Hypergolic fuel
Encyclopedia
A rocket propellant
combination used in a rocket engine
is called hypergolic when the propellants spontaneously ignite
when they come into contact. Strictly speaking it is the combination that is hypergolic, but in less precise usage the individual propellants are also referred to as hypergolic. The two propellant components usually consist of a fuel
and an oxidizer. Although hypergolic propellants tend to be difficult to handle because of their extreme toxicity
and/or corrosiveness, a hypergolic engine is relatively easy to ignite reliably.
In common usage, the terms "hypergol" or "hypergolic propellant" are often used to mean the most common such propellant combination, hydrazine
plus dinitrogen tetroxide
, or their relatives.
experimented with hypergolic fuel as early as 1931. It was initially used for "chemical ignition" of engines, starting kerosene
/nitric acid
engines with an initial charge of phosphorus dissolved in carbon disulfide
. German professor Otto Lutz independently discovered the principle again in 1935. The Wac Corporal
rocket developed in the USA by the Jet Propulsion Laboratory
in 1944 used nitric acid with aniline
fuel.
In Germany from the mid 1930s through World War II
, rocket propellants were broadly classed as monergols, hypergols, non-hypergols and lithergols. The ending ergol is a combination of Greek
ergon or work, and Latin oleum or oil, later influenced by the chemical suffix -ol from alcohol
. Monergols were monopropellant
s, while non-hypergols were bipropellants which required external ignition, and Lithergols were solid/liquid hybrids. Hypergolic propellants (or at least hypergolic ignition) were far less prone to hard start
s than electric or pyrotechnic ignition. The "hypergole" terminology was coined by Dr. Wolfgang Nöggerath, at the Technical University of Brunswick
, Germany.
Hypergolic propellants were used in the Apollo program, notably on the lunar lander
engines, which had to work completely reliably; and on the Saturn 1C F-1 engine which used hypergolic propellants to start the engines.
inherently simple and reliable.
While the larger hypergolic engines used in some launch vehicles
use turbopumps, most hypergolic engines are pressure fed.
A gas, usually helium
, is fed to the propellant tanks under pressure
through a series of check and safety valves.
In turn, the propellants flow through control valves
into the combustion chamber.
They ignite instantly on contact, without any risk that a mixture of
unreacted propellants might build up and ignite in a potentially catastrophic hard start
.
The most common hypergolic fuels, hydrazine
, monomethylhydrazine
and unsymmetrical dimethylhydrazine, and oxidizer, nitrogen tetroxide, are all liquid at ordinary temperatures and pressures. Thus they are sometimes referred to as
storable liquid propellants. They are suitable for use in spacecraft missions lasting for years. In contrast, liquid hydrogen
and liquid oxygen
are both cryogens
whose practical use is limited to space launch vehicles where they need be stored for only a short time.
Because hypergolic rockets do not need an ignition system, they can be fired any number of times by simply opening and closing the propellant valves until the propellants are exhausted. This makes them uniquely suited for spacecraft maneuvering. They are also well suited, though not uniquely so, as upper stages of space launchers such as the Delta II
and Ariane 5
that must perform more than one burn. Restartable cryogenic (oxygen/hydrogen) rocket engines do exist, notably the RL-10
on the Centaur
and the J-2
on the Saturn V
.
and the US Atlas
and Titan-1, used kerosene
and liquid oxygen
. The difficulties of storing a cryogen
like liquid oxygen in a missile that had to be kept launch ready for months or years at a time led to a switch to hypergolic propellants in the US Titan II and in most Soviet ICBMs such as the R-36.
But the difficulties of such corrosive and toxic materials, including leaks
and explosions in Titan-II silos, led to their near universal
replacement with solid-fuel boosters, first in Western submarine-launched ballistic missiles and then in land-based US and Soviet ICBMs.
