Encyclopedia Astronautica
Proton KM-4 Briz M


N2O4/UDMH propellant rocket stage. Loaded/empty mass 22,170/2,370 kg. Thrust 19.60 kN. Vacuum specific impulse 326 seconds. New upper stage for Proton, replacing Energia Corporation's Block DM, making Proton an all-Khrunichev launch vehicle. The Khrunichev-built Briz-M upper stage is a derivative of the flight-proven Briz -K stage (as used on the Rokot booster).

The Briz-M consists of a central cylinder and a jettisonable external propellant tank. Propellant carried is dependent on the specific mission requirements and is varied to maximize performance for the mission. The Briz-M is capable of operating, on-orbit, for a minimum of 24-hours and is controlled by a closed loop, triple redundant guidance system that is commandable in flight.

AKA: Briz M.
Status: Active.
Gross mass: 22,170 kg (48,870 lb).
Unfuelled mass: 2,370 kg (5,220 lb).
Height: 2.61 m (8.56 ft).
Diameter: 2.50 m (8.20 ft).
Span: 4.10 m (13.40 ft).
Thrust: 19.60 kN (4,406 lbf).
Specific impulse: 326 s.
Burn time: 3,000 s.
Number: 26 .

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Associated Countries
Associated Engines
  • 11D458 Isayev N2O4/UDMH rocket engine. 0.392 kN. In Production. Isp=252s. Small attitude control thruster in Briz upper stage propulsion system S5.98M. Total summmary impulse 14,112 kg-s. Minimum impulse 4 kg-s. Specific impulse also reported as 275 sec. More...
  • 17D58E Isayev N2O4/UDMH rocket engine.13 N. In Production. Isp=247s. Small attitude control thruster used in Briz, Briz-M upper stage propulsion system S5.98M. More...
  • RDMT-12 NII Mash N2O4/UDMH rocket engine. 12 N. Almaz, Kvant, Kristall, Spektr, Priroda. In Production. Low-thrust attitude control thruster. Predecessor was RDMT-400. Used in Isayev 17D58E engine. Isp=279s. More...
  • RDMT-400 NII Mash N2O4/UDMH rocket engine. 0.400 kN. Almaz, Kvant, Kristall, Spektr, Priroda. In Production. Low-thrust attitude control thruster. Used in Isayev 11D458 engine. Isp=255s. More...
  • S5.98M Isayev N2O4/UDMH rocket engine. 19.62 kN. Used on Briz and Briz-M upper stages. Isp=325s. Engine system consists of: main engine (2000 kgf, Isp=325.5s) + 4x11D458 (40 kgf, Isp=252s) + 12x17D58E (1.36 kgf, Isp=247s). 8 restarts. First flight 1990. More...

Associated Launch Vehicles
  • Proton/Briz K/M Earlier 8K82K model Proton, but Briz M storable propellant upper stage replaced the Block D cyrogenic stage. More...
  • Proton/Briz M Improved Proton orbital launch vehicle. Improvements in lower stages to reduce structural mass, increase thrust, and fully utilize propellants (reducing release of toxic chemicals in stage impact areas). Briz M storable propellant upper stage replaces Block D cyrogenic stage. More...

Associated Propellants
  • N2O4/UDMH Nitrogen tetroxide became the storable liquid propellant of choice from the late 1950's. Unsymmetrical Dimethylhydrazine ((CH3)2NNH2) became the storable liquid fuel of choice by the mid-1950's. Development of UDMH in the Soviet Union began in 1949. It is used in virtually all storable liquid rocket engines except for some orbital manoeuvring engines in the United States, where MMH has been preferred due to a slightly higher density and performance. More...

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