Rocket Definition and 1000 Threads

A rocket (from Italian: rocchetto, lit. 'bobbin/spool') is a projectile that spacecraft, aircraft or other vehicles use to obtain thrust from a rocket engine. Rocket engine exhaust is formed entirely from propellant carried within the rocket. Rocket engines work by action and reaction and push rockets forward simply by expelling their exhaust in the opposite direction at high speed, and can therefore work in the vacuum of space.
In fact, rockets work more efficiently in space than in an atmosphere. Multistage rockets are capable of attaining escape velocity from Earth and therefore can achieve unlimited maximum altitude. Compared with airbreathing engines, rockets are lightweight and powerful and capable of generating large accelerations. To control their flight, rockets rely on momentum, airfoils, auxiliary reaction engines, gimballed thrust, momentum wheels, deflection of the exhaust stream, propellant flow, spin, or gravity.
Rockets for military and recreational uses date back to at least 13th-century China. Significant scientific, interplanetary and industrial use did not occur until the 20th century, when rocketry was the enabling technology for the Space Age, including setting foot on the Earth's moon. Rockets are now used for fireworks, weaponry, ejection seats, launch vehicles for artificial satellites, human spaceflight, and space exploration.
Chemical rockets are the most common type of high power rocket, typically creating a high speed exhaust by the combustion of fuel with an oxidizer. The stored propellant can be a simple pressurized gas or a single liquid fuel that disassociates in the presence of a catalyst (monopropellant), two liquids that spontaneously react on contact (hypergolic propellants), two liquids that must be ignited to react (like kerosene (RP1) and liquid oxygen, used in most liquid-propellant rockets), a solid combination of fuel with oxidizer (solid fuel), or solid fuel with liquid or gaseous oxidizer (hybrid propellant system). 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 risks.

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  1. narrator

    Bottle Rocket Thrust for Elementary Numeracy?

    Hi, I'm wanting to do a fun numeracy exercise for my students. I'm planning to have them construct bottle rockets, take measurements and then calculate/graph how high their rockets get using simple triangulation. From that, I was hoping to get them to calculate what the thrust was of their...
  2. D

    How does a rocket stay stable during liftoff?

    Because torque is force times distance, wouldn't it only take a relatively small force to make a rocket unstable if the force was applied near the base or the top? How is it kept stable? I just saw SpaceX's future plans to make a fully recyclable launch vehicle; I think it is far fetched TBH.
  3. L

    A rocket accelerates upwards Mechanics

    Homework Statement A rocket accelerates upwards from the ground at 25ms-2 for 2.5 s at an angle of 80 degrees to the horizontal. The rocket motor then stops and eventually falls to the ground. Neglecting air reststance and assuming thet the trajectory during acceleration is a straight...
  4. A

    Rocket Propulsion: Question About Relationship of V and M0/M(t)

    Did a question about this a few weeks ago, but I thought I might do another, as I don't quite get, what is going on. The relationship: v=vex * log(m0/m(t)) tells us that a rocket will attain greater and greater acceleration as time goes. However, when I try to simulate this in Matlab I get...
  5. H

    A Rocket was launched directly upwards from rest.

    Hi, I have this particular question, to which i think my method is correct, though the answer from the book which this question is in gives different to mine. Please! any assistance will be very much appreciated! Question: A Rocket was launched directly upwards from rest. Its motors...
  6. A

    Rocket Propulsion: Understanding the Equation Behind It

    Look at the attached picture, which is taken from my textbook. I don't understand the equation: v = vex * ln(m0/m(t)) If the rocket looses mass at a constant rate, wouldn't that equation then say, that the acceleration decreases as time goes. Since the curve of ln(>1) flattens out. That...
  7. S

    Solve Spivak's Rocket in Empty Space

    I'm reading Spivak's mechanics book and I'm stumped on some of the math in his derivation of an analytic expression for the motion of a rocket in empty space. Let \mathbf{v}(t) be the rockets velocity, let \mathbf{q}(t) be the velocity at which fuel is ejected from the rocket, and let m(t) be...
  8. C

    Exploring the Potential of Fission-Fragment Rocket for High-Speed Space Missions

    Fission-fragment rocket The wiki entry seems to paint this system in a positive light, so is it a workable propulsion system for high speed space missions? How long would a trip to Pluto take with something like this? How many years away is this from becoming a reality?
  9. T

