Liquid rocket propellants
Encyclopedia
The highest specific impulse
chemical rocket
s use liquid propellants. This type of propellant has a long history going back to the first rockets and is still in use, for example in the Space Shuttle
and Ariane 5
.
On March 16, 1926, Robert H. Goddard
used liquid oxygen
(LOX) and gasoline
as propellants for his first successful liquid rocket launch. Both are readily available, cheap, highly energetic, and dense. Oxygen is a moderate cryogen — air will not liquefy against a liquid oxygen tank, so it is possible to store LOX briefly in a rocket without excessive insulation. Gasoline has since been replaced by different hydrocarbon
fuels, for example RP-1
- a highly refined grade of kerosene
. This combination is quite practical for rockets that need not be stored, and to this day, it is used in the first stage
s of most orbital launcher
s, as well as the long-range offensive missiles of China
and North Korea
.
For instance, in the case of nitric acid
, the acid itself (HNO3) is unstable, and gives off NO2 fumes (hence the name white fuming nitric acid). Unlike nitrous oxide
(N2O), these nitrogen dioxide
fumes are extremely toxic. The addition of large amounts of dinitrogen tetroxide
(N2O4) makes the mixture red, but keeps it from changing composition, leaving the problem that nitric acid will eat any container it is placed in, releasing gases that can build up pressure in the process. The breakthrough was the addition of a little hydrofluoric acid
(HF), which forms a self-healing metal fluoride on the interior of tank walls and makes Inhibited Red Fuming Nitric Acid storable. Although the development of military propellants was treated with the greatest secrecy, the trick to inhibiting nitric acid was published shortly after its discovery in 1954 and Russian rockets with the same fuel appeared shortly afterwards, the first being the SS-1B ("Scud
"). Eventually the chemists gave up stabilizing HNO3 with N2O4, and just used straight N2O4, which is a slightly better oxidizer anyway. (In the propellant table below, note that N2O4 is always in equilibrium with NO2, and so mixtures are sometimes quoted with the latter.)
would be a marvellous propellant, since it gives the highest specific impulse
. As hydrogen in any state is very bulky, for flightweight vehicles it is typically stored as a deeply cryogenic liquid. This storage technique was mastered in the 1960s as part of the Saturn
and Centaur
upper-stage programs. Even as a liquid, hydrogen has low density, requiring large, heavy tanks and pumps, and the extreme cold requires heavy and potentially dangerous
tank insulation. This extra weight reduces the mass fraction of the vehicle and offsets the specific impulse advantage. Most rockets that use hydrogen fuel use it in upper stages only, where a low thrust-to-empty-mass ratio can be tolerated and where a hydrogen stage's low total mass reduces the size of the lower stages. Those rockets that use hydrogen fuel in their lower stages, like the Space Shuttle
, Delta IV
, and Ariane 5
, often use powerful and dense solid rocket motors at liftoff to improve their acceleration off the pad and thus reduce gravity losses early in flight.
and fluorine
, with hydrogen added to improve the exhaust thermodynamics (all propellants had to be kept in their own tanks, making this a tripropellant
). The combination delivered 542 s specific impulse in a vacuum, equivalent to an exhaust velocity of 5320 m/s. The impracticality of this chemistry highlights why exotic propellants are not actually used: to make all three components liquids, the hydrogen must be kept below -252°C (just 21 K) and the lithium must be kept above 180°C (453 K). Lithium and fluorine are both extremely corrosive, lithium ignites on contact with air, fluorine ignites on contact with most fuels, and hydrogen, while not hypergolic, is an explosive hazard. Fluorine and the hydrogen fluoride (HF) in the exhaust are very toxic, which makes working around the launch pad difficult, damages the environment, and makes getting a launch license that much more difficult. The rocket exhaust is also ionized, which would interfere with radio communication with the rocket. Finally, both lithium and fluorine are expensive and rare, enough to actually matter. This combination has therefore never flown.
JANAF thermochemical data used throughout. Calculations performed by Rocketdyne, results appear in "Modern Engineering for Design of Liquid-Propellant Rocket Engines", Huzel and Huang. Some of the units have been converted to metric, but pressures have not. These are best-possible specific impulse calculations.
