23_Propulsion 2012 lo - Colorado Space Grant Consortium

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Gateway To Space

ASEN 1400 / ASTR 2500

Class #23

Colorado Space Grant Consortium

T-18

Today:

Announcements

- Guest Lecture – Spacecraft Propulsion

Launch is in 18 days

Announcements…

Brady’s Talk…

- What did you think?

HW #8…

- Everyone turn it in?

Movie Night Tonight…

- Show of hands as to who is coming

3

Next Class…

Guest Lecture on Structures

+ Mission Simulations

Colorado Space Grant Consortium

Next Class…

Guest Lecture on Structures

+ Mission Simulations

Colorado Space Grant Consortium

Mission Simulations…

Bring all hardware

- Be prepared to give a 60 second into

- Be prepared to activate at beginning of class

- Be prepared to give a 60 second wrap up at end

6

Spacecraft Propulsion

Steve Hevert

Lockheed Martin

Colorado Space Grant Consortium

http://my.execpc.com/~culp/space/as07_lau.jpg

An Introduction to

Space Propulsion

Stephen Hevert

Affiliate Professor

Metropolitan State College of Denver

What Is Propulsion?

• Initiating or changing the motion of a body

• Translational (linear, moving faster or slower)

• Rotational (turning about an axis)

• Space propulsion

• Rocket launches

• Controlling satellite motion

• Maneuvering spacecraft

• Jet propulsion

• Using the momentum of ejected mass

(propellant) to create a reaction force , inducing motion

At one time it was believed that rockets could not work in a vacuum -- they needed air to push against!!

Jet Propulsion Classifications

• Air-Breathing Systems

• Also called duct propulsion .

• Vehicle carries own fuel; surrounding air (an oxidizer ) is used for combustion and thrust generation

• Gas turbine engines on aircraft…

…or go karts!

• Rocket Propulsion

• Vehicle carries own fuel and oxidizer, or other expelled propellant to generate thrust:

• Can operate outside of the

Earth’s atmosphere

• Launch vehicles, upper stages, Earth orbiting satellites and interplanetary spacecraft … or

… a rocket powered scooter!

www.gadgets-reviews.com www.the-rocketman.com

Space Propulsion Classifications

Systems that use an expellant (e.g. on-board propellant)

Stored Gas or Vapor o Compressed gas o Ammonia o Butane o Nitrous Oxide

Chemical o Liquid o Solid o Hybrid

Electric o Electrothermal o Electrostatic o Electromagnetic

Solar o Solar thermal o Solar electric

Beamed Energy o Laser thermal o Microwave thermal o Microwave electric

Nuclear o Nuclear thermal o Nuclear electric o Antimatter

We’ll look at some of these today…

Systems that do not carry an expellant (extract energy/force from external source)

Sails o Solar sails (light or solar wind) o M2P2 (charged particles)

Beamed Energy o Laser reflector (light sail) o Microwave (Starwisp)

Interstellar Ramjet o Bussard drive

Tethers o Stationary o Rotating o Electrodynamic o Pumped

Aero/Gravity Assist o Aero assist o Aero braking o Aero capture o Gravity assist

Breakthrough Propulsion Physics o Space drives (warp drives) o Wormholes o Antigravity

Space Propulsion Applications

Terrestrial/Atmosphere/

Suborbital

Tactical Missiles

Sounding Rockets

Ballistic Missiles

Earth to Orbit

Launch Vehicles www.army-technology.com

blog.wired.com

In-Space

Realm of Existing

Technology

Orbit Transfer

Earth Orbiting

Upper Stages

& Satellites

Lunar Missions

Interplanetary Missions

Space

Exploration

The Future

Interstellar Space

Exploration

Star Trek!!

www.psrd.hawaii.edu

Space Propulsion Functions

• Primary propulsion

• Launch and ascent

• Maneuvering

• Orbit transfer, station keeping, trajectory correction

• Auxiliary propulsion

• Attitude control

• Reaction control

• Momentum management www.ksc.nasa.gov www.nasm.si.edu

A Brief History of Rocketry

• China (1232 AD)

• Earliest recorded use of rockets

• Black powder

• Russia (early 1900’s)

• Konstantin Tsiolkovsky

• Orbital mechanics, rocket equation

• United States (1920’s)

• Robert Goddard

• First liquid fueled rocket (1926)

• Germany (1940’s)

• Wernher von Braun

• V-2

• Hermann Oberth

• Russia (USSR)

• Phenomenal contributions…

• Korolev, Glushko, Keldysh onenew.wordpress.com

Wan-Hu tried to launch himself to the moon by attaching 47 black powder rockets to a large wicker chair ! (…Chinese folk tale)

