Encyclopedia Astronautica
Hydrazine


Hydrazine (N2H4) found early use as a fuel, but it was quickly replaced by UDMH. It is still used as a monopropellant for satellite station-keeping motors. Hydrazine (N2H4) found early use as a fuel, but it was quickly replaced by UDMH. It is still used as a monopropellant for satellite station-keeping motors.

Hydrazine marketed for rocket propellant contains a minimum of 97 per cent N2H4, the other constituent being primarily water. Hydrazine is a clear, water-white, hygroscopic liquid. The solid is white. Hydrazine a toxic, flammable caustic liquid and a strong reducing agent. Its odour is similar that of ammonia, though less strong. It is slightly soluble in ammonia and methyl-amine. It is soluble in water, methanol, ethanol, UDMH, and ethylenediamine. Hydrazine is manufactured by the Raschig process, which involves the oxidation of ammonia to chloramine, either indirectly with aqueous sodium hypochlorite or directly with chlorine, and subsequent reaction of chloramine with excess ammonia. Raw materials include caustic, ammonia, and chlorine; these are high-tonnage, heavy chemicals. The cost of anhydrous hydrazine in drum quantities in 1959 was $ 7.00 per kg. The projected price, based on large-scale commercial production, was expected to be $ 1.00 per kg. Due to environmental regulations, by 1990 NASA was paying $ 17.00 per kg.

Hydrazine marketed for rocket propellant contains a minimum of 97 per cent N2H4, the other constituent being primarily water. Hydrazine is a clear, water-white, hygroscopic liquid. The solid is white. Hydrazine a toxic, flammable caustic liquid and a strong reducing agent. Its odour is similar that of ammonia, though less strong. It is slightly soluble in ammonia and methyl-amine. It is soluble in water, methanol, ethanol, UDMH, and ethylenediamine. Hydrazine is manufactured by the Raschig process, which involves the oxidation of ammonia to chloramine, either indirectly with aqueous sodium hypochlorite or directly with chlorine, and subsequent reaction of chloramine with excess ammonia. Raw materials include caustic, ammonia, and chlorine; these are high-tonnage, heavy chemicals. The cost of anhydrous hydrazine in drum quantities in 1959 was $ 7.00 per kg. The projected price, based on large-scale commercial production, was expected to be $ 1.00 per kg. Due to environmental regulations, by 1990 NASA was paying $ 17.00 per kg.

Fuel: Hydrazine. Fuel Density: 1.008 g/cc. Fuel Freezing Point: 2.00 deg C. Fuel Boiling Point: 113 deg C.

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Associated Spacecraft
  • Shenzhou RV Chinese manned spacecraft module. Operational, first launch 1999.11.19. The re-entry vehicle was conceptually based on the Soyuz, but was not a copy. More...
  • Shenzhou OM Chinese manned spacecraft module. Operational, first launch 1999.11.19. The orbital module provided quarters for the crew during the space mission, and could be fitted out with different internal and external equipment according to mission requirements. More...
  • New Horizons American outer planets probe. One launch, 2006.01.19. New Horizons was the first spacecraft targeted on Pluto, the last unvisited body of the nine original planets known at the beginning of the space age. Pluto Flyby. More...
  • Themis American earth magnetosphere satellite. 5 launched, 2007.02.17. More...