Assumptions:
Definitions of some of the mixtures:
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...
chemical rocket
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...
s use liquid propellants. This type of propellant has a long history going back to the first rockets and is still in use, for example in the Space Shuttle
Space Shuttle program
NASA's Space Shuttle program, officially called Space Transportation System , was the United States government's manned launch vehicle program from 1981 to 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...
.
Early development
Robert H. Goddard
Robert Hutchings Goddard was an American professor, physicist and inventor who is credited with creating and building the world's first liquid-fueled rocket, which he successfully launched on March 16, 1926...
used 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:...
(LOX) and gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
as propellants for his first successful liquid rocket launch. Both are readily available, cheap, highly energetic, and dense. Oxygen is a moderate cryogen — air will not liquefy against a liquid oxygen tank, so it is possible to store LOX briefly in a rocket without excessive insulation. Gasoline has since been replaced by different hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
fuels, for example RP-1
RP-1
RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...
- a highly refined grade of 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...
. This combination is quite practical for rockets that need not be stored, and to this day, it is used in the first stage
Multistage rocket
A multistage rocket is a rocket that usestwo or more stages, each of which contains its own engines and propellant. A tandem or serial stage is mounted on top of another stage; a parallel stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or...
s of most orbital launcher
Launcher
Launcher may refer to:* Rocket launcher* Grenade launcher* Application launcher, a kind of utility software...
s, as well as the long-range offensive missiles of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
and North Korea
North Korea
The Democratic People’s Republic of Korea , , is a country in East Asia, occupying the northern half of the Korean Peninsula. Its capital and largest city is Pyongyang. The Korean Demilitarized Zone serves as the buffer zone between North Korea and South Korea...
.
1950s
During the 1950s there was a great burst of activity by propellant chemists to find high-energy liquid propellants better suited to the military. Military rockets need to sit in silos for many years, able to launch at a moment's notice. Propellants requiring continuous refrigeration, and which cause their rockets to grow ever-thicker blankets of ice, are not practical. As the military is willing to handle and use hazardous materials, a great number of dangerous chemicals were brewed up in large batches, virtually all of which were dead ends.For instance, in the case of 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...
, the acid itself (HNO3) is unstable, and gives off NO2 fumes (hence the name white fuming nitric acid). Unlike nitrous oxide
Nitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...
(N2O), these nitrogen dioxide
Nitrogen dioxide
Nitrogen dioxide is the chemical compound with the formula it is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...
fumes are extremely toxic. The addition of large amounts of 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...
(N2O4) makes the mixture red, but keeps it from changing composition, leaving the problem that nitric acid will eat any container it is placed in, releasing gases that can build up pressure in the process. The breakthrough was the addition of a little hydrofluoric acid
Hydrofluoric acid
Hydrofluoric acid is a solution of hydrogen fluoride in water. It is a valued source of fluorine and is the precursor to numerous pharmaceuticals such as fluoxetine and diverse materials such as PTFE ....
(HF), which forms a self-healing metal fluoride on the interior of tank walls and makes Inhibited Red Fuming Nitric Acid storable. Although the development of military propellants was treated with the greatest secrecy, the trick to inhibiting nitric acid was published shortly after its discovery in 1954 and Russian rockets with the same fuel appeared shortly afterwards, the first being the SS-1B ("Scud
Scud
Scud is a series of tactical ballistic missiles developed by the Soviet Union during the Cold War, and exported widely to other countries. The term comes from the NATO reporting name SS-1 Scud which was attached to the missile by Western intelligence agencies...
"). Eventually the chemists gave up stabilizing HNO3 with N2O4, and just used straight N2O4, which is a slightly better oxidizer anyway. (In the propellant table below, note that N2O4 is always in equilibrium with NO2, and so mixtures are sometimes quoted with the latter.)
Hydrogen
Many early rocket theorists believed that hydrogenHydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
would be a marvellous propellant, since it gives the highest specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...
