Educator’s Work Shop8 March 2014

- Basics of RocketryBrian Katz

March 2014

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)

General Overview

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

Session #1: History Of Space Travel

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

Session #2: Orbit and Gravity

Relative weights of objects on planetsMercury 0.38Venus 0.91Earth 1Mars 0.38Jupiter 2.54Saturn 1.08Uranus 0.91Neptune 1.19Pluto 0.06Moon 0.6

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

Session #3: General Rocketry

Session #3: General Rocketry

Session #3: General Rocketry ContinuedNewton’s Laws of Motion

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.

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.

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.

From Newton’s 2nd Law (motion of the Rocket)-

Where: F = force m = mass a = acceleration

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:

or

Where: F = force history profile T = Total time

Session #3: General Rocketry Continued

maF

T

Total FdtI0

TFITotal

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?

Session #4: Rocket Design

Session #4: Rocket Design – Propulsion Systems

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

Session #4: Rocket Design – Propulsion Systems

Liquid vs Solid Propulsion Systems

Session #4: Rocket Design – Liquid Propulsion Systems

Turbo Machinery Boost Pumps Main Pumps

Injector Igniter Combustion Chamber Nozzle Heat Exchanger Mixture and throttle Valves Pneumatic actuation,

pressurant, and purge systems

Session #4: Rocket Design – Liquid Propulsion Systems Rocket Equation Variables:

q = ejected mass flow rate Ve = exhaust gas ejection speed Pe = pressure of the exhaust gases at the nozzle exit Pa = pressure of the ambient atmosphere Ae = area of the nozzle exit At = throat area of the nozzle m0 = initial total mass, including propellant m1 = final total mass ve = effective exhaust velocity go = Gravitational Constant 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

Session #4: Rocket Design – Liquid Propulsion Systems

◦ Major Components◦ Injector◦ Structural Jacket◦ Coolant Liner◦ Coolant Inlet Manifold◦ Nozzle extension attachment

Design Considerations◦ Oxidizer / Fuel Mixing◦ Ignition◦ Flame Holding◦ Cooling◦ Weight◦ Manufacturability◦ Engine Integration

Combustion Chamber

Session #4: Rocket Design – Liquid Propulsion Systems Nozzle is Tightly Integrated with Combustion

Chamber

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

Nozzle Cooling is commonly Achieved by◦ Ablative materials◦ Regenerative cooling◦ Film Cooling

Nozzle

Session #4: Rocket Design – Liquid Propulsion Systems Hypergolic: fuels and oxidizers that ignite

spontaneously on contact with each other and require no ignition source

Nitrogen Tetroxide (NTO, N2O4). red-fuming 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_propellants

Propellants

Session #4: Rocket Design – Liquid Propulsion Systems 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

Space X Kestrel uses LOX/RP-1◦ ISPVac 317 Sec◦ 6.9k lbs of thrust

Pressure Fed System

Session #4: Rocket Design – Liquid Propulsion Systems

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.

ThrustVac : 750,000 lbf (3.3 MN)

Burn Time: 470 s

Design: Gas Generator cycle

Specific impulse: 410 s

Engine weight – dry: 14,762 lb (6696 kg)

Height: 204 in (5.2 m)

Diameter: 96 in (2.43 m)

Overexpanded

Optimum

Underexpanded

Session #4: Rocket Design – Liquid Propulsion Systems

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 de-tanking 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

vs

Liquid Propulsion Solid Propulsion

Current Large Space Launch Vehicles

Atlas V Delta IV Heavy Delta II Falcon 9 Antares

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

Session #4: Rocket Design – Solid Propulsion Systems

Convert chemical energy to heat ==>> Movement of heated gases ==> Energy of motion (Burning Propellant) (through Nozzle exit) (Imparted Force)

Cut-away view of a typical Rocket Motor Propellant

Ignitor

Exhaust Nozzle

Motor Case

o Discuss: - Solid Propellant details - Concept of ground testing – why?

Flight Computer Guidance/Navigation and Control Electrical Power Thrust Vector Control RF

Session #4: Rocket Design – Electrical Systems

o Discuss: - There are lots of different types of engineers who work with rockets – we work as a team

Session #4: Rocket Design – Ordnance Systems

Flight Termination

Payload Separation

Stage Separation

o Discuss: - Why Do we need Flight Termination? - Why Do we need separation mechanisms?

Goal: ◦ Build Rockets/team work/follow instructions – team work

Build Ideas:◦ Students Read Out loud Instructions◦ Students Initial Steps Complete◦ Students Perform Quality Inspections

Launch Ideas:◦ Create Launch Countdown Checklist and Have various students perform

duties Test Conductor Pad Chief Range Safety Officer Counter

 

Session #5 and #6: Rocket Building and Launch