Briz space tug family
A 1-to-10 scale models of Briz-KM (left) and Briz-M upper stages.
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.
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.
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 development team:
14D30 engine specifications:
Page author: Anatoly Zak; Last update: March 18, 2021
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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