. As hydrogen in any state is very bulky, for flightweight vehicles it is typically stored as a deeply cryogenic liquid. This storage technique was mastered in the 1960s as part of the Saturn
Saturn (rocket family)
The Saturn family of American rocket boosters was developed by a team of mostly German rocket scientists led by Wernher von Braun to launch heavy payloads to Earth orbit and beyond. Originally proposed as a military satellite launcher, they were adopted as the launch vehicles for the Apollo moon...
and 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...
upper-stage programs. Even as a liquid, hydrogen has low density, requiring large, heavy tanks and pumps, and the extreme cold requires heavy and potentially dangerous
Space Shuttle Columbia disaster
The Space Shuttle Columbia disaster occurred on February 1, 2003, when shortly before it was scheduled to conclude its 28th mission, STS-107, the Space Shuttle Columbia disintegrated over Texas and Louisiana during re-entry into the Earth's atmosphere, resulting in the death of all seven crew members...
tank insulation. This extra weight reduces the mass fraction of the vehicle and offsets the specific impulse advantage. Most rockets that use hydrogen fuel use it in upper stages only, where a low thrust-to-empty-mass ratio can be tolerated and where a hydrogen stage's low total mass reduces the size of the lower stages. Those rockets that use hydrogen fuel in their lower stages, like the Space Shuttle
Space Shuttle program
NASA's Space Shuttle program, officially called Space Transportation System , was the United States government's manned launch vehicle program from 1981 to 2011...
, Delta IV
Delta IV rocket
Delta IV is an active expendable launch system in the Delta rocket family. Delta IV uses rockets designed by Boeing's Integrated Defense Systems division and built in the United Launch Alliance facility in Decatur, Alabama. Final assembly is completed at the launch site by ULA...
, 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...
, often use powerful and dense solid rocket motors at liftoff to improve their acceleration off the pad and thus reduce gravity losses early in flight.
Lithium/fluorine
The highest specific impulse chemistry ever test-fired in a rocket engine was lithiumLithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
and fluorine
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...
, with hydrogen added to improve the exhaust thermodynamics (all propellants had to be kept in their own tanks, making this a tripropellant
Tripropellant rocket
A tripropellant rocket is a rocket that uses three propellants, as opposed to the more common bipropellant rocket or monopropellant rocket designs, which use two or one fuels, respectively...
). The combination delivered 542 s specific impulse in a vacuum, equivalent to an exhaust velocity of 5320 m/s. The impracticality of this chemistry highlights why exotic propellants are not actually used: to make all three components liquids, the hydrogen must be kept below -252°C (just 21 K) and the lithium must be kept above 180°C (453 K). Lithium and fluorine are both extremely corrosive, lithium ignites on contact with air, fluorine ignites on contact with most fuels, and hydrogen, while not hypergolic, is an explosive hazard. Fluorine and the hydrogen fluoride (HF) in the exhaust are very toxic, which makes working around the launch pad difficult, damages the environment, and makes getting a launch license that much more difficult. The rocket exhaust is also ionized, which would interfere with radio communication with the rocket. Finally, both lithium and fluorine are expensive and rare, enough to actually matter. This combination has therefore never flown.
Monopropellants
- 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...
decomposes to steam and oxygen - 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...
decomposes energetically to nitrogen and hydrogen, making it a fairly good monopropellantMonopropellantMonopropellants 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...
all by itself. - Nitrous oxideNitrous oxideNitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...
decomposes to nitrogen and oxygen - SteamSteamSteam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
when externally heated gives a reasonably modest Isp of up to 190 seconds, depending on material corrosion and thermal limits
Current use
Here are some common liquid fuel combinations in use today:- LOX and kerosene (RP-1RP-1RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...
). Used for the lower stages of most Russian and Chinese boosters, and the first stage of the U.S. Saturn VSaturn VThe 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...
and AtlasAtlas (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...
boosters. Very similar to Robert Goddard's first rocket.
- LOX and liquid hydrogen, used in the stages of the 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...
, 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...
, Delta IV, EnergiaEnergiaEnergia was a Soviet rocket that was designed by NPO Energia to serve as a heavy-lift expendable launch system as well as a booster for the Buran spacecraft. Control system main developer enterprise was the NPO "Electropribor"...
and CentaurCentaur (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...
.
- Nitrogen tetroxideDinitrogen tetroxideDinitrogen 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...
(N2O4) and 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) or one of chemically similar compounds like UDMH. Used in three first stages of the Russian Proton booster, second stage of 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...
, a number of military, orbital and deep space rockets, as this fuel combination is hypergolic and storable for long periods at reasonable temperatures and pressures.