The trend among western space launch agencies is away from large hypergolic rocket engines and toward hydrogen/oxygen engines with higher performance. Ariane 1 through 4, with their hypergolic first and second stages (and optional hypergolic boosters on the Ariane 3 and 4) have been retired and replaced with the Ariane 5, which uses a first stage fueled by liquid hydrogen and liquid oxygen. The Titan II, III and IV, with their hypergolic first and second stages, have also been retired. Hypergolic rockets are still widely used in upper stages when multiple burn-coast periods are required.
The corrosiveness of nitrogen tetroxide can be reduced by adding several percent nitric oxide
(NO), forming MON
.
, which ignites spontaneously in the presence of air, was used for engine starts in the SR-71 Blackbird
and the F-1
engines used in the Saturn V
rocket.
Rocket propellant
Rocket propellant is mass that is stored in some form of propellant tank, prior to being used as the propulsive mass that is ejected from a rocket engine in the form of a fluid jet to produce thrust. A fuel propellant is often burned with an oxidizer propellant to produce large volumes of very hot...
combination used in a rocket engine
Rocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...
is called hypergolic when the propellants spontaneously ignite
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
when they come into contact. Strictly speaking it is the combination that is hypergolic, but in less precise usage the individual propellants are also referred to as hypergolic. The two propellant components usually consist of a fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
and an oxidizer. Although hypergolic propellants tend to be difficult to handle because of their extreme toxicity
Toxicity
Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
and/or corrosiveness, a hypergolic engine is relatively easy to ignite reliably.
In common usage, the terms "hypergol" or "hypergolic propellant" are often used to mean the most common such propellant combination, hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
plus dinitrogen tetroxide
Dinitrogen tetroxide
Dinitrogen tetroxide is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium mixture with nitrogen dioxide; some call this mixture dinitrogen tetroxide, while some call it nitrogen dioxide.Dinitrogen tetroxide is a powerful oxidizer, making it highly...
, or their relatives.
History
Soviet rocket engine researcher Valentin GlushkoValentin Glushko
Valentin Petrovich Glushko or Valentyn Petrovych Hlushko was a Soviet engineer, and the principal Soviet designer of rocket engines during the Soviet/American Space Race.-Biography:...
experimented with hypergolic fuel as early as 1931. It was initially used for "chemical ignition" of engines, starting kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
/nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
engines with an initial charge of phosphorus dissolved in carbon disulfide
Carbon disulfide
Carbon disulfide is a colorless volatile liquid with the formula CS2. The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent...
. German professor Otto Lutz independently discovered the principle again in 1935. The Wac Corporal
Wac Corporal
The WAC or WAC Corporal was the first sounding rocket developed in the United States. Begun as a spinoff of the Corporal program, the WAC was a "little sister" to the larger Corporal. It was designed and built jointly by the Douglas Aircraft Company and the Guggenheim Aeronautical Laboratory.The...
rocket developed in the USA by the Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...
in 1944 used nitric acid with aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
fuel.
In Germany from the mid 1930s through World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, rocket propellants were broadly classed as monergols, hypergols, non-hypergols and lithergols. The ending ergol is a combination of Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
ergon or work, and Latin oleum or oil, later influenced by the chemical suffix -ol from alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
. Monergols were monopropellant
Monopropellant
Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety. While stable under defined storage conditions, they react very rapidly under certain other conditions to produce a large volume of energetic gases...
s, while non-hypergols were bipropellants which required external ignition, and Lithergols were solid/liquid hybrids. Hypergolic propellants (or at least hypergolic ignition) were far less prone to hard start
Hard start
A hard start is a rocketry term referring to an overpressure condition during start of a rocket engine at ignition. In the worst cases this takes the form of an explosion.-Rocket ignition:...
s than electric or pyrotechnic ignition. The "hypergole" terminology was coined by Dr. Wolfgang Nöggerath, at the Technical University of Brunswick
Braunschweig
Braunschweig , is a city of 247,400 people, located in the federal-state of Lower Saxony, Germany. It is located north of the Harz mountains at the farthest navigable point of the Oker river, which connects to the North Sea via the rivers Aller and Weser....
, Germany.
