Space Power Essay Research Paper Space Propulsion

Space Power Essay, Research Paper

Space Propulsion

RESEARCH I/II LARRY PECAN FINAL REPORT 9-27-98 INTRODUCTION The followers is a research undertaking on Space Vehicle Propulsion. It shall dwell of four subdivisions, each discoursing specific subjects. Section One lays out the basic thoughts of rocketry. Section Two compares Rocket Propulsion Systems, and shows the footing for the comparing. It besides shows how each particular Rocket System works and Section Three gives a description of how Space Propulsion has evolved and contains a decision. Section 1 The Basics Section One is a brief description of the basic belongingss of Rocket Systems. It defines the key footings and shows how a basic projectile works. It besides shows the State if The Art. I have chosen to make my undertaking on infinite vehicle propulsion. Basically, this means that my research shall be based chiefly on rocketry. Rocketry is a manner of propulsion that has developed in legion ways since it was foremost used to impel pyrotechnics in the sixteenth century. It has emerged into an highly complicated scientific discipline that few really understand. Most infinite rocketry in America is used in NASA ( National Aeronautics and Space Association ) infinite undertakings. NASA, a authorities association that focuses on infinite geographic expedition, is the chief user of projectile engineering. It is used largely to power their orbiters and birds into infinite. Pushing an object that weighs every bit much as a infinite bird does straight perpendicular until get awaying the Earth s atmosphere requires a enormous sum of power. This is why NASA uses projectiles. Rockets are basically the most powerful signifiers of propulsion there is today. Space Vehicle Propulsion is based projectile engines. The basic rule of projectile engine is that when fuel is burned in the engine, the reaction mass is expelled at high velocities. As a consequence of Newton s jurisprudence of action and reaction this pushes the vehicle in the opposite way of the 1 in which the reaction mass is traveling. Thrust is the force that the engine exerts on all infinite behind it in order to force the vehicle frontward. Efficiency is the manner that the quality of projectile engines is measured by. It is measured by the clip it takes for one kg of propellent to make one kg of push. The end of my research is to happen out what makes these engines more efficient. In rocketry, the province of the art is highly difficult to specify, since there are so many different signifiers of rocketry runing from liquid propellent projectiles to pyrotechnics. The province of the art though is likely atomic powered projectiles. It is much more efficient because it does non utilize chemical burning like most projectiles do. Alternatively NFRRs ( Nuclear Fission Reactor Rockets ) heat H in a fission reactor which expels the propellent at vesicating velocities. Much research is being done with NFRRs. They are still extremely experimental because of the dangers that could be associated with them. The NERVA ( Nuclear Engine for Rocket Vehicle Application ) was one of the most extended NFRR research undertakings, nevertheless it failed because of the inability figure out an attack to seting the research into a developmental phase. Section 2 Specific Rocket Propulsion Systems Section One has laid the foundation for farther research in the are of rocketry. Section two shall discourse belongingss of efficiency in more deepness, it shall put out the types of projectiles in being now. It shall besides demo which type of projectile is the most efficient. After this subdivision, the following one shall depict how the grounds for these specific projectiles efficiency and depending on the result of that study, the subject of the 4th shall be decided. EFFICIENCY Efficiency is the most of import portion of my research as yet. Since the object of my research is to happen out which type of projectiles are the most efficient and why, the reader of this paper must hold a basic apprehension of efficiency. Once this is established, new definitions will come into drama, all