Propellant table
| To approximate Isp at other chamber pressures | |
|---|---|
| Absolute Pressure (atm) Atmosphere (unit) The standard atmosphere is an international reference pressure defined as 101325 Pa and formerly used as unit of pressure. For practical purposes it has been replaced by the bar which is 105 Pa... {psi} | Multiply by |
| 6,895 kPa Pascal (unit) The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre... (68.05) {1000} | 1.00 |
| 6,205 kPa (61.24) {900} | 0.99 |
| 5,516 kPa (54.44) {800} | 0.98 |
| 4,826 kPa (47.63) {700} | 0.97 |
| 4,137 kPa (40.83) {600} | 0.95 |
| 3,447 kPa (34.02) {500} | 0.93 |
| 2,758 kPa (27.22) {400} | 0.91 |
| 2,068 kPa (20.41) {300} | 0.88 |
JANAF thermochemical data used throughout. Calculations performed by Rocketdyne, results appear in "Modern Engineering for Design of Liquid-Propellant Rocket Engines", Huzel and Huang. Some of the units have been converted to metric, but pressures have not. These are best-possible specific impulse calculations.
Assumptions:
- adiabatic combustion
- isentropic expansion
- one-dimensional expansion
- shifting equilibrium
Definitions
| r | Mixture ratio: mass oxidizer / mass fuel |
| Ve | Average exhaust velocity, m/s. The same measure as specific impulse in different units, numerically equal to specific impulse in N·s/kg. |
| C* | Characteristic velocity, m/s. Equal to chamber pressure multiplied by throat area, divided by mass flow rate Mass flow rate Mass flow rate is the mass of substance which passes through a given surface per unit time. Its unit is mass divided by time, so kilogram per second in SI units, and slug per second or pound per second in US customary units... . Used to check experimental rocket's combustion efficiency. |
| Tc | Chamber temperature, °C |
| d | Bulk density Bulk density Bulk density is a property of powders, granules and other "divided" solids, especially used in reference to mineral components , chemical substances, ingredients, foodstuff or any other masses of corpuscular or particulate matter. It is defined as the mass of many particles of the material... of fuel and oxidizer, g/cm³ |
Bipropellants
| Optimum expansion from 68.05 atm to 1 atm | Optimum expansion from 68.05 atm to 0 atm (vacuum) (Areanozzle = 40:1) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Oxidizer | Fuel | comment | Ve | r | Tc | d | C* | Ve | r | Tc | d | C* |
| LOX Lox Lox is salmon fillet that has been cured. In its most popular form, it is thinly sliced—less than in thickness—and, typically, served on a bagel, often with cream cheese, onion, tomato, cucumber and capers... | H2 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... | common | 3816 | 4.13 | 2740 | 0.29 | 2416 | 4462 | 4.83 | 2978 | 0.32 | 2386 |
| H2-Be Beryllium Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl... 49/51 | 4498 | 0.87 | 2558 | 0.23 | 2833 | 5295 | 0.91 | 2589 | 0.24 | 2850 | ||
| CH4 Methane Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel... | 3034 | 3.21 | 3260 | 0.82 | 1857 | 3615 | 3.45 | 3290 | 0.83 | 1838 | ||
| C2H6 Ethane Ethane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas.... | 3006 | 2.89 | 3320 | 0.90 | 1840 | 3584 | 3.10 | 3351 | 0.91 | 1825 | ||
| C2H4 Ethylene Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone... | 3053 | 2.38 | 3486 | 0.88 | 1875 | 3635 | 2.59 | 3521 | 0.89 | 1855 | ||
| RP-1 RP-1 RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser... | common | 2941 | 2.58 | 3403 | 1.03 | 1799 | 3510 | 2.77 | 3428 | 1.03 | 1783 | |
| N2H4 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... | 3065 | 0.92 | 3132 | 1.07 | 1892 | 3460 | 0.98 | 3146 | 1.07 | 1878 | ||
