Encyclopedia Astronautica
Proton 11S824

Block D / 11D68
Aft view of the Block D lunar crasher stage and its 11D68 engine. The Block D would have taken the LK lunar lander to near the surface of the moon. This stage remains in use today atop the Proton rocket.
Credit: © Mark Wade
Lox/Kerosene propellant rocket stage. Loaded/empty mass 13,360/1,800 kg. Thrust 83.30 kN. Vacuum specific impulse 346 seconds. Originally designed as N1-L3 lunar expedition launch vehicle lunar orbit insertion/lunar crasher stage. Before it could fly on the N1, it was adapted for use with Proton UR-500K as a fourth stage for manned circumlunar flight. It was then further used to launch large Lavochkin bureau unmanned lunar/planetary spacecraft. In the 1970's it was adopted by the Soviet military and standardized for launch of geostationary satellites.

Block D, article number 11S824. Without guidance unit (navigation commands come from payload). Adapted for use with Proton UR-500K as a fourth stage for manned circumlunar flight. Further used to launch large Lavochkin bureau unmanned lunar/planetary spacecraft. Flown from 1967 to 1975.

Cost $ : 4.000 million.

AKA: 11S824; Block D; D-1-e.
Status: Retired 1975.
Gross mass: 13,360 kg (29,450 lb).
Unfuelled mass: 1,800 kg (3,900 lb).
Height: 5.50 m (18.00 ft).
Diameter: 3.70 m (12.10 ft).
Span: 3.70 m (12.10 ft).
Thrust: 83.30 kN (18,727 lbf).
Specific impulse: 346 s.
Burn time: 470 s.
Number: 40 .

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-58 Korolev Lox/Kerosene rocket engine. 83.4 kN. Isp=349s. High-performance upper-stage engine developed for N1 lunar crasher stage, but saw general use as restartable Block D upper stage of Proton launch vehicle. First flight 1967. More...

Associated Launch Vehicles
  • Proton-K/D Russian orbital launch vehicle. This four stage version of the Proton was originally designed to send manned circumlunar spacecraft into translunar trajectory. Guidance to the Block D stage must be supplied by spacecraft. The design was proposed on 8 September 1965 by Korolev as an alternate to Chelomei's LK-1 circumlunar mission. It combined the Proton 8K82K booster for the LK-1 with the N1 lunar Block D stage to boost a stripped-down Soyuz 7K-L1 spacecraft around the moon. The Korolev design was selected, and first flight came on 10 March 1967. The crash lunar program led to a poor launch record. Following a protracted ten year test period, the booster finally reached a level of launch reliability comparable to that of other world launch vehicles. 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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