Encyclopedia Astronautica
N1 Block R

KVRB stage
Credit: © Mark Wade
Lox/LH2 propellant rocket stage. Loaded/empty mass 23,000/4,300 kg. Thrust 73.50 kN. Vacuum specific impulse 440 seconds. Designed 1965-1971 as replacement for N-1 Blok D. Cancelled 1971 in favor of Blok Sr; revived and developed in 1974-1976. First static test Oct 12 1976. Two stages tested 1976-1977. Strangely never replaced Blok D on Proton.

Status: Development ended 1971.
Gross mass: 23,000 kg (50,000 lb).
Unfuelled mass: 4,300 kg (9,400 lb).
Height: 8.70 m (28.50 ft).
Diameter: 4.10 m (13.40 ft).
Span: 4.10 m (13.40 ft).
Thrust: 73.50 kN (16,523 lbf).
Specific impulse: 440 s.
Burn time: 1,080 s.
Number: 3 .

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Associated Countries
Associated Engines
  • RD-56 Isayev lox/lh2 rocket engine. 69.6 kN. N1 block R. Development ended 1971. Oxygen-hydrogen engine for cryogenic upper stage. Developed but never flown. Design sold to India in 1990's for GSLV. Isp=462s. More...

Associated Launch Vehicles
  • N1M Russian heavy-lift orbital launch vehicle. The N1M was to be the first Soviet launch vehicle to use liquid oxygen/liquid hydrogen high energy cyrogenic propellants. It was designed to launch payloads in support of the LEK lunar expeditions (two cosmonauts on the surface), the DLB (long-duration lunar base), and heavy unmanned satellites into geosynchronous and interplanetary trajectories. As originally conceived, the advanced propellants would be used in all upper stages. However due to delays in Kuznetsov development of a 200 tonne thrust Lox/LH2 engine, the final version used an N1 first stage, with a Block V-III second stage, and Blocks S and R third and fourth stages. More...
  • N1F-L3M Russian heavy-lift orbital launch vehicle. The N1M was found to be too ambitious. The N1F of 1968 was instead pencilled in to be the first Soviet launch vehicle to use liquid oxygen/liquid hydrogen high energy cyrogenic propellants. The N1F would have only used the Block S and Block R fourth and fifth stages in place of the N1's Block G and Block D. More...

Associated Propellants
  • Lox/LH2 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. Liquid hydrogen was identified by all the leading rocket visionaries as the theoretically ideal rocket fuel. It had big drawbacks, however - it was highly cryogenic, and it had a very low density, making for large tanks. The United States mastered hydrogen technology for the highly classified Lockheed CL-400 Suntan reconnaissance aircraft in the mid-1950's. The technology was transferred to the Centaur rocket stage program, and by the mid-1960's the United States was flying the Centaur and Saturn upper stages using the fuel. It was adopted for the core of the space shuttle, and Centaur stages still fly today. More...

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