| B5H9 Pentaborane Pentaborane, also called pentaborane to distinguish it from B5H11, is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel... | 3124 | 2.12 | 3834 | 0.92 | 1895 | 3758 | 2.16 | 3863 | 0.92 | 1894 | ||
| B2H6 Diborane Diborane is the chemical compound consisting of boron and hydrogen with the formula B2H6. It is a colorless gas at room temperature with a repulsively sweet odor. Diborane mixes well with air, easily forming explosive mixtures. Diborane will ignite spontaneously in moist air at room temperature... | 3351 | 1.96 | 3489 | 0.74 | 2041 | 4016 | 2.06 | 3563 | 0.75 | 2039 | ||
| CH4/H2 92.6/7.4 | 3126 | 3.36 | 3245 | 0.71 | 1920 | 3719 | 3.63 | 3287 | 0.72 | 1897 | ||
| GOX Oxygen Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition... | GH2 Hydrogen Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly... | 3997 | 3.29 | 2576 | - | 2550 | 4485 | 3.92 | 2862 | - | 2519 | |
| F2 Fluorine Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic... | H2 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... | 4036 | 7.94 | 3689 | 0.46 | 2556 | 4697 | 9.74 | 3985 | 0.52 | 2530 | |
| H2-Li Lithium Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly... 65.2/34.0 | 4256 | 0.96 | 1830 | 0.19 | 2680 | |||||||
| H2-Li 60.7/39.3 | 5050 | 1.08 | 1974 | 0.21 | 2656 | |||||||
| CH4 Methane Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel... | 3414 | 4.53 | 3918 | 1.03 | 2068 | 4075 | 4.74 | 3933 | 1.04 | 2064 | ||
| C2H6 Ethane Ethane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas.... | 3335 | 3.68 | 3914 | 1.09 | 2019 | 3987 | 3.78 | 3923 | 1.10 | 2014 | ||
| MMH 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... | 3413 | 2.39 | 4074 | 1.24 | 2063 | 4071 | 2.47 | 4091 | 1.24 | 1987 | ||
| N2H4 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... | 3580 | 2.32 | 4461 | 1.31 | 2219 | 4215 | 2.37 | 4468 | 1.31 | 2122 | ||
| NH3 Ammonia Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or... | 3531 | 3.32 | 4337 | 1.12 | 2194 | 4143 | 3.35 | 4341 | 1.12 | 2193 | ||
| B5H9 Pentaborane Pentaborane, also called pentaborane to distinguish it from B5H11, is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel... | 3502 | 5.14 | 5050 | 1.23 | 2147 | 4191 | 5.58 | 5083 | 1.25 | 2140 | ||
| OF2 Oxygen difluoride Oxygen difluoride is the chemical compound with the formula F2O. As predicted by VSEPR theory, the molecule adopts a "V" shaped structure like H2O, but it has very different properties, being a strong oxidizer.-Preparation:... | H2 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... | 4014 | 5.92 | 3311 | 0.39 | 2542 | 4679 | 7.37 | 3587 | 0.44 | 2499 | |
| CH4 Methane Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel... | 3485 | 4.94 | 4157 | 1.06 | 2160 | 4131 | 5.58 | 4207 | 1.09 | 2139 | ||
| C2H6 Ethane Ethane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas.... | 3511 | 3.87 | 4539 | 1.13 | 2176 | 4137 | 3.86 | 4538 | 1.13 | 2176 | ||
| RP-1 RP-1 RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser... | 3424 | 3.87 | 4436 | 1.28 | 2132 | 4021 | 3.85 | 4432 | 1.28 | 2130 | ||
| MMH 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... | 3427 | 2.28 | 4075 | 1.24 | 2119 | 4067 | 2.58 | 4133 | 1.26 | 2106 | ||
| N2H4 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... | 3381 | 1.51 | 3769 | 1.26 | 2087 | 4008 | 1.65 | 3814 | 1.27 | 2081 | ||
| MMH/N2H4/H20 50.5/29.8/19.7 | 3286 | 1.75 | 3726 | 1.24 | 2025 | 3908 | 1.92 | 3769 | 1.25 | 2018 | ||
| B2H6 Diborane Diborane is the chemical compound consisting of boron and hydrogen with the formula B2H6. It is a colorless gas at room temperature with a repulsively sweet odor. Diborane mixes well with air, easily forming explosive mixtures. Diborane will ignite spontaneously in moist air at room temperature... | 3653 | 3.95 | 4479 | 1.01 | 2244 | 4367 | 3.98 | 4486 | 1.02 | 2167 | ||
