Rocket

A rocket or rocket vehicle is a missile, aircraft or other vehicle which obtains thrust by the reaction of the rocket to the ejection of fast moving fluid from a rocket engine.

Chemical rockets work by the action of hot gas produced by the combustion of the propellant against the inside of combustion chambers and expansion nozzles. This generates forces that accelerate the gas to extremely high speed and exerts a large thrust on the rocket (since every action has an equal and opposite reaction).

The history of rockets goes back to at least the 13th century. By the 20th century, they have enabled human spaceflight to the Moon. In the 21st century, they have made commercial space tourism possible.

Rockets are used for fireworks and weaponry, as launch vehicles for artificial satellites, human spaceflight and exploration of other planets. While inefficient for low speed use, they are, compared to other propulsion systems, very lightweight and powerful, capable of attaining extremely high speeds with reasonable efficiency.

Chemical rockets store a large amount of energy in an easily-released form, and can be very dangerous. However, careful design, testing, construction, and use minimizes the risks.

In antiquity

According to the writings of the Roman Aulus Gellius, in c. 400 BC, a Greek Pythagorean named Archytas propelled a wooden bird using steam. However, the only knowledge that exists of it is in Aulus's writings, which dates from 5 centuries later. No diagrams survive, and whether it was truly propelled by rocket power is unknown.

The availability of black powder (gunpowder) to propel projectiles was a precursor to the development of the first solid rocket. Ninth Century Chinese Taoist alchemists discovered black powder while searching for the Elixir of life; this accidental discovery led to experiments in the form of weapons like bombs, cannon, incendiary fire arrows and rocket-propelled fire arrows.

Exactly when the first flights of rockets occurred is contested. Some say that the first recorded use of a rocket in battle was by the Chinese in 1232 against the Mongol hordes. There were reports of fire arrows and 'iron pots' that could be heard for 5 leagues (15 miles) when they exploded upon impact, causing devastation for a radius of 2,000 feet, apparently due to shrapnel. The lowering of the iron pots may have been a way for a besieged army to blow up invaders. The fire arrows were either arrows with explosives attached, or arrows propelled by gunpowder, such as the Korean Hwacha.

Less controversially, one of the earliest devices recorded that used internal-combustion rocket propulsion was the 'ground-rat,' a type of firework, recorded in 1264 as having frightened the Empress-Mother Kung Sheng at a feast held in her honor by her son the Emperor Lizong.

Subsequently, one of the earliest texts to mention the use of rockets was the Huolongjing, written by the Chinese artillery officer Jiao Yu in the mid-14th century. This text also mentioned the use of the first known multistage rocket, the 'fire-dragon issuing from the water' (huo long chu shui), used mostly by the Chinese navy. Frank H. Winter proposed in The Proceedings of the Twentieth and Twenty-First History Symposia of the International Academy of Astronautics that southern China and the Laotian community rocket festivals might have been key in the subsequent spread of rocketry in the Orient.

Spread of rocket technology

Rocket technology first became known to Europeans following their use by the Mongols Genghis Khan and �gedei Khan when they conquered parts of Russia, Eastern, and Central Europe. The Mongolians had acquired the Chinese technology by conquest of the northern part of China and also by the subsequent employment of Chinese rocketry experts as mercenaries for the Mongol military. Reports of the Battle of Sejo in the year 1241 describe the use of rocket-like weapons by the Mongols against the Magyars. Rocket technology also spread to Korea, with the 15th century wheeled hwacha that would launch singijeon rockets. These first Korean rockets had an amazingly long range at the time, and were designed and built by Byun Eee-Joong. They were just like arrows but had small explosives attached to the back, and were fired in swarms.

Additionally, the spread of rockets into Europe was also influenced by the Ottomans at the siege of Constantinople in 1453, although it is very likely that the Ottomans themselves were influenced by the Mongol invasions of the previous few centuries. They appear in literature describing the capture of Baghdad in 1258 by the Mongols.

In their history of rockets published on the Internet, NASA says �the Arabs adopted the rocket into their own arms inventory and, during the Seventh Crusade, used them against the French Army of King Louis IX in 1268.".

The name Rocket comes from the Italian Rocchetta (i.e. little fuse), a name of a small firecracker created by the Italian artificer Muratori in 1379.

"Artis Magnae Artilleriae pars prima" ("Great Art of Artillery, the First Part", also known as "The Complete Art of Artillery"), first printed in Amsterdam in 1650, was translated to French in 1651, German in 1676, English and Dutch in 1729 and Polish in 1963. For over two centuries, this work of Polish-Lithuanian Commonwealth nobleman Kazimierz Siemienowicz was used in Europe as a basic artillery manual. The book provided the standard designs for creating rockets, fireballs, and other pyrotechnic devices. It contained a large chapter on caliber, construction, production and properties of rockets (for both military and civil purposes), including multi-stage rockets, batteries of rockets, and rockets with delta wing stabilizers (instead of the common guiding rods).

