Rockets are any devices driven forward by escaping gas through a rear vent. They are remarkable; they have taken literally thousands of years to make, going through many stages of development.
Rockets in Ancient Greece
One of the first devices to qualify as a rocket was a wooden bird. The writings of Aulus Gellius tell a story of a Greek named Archytas. Around the year 400 BC he stunned the townspeople by flying a pigeon made of wood. Escaping steam propelled the pigeon suspended on wires. The bird is an example of Newton’s third law of motion- every action has an equal and opposite reaction.
About one hundred years later, a Greek named Hero invented a similar rocket-like device called an aeolipile. It used steam to propel it. Hero put a sphere on top of a water kettle with two L-shaped tubes on opposite sides of the sphere. The tubes let gas escape. A fire below the kettle turned the water into steam, the steam gave the sphere a thrust, and it rotated the sphere.
Rockets in Ancient China
Stories of early rocket devices appear through historical records from different cultures. Maybe the first rockets were accidents. In the first century AD the Chinese were said to have had a simple form of gunpowder made from saltpeter, sulfur, and charcoal dust. To create explosions during religious festivals, they filled bamboo tubes with a special mixture and tossed them into fires. If both ends of the tube weren’t sealed, the escaping gas from the explosion would shoot out the open end, sending the tube in the opposite direction. So the first rockets were probably poorly built fireworks!
The Chinese then started to experiment with these gunpowder filled tubes open at one end. At some point they attached bamboo tubes to arrows and launched them with bows. In time they discovered that the gunpowder filled tubes could launch themselves using just the power of the escaping gas. The true rocket was born.
The Chinese used the rockets when they were at war with the Mongols in 1232. During the battle of Kai-Keng the Chinese fought the Mongols with "arrows of flying fire". The arrow was a simple form of a solid-propellant rocket a rocket that uses a solid, in this case gunpowder, as fuel. A tube that was capped at one end was filled with gunpowder. At the capped end the tube was attached to a long stick. When the gunpowder was ignited, the rapid burning of the powder produced smoke and fire, and gas escaped out the open end, launching the rocket. The stick that was attached was used as an aiming device.
A Chinese official named Wan-Hu made a rocket-powered flying chair. Attached to the chair were two large kites, and fixed to the kites were 47 rockets. At the command of Wan-Hu, 47 men lit the rockets. Suddenly there was a roar and a cloud of smoke appeared. When the smoke cleared, Wan-Hu had disappeared along with the chair. He was probably blown to pieces because the rockets were as likely to explode as they were to fly!
Following their battle with the Chinese, the Mongols produced their own rockets. As the Mongols continued conquering Asia and moving toward Europe, the rocket spread through Europe. The Mongols had taken over what is now part of Asia and Europe. In England, a monk named Roger Bacon worked on improved forms of gunpowder. The powder greatly increased the distance rockets could fly. In France, Jean Froissart discovered that launching rockets through tubes caused more accurate flights. That idea was the early version of the modern bazooka. Joans de Fontana of Italy made a surface-running rocket-powered torpedo that set enemy ships on fire.
By the 16th century rockets fell into disuse as weapons of war. They were used primarily for fireworks displays. Johann Schmidlad, a German fireworks maker, invented the "step rocket", a multi-staged vehicle for lifting fireworks to higher altitudes. A large sky rocket carried a smaller sky rocket. When the first rocket burned out, the second would continue up until that would burn out and fill the sky with fireworks. His idea is the basic design of many rockets flying into outer space today!
The Science of Rocketry
Around 1720, a Dutch professor, Willem Gravesande, built cars propelled by jets of steam. German and Russian scientists began experimenting with rockets so powerful that their escaping exhausts flames made holes in the ground even before lift-off.
During the late 18th century and into early the 19th century, rockets were briefly used for weapons of war. The Indians were successful using rockets in battles in 1792 and in 1799. It caught the interest of Colonel William Congreve, an artillery expert, and he made new designs of rockets for the British military. His rockets were successful in battles. Used by British ships against Fort McHenry in the War of 1812, they inspired Francis Scott Key to write "and the rockets red glare" in the poem that later became "The Star-Spangled Banner".
In 1898, a Russian schoolteacher, Konstantin Tsiolkovsky, thought about exploring space by rocket. In a report he published in 1903, he suggested the use of liquid fuel for rockets in order to make them fly farther. Before that they used solid fuel, like gunpowder.
In the early 20th century, an American, Robert H. Goddard, conducted experiments in rocketry. His early experiments were with solid fuel. These experiments led him to believe that a rocket could be propelled better by liquid fuel. No one had ever built a successful liquid-propellant rocket before. He succeeded on March 26,1926. Liquid oxygen and gasoline fueled it. The rocket only flew for a little over 2 seconds, and it flew about 15 feet (12.5 meters). Compared to today’s flights, that flight was unimpressive, but his gasoline rocket was the early edition of a whole new rocket era.
Goddard’s experiments with liquid-propellant rockets continued for many years. His rockets became bigger and flew higher. Parachutes were attached to rockets so the rocket and instruments returned safely. Because of Goddard’s accomplishments he has been called the father of modern rocketry.
The V-2 rocket was small compared to today’s rockets. With a burning mixture of liquid oxygen and alcohol at a rate of about one ton every second, this rocket had great power. Once the V-2 was launched it could blow up whole city blocks. The Nazis used the V-2 rocket to attack Great Britain across the English Channel during World War II.
On October 4, 1957 the world was stunned when the Soviet Union launched an Earth-orbiting satellite called Sputnik. It was the first successful satellite entry in a race for space between two superpower nations- the Soviet Union (USSR) and the Untied States.
A few months after Sputnik, the US launched a satellite of its own, Explorer I, on January 31, 1958. In October of that year the National Aeronautics and Space Administration (NASA) was created.
Soon, many people and machines were being launched into space. Astronauts orbited Earth and landed on the Moon. Robot spacecraft traveled to the planets. Space was suddenly opened up to exploration. Satellites enabled scientists to investigate our world, forecast the weather, and to communicate instantly around the globe. Rockets have even opened the universe to direct exploration by humankind.
At this time, there are 18 nations that have rockets capable of orbiting around the Earth. The United States and Russia have launched men into space. Japan, China, and 13 other nations hope to orbit astronauts before the year 2005.
Unless otherwise noted, all images courtesy of NASA. Permission for use at http://www.nasa.gov/gallery/photo/guideline.html.
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