Encyclopedia Astronautica
Proton 11S86


Lox/Kerosene propellant rocket stage. Loaded/empty mass 17,550/2,300 kg. Thrust 85.02 kN. Vacuum specific impulse 352 seconds. Also known as Block DM; article number 11S86. With guidance unit, designed for insertion of military spacecraft into geosynchonous/ medium earth orbit. Used from 1974 to 1990. Succeeded by 11S861.

Cost $ : 4.000 million.

AKA: Block DM; D-1-e.
Status: Retired 1990.
Gross mass: 17,550 kg (38,690 lb).
Unfuelled mass: 2,300 kg (5,000 lb).
Height: 7.10 m (23.20 ft).
Diameter: 3.70 m (12.10 ft).
Span: 3.70 m (12.10 ft).
Thrust: 85.02 kN (19,113 lbf).
Specific impulse: 352 s.
Burn time: 610 s.
Number: 66 .

More... - Chronology...


Associated Countries
Associated Engines
  • 11D79 Stepanov N2O4/UDMH rocket engine. 44 kN. Blok D SOZ. In Production. Thrust 1.1-4.5 tf variable. More...
  • RD-58M Korolev Lox/Kerosene rocket engine. 83.4 kN. Proton 8K824K / 11S824M; 11S824F; 11S86; 11S861; 17S40 stage 4 (block DM). In production. Isp=353s. First flight 1974. More...

Associated Launch Vehicles
  • Proton-K/DM Russian orbital launch vehicle. The original four stage Proton / Block D configuration was used until 1976, at which time it was replaced by a modernised version equipped with N2O4/UDMH verniers for precise placement of payloads in geosynchronous orbit and its own self-contained guidance unit. This was accepted into military service in 1978 with the first Raduga launch. The stage was first developed for launch of gesynchronous military communications and early warning satellites (Raduga, Ekran, Gorizont, Potok, SPRN). Its later versions continue in use for launch of MEO and geosynchronous comsats, and was Russia's most successful commercial launcher. More...

Associated Propellants
  • Lox/Kerosene Liquid oxygen was the earliest, cheapest, safest, and eventually the preferred oxidiser for large space launchers. Its main drawback is that it is moderately cryogenic, and therefore not suitable for military uses where storage of the fuelled missile and quick launch are required. In January 1953 Rocketdyne commenced the REAP program to develop a number of improvements to the engines being developed for the Navaho and Atlas missiles. Among these was development of a special grade of kerosene suitable for rocket engines. Prior to that any number of rocket propellants derived from petroleum had been used. Goddard had begun with gasoline, and there were experimental engines powered by kerosene, diesel oil, paint thinner, or jet fuel kerosene JP-4 or JP-5. The wide variance in physical properties among fuels of the same class led to the identification of narrow-range petroleum fractions, embodied in 1954 in the standard US kerosene rocket fuel RP-1, covered by Military Specification MIL-R-25576. In Russia, similar specifications were developed for kerosene under the specifications T-1 and RG-1. The Russians also developed a compound of unknown formulation in the 1980's known as 'Sintin', or synthetic kerosene. More...

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