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astronautix.com LF2/Ammonia





Oxidiser: LF2. Oxidiser Density: 1.51 g/cc. Oxidiser Freezing Point: -219.00 deg C. Oxidiser Boiling Point: -188.00 deg C.

Liquid Fluorine is the highest performance oxidiser and in the early 1960's it seemed in both American and Russia that a new generation of higher performance engines would emerge. However although test engines were built, fluorine was found to be just too toxic and reactive to be safely used as a propellant. Liquid fluorine is essentially 100 per cent pure, containing only traces of oxygen, nitrogen, and hydrogen fluoride. The liquid exhibits a clear; yellow colour, while the gas has a pale greenish-yellow colour at ambient temperature. Fluorine is the strongest oxidising agent known. Under proper conditions, fluorine reacts with practically every element or compound except the inert gases. It is stable to shock, heat, and electric spark. It is non-flammable with air. Fluorine is highly toxic and irritating to all tissues. It has a characteristic pungent halogen odour and is irritating to the respiratory tract. Fluorine is produced from a molten mixture of HF and KF by an electrolytic procedure. The 1959 United. States production of liquid fluorine was estimated at 40,000 tonnes/year. Liquid fluorine's cost, ex-works, was then $ 6.00 per kg. In the Soviet Union Glushko founded a plant for production of fluorine propellants 23 km from Leningrad at Karlelsko. The population eventually reached 120,000, but although one engine was ready for production, this was never authorised due to the safety problems in case of a launch vehicle failure.


Fuel: Ammonia. Fuel Density: 0.60 g/cc. Fuel Freezing Point: -78.00 deg C. Fuel Boiling Point: -33.00 deg C.

Ammonia (NH3) is a colourless gas and liquid with a strong irritating characteristic odour. It is a relatively high-boiling gas with a vapour pressure of 8.7 bar at 20 deg C. Ammonia. is toxic, and will dissolve easily in water. It will form flammable and explosive mixtures with air. Although ammonia itself is toxic, the exhaust gases from the combustion of ammonia and oxygen are not. Ammonia is produced by a Haber-Bosch process, in which the elements, nitrogen and hydrogen, are united at a temperature of 500 to 600 deg C and a. pressure of approximately 200 bar in the presence of a promoted iron catalyst. It is estimated that 4 million tonnes of anhydrous synthetic ammonia were produced in 1959 in the United States, at which time the price of tank-car quantities of refrigeration-grade anhydrous ammonia was $ 80 per tonne.

Engines Using LF2/Ammonia

Eng-engineslink Thrust(vac)-kgf Thrust(vac)-kN Isp-sec Isp (sea level)-sec Designed for Status
RD-301 9,860 96.67 400   Upper Stages Developed 1965-77
RD-302 10,000 98.00 405   Upper Stages Developed 1960-69


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