Rocketry

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Brian Katz
March 2014
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Space/Rocket Curriculum Goals
◦ Provide Information About Space, Science, Rocketry and
Transportation Machines
◦ Stimulate Interest in School/Learning/Goals/Better One’s-Self
◦ Promote Open Discussions, Allow Students To Think, Express and
Brainstorm
◦ Teach Students How To Follow Instructions and Complete a Project working together as a team (Build and Possibly Launch a Rocket)
Sessions
◦ #1: History of Space Travel
◦ #2: Orbits and Gravity
◦ #3: General Rocketry
◦ #4: Rocket Design
◦ #5: Build Rocket(s)
◦ #6: Launch
Session Formats
◦ Imagery (online videos): “Fire and Smoke”
◦ Rocket building project and launch (rocket derby)
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Goal
◦ Familiarize Students with the Fascinating History of Rocketry
◦ Talk about how to accomplish a “big” project – break it down into sub sections and
accomplish piece by piece (Mercury/Gemini/Apollo)
See attachment 1: History of Space Travel Presentation – walk through this
Videos:
◦ http://www.youtube.com/watch?v=kEdtvct6Tf0
◦ http://www.youtube.com/watch?v=8y3fIr4dVYE&feature=related
◦ http://www.youtube.com/watch?v=awyuMF9rYhQ
◦ http://www.youtube.com/watch?v=CdQFZRJhkCk
◦ http://www.youtube.com/watch?v=vFwqZ4qAUkE
Side topics/discussions:
◦ Balloons, Airplanes, Helicopters, Rockets – Why/How Do They Fly
◦ Emphasize Ingenuity/Motivation to Create
 Digress – Find Their Interests, Search For Ideas, What Have they ever built, want to
build, etc…
◦ Watch October Sky and Apollo 13
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Goal:
◦ Instruct Students on where we are going – to space, what is space?
Discuss Orbit, Gravity and Atmosphere
◦ Orbit:
What is an Orbit: Show Video With Canyon Ball:
http://spaceplace.jpl.nasa.gov/en/kids/orbits1.shtml
◦ Gravity:
a. Talk about how ideally, all masses fall to ground at same
acceleration; discuss big rock/little rock when dropped will hit
ground at the same time
b. Talk about gravity around all planets/moons
c. Discuss table of relative body weights on other planets ready
d. Show video of Astronauts In Space Shuttle and explain that they
are floating because they are FALLING!! Use dropping elevator
scenario or the dropping airplane scenario
◦ Atmosphere:
◦ Talk about friction, rub hands together for younger kids
Relative weights of objects on
planets
Mercury
0.38
Venus
0.91
Earth
1
Mars
0.38
Jupiter
2.54
Saturn
1.08
Uranus
0.91
Neptune
1.19
Pluto
0.06
Moon
0.6
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Goal
◦ Instruct Students on General Rocketry – what are rockets, their uses, their operation
principles
Basic Operation
◦ How/Why Rockets Fly – fire/smoke out the backend – equal and opposite reaction,
payload upfront, separation of stages – why?
◦ Temperatures/Speeds/Materials
◦ Newton’s Laws (see next slide)
 Digress – Talk about science, science laws and our world
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1st Law (Inertia):
◦ “In the absence of contrary forces, the speed and direction of an
object’s movement will remain constant.”
 Explanation: The force generated by the escaping gasses from the
rocket motor must be great enough to lift the rocket’s total mass from
the launch pad, or it will not fly.
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2nd Law (Acceleration):
◦ “A body that is subject to forces moves at a speed which is
proportional to the amount of force applied.”
 Explanation: The greater the force supplied by the rocket motor, in
relation to the total mass of the rocket vehicle, the faster it will go.
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3rd Law (Action/Reaction):
◦ “For every force action there is an equal and opposite reaction.”
 Explanation: Release of gases through the nozzle (action) produces a
force on the rocket (reaction) in the opposite direction, causing the
rocket to accelerate.
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From Newton’s 2nd Law (motion of the Rocket)-
F  ma
 Where:
 F = force
 m = mass
 a = acceleration
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The rocket motor’s total energy is called its total “Impulse” and is a
measure of rocket motor’s overall performance Impulse is the sum (or integral) of total force imparted over the time
it acts upon the rocket:
I Total 
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T
0
Fdt
or
 Where:
 F = force history profile
 T = Total time
I Total  F  T
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Goal:
◦ Dig in deep to rocket design - learn the major components and systems
◦ Discuss Design, Analysis, Test, Build
Discussion:
◦ Propulsion (Solid, Liquid)
◦ Fins – why do we need them
◦ Nose Cone – Aerodynamics and payload protection
◦ Nozzle – essence of the propulsion system
◦ Igniter – gets it all started
Operation
◦ How do we Maneuver Rockets
◦ Flight Termination
◦ Countdown/procedures
Show Rockets That Didn’t Make It Video
◦ http://www.youtube.com/watch?v=13qeX98tAS8
◦ What can we learn from this video?
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By 1926, Goddard had constructed and
tested successfully first rocket using
liquid fuel on March 16,1926, at Auburn,
Massachusetts.