Associated Engines
  • DOK-10 Isayev monopropellant rocket engine. 10 N. In Production. Pressure-fed monopropellant engine. Thermal decomposition of hydrazine by an iridium-based catalyst, which heated to increase stability. 40,000 ignitions Isp=229s. More...
  • DOK-50 Isayev monopropellant rocket engine. 0.050 kN. In Production. Pressure-fed monopropellant engine. Thermal decomposition of hydrazine by an iridium-based catalyst, which heated to increase stability. 40,000 ignitions Isp=229s. More...
  • DOT-25 Isayev monopropellant rocket engine. 0.025 kN. In Production. Pressure-fed monopropellant engine. Thermal decomposition of hydrazine by a wire catalyst, which is electrically heated to 620 K. 60,000 ignitions Isp=234s. More...
  • DOT-5 Isayev monopropellant rocket engine. 5 N. In Production. Pressure-fed monopropellant engine. Thermal decomposition of hydrazine by a wire catalyst, which is electrically heated to 620 K. 550,000 ignitions Isp=230s. More...
  • MR-111 Redmond hydrazine monopropellant rocket engine. 4.4 N. Attitude control, Intelsat 5, ERBS, ACTS, Radarsat, MMAS 4000, 5000, and. 7000, Wind/Polar Landsat, and Mars Observer. In Production. Isp=229s. First flight 1980. More...
  • MR-120 Redmond Hydrazine rocket engine. 0.090 kN. Small ICBM. In Production. Developed as an attitude control thruster for the small ICBM. Isp=229s. More...
  • MR-107 Redmond hydrazine monopropellant rocket engine. 0.257 kN. Spacecraft and upper stage attitude control and dV corrections, Delta 2, Titan 2, PAM D, SICBM, HAS/Peace Courage, Atlas roll control module, STEP, Pegasus. Isp=236s. First flight 1990. More...
  • MR-106 Redmond hydrazine monopropellant rocket engine. 0.027 kN. Spacecraft and upper stage attitude control and velocity corrections, PAM A/S,. Radarsat, GPS Block 2R, HAS/Peace Courage, Titan Centaur, Atlas Centaur. In Production. Isp=232s. More...
  • MR-104 Redmond hydrazine monopropellant rocket engine. 0.441 kN. Attitude control and velocity corrections, Voyager, Magellan, DMSP, Tiros N, Landsat. In Production. Isp=239s. First flight 1977. More...
  • MR-103 Redmond hydrazine monopropellant rocket engine. 1.12 N. Attitude control thruster for Voyager, GPS, Intelsat 5, MMAS 3000, 4000,. 5000, and 7000, Mars Observer, ACTS, and Magellan. In Production. Isp=227s. First flight 1974. More...
  • MR-501B Redmond Hydrazine rocket engine. 369 mN. BSAT-2 communications satellite. In Production. Electrothermal hydrazine thruster (EHT). 493 W input power at 24 V DC. Isp=303s. More...
  • MR-502 Redmond hydrazine monopropellant rocket engine. 500 mN. Communications satellite N-S stationkeeping, MMAS 5000. In Production. Isp=304s. First flight 1991. More...
  • MR-508 Redmond hydrazine monopropellant rocket engine. 230 mN. Communications satellite N-S stationkeeping, MMAS 7000. In Production. Isp=502s. First flight 1993. More...
  • MR-509 Redmond Hydrazine rocket engine. 254 mN. In Production. Low-power arcjet system. Input power 1800 W at 65 V DC. Isp=502s. More...
  • MR-510 Redmond Hydrazine rocket engine. 254 mN. In Production. Arcjet system. Isp=600s. More...
  • MR-512 Redmond Hydrazine rocket engine. 254 mN. In Production. Low-voltage bus arcjet system. Input power 1780 W at 35 V DC. Isp=502s. More...
  • MR-50 Redmond hydrazine monopropellant rocket engine. 0.022 kN. Attitude control for SMS, Viking, Metosat, GOES, Voyager, GPS, Intelsat 5,. Scatha, MMAS 5000, Delta Star, Magellan, Wind/Polar. In Production. Isp=228s. First flight 1974. More...
  • MRE-15/OMV TRW hydrazine monopropellant rocket engine. 0.089 kN. In Production. Isp=225s. Mono-propellant Hydrazine Thrusters. More...
  • MRM-106 Redmond Hydrazine rocket engine. 0.027 kN. In Production. Steady-state thrust 9 N. Isp=231s. More...
  • MRM-122 Redmond Hydrazine rocket engine. 0.142 kN. In Production. Steady-state thrust 51 N. Isp=228s. More...
  • MRM-103 Redmond Hydrazine rocket engine. 0.22 N. In Production. Steady-state thrust 0.22 N. Isp=224s. More...
  • REA 39-2 Marquardt hydrazine monopropellant rocket engine. 2.22 N. In Production. More...
  • REA 16 Marquardt hydrazine monopropellant rocket engine. 0.020 kN. In Production. More...
  • REA 17-12 Marquardt hydrazine monopropellant rocket engine. 4.45 N. In Production. More...
  • REA 17-6 Marquardt hydrazine monopropellant rocket engine. 2.22 N. In Production. More...
  • REA 20-4 Marquardt hydrazine monopropellant rocket engine. 0.556 kN. In Production. More...
  • REA 22-16 Marquardt hydrazine monopropellant rocket engine. 0.130 kN. In Production. More...
  • REA 22-17 Marquardt hydrazine monopropellant rocket engine. 0.178 kN. In Production. More...
  • REA 22-2 Marquardt hydrazine monopropellant rocket engine. 0.090 kN. In Production. More...
  • REA 22-5 Marquardt hydrazine monopropellant rocket engine. 0.050 kN. In Production. More...
  • REA 10 Marquardt hydrazine monopropellant rocket engine. 890 mN. In Production. More...
  • RM-01 Rocketdyne hydrazine monopropellant rocket engine. 44 mN. Spacecraft. Pressure-fed. Isp=91s. More...

Associated Stages
  • LK-4 Hydrazine propellant rocket stage. Loaded/empty mass 237/71 kg. Thrust 0.40 kN. Vacuum specific impulse 200 seconds. Upper stage for orbital insertion of Shavit or Leolink payloads. More...
  • OAM Hydrazine propellant rocket stage. Loaded/empty mass 714/360 kg. Thrust 0.88 kN. Vacuum specific impulse 222 seconds. Monopropellant final stage providing precise orbital injection. Pressure-fed, indefinite number of restarts. More...
  • Pegasus-4 Hydrazine propellant rocket stage. Loaded/empty mass 90/17 kg. Thrust 0.67 kN. Vacuum specific impulse 236 seconds. More...
  • RSA-4-4 Hydrazine propellant rocket stage. Loaded/empty mass 300/100 kg. Thrust 0.40 kN. Vacuum specific impulse 230 seconds. Specific impulse estimated. Maximum propellant load indicated (hydrazine monopropellnat contained in 4 x 50 l tanks). Upper stage used for orbit circularization at apogee, dispensing of dual payloads, third station nutation damping. Equipped with 2 x 200 N engines for maneuver, 4 x 200 N for roll control, and 4 x 25 N for yaw and pitch. More...

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