10/10/2006 Katie Smith CBE 555

Green Rocket Fuel

10/10/2006 Katie Smith CBE 555

Overview

• History of the NASA Space Program• Rockets 101• Rocket Fuel Today• Green Rocket Fuel

10/10/2006 Katie Smith CBE 555

NASA Space Program: Space Race

• Rocket technology dates back as far as the 11th century• Late 19th and early 20th centuries studied liquid fuels

→ Research conducted primarily by Russian and American scientists

→ American Robert Goddard the first to develop a practical liquid rocket fuel in 1926

• With WWII came acute international tensions between the USSR and the United States→ Tensions bled into scientific communities

• Space Race effectively began on October 4, 1957 with the Soviet military’s launch of artificial satellite Sputnik 1

10/10/2006 Katie Smith CBE 555

10/10/2006 Katie Smith CBE 555

NASA Space Program: Space Race

• Prior to the launch of Sputnik 1, space exploration in the United States was primarily a military endeavor

• US Government deemed its military infrastructure incapable of keeping up in the Space Race→ Prompted the National Aeronautics and Space Act

▪ Created the National Aeronautics and Space Administration (NASA)

▪ Oversees both military and civilian space exploration• The Act was signed by President Eisenhower on July 29,

1958• Space Race lasted until 1975

10/10/2006 Katie Smith CBE 555

NASA Space Program: Human Spaceflight

• NASA’s earliest research was in how to send a human into space→ Project Mercury: can a human survive in space?→ Project Gemini: conducted experiments relating to a moon

mission→ Apollo Program: designed to land humans on the moon

and bring them safely back to Earth• Probe missions conducted concurrently to provide

further data for human spaceflight→ Pioneer Program→ Ranger Program→ Lunar Orbiter Program→ Surveyor Program

10/10/2006 Katie Smith CBE 555

10/10/2006 Katie Smith CBE 555

NASA Space Program: the Shuttle Era

• Began in the late 1970s-1980s→ First orbital spacecraft designed for partial reusability

• Composed of three main assemblies→ Orbiter Vehicle (OV) + Space Shuttle Main Engines (SSMEs)→ External Tank (ET)→ Solid Rocket Boosters (SRBs)

• Each shuttle (4 total) designed for a lifespan of ~100 launches (approximately 10 years)

• Space shuttle to be retired in 2010 and replaced with new, manned spacecraft Orion

10/10/2006 Katie Smith CBE 555

10/10/2006 Katie Smith CBE 555

Rockets 101

• Most broad definition: any vehicle that obtains thrust by the reaction to the ejection of fast-moving fluid from within an engine→ water→ steam→ chemical (solid, liquid, hybrid)***

• Chemically powered rockets can have→ internal combustion engines (heat supplied from the

propellant’s reaction)→ external combustion engines (heat supplied from

something other than the propellant)

• Basic design…

10/10/2006 Katie Smith CBE 555

Rockets 101

10/10/2006 Katie Smith CBE 555

Rockets 101

• Casing can be a wide range of materials→ Dependent on rocket’s use→ SRBs made of steel→ Any rocket with steel casing requires a government permit

• Nozzle designed to dramatically accelerate mass by converting thermal energy into kinetic energy→ Propellant flow goes sonic at the throat (up to M > 10)→ Expansion ratio multiplies exhaust flow speed by an

additional factor

10/10/2006 Katie Smith CBE 555

Rockets 101

10/10/2006 Katie Smith CBE 555

Rockets 101

• Design specifications lead to a system of equations:→Fuel burns at a predictable rate, given its physical

state and the chamber pressure→Chamber pressure determined by the nozzle orifice

diameter and the fuel burn rate→Allowable chamber pressure is a function of casing

design→Length of burn time is determined by fuel’s physical

state

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Rockets 101

• Specific to the Space Shuttle:→OV composed primarily of aluminum alloy; SSMEs

made of titanium alloy→ET composed of 1/8”-thick aluminum-lithium alloy→SRBs composed of 1/2”-thick steel

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Rocket Fuel Today

• Aluminum• Aerozine 50• Black Powder• Decaborane• Diborane• Guanidine Nitrate• Hydrazinium Nitroformate

(HNF)• Hexanitrohexaazaiso-

wurtzitane• Hydrazine• Hydroxyl-terminated

polybutadiene

• Hydroxylamine• Hydroxylammonium nitrate• Liquid Hydrogen• Liquid Oxygen• Monomethylhydrazine

(MMH)• Polybutadiene Acrylonirile

(PBAN)• Pentaborane• RP-1• Triethylborane• Unsymmetrical Dimethyl

Hydrazine• UH 25

10/10/2006 Katie Smith CBE 555

Rocket Fuel Today: SRBs

• Solid rocket fuel is in granular form, composed of:→ thermoset elastomers (rigid structure)→ fuel (hydrocarbon)→ oxidizer→ catalyst

