This page no longer updated from 31 October 2001. Latest version can be found at N2O4/Alumizine

Oxidiser: N2O4. Oxidiser Density: 1.45 g/cc. Oxidiser Freezing Point: -11.00 deg C. Oxidiser Boiling Point: 21.00 deg C.

Nitrogen tetroxide became the storable liquid propellant of choice from the late 1950's. Nitrogen tetroxide consists principally of the tetroxide in equilibrium with a small amount of nitrogen dioxide (NO2). The purified grade contains less than 0.1 per cent water. Nitrogen tetroxide (N2O4) has a characteristic reddish-brown colour in both liquid and gaseous phases. The solid tetroxide is colorless. N2O4 has an irritating, unpleasant acid-like odour. N2O4 is a very reactive, toxic oxidiser. It is non-flammable with air; however, it will inflame combustible materials. It is not sensitive to mechanical shock, heat, or detonation. Nitrogen dioxide is made by the catalytic oxidation of ammonia; steam is used as a diluent to reduce the combustion temperature. Most of the water is condensed out, and the gases are further cooled; the nitric oxide is oxidised to nitrogen dioxide, and the remainder of the water is removed as nitric acid. The gas is essentially pure nitrogen tetroxide, which is condensed in a brine-cooled liquefier. 1959 production amounted to 60,000 tonnes per year. In carload lots of one-ton cylinders, the price was $ 0.15 per kg. By 1990 NASA was paying $ 6.00 per kg due to environmental regulations.

Fuel: Alumizine.

Alumizine was a mixture of 43% aluminum powder suspended in anhydrous hydrazine with a gelling agent. The idea was to increase the heat of combustion due to the high enthalpy of formation of aluminum oxide as a combustion product, similar to the metallized kerosene ("Kerosol") tested by Saenger in the 30's. Alumizine was never flown and was only tested in static ground tests. A drum of alumizine exploded in California when it was not disposed of safely. The fuel was proposed for some pressure-fed 'big dumb booster' designs of the late 1960's.

Engines Using N2O4/Alumizine

Eng-engineslink Thrust(vac)-kgf Thrust(vac)-kN Isp-sec Isp (sea level)-sec Designed for Status
PF N204/Alumizine-1925k 1,924,600 18,873.00 280 260 First Stages Design concept 1960's
PF N204/Alumizine-2300k 2,300,800 22,562.00 280 260 First Stages Design concept 1960's

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Last update 3 May 2001.
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© Mark Wade, 2001 .