Rockets

Rubric: [[file:Space Exploration Adventure Rubric.doc]], [[file:Space Exploration Adventure Rubric.pdf]]
A rocket is a cylindrical vehicle that uses either has solid or liquid propellants (fuel) which produse hot gasses that are ejected rearward throught the nozzle. in doing so, creates an action force accompanied by a reaction force, that drives the rocket upwards. Rockets are either classified as liquid or solid rockets. Which means they take either solid or liquid fuel/propellants. In solid rockets the propellant, which is usualy a grain such as patassium nitrate is packed in a solid casing and slid up into the body of the rocket. The casing is connected to a fuse witch is lit by the electricity in the launch pad. So once the casing is lit, the rocket takes off. Solid rockets are very simple, and are usualy just model rockets, because the casing runs out to fast. The booster rockets attached to the space shuttle; however, are solid rockets because they need to return to earth. Once they run out of patassium nitrate the nose cone comes open and a parachute comes out, that safely returns them back to earth. This is the same concept as model rocketry. You cannot conroll the speed of a solid rocket because the proppelant burns at its own pace.
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Liquid propellant rockets are the other main type of rocket. Liquid rockets are very complex, and are the rockets that have a controllable thrust? speed and can penetrate the atmosphere. They have two large tanks inside them. one conains liquid fuel such as kerosene and on contains liquid oxegen. When the rocket is fired, pumps feed feed the proppelants into a combustion chamber where the fuel and the oxegen mix, making a huge explosion. The explosion is forced downwards out of the nozzle propelling the rocket upwards.

Visuals
 * >  ||> [[image:http://t0.gstatic.com/images?q=tbn:ANd9GcRkGzmDddKkq1D0ZkDQ0rRu3ixcdW7fFHHVQRszH-CcX4-o4kjEdT3wsVhk width="231" height="218" caption="Solid v.s Liquid propelant rockets (indomil.wordpress.com)"]] ||> [[image:http://www.eduweb.com/rockets/images/Henry-w-stormcaster.jpg width="273" height="203" caption="A boy and his rocket ( rocket cinema.com by David T. Schaller) "]] ||
 * >  ||>   ||> [[image:http://www.aerospaceguide.net/spacepictures/shuttle_endeavour.jpg width="210" height="281" caption="Space shuttle launch (aerospaceguide.net)"]] ||



**Works Cited**

www.nasa.gov/audience/for**educators**/topnav/materials/.../**Rockets**.ht... [|Cached] - [|Similar] []

The Blackbird encyclopedia of science and invention [|www.**aerospaceguide**.net/planet/planetearth.html]

**Topic: Research Focus**
 * What is your topic? How rockets work**
 * State the focus of your research: To inform others how rockets work.**

**Notes**

rocket Pronunciation: \rä-kət\ noun (It rocchetta)A vehicle, typically cylindrical, containing liquid or solid propellants which produce hot gases or ions that are ejected rearward through a nozzle and, in doing so, crUeates an action force accompanied by an opposite and equal rNIeaction force driving the vehicle forward. Because rTEockets are self-contained, they are able to operate in outer space When a rocket lifts off, the combustion products from the burning propellants accelerate rapidly out of the engine. The rocket, on the other hand, slowly accelerates skyward. It would appear that something is wrong here if the action and reaction are supposed to be equal. They are equal, but the mass of the gas, smoke, and flames being propelled by the engine is much less than the mass of the rocket being propelled in the opposite direction. Even though the force is equal on both, the effects are different. Newton’s first law, the law of inertia, explains why. The law states that it takes a force to change the motion of an object. The greater the mass, the greater the force required to move it.

Rockets are generally classified as either solid or liquid. They produce thrust by burning propellants and expelling the combustion products out of the engine. Propellants are simply a combination of fuel and oxidizer. The oxidizer for solid propellants is a chemical containing oxygen. For example, gunpowder, used in the engines of model rockets, contains potassium nitrate (KNO3). Potassium nitrate provides the oxygen needed for the other gunpowder chemicals to burn rapidly. The oxidizer for liquid rockets is usually pure oxygen chilled to 90 K (-183oC or -297.3oF) so that it condenses into liquid oxygen (LOX). The propellants for rockets are held in tanks or within cases. This is both an advantage and a disadvantage. Because they carry their propellants (oxygen onboard), rockets can work in space. No other presently available vehicle can do that. A jet engine cannot function in space because it is an “air-breather.” Although jets and rockets both employ Newton’s law of action and reaction, the jet needs to draw in air from the atmosphere to burn its fuel. This limits the altitude of a jet plane.

Solid Propellant Rockets The first true rockets, “fire arrows” invented by the Chinese, employed solid propellants. An early form of gunpowder was packed into a cylinder closed off at one end. On the other end was an opening. When the gunpowder was ignited, it burned very quickly and created great quantities of gas and other combustion products that rushed out of the hole. This produced thrust. Flight control was accomplished by attaching a long stick to the rocket to create drag as the rocket sailed through the air. This wasn’t a very accurate system, but the rocket usually flew in the intended direction. More than 1,000 years later, solid propellant rockets are not appreciably different from the Chinese fire arrows. The solid rocket boosters (SRBs) for the space shuttle are very large tubes packed with propellants that are closed off at one end and have a hole at the other. The SRBs do have many other sophisticated innovations, but, in principle, they are no different from their primitive ancestors. Solid propellant rockets have a simple design. They consist of a case or tube in which the propellants are packed. Early rockets used cases made of paper, leather, and iron. Modern rockets use a thin and lightweight metal such as aluminum. Making the case from thin metal reduces the overall weight of the structure and increases flight performance. However, the heat from the burning propellants could easily melt through the metal. To prevent this, the inner walls of the case have to be insulated. The upper end of the rocket is closed off and capped with a payload section or recovery parachutes. The lower end of the rocket is constricted with a narrow opening called the throat, above a larger cone-shaped structure, called the nozzle. By constricting the opening, the throat causes the combustion products to accelerate greatly as they race to the outside (second law). The nozzle aims the exhaust straight downward so that the rocket travels straight upward (third law). To appreciate how the throat of the rocket accelerates the combustion products, turn on the water for a garden hose. Open the nozzle to the widest setting. Water slowly flows out. Next, reduce the opening of the nozzle. Water quickly shoots out in a long stream (second law) and the hose pushes back on you (third law). The propellant in solid rockets is packed inside the insulated case. It can be packed as a solid mass or it may have a hollow core. When packed as a solid mass, the propellant burns from the lower end to the upper end. Depending upon the size of the rocket, this could take a while. With a hollow core, the propellants burn much more rapidly because the entire face of the core is ignited at one time

Liquid Propellant RocketsLiquid propellant rockets are an invention of the twentieth century. They are far more complex than solid rockets. Generally, a liquid rocket has two large tanks within its body. One tank contains a fuel, such as kerosene or liquid hydrogen. The other tank contains liquid oxygen. When the liquid rocket engine is fired, high-speed pumps force the propellants into a cylindrical or spherical combustion chamber. The fuel and oxidizer mix as they are sprayed into the chamber. There they ignite, creating huge quantities of combustion products that shoot through the throat and are focused downward by the nozzle. (Remember how the laws control this!) Liquid propellant engines have a number of advantages over solid propellant engines. A wider array of propellant combinations are available for different applications. Some of these require an ignition system and others simply ignite on contact. Monomylmethylhydrozene (fuel) and nitrogen tetroxide (oxidizer) ignite spontaneously. These are called hypergolic propellants. With hypergolic propellants, a rocket engine does not need an ignition system. Hypergolic propellants are great for attitude control rockets like those that will be arrayed around the Orion service