The trophy piece of technology in any modern rocket system is without question the liquid bi-propellant engine. Despite their sophistication, power, and precision the workhorse responsible for launching men and machines into space is based on solid rocket technology more than 700 years old. The earliest historical use of gunpowder dates back to the 300 B.C where in modern day China bamboo tubes filed with gunpowder were thrown into fires during celebrations, the noise warding away evil spirits. 500 years later in 1232 A.D at the battle of Kai-fung-fu the Chinese military used the first recorded rockets against the invading Mongol Horde. As the Mongols moved through china, they took emerging technologies with them and by 1241 A.D, the rocket had made it to the battlefields of Europe. By 1300 A.D, arsenals around Europe had some rocket technology, based entirely on the use of gunpowder for propulsive motive. A lack of control over rocket trajectories hindered much development by western militaries, who also found the tendency of a misguided missile to start a fire counterproductive. In the Eighteenth century, work had begun on developing a more powerful propellant, and although some progress had been made the independent work of Robert Goddard and Konstantin Tsailovsky concluded that liquid propellants were the only rational solution to the power problem. Because of this finding, little effort was put into solid propellant design until 1942 when the Jet Propulsion Laboratories introduced composite propellants. Almost all composite propellants are combinations of an organic binder, aluminum powder, and ammonium perchlorate as an oxidizer. Although the majority of on orbit operations require the use of liquid propellants for adequate thrust control and on-off capabilities, virtually all launch, orbital transfer, and atmospheric missiles utilize the above composite propellant for transfer into Low Earth Orbit.

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