Hypergolic propellants were used in the Apollo program, notably on the lunar lander
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...
engines, which had to work completely reliably; and on the Saturn 1C F-1 engine which used hypergolic propellants to start the engines.
Advantages
Hypergolic rockets do not need an ignition system, so they tend to beinherently simple and reliable.
While the larger hypergolic engines used in some launch vehicles
use turbopumps, most hypergolic engines are pressure fed.
A gas, usually helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
, is fed to the propellant tanks under pressure
through a series of check and safety valves.
In turn, the propellants flow through control valves
into the combustion chamber.
They ignite instantly on contact, without any risk that a mixture of
unreacted propellants might build up and ignite in a potentially catastrophic hard start
Hard start
A hard start is a rocketry term referring to an overpressure condition during start of a rocket engine at ignition. In the worst cases this takes the form of an explosion.-Rocket ignition:...
.
The most common hypergolic fuels, hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
, monomethylhydrazine
Monomethylhydrazine
Monomethylhydrazine is a volatile hydrazine chemical with the chemical formula CH3 NH2. It is used as a rocket propellant in bipropellant rocket engines because it is hypergolic with various oxidizers such as nitrogen tetroxide and nitric acid...
and unsymmetrical dimethylhydrazine, and oxidizer, nitrogen tetroxide, are all liquid at ordinary temperatures and pressures. Thus they are sometimes referred to as
storable liquid propellants. They are suitable for use in spacecraft missions lasting for years. In contrast, liquid hydrogen
Liquid hydrogen
Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be...
and liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
are both cryogens
Cryogenics
In physics, cryogenics is the study of the production of very low temperature and the behavior of materials at those temperatures. A person who studies elements under extremely cold temperature is called a cryogenicist. Rather than the relative temperature scales of Celsius and Fahrenheit,...
whose practical use is limited to space launch vehicles where they need be stored for only a short time.
Because hypergolic rockets do not need an ignition system, they can be fired any number of times by simply opening and closing the propellant valves until the propellants are exhausted. This makes them uniquely suited for spacecraft maneuvering. They are also well suited, though not uniquely so, as upper stages of space launchers such as the Delta II
Delta II
Delta II was an American space launch system, originally designed and built by McDonnell Douglas. Delta II is part of the Delta rocket family and was in service from 1989 until November 1, 2011...
and Ariane 5
Ariane 5
Ariane 5 is, as a part of Ariane rocket family, an expendable launch system used to deliver payloads into geostationary transfer orbit or low Earth orbit . Ariane 5 rockets are manufactured under the authority of the European Space Agency and the Centre National d'Etudes Spatiales...
that must perform more than one burn. Restartable cryogenic (oxygen/hydrogen) rocket engines do exist, notably the RL-10
RL-10
The RL10 was USA's first liquid hydrogen fueled rocket engine. An updated version is used in several current launch vehicles. Six RL10 engines were used in the S-IV second stage of the Saturn I rocket. One or two RL10 engines are used in the Centaur upper stages of Atlas and Titan rockets...
on the Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...
and the J-2
J-2 (rocket engine)
Rocketdyne's J-2 rocket engine was a major component of the Saturn V rocket used in the Apollo program to send men to the Moon. Five J-2 engines were used on the S-II second stage, and one J-2 was used on the S-IVB third stage. The S-IVB was also used as the second stage of the smaller Saturn IB...
on the Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...
.
Use in ICBMs
The earliest ballistic missiles, such as the Soviet R-7 that launched Sputnik 1Sputnik 1
Sputnik 1 ) was the first artificial satellite to be put into Earth's orbit. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957. The unanticipated announcement of Sputnik 1s success precipitated the Sputnik crisis in the United States and ignited the Space...
and the US Atlas
Atlas (rocket family)
Atlas is a family of U.S. space launch vehicles. The original Atlas missile was designed in the late 1950s and produced by the Convair Division of General Dynamics, to be used as an intercontinental ballistic missile...
and Titan-1, used kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
and liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
. The difficulties of storing a cryogen
Cryogenics
In physics, cryogenics is the study of the production of very low temperature and the behavior of materials at those temperatures. A person who studies elements under extremely cold temperature is called a cryogenicist. Rather than the relative temperature scales of Celsius and Fahrenheit,...
like liquid oxygen in a missile that had to be kept launch ready for months or years at a time led to a switch to hypergolic propellants in the US Titan II and in most Soviet ICBMs such as the R-36.