Dr. Goddard goddard.littleto

npublicschools

.net

Prof. Tsiolkovsky www.geocities.com www.britannica.com Dr. von Braun

Stored Gas Propulsion

Fill

Valve

Low Pressure

Isolation

Valve

Gas

Propellant

Tank

P

Pressure

Gage

Filter

High Pressure

Isolation

Valve

Pressure

Regulator

Thruster

• Primary or auxiliary propulsion

• High pressure gas ( propellant ) is fed to low pressure nozzles through pressure regulator

• Release of gas through nozzles ( thrusters ) generates thrust

• Currently used for momentum management of the Spitzer

Space telescope

• Propellants include nitrogen, helium

• Very simple in concept

Chemical Propulsion Classifications en.wikivisual.com www.aerospaceweb.org

• Liquid Propellant

• Pump Fed

• Launch vehicles, large upper stages

• Pressure Fed

• Smaller upper stages, spacecraft

• Monopropellant

• Fuel only

• Bipropellant

• Fuel & oxidizer

• Solid Propellant

• Launch vehicles, Space

Shuttle, spacecraft

• Fuel/ox in solid binder

• Hybrid

• Solid fuel/liquid ox

• Sounding rockets, X Prize news.bbc.co.uk

Monopropellant Systems

Nitrogen or helium

Hydrazine

Fuel Fill Valve

Isolation Valve

P

Filter

Propellant

Tank

Pressure

Gage

• Hydrazine fuel is most common monopropellant.

• N

2

H

4

• Decomposed in thruster using iridium catalyst to produce hot gas for thrust.

• Older systems used hydrogen peroxide (H

2

O

2

) before the advent of hydrazine catalysts.

• Typically operate in blowdown mode (pressurant and fuel in common tank).

Thrusters

Thrusts of 1 to 400 N (0.2 to

100 lb f

) are common.

Monopropellant Systems

5 lbf thrusters used on the Compton

Space Telescope (Gamma Ray

Observatory)

Northrop Grumman

1 lbf thrusters manufactured by

Northrop Grumman www.aerojet.com

Bipropellant Systems

FUEL

Engine

P P

OX

Isolation

Valves

Thrust Chamber

Nozzle

• A fuel and an oxidizer are fed to the engine through an injector and combust in the thrust chamber of the engine

• Combustion products accelerate in a convergingdiverging nozzle

• Hypergolic : no igniter needed -propellants react on contact in thrust chamber

• Cryogenic propellants include

LOX (-423 ºF) and LH2 (-297 ºF).

• Igniter required

• Storable propellants include kerosene (RP-1), hydrazine, nitrogen tetroxide (N

2

O

4

), monomethylhydrazine (MMH)

Bipropellant Thrusters

AMPAC-ISP

Bipropellant thrusters are used for orbit transfer and for attitude control, with thrusts ranging from 4 to 440 N (1 to 100 lb f

)

AMPAC-ISP

4 N

Astrium

Liquid Propellant Systems

• Pump fed systems

• Propellant delivered to engine using turbopump

• Gas turbine drives centrifugal or axial flow pumps

• Large, high thrust, long burn systems: launch vehicles, space shuttle

• Different cycles developed.

F-1 engine turbopump:

• 55,000 bhp turbine drive

• 15,471 gpm (RP-1)

• 24,811 gpm (LOX)

A 35’x15’x4.5’ (ave.

depth) backyard pool holds about 18,000 gallons of water.

How quickly could the F-1 turbopumps empty it ?

Ans: In ~27 seconds!

Photos history.nasa.gov

F-1 Engine Turbopump

H-1 Engine Turbopump

Rocket Engine Power Cycles

• Gas Generator Cycle

• Simplest

• Most common

• Small amount of fuel and oxidizer fed to gas generator

• Gas generator combustion products drive turbine

• Turbine powers fuel and oxidizer pumps

• Turbine exhaust can be vented through pipe/nozzle, or dumped into nozzle

• Saturn V F-1 www.aero.org/publications/ crosslink/winter2004/03_side bar3.html

www.answers.com

Rocket Engine Power Cycles - cont

• Expander

• Fuel is heated by nozzle and thrust chamber to increase energy content

• Sufficient energy provided to drive turbine

• Turbine exhaust is fed to injector and burned in thrust chamber

• Higher performance than gas generator cycle

• Pratt-Whitney RL-10 www.aero.org/publications/ crosslink/winter2004/03_sidebar3.

html science.nasa.gov

Rocket Engine Power Cycles - cont www.aero.org/publications/ crosslink/winter2004/03_side bar3.html

• Staged Combustion www.rocketrelics.com

• Fuel and oxidizer burned in preburners (fuel/ox rich)

• Combustion products drive turbine

• Turbine exhaust fed to injector at high pressure

• Used for high pressure engines

• Most complex, requires sophisticated turbomachinery

• Not very common, but

very high performance

• SSME (2700 psia) shuttle.msfc.nasa.gov

The Big Engines…

F-1 Engine

Saturn V

1.5 million lbs thrust (SL)

LOX/Kerosene www.flickr.com

Main Engine

Space Shuttle

374,000 lbs thrust (SL)

LOX/H

2 spaceflight.nasa.gov

RD-170

1.78 million lbs thrust (SL)

LOX/Kerosene www.aerospaceguide.net

Solid Propellant Motors

• Fuel and oxidizer are in solid binder.