of these shall be important in the apprehension of the paper. Footings Needed To Understand Efficiency G- a unit of acceleration [ equal to 9.8 meters/second/second ( speed uping at a gait of 9.8 metres per 2nd every second ) ] Specific Impulse ( Isp ) – A measuring in seconds of efficiency. Properties of Efficiency Efficiency is the most accurate index of projectiles public presentation. As stated in the aforesaid definitions, specific urge is the basic unit of measuring of projectile efficiency. Isp is found by spliting the exhaust speed by g ( definition besides mentioned above ) . Since speed is measured in m/s ( metres per second ) and each g is equal to 9.8 m/s/s ( metres per 2nd every second ) , the footings cancel to go forth merely a unit in seconds. The resulting figure, is the continuance of clip for which one kg of propellent can bring forth one kg of push. Therefore, a higher figure represents a better, and more efficient projectile. To give the reader an thought of the mean Isp of several type of projectiles, I have listed some mean figures for efficiency of certain types of projectiles below. Average Efficiencies of Certain Rockets Next, I have listed the Isp values for some basic types of projectiles. After that I shall explicate some of the most good known types of projectiles. Basic Rocket Types An RPS ( projectile propulsion system ) is a powerplant that pushes a vehicle frontward by chuck outing affair that is stored within the vehicle. This affair is called propellent. The propellent is the most important portion of traveling a vehicle through infinite. Their energy beginning, the vehicles they are used on, and the type of propellent sort the specific types of systems. Liquid Propellant Rockets All LPRs ( Liquid Propelled Rockets ) contain the same basic devices. The following paragraph shall discourse these maps and analyze their intent. The first such device is the thrust chamber. The thrust chamber contains an injector, a burning chamber and a nose. The thrust chamber is the topographic point where the propellents are injected, atomized, so assorted and eventually burned to organize reaction merchandises in the signifier of gas. Following, the merchandises are accelerated and ejected at highly high speeds to make push. The injector is a series of pipes that allow the liquid propellent to travel into the burning chamber chamber to be made into push while atomising and blending them. The exhaust nose is the last measure in the releasing of push. It allows the hot gas to spread out and so accelerates them to supersonic speeds. On some vehicles, the nozzle Acts of the Apostless as a maneuvering mechanism by puting it on an electronic axis for which it can be turned by an machine-controlled guidance wheel. There are two major types of provender systems used by LPRs ; one uses pumps to travel propellents to burning Chamberss ; the other, uses high force per unit area to throw out propellents from their armored combat vehicles. On most infinite vehicles the engines are mounted in braces at the margin of the trade. Normally to opposite confronting thrust Chamberss are controlled automatedly to turn the ship. Generally, a lower limit of 12 thrust Chamberss is required for turning. Solid Propellant Rockets Solid Propellant Rockets ( SPRs ) contains a immense figure of types of engines. The propellent that is to be burned is held in the burning chamber. The propellent charge ( grain ) contains chemical elements for complete combustion. When it is ignited, it burns on all its exposed sides. If the design of the grain is changed, so less can be exposed ; the less open, the less fuel burned. The mean combustion rate is around 1.8 milliliters per second. The rate usually depends on the propellent ingredients. The more chamber force per unit area, the more propellent burnt. The manner to do an efficient SPR is to pack as much solid propellent into a chamber volume as possible. Theoretically, it would be ideal to fire the propellent like a cigar, from one terminal to the other. For this ground, scientists created an end-burning grain, which has proved highly successful. Electric Rockets There are three types