Rocket used cylindrical combustion
chamber with impinging jets to mix and
atomize liquid oxygen and gasoline
The rocket, which was dubbed "Nell",
rose just 41 feet during a 2.5-second
flight that ended 184 feet away in a
cabbage field
US and German engineers quickly ran
with this idea and greatly expanded on
the technology
Liquid vs Solid Propulsion Systems
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Turbo Machinery
 Boost Pumps
 Main Pumps
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Injector
Igniter
Combustion Chamber
Nozzle
Heat Exchanger
Mixture and throttle Valves
Pneumatic actuation,
pressurant, and purge
systems
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Rocket Equation Variables:
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q = ejected mass flow rate
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Ve = exhaust gas ejection speed
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Pe = pressure of the exhaust gases at the nozzle exit
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Pa = pressure of the ambient atmosphere
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Ae = area of the nozzle exit
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At = throat area of the nozzle
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m0 = initial total mass, including propellant
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m1 = final total mass
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ve = effective exhaust velocity
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go = Gravitational Constant
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Pc = Chamber Pressure
F (ThrustVac) = Force produced by the engine at 100%
throttle in a vacuum environment
Δv = maximum change of velocity
Isp = Ratio of the thrust to the ejected mass flow rate used
as the primary efficiency measure
C* (C-Star) = characteristic exhaust velocity term used as
a primary engine development value
◦ Major Components
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Injector
Structural Jacket
Coolant Liner
Coolant Inlet Manifold
Nozzle extension attachment
Design Considerations
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Oxidizer / Fuel Mixing
Ignition
Flame Holding
Cooling
Weight
Manufacturability
Engine Integration
Combustion Chamber
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Nozzle is Tightly Integrated with Combustion
Chamber
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Nozzle can be an awkward part of engine that
makes packaging difficult
◦ Extendable Nozzles are complicated and
expensive, (Delta 4 and Arianne upper
stages are examples)
◦ Fixed nozzles are bulky and extend vehicle
length, and increase re-contact risks
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Nozzle Cooling is commonly Achieved by
◦ Ablative materials
◦ Regenerative cooling
◦ Film Cooling
Nozzle
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Hypergolic: fuels and oxidizers that ignite
spontaneously on contact with each other
and require no ignition source
 Nitrogen Tetroxide (NTO, N2O4). redfuming nitric acid
 N2H4 - Hydrazine
 UDMH – Unsymmetrical dimethyl
hydrazine (Lunar lander RCS
UDMH/N2O4)
 Aerozine 50 (or "50-50"), which is a
mixture of 50% UDMH and 50% hydrazine
 MMH (CH3(NH)NH2) Monomethylhydrazine
 NTO/Aerozine 50 for Delta II second stage
 NTO/MMH is used in the Shuttle OMS
http://en.wikipedia.org/wiki/Liquid_rocket_pr
opellants
Propellants
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Simplest of the Power Cycles
No turbo-machinery making it one step up
in complexity over solid motors
Requires high pressure tank structure to
provide sufficient inlet pressures
Common for hypergolic engines which
also eliminates the need for an ignition
source
Chamber pressures ~100 to 200 psi
AJ-10 uses NTO/A50
◦ ISPVac 271 Sec
◦ 7.5k lbs thrust
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Space X Kestrel uses LOX/RP-1
◦ ISPVac 317 Sec
◦ 6.9k lbs of thrust
Pressure Fed System
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Engines are commonly tested at ground
level, usually in vertical configuration or
horizontal configuration with slight slant
Upper stage engines are commonly
testing in altitude chambers
 Exhaust gas flow detachment will occur
in a grossly over-expanded nozzle.
Underexpanded
Optimum
Overexpanded
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ThrustVac : 750,000 lbf (3.3 MN)
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Burn Time: 470 s
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Design: Gas Generator cycle
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Specific impulse: 410 s
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Engine weight – dry: 14,762 lb (6696 kg)
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Height: 204 in (5.2 m)
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Diameter: 96 in (2.43 m)
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Ground systems for liquid rockets are
commonly more complex than the
rocket itself
Atlas V pad has accommodations for
LOX, RP, H2, N2, and He
Extensive plumbing, tanking and detanking capabilities
Electrical control to ensure proper filling
and top-off
 Significant leak, thermal, flammability,
oxygen deficiency and explosive
concerns
 Day of launch operations are extensive
and very dynamic during preparation,
fueling, monitoring, top-off, startup
verification, liftoff disconnects, and
possible shutdown and de-tanking
operations
Solid Propulsion
Liquid Propulsion
vs
o Discuss:
- Vastness of these engineering marvels – as tall as a 10 – 20 story building
- Attention to detail, ask questions, learn, communicate with each other
Atlas V
Delta IV Heavy
Delta II
Falcon 9
Antares
o Discuss:
- Solid Propellant details
- Concept of ground testing – why?
Convert chemical energy to heat ==>> Movement of heated gases ==> Energy of motion
(Burning Propellant)
(through Nozzle exit)
(Imparted Force)
Exhaust Nozzle
Cut-away view of a
typical Rocket Motor
Ignitor
Propellant
Motor Case
o Discuss:
- There are lots of different types of engineers who work with rockets – we work as a team
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Flight Computer
Guidance/Navigation and Control
Electrical Power
Thrust Vector Control
RF
o Discuss:
- Why Do we need Flight Termination?
- Why Do we need separation mechanisms?
Flight Termination
Payload Separation
Stage Separation
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Goal:
◦ Build Rockets/team work/follow instructions – team work
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Build Ideas:
◦ Students Read Out loud Instructions
◦ Students Initial Steps Complete
◦ Students Perform Quality Inspections
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Launch Ideas:
◦ Create Launch Countdown Checklist and Have various students perform
duties
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Test Conductor
Pad Chief
Range Safety Officer
Counter
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