| B5H9 Pentaborane Pentaborane, also called pentaborane to distinguish it from B5H11, is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel... | 3539 | 4.16 | 4825 | 1.20 | 2163 | 4239 | 4.30 | 4844 | 1.21 | 2161 | ||
| F2 Fluorine Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic... /O2 Oxygen Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition... 30/70 | H2 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... | 3871 | 4.80 | 2954 | 0.32 | 2453 | 4520 | 5.70 | 3195 | 0.36 | 2417 | |
| RP-1 RP-1 RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser... | 3103 | 3.01 | 3665 | 1.09 | 1908 | 3697 | 3.30 | 3692 | 1.10 | 1889 | ||
| F2/O2 70/30 | RP-1 RP-1 RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser... | 3377 | 3.84 | 4361 | 1.20 | 2106 | 3955 | 3.84 | 4361 | 1.20 | 2104 | |
| F2/O2 87.8/12.2 | MMH 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... | 3525 | 2.82 | 4454 | 1.24 | 2191 | 4148 | 2.83 | 4453 | 1.23 | 2186 | |
| Oxidizer | Fuel | comment | Ve | r | Tc | d | C* | Ve | r | Tc | d | C* |
| N2F4 Tetrafluorohydrazine Tetrafluorohydrazine, , is a colourless, reactive inorganic gas. It is a fluorinated analog of hydrazine. It is a highly hazardous chemical. In presence of organic materials it explodes.... | CH4 Methane Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel... | 3127 | 6.44 | 3705 | 1.15 | 1917 | 3692 | 6.51 | 3707 | 1.15 | 1915 | |
| C2H4 Ethane Ethane is a chemical compound with chemical formula C2H6. It is the only two-carbon alkane that is an aliphatic hydrocarbon. At standard temperature and pressure, ethane is a colorless, odorless gas.... | 3035 | 3.67 | 3741 | 1.13 | 1844 | 3612 | 3.71 | 3743 | 1.14 | 1843 | ||
| MMH 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... | 3163 | 3.35 | 3819 | 1.32 | 1928 | 3730 | 3.39 | 3823 | 1.32 | 1926 | ||
| N2H4 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... | 3283 | 3.22 | 4214 | 1.38 | 2059 | 3827 | 3.25 | 4216 | 1.38 | 2058 | ||
| NH3 Ammonia Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or... | 3204 | 4.58 | 4062 | 1.22 | 2020 | 3723 | 4.58 | 4062 | 1.22 | 2021 | ||
| B5H9 Pentaborane Pentaborane, also called pentaborane to distinguish it from B5H11, is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel... | 3259 | 7.76 | 4791 | 1.34 | 1997 | 3898 | 8.31 | 4803 | 1.35 | 1992 | ||
| ClF5 Chlorine pentafluoride Chlorine pentafluoride is an interhalogen compound with formula ClF5. It was first synthesized in 1963.Its square pyramidal structure with C4v symmetry was confirmed by its high resolution19F NMR spectrum.-Preparation:... | MMH 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... | 2962 | 2.82 | 3577 | 1.40 | 1837 | 3488 | 2.83 | 3579 | 1.40 | 1837 | |
| N2H4 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... | 3069 | 2.66 | 3894 | 1.47 | 1935 | 3580 | 2.71 | 3905 | 1.47 | 1934 | ||
| MMH/N2H4 86/14 | 2971 | 2.78 | 3575 | 1.41 | 1844 | 3498 | 2.81 | 3579 | 1.41 | 1844 | ||
| MMH/N2H4/N2H5NO3 55/26/19 | 2989 | 2.46 | 3717 | 1.46 | 1864 | 3500 | 2.49 | 3722 | 1.46 | 1863 | ||
| ClF3 Chlorine trifluoride Chlorine trifluoride is an interhalogen compound with the formula ClF3. This colourless, poisonous, corrosive and very reactive gas condenses to a pale-greenish yellow liquid, the form in which it is most often sold... | MMH 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... /N2H4 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... /N2H5NO3 55/26/19 | hypergolic | 2789 | 2.97 | 3407 | 1.42 | 1739 | 3274 | 3.01 | 3413 | 1.42 | 1739 |
