Solid-fuel rockets

Two Workers Die and Solid Rocket Fuel Supply Destroyed ... 

May 4, 1988, explosions leveled a Pacific Engineering Production Co. (PEPCO) plant, at Henderson, NV, one of only two U.S. plants producing 20 million lb/ year (maximum of 40 million Ib/year - see Table 7.1-2) ammonium perchlorate for solid rocket fuel. It was the principal supplier for the space shuttle and sole supplier for the Titan rocket and several military missiles. 

The concept of linear burning rate is not confined to the reaction of a gas with a solid. The fuses on fireworks are designed to bum at a constant linear rate. The flame front on solid rocket fuel progresses at a constant linear rate. Both examples have two reactants (a fuel and an oxidizer) premixed in the soUd. Heat transfer limits the burning rate. These materials are merely fast burning. Unlike explosives, they not do propagate a sonic shockwave that initiates further reaction. 

Another groundwater contaminant that can be removed by reduction reactions is perchlorate. Ammonium perchlorate is a solid rocket fuel, and wastes from its manufacturing have contaminated some irrigation and drinking water sources, among them the lower Colorado River in the American Southwest. Elevated perchlorate levels have been linked to human health effects, and because perchlorate has been found in vegetable crops such as lettuce, there is concern that this contamination could have serious consequences. 

Perchlorate is the oxidation product of chlorate. It forms a variety of compounds, including ammonium perchlorate, potassium perchlorate, sodium perchlorate, and perchloric acid. Perchlorate is highly reactive in its solid state, and as ammonium perchlorate it is used as the oxidizer in solid rocket fuel. Because of its limited shelf life, it must be periodically washed out of the country s rocket and missile inventory and replaced. Large volumes of the chemical have been disposed of since the 1950s, and perchlorate has been detected in large concentrations in both groundwater and surface water. Perchlorate has also been used in the manufacture of matches, munitions, fireworks, and in analytical chemistry. 

Perchlorate C black form a solid rocket fuel Refs 1) Beil, not found 2) W.A. Gey R. Reed Jr, USP 3121748(1964) CA 60, 11897g (1964)... 

Ammonium perchlorate is used as a component of perchlorate high explosives. Lately it has been brought into prominence as a constituent of solid rocket fuels, the combustible components of which include such polymers as thiokol and methyl polymethacrylate (Vol. III). Hence a considerable interest has recently been taken in ammonium perchlorate. 

The most significant improvement came in the early 1940s when a method for preparing thiol-terminated liquid polysulfides was developed. Cure of the liquid polysulfides could be accomplished by oxidative coupling. Thus, in effect, a mbber could be compounded without the need of heavy mixing equipment. One of the first large-scale applications of the liquid polysulfides was as a binder for solid rocket fuel. From about 1946 until 1958, these binders were used in various rocket systems and the aliphatic polysulfides achieved commercial success. The switch to predominately liquid-fueled rockets in 1958 ended this phase of the polysulfide business. 

Polymers are produced on an industrial scale primarily, although not exclusively, for use as structural materials. Their physical properties are particularly important in determining their usefulness, be it as rubber tires, sidings for buildings, or solid rocket fuels. 

Among Ya.B. s interests were the combustion of gases and solid rocket fuels, of condensed liquid explosives and powders, the combustion of premixed fuel compounds, and diffusive combustion. In every one of his lines of inquiry he obtained fundamental results which served as starting points for numerous theoretical and experimental studies in the USSR and worldwide. 

With Ya.B. s active participation Soviet science achieved great success in the theory of combustion and in the practical use of solid rocket fuels (powders). This volume contains Ya.B. s basic ground-laying paper (24). 

Silanfyev, Tverdyiye Raketnyiye Topliva (Solid Rocket Fuels), Voyenizdat, Moscow (1964) 86) A. A. Shidlovskii, Osnovy Piro-... 

Perchlorates are the most oxidized of the salts of the chlorooxyacids. Although perchlorates are not particularly toxic, ammonium perchlorate (NH4C104) should be mentioned because it is a powerful oxidizer and reactive chemical produced in large quantities as a fuel oxidizer in solid rocket fuels. Each of the U.S. space shuttle booster rockets contains about 350,000 kg of ammonium perchlorate in its propellant mixture. By 1988, U.S. consumption of ammonium perchlorate for rocket fuel uses was of the order of 24 million kg/year. In May 1988, a series of massive explosions in Henderson, Nevada, demolished one of only two plants producing ammonium perchlorate for the U.S. space shuttle, MX missile, and other applications, so that supplies were severely curtailed. The plant has since been rebuilt. 

Sodium chlorate forms colorless, odorless crystals or white granules. The melting point of the crystals is 248 Celsius, but it begins to decompose into oxygen and sodium perchlorate when heated to 300 Celsius. The crystals are highly soluble in water, but relatively insoluble in alcohol, and most common organic solvents. Sodium chlorate is widely used in pyrotechnic compositions, and in the preparation of ammonium chlorate, and perchlorate, which are used in powerful solid rocket fuels. 

Standard combustion chambers and laboratory combustion chambers ) have been developed for testing the behavior of solid rocket fuels and for the determination of their characteristic properties. 

Composite propellants are solid rocket fuels, consisting of oxygendo-nating inorganic salts and a binder made of plastic. 

B. V. Novozhilov, Nonstationary Combustion of Solid Rocket Fuels, Moscow Nauka, (1973). 

The addition of a small amount of a combustion catalyst as in solid rocket fuel for example gives a different effect according to the kind of oxidizer in the composition. For example, 2% of potassium bichromate is quite effective for ammonium perchlorate or potassium nitrate, but almost ineffective with potassium chlorate or perchlorate. 

Ammonium perchlorate has been studied quite often in recent times because it is used for solid rocket fuel(H.Osada and E.Sakamoto Thermal decomposition of ammonium perchlorate, J.Exp.Soc.,JapanNo.5, P 236 (1963) H.Osada and S.Kakinouchi Initiation of the ignition of solid composite propellant, No., p.290(1965)) It is thought that there are two kinds of decomposition the first occurs below 300 0, and the other over 300 0. The reactions seem to be different from each other. They are very complicated and the products are detected as N iO, N i, NO, NO., NHj, HCIO, HNO3, HCl, HNOj, 0. ... 

Ammonium perchlorate (NH4CIO4) is a solid rocket fuel used in space shuttles. When heated above 200°C, it decomposes to a variety of gaseous products, of which the most important are N2, CI2, O2, and water vapor. 

Because perchlorate is highly soluble, it is not expected to concentrate in soil. Due in part to improved analytical methods, perchlorate has been detected in surface water and groundwater near various facilities that have manufactured and tested solid rocket fuels, most notably in California, Nevada, and Utah. Perchlorate has been measured in the public drinking water supply in several areas in California and in Lake Mead in Nevada. 

---