• Grains can be:→ solid cylinders (slow-burning)→ other geometry with hollowed-out core (variable burn

rates)• Thrust profile is controlled by grain geometry

10/10/2006 Katie Smith CBE 555

Rocket Fuel Today: SRBs

10/10/2006 Katie Smith CBE 555

Rocket Fuel Today: ET

• Most common liquid propellant combinations:→ liquid oxidizer: oxygen, nitrogen tetroxide, hydrogen

peroxide→ liquid fuel: kerosene, hydrogen, hydrazines

• ET formula:→ LOX + liquid hydrogen

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Rocket Fuel Today: ET

10/10/2006 Katie Smith CBE 555

Rocket Fuel Today: comparison

• Solid fuels→ easier to handle and store→ lower specific impulse→ large mass ratio becomes an issue→ difficult to throttle→ defects in grain formation can cause runaway reactions

leading to explosion

• Liquid fuels→ very difficult to store and handle→ better specific impulse→ tanks require less material→ cheaper than solid propellants, but affect rocket design

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Rocket Fuel Today: environment

• Byproducts of burning rocket fuel:→metal (aluminum) oxides→ acidic gases (hydrogen chloride)→ perchlorate→ noxious chemicals

• Early testing created water pollution→ byproducts still found in water today

• Human ingestion leads to blood and endocrine problems→ excess amounts of perchlorate cause hypothyroidism

• Online advocacy groups:→ FreeDrinkingWater.com→ Environmental Working Group→ Environmentalists Against War

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Green Rocket Fuel: the Candlestick Rocket

• New fuel: paraffin candle wax→ same material used to make “hurricane” candles

• Paraffin basics→ also called kerosene→ product of crude oil refining→ saturated, C18 to C36→melting points from 28 oC to 160+ oC

• Byproducts:→ carbon dioxide→ water

10/10/2006 Katie Smith CBE 555

Green Rocket Fuel: the Candlestick Rocket

• Theory behind paraffin-based rocket fuels developed by Stanford scientist, Arif Karabeyoglu

• Key is how the paraffin is burned:→ in the presence of pure oxygen gas (hotter temperature)

▪ this had been done in the past

→ blow the oxygen past the melted paraffin surface▪ causes the solid to evaporate quickly (think “sea spray”)▪ tiny paraffin droplets burn much more rapidly

» tripled rate of combustion

• Thus, new fuel is a hybrid (solid + fluid)

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Green Rocket Fuel

• Testing currently underway at the NASA Ames Hybrid Combustion Facility→ first successful test on September 24, 2001

▪ test chamber accommodates pressures up to 60 atm

→ Phase 1: 40 runs to answer the question Will it burn?

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Green Rocket Fuel

• Engineers will conduct ~200 tests during the project’s lifetime→ one test per day, each lasting 20 seconds or less→ Next Phase: new combustion chamber with sapphire

windows installed to allow observation of the combustion process using optical instruments

• Paraffin-based SRBs still many years down the road…→ project still considered to be in the ‘demonstration phase’→ likely to be tested on smaller rockets before use on the

Space Shuttle or Orion

10/10/2006 Katie Smith CBE 555

Green Rocket Fuel

10/10/2006 Katie Smith CBE 555

Green Rocket Fuel

10/10/2006 Katie Smith CBE 555

Green Rocket Fuel

10/10/2006 Katie Smith CBE 555

Green Rocket Fuel

10/10/2006 Katie Smith CBE 555

Green Rocket Fuel

10/10/2006 Katie Smith CBE 555

References

• Technical:→ http://www.lockheedmartin.com/wms/findPage.do?dsp=fnec&ti=122&ci=13

267&rsbci=13267→ http://www.pratt-whitney.com/prod_space.asp→ http://www.boeing.com/defense-space/space/hsfe_shuttle/what_is.html→ http://www.unitedspacealliance.com/news/missions/default.asp

• Green Rocket Fuel:→ http://www.sciencedaily.com/releases/2003/01/030115070306.htm→ http://science.nasa.gov/headlines/y2003/28jan_envirorocket.htm→ http://www.nasa.gov/centers/ames/news/releases/2003/03images/paraffin/

paraffin.html

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References, cont’d

• Background (directed from NASA and ScienceDaily):→ http://en.wikipedia.org/wiki/NASA→ http://en.wikipedia.org/wiki/National_Aeronautics_and_Space_Act→ http://en.wikisource.org/wiki/National_Aeronautics_and_Space_Act→ http://en.wikipedia.org/wiki/Space_Race→ http://en.wikipedia.org/wiki/Robert_Goddard_%28scientist%29→ http://en.wikipedia.org/wiki/Sputnik_1→ http://en.wikipedia.org/wiki/Project_Mercury→ http://en.wikipedia.org/wiki/Space_Shuttle→ http://en.wikipedia.org/wiki/Rocket→ http://en.wikipedia.org/wiki/Solid-fuel_rocket→ http://en.wikipedia.org/wiki/Rocket_engine→ http://en.wikipedia.org/wiki/Rocket_equation→ http://en.wikipedia.org/wiki/Delta-v→ http://en.wikipedia.org/wiki/Specific_impulse→ http://en.wikipedia.org/wiki/Rocket_fuel