When the two are mixed and ignited, the rocket is active and produces thrust. The advantage of a liquid propellant rocket is that the thrust is controllable by how much propellant is allowed to ignite at a time. In addition to his work for Demand Studios, Scott spends much of his time writing poetry and a novel. The Basics of a Rocket A rocket is a device that channels explosive force to create thrust.
Related Articles Principles of Pneumatic Systems. Types of Combustion. How Does a Reciprocating Compressor Work? Stages of a Rocket Launch. Pneumatic Cylinder Definition. How a Hydraulic Jack Works. How Do Butane Lighters Work? The structural system , or frame, is similar to the fuselage of an airplane. The frame is made from very strong but light weight materials, like titanium or aluminum, and usually employs long "stringers" which run from the top to the bottom which are connected to "hoops" which run around around the circumference.
The "skin" is then attached to the stringers and hoops to form the basic shape of the rocket. The skin may be coated with a thermal protection system to keep out the heat of air friction during flight and to keep in the cold temperatures needed for certain fuels and oxidizers. Fins are attached to some rockets at the bottom of the frame to provide stability during the flight. The payload system of a rocket depends on the rocket's mission. The earliest payloads on rockets were fireworks for celebrating holidays.
Today's large, space-bound rockets consist of at least two stages, sections stacked in a shared cylindrical shell. Each stage has its own engines, which can vary in number. The first stage of SpaceX's Falcon 9 rocket has nine engines, while the first stage of Northrop Grumman's Antares rocket has two.
A rocket's first stage gets the rocket out of the lower atmosphere, sometimes with the help of extra side boosters. Because the first stage must lift the entire rocket, its cargo or payload , and any unused fuel, it's the biggest and most powerful section. The faster a rocket goes, the more air resistance it encounters. But the higher the rocket goes, the thinner the atmosphere gets. Combined, these two factors mean that the stress on a rocket rises and then falls during a launch, peaking at a pressure known as max q.
For the SpaceX Falcon 9 and the United Launch Alliance Atlas V , max q occurs at 80 to 90 seconds after liftoff, at altitudes between seven and nine miles. Once the first stage has done its job, the rocket drops that portion and ignites its second stage. The second stage has a lot less to transport, and it doesn't have to fight through the thick lower atmosphere, so it usually has just one engine. At this point, rockets also let go of their fairings, the pointed cap at the rocket's tip that shields what the rocket is carrying—its payload—during the launch's first phase.
Historically, most of a rocket's discarded parts were left to fall back down to Earth and burn up in the atmosphere. But starting in the s with NASA's space shuttle , engineers designed rocket parts that could be recovered and reused.
Private companies including SpaceX and Blue Origin are even building rockets with first stages that return to Earth and land themselves. The more that a rocket's parts can be reused, the cheaper rocket launches can get. Sounding rockets launch high in the air on ballistic arcs, curving into space for five to 20 minutes before they crash back to Earth. They're most often used for scientific experiments that don't need a lot of time in space.
Where exactly is the edge of the space? The answer is surprisingly complex. Suborbital rockets such as Blue Origin's New Shepard are strong enough to temporarily enter space, either for scientific experiments or space tourism. Orbital-class rockets are powerful enough to launch objects into orbit around Earth. Depending on how big the payload is, they also can send objects beyond Earth, such as scientific probes or sports cars.
Ferrying satellites to orbit or beyond requires serious power. For a satellite to remain in a circular orbit miles above Earth's surface, it must be accelerated to more than 16, miles an hour. This concept of "throwing mass and benefiting from the reaction" can be hard to grasp at first, because that does not seem to be what is happening.
Rocket engines seem to be about flames and noise and pressure, not "throwing things. Tune in to the Turbo Channel -- the place to be for programming about cars, motorcycles, planes and everything else with a motor. Imagine the following situation: You are wearing a space suit and you are floating in space beside the space shuttle ; you happen to have a baseball in your hand.
If you throw the baseball , your body will react by moving in the opposite direction of the ball. The thing that controls the speed at which your body moves away is the weight of the baseball that you throw and the amount of acceleration that you apply to it.
So let's say that the baseball weighs 1 pound, and your body plus the space suit weighs pounds. You throw the baseball away at a speed of 32 feet per second 21 mph. That is to say, you accelerate the 1-pound baseball with your arm so that it obtains a velocity of 21 mph. Your body reacts, but it weighs times more than the baseball.
Therefore, it moves away at one-hundredth the velocity of the baseball, or 0. If you want to generate more thrust from your baseball, you have two options: increase the mass or increase the acceleration. You can throw a heavier baseball or throw a number of baseballs one after another increasing the mass , or you can throw the baseball faster increasing the acceleration on it.
But that is all that you can do. A rocket engine is generally throwing mass in the form of a high-pressure gas. The engine throws the mass of gas out in one direction in order to get a reaction in the opposite direction. The mass comes from the weight of the fuel that the rocket engine burns. The burning process accelerates the mass of fuel so that it comes out of the rocket nozzle at high speed.
The fact that the fuel turns from a solid or liquid into a gas when it burns does not change its mass. If you burn a pound of rocket fuel, a pound of exhaust comes out the nozzle in the form of a high-temperature, high-velocity gas. The form changes, but the mass does not. The burning process accelerates the mass. The "strength" of a rocket engine is called its thrust. Thrust is measured in "pounds of thrust" in the U.
A pound of thrust is the amount of thrust it would take to keep a 1-pound object stationary against the force of gravity on Earth. So on Earth , the acceleration of gravity is 32 feet per second per second 21 mph per second.
If you were floating in space with a bag of baseballs and you threw one baseball per second away from you at 21 mph, your baseballs would be generating the equivalent of 1 pound of thrust. If you were to throw the baseballs instead at 42 mph, then you would be generating 2 pounds of thrust.
If you throw them at 2, mph perhaps by shooting them out of some sort of baseball gun , then you are generating pounds of thrust, and so on. One of the funny problems rockets have is that the objects that the engine wants to throw actually weigh something, and the rocket has to carry that weight around.
So let's say that you want to generate pounds of thrust for an hour by throwing one baseball every second at a speed of 2, mph. That means that you have to start with 3, 1-pound baseballs there are 3, seconds in an hour , or 3, pounds of baseballs.
Since you only weigh pounds in your spacesuit , you can see that the weight of your "fuel" dwarfs the weight of the payload you. In fact, the fuel weights 36 times more than the payload. And that is very common. That is why you have to have a huge rocket to get a tiny person into space right now -- you have to carry a lot of fuel.
You can see the weight equation very clearly on the Space Shuttle. If you have ever seen the Space Shuttle launch, you know that there are three parts:. The Orbiter weighs , pounds empty.
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