of electric propulsion systems (EPS); the three include electromagnetic, electrothermal and electrostatic. They are, in some ways more a rocket of the future then one of the present, somewhat like the NERVA project (see next section). In the electrothermal system the propellant is heated or vaporized electric heaters. The hot gas is then expanded through a nozzle the way it is in a chemical rocket. In an electrostatic system, interacting electrostatic fields and small charged particles such as colloidal particles achieve acceleration. In an electromagnetic rocket, acceleration is achieved by placing propellant plasma (a high temperature, electrically natural gas that contains electrons, ions and neutral molecular species) in an electromagnetic field thus causing a reaction that releases thrust. Nuclear Rockets Unlike the aforementioned rockets, nuclear rockets do not generate its power through chemical combustion. The way its power is formed, is through nuclear fission. It heats a propellant like hydrogen in a fission reactor and the explosion expels the propellant at amazing speeds, which exceed twice what any other rocket can produce. Its efficiency rating is around 850, as compared to the 450 of the next best type, the cryogenic rocket. Unfortunately due to the extreme dangers of nuclear fission inside a shuttle, the main project for researching the nuclear rockets, NERVA, was scrubbed. Most likely, in the future, scientists will devise a plan to minimize the risks, whereupon research will begin again. SECTION 3 A History INTRODUCTION The third section of this report shall begin by indicating the steps in which rocketry was created, as to allow the reader of this paper to better understand the way rockets work. It shall show the works of Tsiolkovsky, Goddard, Oberth and a few others. The report shall then end in a detailed conclusion. The conclusion will be based on the summary and discuss all that has been written. It shall end in giving opinions as to the future uses of the specific areas found in the research. Development of Modern Rocketry EARLY HISTORY In around 1232 AD, in China, rockets were created. During the war with the Mongols, the Chinese would strap an early form of gunpowder to the shaft of an arrow. This made them fly longer and faster than any of the regular arrows that the Mongols used. About ten years later, in Europe, another major discovery was made. An Englishman, Robert Bacon, created a more practical formula for gunpowder. He did this by mixing 41.2 parts saltpeter, 29.4 parts charcoal and 29.4 parts sulfur. He was able to distill saltpeter, which produces oxygen, to allow the rocket to burn faster. In the 18th century, the British encounter encountered rocket warfare with India. The Indians probably learned the secret of rocket treat from Arab traders in the 17th century. The Indians, who were led by Hyder Ali, gave thousands of men the task of throwing rockets. The rockets were first thrown, then propelled itself. They attached an eight foot long bamboo stalk to six pound iron tube filled with fuse and powder. The rockets were able to fly up to 1.5 miles. Modern Discoveries Tsiolkovsky Tsiolkovsky, a Russian teacher, established that a rocket would work in the vacuum of space, in 1883. In 1903, he wrote a book explaining how space travel was possible, using liquid propelled rockets. He created drawings of possible space ships propelled by either liquid oxygen and liquid hydrogen or liquid oxygen and kerosene. The sketches also show valves to transport the liquid propellant into a combustion chamber and showed how vanes could be created in the exhaust for steering. He also illustrated the crew lying on their backs in a pressurized cabin in order to withstand the pressure of such high speeds. Tsiolkovsky also thought of rocket staging. Rocket staging is a series of rockets that fire one after the other. When one finishes and the other fires, the useless rocket is jettisoned. He thought this was the only way to put heavy objects such as satellites into space. Goddard Although Tsiolkovsky thought up the ideas of advanced rocketry, still more had to be considered, and it had to become reality. The next pioneer, was the father of American rocketry, Robert Goddard. He first, created a bazooka type rocket. The bazooka was fairly large solid-propellant rocket. In 1919, he wrote a text called A Method of Reaching Extreme Altitudes. Two years later, he bagan to experiment with the liquid fuels that Tsiolkovsky. In 1926, Goddard finally launched the first liquid propelled rocket. It was fueled by gasoline and liquid oxygen. It rose to a height of 41 feet and traveled at 60 miles per hour. It only traveled 56 meters but it set the foundation for the future of rocketry. In May 1935, he released a rocket that featured gyro controlled exhaust vanes which pushed it to travel 1.5 miles above the ground at a totally unprecedented 700 miles per hour. GERMAN ROCKET SCIENTISTS In 1923 a German rocket scientist Hermann Oberth published The Rocket Into Planetary Space. He favored liquid propellants, as Goddard, because of their power. His experimentation inspired the creation of the Society for Space Travel. The society passionately experimented with ways to improve the liquid propellant rocket. On February 21, 1931, a member of The Society for Space Travel, Johannes Winkler, launched the second liquid fuel rocket. Winkler s rocket was propelled by liquid methane and liquid oxygen. It failed totally, going a mere ten feet forward. Three weeks later another rocket ascended to about 2000 feet. The entire Society for Space Travel began working on two rocket series, the Mirak and Repulsor. The late model Repulsors could reach an altitude of 1 mile. When The Society for Space Travel ran out of money, they made a demonstration of the Repulsor for the German Army. A member, Werner Von Braun compiled some statistics for the army who gave it to Hitler. They realized that this did not violate the treaty which did not allow them to build airplanes. Hitler started the Army Weapons Department. Von Braun was placed in charge of rocket development. Within a few years Von Braun was experimenting with highly developed rockets and was firing them in secret at the island of Birkum. In 1934 he created two rockets, that could ascend to over 1.5 miles. After that, The Society for Space Travel fell apart due to financial problems. In 1937, a rocket research station was constructed on the Baltic coast. Here the Germans created such rockets as the famous V-1 Buzz Bombs, and the mammoth V-2 which were really rocket-powered flying bombs. Conclusion In this research, it has been demonstrated how all rocket engines work. It illustrates how propellants are moved into a combustion chamber, and expelled at extremely high speeds. It shows the properties of efficiency, the basic measure by which all rockets are compared. It shows how efficiency is measure by specific impulse, which is calculated by the propellants exhaust velocity divided by g. It has given a basic comparison as to the efficiency of various rockets and has shown the reasons for being at their respective ranks. Also shown, is the pioneering of rocketry starting in the mid 1200s. All this has shown the basic properties of space propulsion Bibliography – the Rocket Engine Specifications page from the Artemis Project ( ) Data Book -the Orbital Report News Agency’s Launch Vehicle database – JPL’s Mission & Spacecraft Library – Mark Wade’s “Encyclopedia Astronautica” – The Space Shuttle Reference Manual – Solar electric propulsion on the Deep Space 1 probe Rockets Sutton, George P Groliers Online Encyclopedia

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