-KS promised to increase the payload of the Rockot booster from 1.95 tons (for Briz-KM) to 2.4 tons (later reduced to 2.3 tons), when flying from Plesetsk to a 200-kilometer circular orbit with an inclination 63 degrees toward the Equator.

Propulsion system

All stages in the Briz family used an engine developed by KB Khimmash with a thrust of about two tons and burning storable propellant combination of nitrogen tetroxide as oxidizer and unsymmetrical dimethyl hydrazine as fuel. The engine had a specific impulse of 328.1 seconds and was designed for eight firings during a mission.

The Briz-KM stage is equipped with a single 14D30 engine installed in gimbal suspension. It reportedly uses a single burn mode without thrust variations. The engine' design was based on the S5.92 engine which was first used in the Phobos missions. The stage also features four 11D458 engines with a thrust of 40 kilograms, which serve as orbit correction system, DKI. It also has 12 17D58E vernier engines with a thrust of 1.3 kilograms, which are used for attitude control and stabilization, DOS.

Flight control system

OKB Mars developed a flight control computer for the Briz-M upper stage designated Mars-3. It was used in the first seven missions of the stage, after which a modified version designated Mars-3M was introduced during the launch of Intelsat-10-02 satellite.


Briz family specifications:

- Briz-M Briz-KM Briz-KS
Dry mass 2.39 tons 1.14 tons 0.95 tons
Propellant mass approx. 20 tons approx. 5 tons approx. 5 tons
Length 2.65 meters 2.60 meters 2.57 meters
Diameter 4.0 meters 2.5 meters 2.5 meters


Briz development team:

GKNPTs Khrunichev (Moscow) Prime contractor and system integrator
KB Khimmash (Korolev) Propulsion system
MOKB Mars Inertial flight control system
NII KP (St. Petersburg) Gyroscopic stabilization platform
AO Radiophisika and RNII KP Telemetry systems
AO Savma Hardware


14D30 engine specifications:

Thrust in vacuum 2,000 kilograms (19.62 kN)
Specific impulse 328 seconds
A total firing duration 3,200 seconds
Number of ignitions in flight 8
Dry mass 95 kilograms
Dimensions 1,150 by 948 millimeters

Page author: Anatoly Zak; Last update: November 5, 2015

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