Encyclopedia Astronautica
YaRD Type A


Korolev nuclear/lh2 rocket engine. 177 kN. Study 1963. Design considered in N1 nuclear upper stage studies. Outgrowth of work done by Bondaryuk and Glushko on YaRD engines for nuclear ICBM's, but using liquid hydrogen as propellant. Isp=900s.

Application: nuclear ICBM.

Engine: 4,800 kg (10,500 lb). Thrust to Weight Ratio: 3.75.

Status: Study 1963.
Unfuelled mass: 4,800 kg (10,500 lb).
Thrust: 177.00 kN (39,791 lbf).
Specific impulse: 900 s.
Burn time: 700 s.

More... - Chronology...


Associated Countries
See also
Associated Launch Vehicles
  • N1 Nuclear A Russian nuclear orbital launch vehicle. A version of the N1 with a nuclear upper stage was studied by Korolev in 1963. It was concluded that the optimum design would allow a single N1 to launch a direct manned lunar landing and return. However for manned Mars missions, a nuclear electric engine was found to be much more efficient. This essentially killed further consideration of thermal nuclear upper stages within the bureau. More...

Associated Manufacturers and Agencies
  • Korolev Russian manufacturer of rockets, spacecraft, and rocket engines. Korolev Design Bureau, Kaliningrad, Russia. More...

Associated Propellants
  • Nuclear/LH2 Nuclear thermal engines use the heat of a nuclear reactor to heat a propellant. Although early Russian designs used ammonia or alcohol as propellant, the ideal working fluid for space applications is the liquid form of the lightest element, hydrogen. Nuclear engines would have twice the performance of conventional chemical rocket engines. Although successfully ground-tested in both Russia and America, they have never been flown due primarily to environmental and safety concerns. 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...

Bibliography
  • Vetrov, G S, S. P. Korolev i evo delo, Nauka, Moscow, 1998.

Associated Stages
  • N1 Nuclear A Nuclear/LH2 propellant rocket stage. Loaded/empty mass 700,000/250,000 kg. Thrust 6,860.00 kN. Vacuum specific impulse 900 seconds. N1 nuclear upper stage study, 1963. Figures calculated based on given total stage thrust, specific impulse, engine mass. More...

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