    Understanding Rocket Burn Time and Impulse Calculation for Hybrid Rocket Motors

    Homework Statement We have some data for a rocket test, and I have plotted thrust against time. To find the total impluse, we were told to find the area under the thrust graph. But I am a little confused about something. I defined my zero time as the time the thrust started to increase, but...
  10. U

    Rocketdyne H-1 Rocket Engine, plans/blueprints

    Hello, I am searching for plans or copies of the blueprints for the Rocketdyne H-1 engine used in the Saturn I/IB rocket, any help would be appreciated.
  11. P

    Rocket Question~~Max Velocty and Ff

    Homework Statement ok, so i need to find max velocity and force of friction of a model rocket. The rocket weights 83.8 g, accelerates at 5.78 m/ss. Its max height is 84.99 m. please help Homework Equations ok for Ff = μkFn as for Vmax i have no idea The Attempt at a Solution ok...
  12. P

    Are My Calculations for Proper Time on a Rocket in General Relativity Correct?

    Assume we are on a non rotating planet and shoot a rocket straight with a given velocity (smaller than the escape velocity) and we want to calculate using the Schwarzschild solution the coordinate and proper time, both for an observer on the planet and rocket, between lift off and return to the...
  13. P

    How Can a Clinometer Help Determine the Max Height of a Rocket?

    Ok, so i need to find the max height that my rocket travelled, however, the only thin gi got is that a reader holding a clinometer is 50m form the launch site and is 1.78m heigh. According to him, my rocket traveled with a 59 degree in 3.83 sec (taken when the rocket's parachute came out at the...
  14. B

    "5000kg Interceptor Rocket Trajectory & Speed

    Homework Statement A 5000kg interceptor rocket is launched at an angle of 44.7 degrees. The thrust of the rocket motor is 140,700N a) Find an equation y(x) that describes the rocket's trajectory b) What shape is the trajectory? c) At what elevation does the rocket reach the speed of sound...
  15. D

    What is the maximum height of the rocket?

    Homework Statement A rocket has a body which consists of 0.49kg of material. This body holds 1.47kg of fuel. The fuel is consumed at a rate of 0.49kg/s, and the exhaust speed of the fuel is 60m/s. Assuming that the rocket starts from rest, what is the maximum height the rocket reaches...
  16. E

    Rocket launches up starting from zero, conservation momentum

    Homework Statement A rocket ejects exhaust with an velocity of u. The rate at which the exhaust mass is used (mass per unit time) is b. We assume that the rocket accelerates in a straight line starting initial mass (fuel plus the body and payload) be mi, and mf be its final mass, after all...
  17. O

    How to solve air dynamic issue for rocket?

    Does anyone have any suggestions on existing technology to solve air dynamic issue for rocket? Thanks in advance for any suggesitons
  18. O

    Maximum thrust - theory of rocket propulsion

    Hello all, Just wondering if anyone can give me some guidance on this: the problem is an apparent contradiction I've stumbled upon. Some sources (e.g. www.braeunig.us) suggest that maximum thrust is achieved when Pe=Pamb (i.e. exhaust pressure = ambient pressure)l whereas others say that...
  19. N

    Propelling A Small Rocket With Magnets?

    My senior project for high school is to prove that NASA can make their launch more efficient by adding electromagnets to launch. I was thinking just magnets lining a tunnel coming from underground that move the payload a lot like a maglev. My job is to make a model of this, and I'd like to make...
  20. F

    How much additional altitude can rocket obtain with launch assist.

    Homework Statement We have 2 model rockets identical in all ways (weight, height, mass, propellant, etc). The first rocket is launched like most rockets (0 ft/sec) and reaches 1000ft. For the second rocket we use a SUPER rubberband launch system. The launch system sends the rocket to say, 150...
  21. J

    Motion in One Dimension: Model Rocket

    Homework Statement A model rocket accelerates upward from the ground with a constant acceleration, reaching a height of 76 m in 7.2 s. What is the acceleration (in m/s 2)? What is the speed (in m/s) at a height of 76 m? Homework Equations V=Vo+at X=Xo+Vot+1/2at^2 V^2=Vo^2+2at(X-Xo)...
  22. N

    What Is the Velocity of a Leaking Bucket at the Moment It Empties?