But the difficulties of such corrosive and toxic materials, including leaks
and explosions in Titan-II silos, led to their near universal
replacement with solid-fuel boosters, first in Western submarine-launched ballistic missiles and then in land-based US and Soviet ICBMs.
Common hypergolic propellant combinations
- Aerozine 50Aerozine 50Aerozine 50 is a 50/50 mix of hydrazine and unsymmetrical dimethylhydrazine . Originally developed in the late 1950s by Aerojet General Corporation as a storable, high-energy, hypergolic fuel for the Titan II ICBM rocket engines, Aerozine continues in wide use as a rocket fuel, typically with...
(a hydrazineHydrazineHydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
and unsymmetrical dimethylhydrazine (UDMH) mix) + nitrogen tetroxide - widely used in historical American rockets, including the Titan 2; all engines in the Apollo Lunar ModuleApollo Lunar ModuleThe Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...
; and the Service Propulsion System in the Apollo Service Module
- Aerozine 50Aerozine 50Aerozine 50 is a 50/50 mix of hydrazine and unsymmetrical dimethylhydrazine . Originally developed in the late 1950s by Aerojet General Corporation as a storable, high-energy, hypergolic fuel for the Titan II ICBM rocket engines, Aerozine continues in wide use as a rocket fuel, typically with...
is a mixture of 50% UDMHUDMHUnsymmetrical dimethylhydrazine is a toxic volatile hygroscopic clear liquid, with a sharp, fishy, ammoniacal smell typical for organic amines. It turns yellowish on exposure to air and absorbs oxygen and carbon dioxide. It mixes completely with water, ethanol, and kerosene. In concentration...
and 50% straight hydrazineHydrazineHydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
(N2H4).- Unsymmetrical dimethylhydrazine (UDMH) + nitrogen tetroxide - frequently used by the Russians, such as in the Proton rocketProton rocketProton is an expendable launch system used for both commercial and Russian government space launches. The first Proton rocket was launched in 1965 and the launch system is still in use as of 2011, which makes it one of the most successful heavy boosters in the history of spaceflight...
and supplied by them to France for the Ariane 1 first and second stages (replaced with UH 25); ISRO PSLV second stage - UH 25UH 25UH 25 is a fuel mixture for rockets. It was developed for the European Ariane 2-4 launch vehicles.UH 25 was developed after a disaster during flight 2 of the Ariane 1 rocket. During launch, one of the four Viking engines on the first stage developed a combustion instability which lead to an engine...
+ nitrogen tetroxide - large engines: Ariane 1Ariane 1Ariane 1 is the first version of the Ariane launcher family. Ariane 1 was designed primarily to put two telecommunications satellites at a time into orbit, thus reducing costs. As the size of the satellites grew Ariane 1 gave way to the more powerful Ariane 2 and Ariane 3 launchers.- Vehicle...
through Ariane 4Ariane 4Ariane 4 was an expendable launch system, designed by the Centre National d'Etudes Spatiales and manufactured and marketed by its subsidiary Arianespace. Ariane 4 was justly known as the ‘workhorse’ of the Ariane family. Since its first flight on 15 June 1988 until the last, on 15 February 2003, it...
first and second stages
- Unsymmetrical dimethylhydrazine (UDMH) + nitrogen tetroxide - frequently used by the Russians, such as in the Proton rocket
- UH 25UH 25UH 25 is a fuel mixture for rockets. It was developed for the European Ariane 2-4 launch vehicles.UH 25 was developed after a disaster during flight 2 of the Ariane 1 rocket. During launch, one of the four Viking engines on the first stage developed a combustion instability which lead to an engine...
is a mixture of 25% hydrazineHydrazineHydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
hydrate and 75% UDMHUDMHUnsymmetrical dimethylhydrazine is a toxic volatile hygroscopic clear liquid, with a sharp, fishy, ammoniacal smell typical for organic amines. It turns yellowish on exposure to air and absorbs oxygen and carbon dioxide. It mixes completely with water, ethanol, and kerosene. In concentration...