In 1792, iron-cased rockets were successfully used militarily by Tipu Sultan, Ruler of the Kingdom of Mysore in India against the larger British East India Company forces during the Anglo-Mysore Wars. The British then took an active interest in the technology and developed it further during the 19th century. The major figure in the field at this time was William Congreve. From there, the use of military rockets spread throughout Europe. At the Battle of Baltimore in 1814, the rockets fired on Fort McHenry by the rocket vessel HMS Erebus were the source of the rockets' red glare described by Francis Scott Key in The Star-Spangled Banner. Rockets were also used in the Battle of Waterloo.

Accuracy of early rockets

Early rockets were very inaccurate. Without the use of spinning or any gimballing of the thrust, they had a strong tendency to veer sharply off course. The early British Congreve rockets reduced this somewhat by attaching a long stick to the end of a rocket (similar to modern bottle rockets) to make it harder for the rocket to change course. The largest of the Congreve rockets was the 32-pound (14.5 kg) Carcass, which had a 15-foot (4.6 m) stick. Originally, sticks were mounted on the side, but this was later changed to mounting in the center of the rocket, reducing drag and enabling the rocket to be more accurately fired from a segment of pipe.

The British were greatly impressed by the Mysorean Rocket artillery made from iron tubes used by the armies of Tipu Sultan and his father, Haidar Ali. Tipu Sultan championed the use of mass attacks with rocket brigades in the army. The effect of these weapons on the British during the Second, Third and Fourth Mysore Wars was sufficiently impressive to inspire William Congreve to develop his own rocket designs. Several Mysore rockets were sent to England, and after thoroughly examining the Indian specimens, from 1801, William Congreve, son of the Comptroller of the Royal Arsenal, Woolwich, London, set on a vigorous research and development programme at the Arsenal's laboratory. Congreve prepared a new propellant mixture, and developed a rocket motor with a strong iron tube with conical nose, weighing about 32 pounds (14.5 kilograms). The Royal Arsenal's first demonstration of solid fuel rockets was in 1805. The rockets were effectively used during the Napoleonic Wars and the War of 1812. Congreve published three books on rocketry.

In 1815, Alexander Dmitrievich Zasyadko began his work on creating military gunpowder rockets. He constructed rocket-launching platforms, which allowed to fire in salvos (6 rockets at a time), and gun-laying devices. Zasyadko elaborated a tactic for military use of rocket weaponry. In 1820, Zasyadko was appointed head of the Petersburg Armory, Okhtensky Powder Factory, pyrotechnic laboratory and the first Highest Artillery School in Russia. He organized rocket production in a special rocket workshop and created the first rocket sub-unit in the Russian army.

The accuracy problem was mostly solved in 1844 when William Hale modified the rocket design so that thrust was slightly vectored, causing the rocket to spin along its axis of travel like a bullet. The Hale rocket removed the need for a rocket stick, travelled further due to reduced air resistance, and was far more accurate.

Early manned rocketry

According to legend, a manned rocket sled with 47 gunpowder-filled rockets was attempted in China by Wan Hu in the 16th Century. The alleged flight is said to have been interrupted by an explosion at the start, and the pilot did not seem to have survived (he was never found). There are no known Chinese sources for this event, and the earliest known account is an unsourced reference in a book by an American, Herbert S. Zim in 1945.

In Ottoman Turkey in 1633, Lagari Hasan �elebi took off with what was described as a cone-shaped rocket, glided with wings through Bosporus from Topkap Palace, and made a successful landing, winning him a position in the Ottoman army. The flight was accomplished as a part of celebrations performed for the birth of Ottoman Emperor Murat IV's daughter and was rewarded by the sultan. The device was composed of a large winged cage with a conical top with 7 rockets filled with 70 kg of gunpowder. The flight was estimated to have lasted about 200 seconds and the maximum height reached around 300 metres.

Theories of interplanetary rocketry

In 1903, high school mathematics teacher Konstantin Tsiolkovsky (1857-1935) published Исследование мировых пространств реактивными приборами (The Exploration of Cosmic Space by Means of Reaction Devices), the first serious scientific work on space travel. The Tsiolkovsky rocket equation�the principle that governs rocket propulsion�is named in his honor (although it had been discovered previously). His work was essentially unknown outside the Soviet Union, where it inspired further research, experimentation and the formation of the Cosmonautics Society.

In 1920, Robert Goddard published A Method of Reaching Extreme Altitudes, the first serious work on using rockets in space travel after Tsiolkovsky. The work attracted worldwide attention and was both praised and ridiculed, particularly because of its suggestion that a rocket theoretically could reach the Moon. A New York Times editorial famously expressed disbelief that it was possible at all as it stated that: "after the rocket quits our air and really starts on its longer journey it will neither be accelerated nor maintained by the explosion of the charges it then might have left" and suggested that Professor Goddard actually: "does not know of the relation of action to reaction, and the need to have something better than a vacuum against which to react" and talked of "such things as intentional mistakes or oversights."

Goddard, the Times declared, apparently suggesting bad faith, "only seems to lack the knowledge ladled out daily in high schools."

