Encyclopedia Astronautica
8D43 + 11D43


Kosberg N2O4/UDMH rocket engine. 2247.450 kN. Design 1962. Isp=310s. Originally the first stage of the Proton was designed for 4 x fixed 11D43 and 4 x gimballed Kosberg 8D43; replaced by 6 x 11D48 from Glushko in final Proton design.

Application: UR-500 stage 1 original concept.

Thrust (sl): 1,980.000 kN (445,120 lbf). Thrust (sl): 202,000 kgf.

Status: Design 1962.
Thrust: 2,247.45 kN (505,247 lbf).
Specific impulse: 310 s.
Specific impulse sea level: 280 s.
Burn time: 115 s.

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Associated Countries
See also
Associated Launch Vehicles
  • Monoblock UR-500 Russian orbital launch vehicle. During UR-500 design studies, two variants of the first stage were considered: polyblock and monoblock. The monoblock approach was that the first stage be assembled from two separate modules with the same diameter: an upper oxidiser module and a lower fuel and engine block. In assembly trials of this design it proved difficult, because of the height of the first stage, to obtain access to the upper stages and payload atop the rocket. Although there was a payload advantage compared to the more compact polyblock design, this was relatively small and outweighed by the operational difficulties. More...
  • Polyblock UR-500 Russian orbital launch vehicle. UR-500 design studies considered two variants of the first stage: polyblock and monoblock. The polyblock variant consisted of a centre large diameter oxidizer tank surrounded by several smaller diameter fuel tanks. This version could be assembled in a special rig with the lateral blocks being sequentially mounted on the centre. In January 1962 this design was chosen as most advantageous, following studies that indicated improved wind loads and bending moment characteristics compared to the monoblock design. The developed version of the design would become known as the Proton. More...

Associated Manufacturers and Agencies
  • Kosberg Russian manufacturer of rocket engines. Kosberg Design Bureau, Russia. 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...

Associated Stages
  • UR-500 Monoblok Stage 1M N2O4/UDMH propellant rocket stage. Loaded/empty mass 367,360/25,560 kg. Thrust 8,989.70 kN. Vacuum specific impulse 310 seconds. Original conventional 'Monoblock' design for Proton first stage. More...
  • UR-500 Polyblock Stage 1P N2O4/UDMH propellant rocket stage. Loaded/empty mass 378,900/26,900 kg. Thrust 8,989.70 kN. Vacuum specific impulse 310 seconds. Original 'Polyblock' design for Proton first stage. This was selected configuration; although somewhat greater in dry mass, it had the advantages of shorter length. More...

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