.- MonomethylhydrazineMonomethylhydrazineMonomethylhydrazine is a volatile hydrazine chemical with the chemical formula CH3 NH2. It is used as a rocket propellant in bipropellant rocket engines because it is hypergolic with various oxidizers such as nitrogen tetroxide and nitric acid...
(MMH) + nitrogen tetroxide - smaller engines and reaction control thrusters: Apollo Command Module reaction control system; Space ShuttleSpace ShuttleThe Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
OMS and RCS; Ariane 5Ariane 5Ariane 5 is, as a part of Ariane rocket family, an expendable launch system used to deliver payloads into geostationary transfer orbit or low Earth orbit . Ariane 5 rockets are manufactured under the authority of the European Space Agency and the Centre National d'Etudes Spatiales...
EPS; DracoDraco (rocket engine)Draco is a small hypergolic rocket engine designed by SpaceX for use on their Dragon spacecraftand the upper stage of their Falcon 9 rocket.-Performance and use:...
thrusters used in SpaceXSpaceXSpace Exploration Technologies Corporation, or more popularly and informally known as SpaceX, is an American space transport company that operates out of Hawthorne, California...
Falcon 9 second stageFalcon 9Falcon 9 is a rocket-powered spaceflight launch system designed and manufactured by SpaceX. Both stages of its two-stage-to-orbit vehicle use liquid oxygen and rocket-grade kerosene propellants...
and Dragon spacecraft.
- Monomethylhydrazine
The trend among western space launch agencies is away from large hypergolic rocket engines and toward hydrogen/oxygen engines with higher performance. Ariane 1 through 4, with their hypergolic first and second stages (and optional hypergolic boosters on the Ariane 3 and 4) have been retired and replaced with the Ariane 5, which uses a first stage fueled by liquid hydrogen and liquid oxygen. The Titan II, III and IV, with their hypergolic first and second stages, have also been retired. Hypergolic rockets are still widely used in upper stages when multiple burn-coast periods are required.
Less common and obsolete combinations
- HydrazineHydrazineHydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
+ nitric acidNitric acidNitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
(toxic but stable) , also known as "Devil's venomDevil's venomDevil's venom was a nickname coined by Soviet rocket scientists for a liquid rocket fuel composed of a dangerous combination of nitric acid and hydrazine -- specifically, hypergolic UDMH-nitric acid. It is extremely corrosive and toxic , but is used in rocketry because of its extreme efficiency.-...
", as used in the Soviet R-16 rocket of the Nedelin catastropheNedelin catastropheThe Nedelin catastrophe or Nedelin disaster was a launch pad accident that occurred on 24 October 1960, at Baikonur Cosmodrome during the development of the Soviet R-16 ICBM...
. - AnilineAnilineAniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
+ nitric acidNitric acidNitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
(unstable, explosive), used in the Wac CorporalWac CorporalThe WAC or WAC Corporal was the first sounding rocket developed in the United States. Begun as a spinoff of the Corporal program, the WAC was a "little sister" to the larger Corporal. It was designed and built jointly by the Douglas Aircraft Company and the Guggenheim Aeronautical Laboratory.The... - AnilineAnilineAniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
+ hydrogen peroxideHydrogen peroxideHydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
(dust-sensitive, explosive) - Furfuryl alcoholFurfuryl alcoholFurfuryl alcohol, also called 2-furylmethanol or 2-furancarbinol, is an organic compound containing a furan substituted with a hydroxymethyl group. It is a clear colorless liquid when pure, but becomes amber colored upon prolonged standing. It possesses a faint burning odor and a bitter taste. ...