After these and other scathing criticisms, Goddard began working in isolation, and avoided publicity.

Nevertheless, in Russia, Tsiolkovsky's work was republished in the 1920s in response to Russian interest raised by the work of Robert Goddard. Among other ideas, Tsiolkovsky accurately proposed to use liquid oxygen and liquid hydrogen as a nearly optimal propellant pair and determined that building staged and clustered rockets to increase the overall mass efficiency would dramatically increase range.

In 1923, Hermann Oberth (1894-1989) published Die Rakete zu den Planetenr�umen ("The Rocket into Planetary Space"), a version of his doctoral thesis, after the University of Munich rejected it.

Modern rocketry

Modern rockets were born when Goddard attached a supersonic (de Laval) nozzle to a liquid fuelled rocket engine's combustion chamber. These nozzles turn the hot gas from the combustion chamber into a cooler, hypersonic, highly directed jet of gas, more than doubling the thrust and raising the engine efficiency from 2% to 64%. Early rockets had been grossly inefficient because of the thermal energy that was wasted in the exhaust gases. In 1926, Robert Goddard launched the world's first liquid-fueled rocket in Auburn, Massachusetts.

During the 1920s, a number of rocket research organizations appeared in America, Austria, Britain, Czechoslovakia, France, Italy, Germany, and Russia. In the mid-1920s, German scientists had begun experimenting with rockets which used liquid propellants capable of reaching relatively high altitudes and distances. 1927 the German car manufacturer Opel began to research with rockets together with Mark Valier and the rocket builder Friedrich Wilhelm Sander. In 1928, Fritz von Opel drove with a rocket car, the Opel RAK1 on the Opel raceway in R�sselsheim, Germany. In 1929 von Opel started at the Frankfurt-Rebstock airport with the Opel-Sander RAK 1-airplane. This was maybe the first flight with a manned rocket-aircraft. In 1927 and also in Germany, a team of amateur rocket engineers had formed the Verein f�r Raumschiffahrt (German Rocket Society, or VfR), and in 1931 launched a liquid propellant rocket (using oxygen and gasoline).

From 1931 to 1937, the most extensive scientific work on rocket engine design occurred in Leningrad, at the Gas Dynamics Laboratory. Well-funded and staffed, over 100 experimental engines were built under the direction of Valentin Glushko. The work included regenerative cooling, hypergolic propellant ignition, and fuel injector designs that included swirling and bi-propellant mixing injectors. However, the work was curtailed by Glushko's arrest during Stalinist purges in 1938. Similar work was also done by the Austrian professor Eugen S�nger who worked on rocket powered spaceplanes such as Silbervogel (sometimes called the 'antipodal' bomber.)

On November 12, 1932 at a farm in Stockton NJ, the American Interplanetary Society's attempt to static fire their first rocket (based on German Rocket Society designs) fails in a fire.

In 1932, the Reichswehr (which in 1935 became the Wehrmacht) began to take an interest in rocketry. Artillery restrictions imposed by the Treaty of Versailles limited Germany's access to long distance weaponry. Seeing the possibility of using rockets as long-range artillery fire, the Wehrmacht initially funded the VfR team, but seeing that their focus was strictly scientific, created its own research team, with Hermann Oberth as a senior member. At the behest of military leaders, Wernher von Braun, at the time a young aspiring rocket scientist, joined the military (followed by two former VfR members) and developed long-range weapons for use in World War II by Nazi Germany, notably the A-series of rockets, which led to the infamous V-2 rocket (initially called A4).

World War II

In 1943, production of the V-2 rocket began. The V-2 had an operational range of 300 km (185 miles) and carried a 1000 kg (2204 lb) warhead, with an amatol explosive charge. Highest point of altitude of its flight trajectory is 90 km. The vehicle was only different in details from most modern rockets, with turbopumps, inertial guidance and many other features. Thousands were fired at various Allied nations, mainly England, as well as Belgium and France. While they could not be intercepted, their guidance system design and single conventional warhead meant that the V-2 was insufficiently accurate against military targets. The later versions however, were more accurate, sometimes within metres, and could be devastating. 2,754 people in England were killed, and 6,523 were wounded before the launch campaign was terminated. While the V-2 did not significantly affect the course of the war, it provided a lethal demonstration of the potential for guided rockets as weapons.

Under Projekt Amerika Nazi Germany also tried to develop and use the first submarine-launched ballistic missile (SLBMs) and the first intercontinental ballistic missiles (ICBMs) A9/A10 Amerika-Raketen to bomb New York and other American cities. The tests of SLBM-variants of the A4 rocket was achieved with U-boat submarines towing launch platforms. The second stage of the A9/A10 rocket was tested a few times in January, February and March 1945.

In parallel with the guided missile programme in Nazi Germany, rockets were also being used for aircraft, either for rapid horizontal take-off (JATO) or for powering the aircraft (Me 163,etc) and for vertical take-off (Bachem Ba 349 "Natter").