    Homework Statement A bucket of mass M (when empty) initial at rest and containing a mass of water is being pulled up a well by a rope exerting a steady force P. The water is leaking out of the bucket at a steady rate such that the bucket is empty after a time T. Find the velocity of the bucket...
  23. M

    Separation of Variables for a Rocket Launched in a Gravitational Field

    Homework Statement Taking the equation of motion for a rocket launched from rest in a gravitational field g, m\dot{v} = -\dot{m}v_{ex} - mg , and knowing that the rocket ejects mass (fuel) at a constant rate \dot{m} = -k (where k is a positive constant), so that m = m_{o} - kt . Solve...
  24. N

    Rocket accelaation at the start of fuel burn

    Hi Guys this is the problem I am stuck at: The solid fuel of a 420.0 kg rocket traveling at 18100.0 km/hr is ignited to correct the rocket trajectory in mid-flight to Mars. 5.00 kg of fuel is burnt in 13.0 s. If the exhaust velocity of the fuel, relative to the rocket, is 3650.00 km/hr, what...
  25. T

    Expelled rocket fuel pushing against something the rocket is attached to?

    Sorry the title sucks. It's hard to be descriptive about this in a title. I did a cursory check of the other topics and I didn't see this and assumed I probably wouldn't. I get very most basic idea behind rockets, every action with an equal and opposite reaction and all that jazz. Something...
  26. L

    Vertically launched rocket problem with integration

    Homework Statement Find the Rockets height as a function of time It is in a constant field g. u refers to the exhaust speed and M is the initial mass. Starts from rest. and is single stage. Homework Equations 1) m * dv/dt= -dm/dt * u-mg 2)Show that height as t is: y(t)= u*t- 1/2*g*t^2-...
  27. D

    Rocket Launch: Solving for Height and Time

    Homework Statement A rocket is launched off and accelerates vertically up at 10 m/s 2. At 20 seconds, the motors are turned off, but the rocket keeps going up. a) What height did it reach? b) What was the time it needed to reach that height? g: - 9.8 m/s2 a: 10 m/s2 final velocity: 0 m/s...
  28. P

    Velocity of a rocket which never returns to earth

    Homework Statement With what speed should a rocket be fired upward so that it never returns to earth? (Neglect all forces except the Earth's gravitational attraction) Homework Equations The ONLY thing gone over so far involving rockets is the following formula: Let the altitude of the...
  29. P

    Maximum height of a toy rocket?

    maximum height of a toy rocket?? Homework Statement A toy rocket is launched vertically from ground level(y=0) at time t=0s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 49 m and acquired a velocity of...
  30. A

    Rocket fires its engine, force/acceleration

    Homework Statement A small space probe of mass 235 kg is traveling at 85.0 m/s. It fires its main engine at an angle of 63.00 to its original direction of travel. The engine produces a thrust of 12,000 N and there is enough fuel on board for a 10.0 s burn. What distance will it have traveled...
  31. B

    Solving a 1000kg Weather Rocket Homework Problem

    Homework Statement A 1000 kg weather rocket is launched straight up. The rocket motor provides constant acceleration for 16 s, then the motor stops. The rocket altitude 20 s after launch is 5100 m. You can ignore any effects of air resistance. a) What was the rocket's acceleration during the...
  32. C

    Gaseous Core Nuclear Thermal Rocket

    http://www.projectrho.com/rocket/enginelist.php#id--Gaseous_Core_Nuclear_Thermal_Rocket http://en.wikipedia.org/wiki/Gas_core_reactor_rocket How practical would this be? How much of a technological leap would be needed to achieve this? Would it make outer solar system missions possible...
  33. QuarkCharmer

    How High Will a Failing Rocket Reach?

    Homework Statement A 7600 kg rocket blasts off vertically from the launch pad with a constant upward acceleration of 2.35 m/s^2 and feels no appreciable air resistance. When it has reached a height of 570 m, its engines suddenly fail so that the only force acting on it is now gravity...
  34. A

    Constant acceleration of rocket car

    A "rocket car" is launched along a long straight track at t=0s. It moves with constant acceleration a1=1.2m/s2. At t=2s a second car is launched with constant acceleration a2=7.2m/s2. At what time does the second car catch up with the first? How far down the track do they meet? I...
  35. L

    How High Does a Rocket Go with Initial Acceleration of 250 m/s²?

    Homework Statement A rocket is red vertically with an acceleration of 250 m/s2. After 30 seconds, the rocket's motor shuts o . Find the maximum altitude achieved by the rocket and the total time from take-o to return to the surface of the earth, assuming that the rocket's design makes...
  36. D

    Thrust of a Rocket: Calculating Force

    Homework Statement [PLAIN]http://img714.imageshack.us/img714/8184/rocketj.png I am not sure if the problem has enough information to find. However, i tried some of the works. g=10m/s2( i use gravity as 10 .) Homework Equations No idea... The Attempt at a Solution I am...
  37. P

    Rocket acceleration/time problem?