+ IRFNARed fuming nitric acidRed fuming nitric acid is a storable oxidizer used as a rocket propellant. It consists mainly of nitric acid , also containing 13% dinitrogen tetroxide and 3% water. The dissolved nitrogen dioxide is very concentrated and can be found at room temperature...
( or white fuming nitric acidWhite fuming nitric acidWhite fuming nitric acid is a storable liquid oxidizer used with kerosene and hydrazine rocket fuel. It consists of nearly pure nitric acid . WFNA is commonly specified as containing no more than 2% water and less than 0.5% dissolved nitrogen dioxide or dinitrogen tetroxide.WFNA was sometimes...
) - UDMH + IRFNARed fuming nitric acidRed fuming nitric acid is a storable oxidizer used as a rocket propellant. It consists mainly of nitric acid , also containing 13% dinitrogen tetroxide and 3% water. The dissolved nitrogen dioxide is very concentrated and can be found at room temperature...
- MGM-52 Lance missile system - T-StoffT-StoffT-Stoff was the oxidizer part of a bipropellant rocket fuel combination used in Germany during World War II. It is a stabilized high test peroxide...
+ C-StoffC-StoffC-Stoff was a reductant used in bipropellant rocket fuels developed by Hellmuth Walter Kommanditgesellschaft in Germany during World War 2...
- Messerschmitt Me 163Messerschmitt Me 163The Messerschmitt Me 163 Komet, designed by Alexander Lippisch, was a German rocket-powered fighter aircraft. It is the only rocket-powered fighter aircraft ever to have been operational. Its design was revolutionary, and the Me 163 was capable of performance unrivaled at the time. Messerschmitt...
World War II German rocket fighter aircraft, for its Walter 109-509AWalter HWK 109-509-See also:-Bibliography:*Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7-External links:*...
engine - KeroseneKeroseneKerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
+ hot hydrogen peroxideHydrogen peroxideHydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
- Gamma, with the peroxide first decomposed by a catalyst. Because of the heat from H2O2 decomposition, this is arguably not a true hypergolic combination. Cold (undecomposed) hydrogen peroxideHydrogen peroxideHydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
and keroseneKeroseneKerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
are not hypergolic.
The corrosiveness of nitrogen tetroxide can be reduced by adding several percent nitric oxide
Nitric oxide
Nitric oxide, also known as nitrogen monoxide, is a diatomic molecule with chemical formula NO. It is a free radical and is an important intermediate in the chemical industry...
(NO), forming MON
Mixed Oxides of Nitrogen
Mixed oxides of nitrogen are solutions of nitric oxide in dinitrogen tetroxide/nitrogen dioxide . It may be used as an oxidizing agent in rocket propulsion systems. A broad range of compositions is available, and can be denoted as MONi, where i represents the percentage of nitric oxide in the...
.
Related technology
Although not hypergolic in the strict sense (but rather pyrophoric), triethylboraneTriethylborane
Triethylborane , also called triethylborine and triethylboron, is an organoborane , a near-colorless to yellowish transparent liquid with pungent ether-like odor. Its chemical formula can be written as C6H15B, or 3B, or 3B, or Et3B.Triethylborane is strongly pyrophoric, igniting spontaneously in...
, which ignites spontaneously in the presence of air, was used for engine starts in the SR-71 Blackbird
SR-71 Blackbird
The Lockheed SR-71 "Blackbird" was an advanced, long-range, Mach 3+ strategic reconnaissance aircraft. It was developed as a black project from the Lockheed A-12 reconnaissance aircraft in the 1960s by the Lockheed Skunk Works. Clarence "Kelly" Johnson was responsible for many of the...
and the F-1
F-1 (rocket engine)
The F-1 is a rocket engine developed by Rocketdyne and used in the Saturn V. Five F-1 engines were used in the S-IC first stage of each Saturn V, which served as the main launch vehicle in the Apollo program. The F-1 is still the most powerful single-chamber liquid-fueled rocket engine ever...
engines used in the Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...
rocket.