Rockets 101 AIAA – March 2009 Theory of Rockets Dr. Eric Besnard California State University, Long...
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Transcript of Rockets 101 AIAA – March 2009 Theory of Rockets Dr. Eric Besnard California State University, Long...
Rockets 101 AIAA – March 2009
Theory of Rockets
Dr. Eric Besnard
California State University, Long Beach
Project Director, California Launch Vehicle Education Initiativehttp://www.csulb.edu/rockets/
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Rockets 101 AIAA – March 2009
How does a rocket work?
• Exercise 1: – Take a balloon and blow it up – Do not tie it– Release the balloon– What happens? Why?
• Exercise 2:– Take a cart with a pile of bricks on it– Stand on the cart and throw bricks backward– If there is no friction on the wheel, what happens? Why?
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Rockets 101 AIAA – March 2009
Thrust
• This effect comes from conservation of momentum– Momentum:
• Definition: mass x velocity (speed)
• A truck at 40 miles per hour has more momentum than a car at 40 miles per hour
• A car at 40 miles per hour has more momentum than a car at 20 miles per hour
– Newton’s first law of motion: When no external forces are applied on the object, momentum is conserved
– Mass exits backwards at a certain speed or velocity
– Therefore object moves forward at a speed which will conserve momentum:
→ THRUST is generated
Rocket
(large mass, “small” velocity)
Gas
(small mass, large velocity)
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Rockets 101 AIAA – March 2009
Rocket flight
• Newton’s second law of motion: forces acting on the object will change the momentum of the object:
F = m a– F: Sum of all forces
– m: mass of object
– A: acceleration of object
• Forces on our rocket:– Drag (air)
– Weight (gravity)
– Thrust (engine)
• Fins are added for stability of the rocket
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Rockets 101 AIAA – March 2009
Rocket engines
• Generate high velocity gas by chemical reaction (burning) of propellants:
– Something which burns: fuel– Something which carries oxygen: oxidizer
• Unlike aircraft engines which take the oxygen from the atmosphere (“air-breathing” engines), rocket engines carry their own oxygen so they can fly in space (where there is no atmosphere)
LOX tank
LH2
tank
Solid Rocket Booster
Orbiter
• Types of propellants:– Solids. Ex: gun powder, Estes rockets– Liquids. Examples:
• Oxidizer: liquid oxygen, LOX (≈ -320 F)
• Fuel: liquid hydrogen, LH2 (≈ -425 F) or kerosene
– Hybrids: nitrous oxide (laughing gas) & rubber
• Propellant is burnt and accelerated with a nozzle
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Rockets 101 AIAA – March 2009
A Really BIG rocket engine
• 5 F-1 engines were used on the Saturn V on its way to the Moon
• 1.5 million pounds each!
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Rockets 101 AIAA – March 2009
Smaller rockets, same technology…
Designed and integrated by Long Beach State students
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Rockets 101 AIAA – March 2009
Aerospike rocket engine static fire test
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Rockets 101 AIAA – March 2009
When something goes wrong…
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Rockets 101 AIAA – March 2009
Prospector-4 flight
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Rockets 101 AIAA – March 2009
A slightly bigger rocket: size for 20 lb to orbit!
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Rockets 101 AIAA – March 2009
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Rockets 101 AIAA – March 2009
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Rockets 101 AIAA – March 2009
Your rocket
Nozzle
Solid propellant
Ejection charge for deployment of recovery system
Non-thrust delay and smoke tracking charge
High thrust charge for lift-off and acceleration