    Homework Statement A 200kg weather rocket is loaded with 100kg of fuel and fired straight up. It accelerates upward at 34m/s^2 for 32s , then runs out of fuel. Ignore any air resistance effects. how long is the rocket in the air? Homework Equations d=Vit +1/2at^2 Vf=Vi + at V=d/t...
  38. M

    Rocket with constant acceleration - am i right or not ?

    Homework Statement A rocket is fired vertically and contiues for 1 minute with the acceleration 20 m/s^2. Then it has used up all the fuel , and the rocket continues in free fall. a) How high does the rocket come? Homework Equations s(displacement)=v_0t + \frac 12 at^2 The...
  39. L

    Designing an Antimatter Rocket - Questions for Help

    To put it short, I'm designing an antimatter rocket that a guy at NASA want's to see. I'm working hard but had a few questions for you guys: 1. What's the easiest way to get Positrons? 2. Any ideas on either storing it for a month or having a machine keep feeding the engine positrons like a...
  40. A

    How to interper thrust of the rocket

    For example then talking about the rocket the trust is: F_thrust = u*dm/dt where u is speed of the gases relative to the rocket, and dm/dt rate of change of ejected mass of gases. Now if the rocket is being launched vertically so force of gravity acts upon it and: F_net = F_thrust -...
  41. T

    Could a model rocket be launched into space by balloon?

    Say you had a small platform lifted by a high altitude balloon capable of reaching 30 miles above the earth. And on the platfrom you had a small model rocket. If you launched this small rocket from 30 miles above the earth, could it reach the Kármán line? How powerful would the rocket have to be?
  42. S

    Is a Rocket-Propelled Shell with Solid State Fuel and Compressed Oxygen Viable?

    Hello I am currently studying for a BA iin mech eng. Now, i have been thinking recently, is it possible to produce a lightweight artillary shell, that can contain a solid state rocket fuel, and a compressed oxygen canister? If so, would it not be all that impossible to fire this 'shell'...
  43. G

    Can capacitors be used for rocket ignition instead of batteries?

    I've been wanting to use capacitors instead of multiple batteries to launch rockets. I also want to see how a capacitor driven ignitor works compared to a normal battery driven with clusters of motors. I've been having a couple problems. Problem 1:The switch sparks, which I believe causes...
  44. M

    Horizontal water rocket thrust calculations - HELP

    Horizontal water rocket thrust calculations - HELP! Hi All, I want to accelerate a 90kg body at a rate of 2 m/s2 for a period of 1 second using thrust developed from a number of water bottle rocket jets. Based on the drag coeff calculated I believe I need to develop 190N of force. A...
  45. B

    Maximizing Water Rocket Glider Performance in High School Project

    Hi, we are doing a project in school where we have to launch a water-rocket at 45 degrees and get it the furthest distance from the launch pad with the 'egg-stronaut' still intact. Here is my idea. We make the wings in the shape of a glider, similar to the shape of the space shuttle's wings...
  46. S

    Paying money for rocket designing request.

    Greetings, I've been looking at Physics forums few months ago, but I never taught of making an account. So now I'am motivated and I have made one and this is my first post. I'am 17 years old, I'am a Java programmer. I have wide knowledge of many things in the computer world. I have a...
  47. I

    Rocket Net Force: Understanding Internal & External Forces

    Some of the following is more or less Halliday & Resnick, 4th Ed., section 9.8 (not the whole section and I added a lot): Assume motion in a stright line. Therefore, for position, velocity, acceleratiom, force, momentum, etc., d/dt|vector|=|d/dt(vector)|. This is not true in general for...
  48. M

    Exploring the Limits of My Rocket

    I've built a model rocket with the longest burning engine I could find, a light sensor in the nose cone, accelerometers on the forward fins all connected to an Arduino pro mini microcontroller programmed to keep it pointed at the brightest source of light. If I attach this rocket to a balloon...
  49. P

    Could a rocket come close to the speed of light?

    Hey everyone! So a guy at work today said "if you have a rocket with unlimited fuel(hypothetically speaking of coarse) at a constant accelleration, and was in space. It's velocity could reach like 99% the speed of light" I argued that it was not possible, as it approached the speed of light...
  50. I

    Small Liquid Rocket Engines for Sale | Glow Fuel Propellant

    Hello, I'm in the process of building a small liquid rocket engine that uses glow fuel as propellant. Can anyone direct me to a company that sells small liquid rocket engines? Thank you.
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