• Single use -- no restart capability.

• Lower performance than liquid systems, but much simpler.

• Applications include launch vehicles, upper stages, and space vehicles.

www.aerospaceweb.org

www.propaneperformance.com www.nationalmuseum.af.mil

Hybrid Motors

Oxidizer Tank

Ox Control Valve

Solid

Propellant

Nozzle

• Combination liquid-solid propellant

• Solid fuel

• Liquid oxidizer

• Multi-start capability

• Terminate flow of oxidizer

• Fuels consist of rubber or plastic base, and are inert.

• Just about anything that burns…

• Oxidizers include LO

2

, hydrogen peroxide (H

2

O

2

) and nitrous oxide (NO

2

)

• Shut-down/restart capability.













Propulsion Calculations

• Thrust & Specific Impulse

• Thrust is the amount of force generated by the rocket.

• Specific impulse is a measure of performance

(analogous to miles per gallon)

• Units are seconds

I sp

F w

F

rocket thrust w

weight flowrate of propellant

• Rocket Equation

V

 gI sp ln m i m f g

9.8 m /s

2 m i

mass of vehicle before burn m m f p

mass of vehicle after burn

mass of propellant for

V

 m i

 m f m p

 m i





1

 e



V gI sp





Rocket equation assumes no losses (gravity effects, aerodynamic drag).

Actually very accurate for short burns in Earth orbit or in deep space!

Specific Impulse Comparison

• Stored gas

• Monopropellant hydrazine

• Solid rocket motors

• Hybrid rockets

• Storable bipropellants

• LOX/LH2 www.rocketrelics.com

• 60-179 sec

• 185-235 sec

• 280-300 sec

• 290-340 sec

• 300-330 sec

• 450 sec

Specific impulse depends on many factors: altitude, nozzle expansion ratio, mixture ratio

(bipropellants), combustion temperature, combustion pressure

This thruster was used on the

Viking Lander. It has a specific impulse of about 225 seconds.

Mission Delta-V Requirements

Mission (duration)

Earth surface to LEO

LEO to Earth Escape

LEO to Mars (0.7 yrs)

LEO to Neptune (29.9 yrs)

LEO to Neptune (5.0 yrs)

LEO to Alpha-Centauri (50 yrs)

ΔV (km/sec)

7.6

3.2

5.7

13.4

70

30,000

LEO = Low Earth orbit (approx. 274 km)

That’s actually very low….



Propellant Calculation Exercise

• Determine the mass of propellant to send a 2500 kg spacecraft from LEO to Mars (0.7 yr mission).

• Assume the 2500 kg includes the propellant on-board at the start of the burn.

• Assume our engine has a specific impulse of 310 sec

(typical of a small bipropellant engine).

• Use the rocket equation: m p

 

2500









1

 e

9 .

5700

 









2117 kg

Most of our spacecraft is propellant! Only 383 kg is left for structure, etc! How could we improve this?

Electric Propulsion

• Classifications

• Electrothermal

• Electrostatic

• Electromagnetic

• Characteristics

• Very low thrust

• Very high Isp

• > 1000 sec

Requires large amounts of power

(kilowatts)

This image of a xenon ion engine , photographed through a port of the vacuum chamber where it was being tested at NASA's Jet Propulsion Laboratory, shows the faint blue glow of charged atoms being emitted from the engine. The ion propulsion engine is the first non-chemical propulsion to be used as the primary means of propelling a spacecraft.

