Encyclopedia Astronautica
Proton 11S861-01


Lox/Kerosene propellant rocket stage. Loaded/empty mass 18,650/2,650 kg. Thrust 83.45 kN. Vacuum specific impulse 361 seconds. Also known as Block DM-2M, article number 11S861-01. Commercial versions are Block DM3, with Saab payload dispenser, for insertion of Hughes HS 601 bus spacecraft into geosynchronous orbit; and Block DM4, for insertion of FS-1300 bus spacecraft into geosynchronous orbit.. With guidance unit, originally designed for insertion of military spacecraft into geosynchonous orbit. Capable of boosting heavier payloads than 11S861 through use of higher-performance 'sintin' synthetic kerosene fuel.

Cost $ : 4.000 million.

AKA: Block DM; D-1-e.
Status: Active.
Gross mass: 18,650 kg (41,110 lb).
Unfuelled mass: 2,650 kg (5,840 lb).
Height: 7.10 m (23.20 ft).
Diameter: 3.70 m (12.10 ft).
Span: 3.70 m (12.10 ft).
Thrust: 83.45 kN (18,760 lbf).
Specific impulse: 361 s.
Burn time: 680 s.
Number: 46 .

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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-58S Korolev Lox/Kerosene rocket engine. 86.3 kN. Proton 8K82K / 11S861-01 stage 4 (block DM). Version 17D12 for Buran OMS. Version uses synthetic kerosene ('Sintin') for higher specific impulse. Isp=361s. First flight 1994. More...

Associated Launch Vehicles
  • Proton-K/DM-2M This four stage version uses the Block DM-2M / 11S861-01 upper stage, which has its own self-contained guidance unit. This reduces payload but does not require the spacecraft's guidance system to provide steering commands to booster. Used for launches of Russian geosynchronous satellites from 1994 on. More...
  • Proton-K/DM-2M DM4 Russian orbital launch vehicle. Version of the 11S861-01 with Saab payload adapter-seperation system for insertion of FS-1300 bus spacecraft into geosynchronous orbit. 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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