Solid rockets, space application

Hercopel a unique all-epoxide cure composite solid propellant with excellent mechanical and ballistic properties. Its outstanding performance in extended environments makes it well suited for tactical missiles Double-Base Solid Propellants a wide variety of physical and ballistic properties which can be tailored to meet specific performance requirements. Their high specific impulse and excellent reproducibility are two of the many reasons Hercules double-base propellants are found in many of our rocket motors and gas generators used for both military and space applications... 

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. 

Fig. 37.18. The solid booster rockets for the space shuttle are one of the most widely publicized applications of solid rocket propellants.

Measuring acid concentration is important for many applications, specifically for space and homeland security applications. Hydrochloric acid is released from the exhaust plume of solid rocket motors that use ammonium perchlorate as the rocket propellant. This plume can be dangerous in high concentrations and monitoring its concentration and dispersion are important tasks. Hydrochloric acid and other acid gases like nitric acid and hydrofluoric acid are also important and very dangerous toxic industrial chemicals and need to be monitored because of their low permissible exposure limits. 

A model was developed to estimate properties of polymer composites which have voids of various sizes (large and small). Such voids are typically found between fiber tows (macrovoids) and inside the fiber tows (microvoids) in composites produced by liquid molding. The presence of these voids does prevent the matrix from adhering to the fiber which reduces the composite s mechanical performance. Larger voids do not seem to afiect performance as much as smaller voids do. In practice, the volume of voids in normal production is within 5% of the total volume of the composite. At 5% void volume, the mechanical strength of composite can be reduced by as much as 30%. This is considered a substantial imperfection but it is found in practice. The model developed predicts values of mechanical properties which correlate with void volume. In another application, magnetic resonance imaging helped to determine voids in solid rocket propellants and liners similar to those used in space shuttle. The voids were found to be in close proximity to the filler particles. 

During the last decade, the tremendous strides taken in the exploration and exploitation of space have placed new environmental demands on the engineering use of elastomers. In particular, the use of rubber polymers in cryogenic and space applications (in the binder of some solid rocket propellants and in low temperature seals, for example) requires that rubber withstand extremely low temperatures. Under these conditions, rubber can become brittle and cracks can propagate easily through the material. In the case of solid rocket propellants, these cracks can lead to uneven and uncontrolled burning. As one practical technique for increasing... 

In sending a rocket into the sky we are calling into action several laws of physics and chemistry, and the same laws apply whether the application is a small firework rocket weighing a few ounces or a solid propellant booster for the space shuttle containing around 300 tons of propellant. These fundamental processes may be conveniently divided into internal ballistics and external ballistics. 

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