Electrothermal Propulsion rocket.itsc.uah.edu

• Electrical power is used to add energy to exhaust products

• Resistojet

• Catalytic decomposition of hydrazine is augmented with high power electric heater

• 800 – 5,000 W

• Arcjet

• High voltage arc at nozzle throat adds thermal energy to exhaust

• Various gaseous or vaporized propellants can be used.

www.fathom.com www.waynesthisandthat.com

www.nasa.gov

Electrostatic Propulsion www.plasma.inpe.br

• Electrostatic forces are used to accelerate charged particles to very high velocities

• Xenon Ion Thruster

• Xenon propellant

• Xenon is ionized by electron bombardment

• Thermionic cathode

• Positively charged particles accelerated by grid

• Electrons routed to second anode and injected into beam to neutralize aerospace.engin.umich.edu

ESA’s SMART-1 uses a xenon ion propulsion system (XIPS)

Electromagnetic Propulsion

• Electromagnetic forces are used to accelerate a plasma

• A gas consisting of positive ions, electrons

• 5000 – 9000 R

• Neutral beam is produced

• Higher thrust per unit area than electrostatic thruster

• Classifications

• Magnetoplasmadynamic

Pulsed plasma

• Electric discharge creates plasam from solid Telfon

• Hall effect

• Developed in Russia

• Flew on U.S. STEx mission (1998) www.nasa.gov

Interstellar Missions – The Future

• The challenges are formidable

• Immense distances…

• Alpha Centauri = 4.5 LY (closest interstellar neighbor)

1 LY = 9.46x10

12 km = 5.878x10

12 mi

Universe = ~156 billion LY across

• Immense size & mass & energy & speeds required…

• Propulsion systems with dimensions of 1000’s km

• Power levels 1000’s x greater than Human Civilization now produces ( > 14 TW est.)

• Speeds ~ .4c - .6c (c = speed of light)

• Trip times… Robotic Rendezvous goals

• 4.5 LY in < 10 years

• 40 LY in < 100 years (radius of nearest 1000 stars)

• Relativistic effects…

• Because of time dilation and mass increase; length contraction

• On telecommunications

• From collisions with interstellar matter

Consider the Voyager I Spacecraft… spacetoday.org

• 29 years after launch in 1977:

• It had travelled ~100 AU

• Far beyond Pluto

• ~150 million km

• 13.9 light-hours from sun

• Moving at 17.4 km/s

• 0.006% of the speed of light

• One of the fastest man-made vehicles

• It would take another 74,000 years to reach Alpha

Centauri at this rate

• Advanced technologies and breakthroughs will be necessary to reach the stars…

Source: Frisbee, R., “Impact of Interstellar Vehicle Acceleration and

Cruise Velocity on Total Mission Mass and Trip Time,” AIAA 2006-

5224, July 2006

Future Propulsion Technologies

Interstellar Ramjet

• Bussard Drive (1960)

• Electromagnetic scoop gathers interstellar hydrogen for propellant

• EM “Scoop” is 1000’s of km in size!

daviddarling.info

Beamed Energy

• Laser Light Sails

• Driven by massive spacebased laser and spacebased optics bibliotecapleyades.net

Future Propulsion Technologies- cont

Matter-Antimatter

• Highest energy per unit mass of any reaction known in physics

• Energy released by annihilation of matter by antimatter counterpart

Other Space Drive Ideas…

Future Propulsion Technologies- cont

Breakthrough Physics

• Yes, NASA funds research on

• Wormholes

• Warp drives bibliotecapleyades.net

Wormhole: a

“shortcut” through the spacetime continuum daviddarling.info

When I began my career in the late

1970’s, we’d joke about electric propulsion being the “propulsion of the future…and always will be!” Today it is used on communications satellites and interplanetary spacecraft.

What does the future hold for interstellar propulsion? Now it is the

“propulsion of the future”... but will it always be?

References

• Theory and design

• Sutton, G. P. and Biblarz, O., Rocket Propulsion

Elements, 7th ed.

,Wiley, 1987

• A classic; covers most propulsion technologies

• Huzel, D.K, and Huang, D. H., Modern Engineering for

Design of Liquid Propellant Rocket Engines (revised

edition), Progress in Aeronautics and Astronautics, Vol.

147, American Institute for Aeronautics and

Astronautics, 1992

• Dieter Huzel was one of the German engineers who came to the U.S. after WW II.

• Humble, R. W., et. al., Space Propulsion Design and

Anaylsis (revised edition), McGraw-Hill, 1995

• Covers chemical (liquid, solid, hybrid), nuclear, electric, and advanced propulsion systems for deep space travel

References - cont

• Rocket engine history

• Macinnes, P., Rockets: Sulfur, Sputnik and Scramjets,

Allen & Unwin, 2003

• Clary, D. A., Rocket Man: Robert H. Goddard and the

Birth of the Space Age , Hyperion Special Markets, 2003

• Ordway, F. I. and Sharpe, M., The Rocket Team , Apogee

Books, 2003

• The story of Werner von Braun, the V-2 and the transition of the German engineers to the United

States following WW II

• Sutton, G. P., History of Liquid Propellant Rocket

Engines , American Institute for Aeronautics and

Astronautics, 2006

• New, over 800 pages of rocket engine history

When things go badly… http://www.youtube.com/watch?v=gDnkEOKR1BE

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