This page no longer updated from 31 October 2001. Latest version can be found at N1 Nuclear A

Family: N. Country: Russian. Status: Study 1963.

Following abandonment of the nuclear-ammonia ICBM projects, the engine bureaux of Bondaryuk (OKB-670) and Glushko (OKB-456) continued study of nuclear propulsion, but using liquid hydrogen for upper stage applications. Engines of 200 tonnes and 40 tonnes thrust with a specific impulse of 900 to 950 seconds were being considered. At the end of 1961 both bureaux completed their draft projects and it was decided to continue work on development of an engine in the 30 to 40 tonne thrust range. In the following year Korolev was asked to study application of such engines, followed by a specific demand in May 1963 from the Scientific-Technical Soviet for specific recommendations.

Korolev considered three variants based on the N1:

Considered for each case were nuclear engine designs Type A (18 tonnes thrust, 4.8 tonnes mass), AF (20 tonnes thrust, 3.25 tonnes mass), V (40 tonnes thrust, 18 tonnes mass), and V with a bioshield for use on manned flights (40 tonnes thrust, 25 tonnes mass).

The study concluded that the two stage vehicle was the most promising. Compared to an equivalent vehicle using liquid oxygen/liquid hydrogen, mass in low earth orbit would be more than doubled. Optimal stage size was 700 to 800 tonnes for the Type A engines and 1,500 to 2,000 tonnes for the type V engines (this resulted in a halaciously large number of nuclear engines by Western standards). Use of the nuclear stage would result in a single N1 launch being able to launch a round-trip lunar landing (mass landed on lunar surface over 24 tonnes with return of a 5 tonne capsule to earth).

For a Mars expedition, it was calculated that the AF engine would deliver 40% more payload than a chemical stage, and the V would deliver 50% more. But Korolevís study also effectively killed the program by noting that his favoured solution, a nuclear electric ion engine, would deliver 70% more payload than the Lox/LH2 stage.

Further investigation of nuclear thermal stages for the N1 does not seem to be pursued. Bondaryuk and Glushko turned to Chelomei and his competing UR-700 rocket for future application of such stages.


LEO Payload: 270,000 kg. to: 220 km Orbit. at: 51.6 degrees. Payload: 24,600 kg. to a: lunar surface trajectory. Liftoff Thrust: 3,600,000 kgf. Total Mass: 2,400,000 kg. Core Diameter: 17.0 m. Total Length: 180.0 m.

N1 Nuclear A Chronology

- 1963 May -


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Last update 12 March 2001.
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