| N2H4 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... | hypergolic | 2885 | 2.81 | 3650 | 1.49 | 1824 | 3356 | 2.89 | 3666 | 1.50 | 1822 | |
| N2O4 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... | MMH 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... | hypergolic, common | 2827 | 2.17 | 3122 | 1.19 | 1745 | 3347 | 2.37 | 3125 | 1.20 | 1724 |
| MMH 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... /Be Beryllium Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl... 76.6/29.4 | 3106 | 0.99 | 3193 | 1.17 | 1858 | 3720 | 1.10 | 3451 | 1.24 | 1849 | ||
| MMH/Al Aluminium Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances.... 63/27 | 2891 | 0.85 | 3294 | 1.27 | 1785 | |||||||
| MMH/Al 58/42 | 3460 | 0.87 | 3450 | 1.31 | 1771 | |||||||
| N2H4 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... | hypergolic, common | 2862 | 1.36 | 2992 | 1.21 | 1781 | 3369 | 1.42 | 2993 | 1.22 | 1770 | |
| N2H4/UDMH 50/50 | hypergolic, common | 2831 | 1.98 | 3095 | 1.12 | 1747 | 3349 | 2.15 | 3096 | 1.20 | 1731 | |
| N2H4/Be 80/20 | 3209 | 0.51 | 3038 | 1.20 | 1918 | |||||||
| N2H4/Be 76.6/23.4 | 3849 | 0.60 | 3230 | 1.22 | 1913 | |||||||
| B5H9 Pentaborane Pentaborane, also called pentaborane to distinguish it from B5H11, is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel... | 2927 | 3.18 | 3678 | 1.11 | 1782 | 3513 | 3.26 | 3706 | 1.11 | 1781 | ||
| NO 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... /N2O4 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... 25/75 | MMH 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... | 2839 | 2.28 | 3153 | 1.17 | 1753 | 3360 | 2.50 | 3158 | 1.18 | 1732 | |
| N2H4 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... /Be Beryllium Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl... 76.6/23.4 | 2872 | 1.43 | 3023 | 1.19 | 1787 | 3381 | 1.51 | 3026 | 1.20 | 1775 | ||
| IRFNA IIIa | UDMH/DETA 60/40 | hypergolic | 2638 | 3.26 | 2848 | 1.30 | 1627 | 3123 | 3.41 | 2839 | 1.31 | 1617 |
| MMH 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... | hypergolic | 2690 | 2.59 | 2849 | 1.27 | 1665 | 3178 | 2.71 | 2841 | 1.28 | 1655 | |
| UDMH | hypergolic | 2668 | 3.13 | 2874 | 1.26 | 1648 | 3157 | 3.31 | 2864 | 1.27 | 1634 | |
| IRFNA IV HDA | UDMH/DETA 60/40 | hypergolic | 2689 | 3.06 | 2903 | 1.32 | 1656 | 3187 | 3.25 | 2951 | 1.33 | 1641 |
| MMH 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... | hypergolic | 2742 | 2.43 | 2953 | 1.29 | 1696 | 3242 | 2.58 | 2947 | 1.31 | 1680 | |
| UDMH | hypergolic | 2719 | 2.95 | 2983 | 1.28 | 1676 | 3220 | 3.12 | 2977 | 1.29 | 1662 | |
| H2O2 Hydrogen peroxide Hydrogen 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... | MMH 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... | 2790 | 3.46 | 2720 | 1.24 | 1726 | 3301 | 3.69 | 2707 | 1.24 | 1714 | |
| N2H4 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... | 2810 | 2.05 | 2651 | 1.24 | 1751 | 3308 | 2.12 | 2645 | 1.25 | 1744 | ||
| N2H4 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... /Be Beryllium Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl... 74.5/25.5 | 3289 | 0.48 | 2915 | 1.21 | 1943 | 3954 | 0.57 | 3098 | 1.24 | 1940 | ||
| B5H9 Pentaborane Pentaborane, also called pentaborane to distinguish it from B5H11, is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel... | 3016 | 2.20 | 2667 | 1.02 | 1828 | 3642 | 2.09 | 2597 | 1.01 | 1817 | ||
| N2H4 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... | B2H6 Diborane Diborane is the chemical compound consisting of boron and hydrogen with the formula B2H6. It is a colorless gas at room temperature with a repulsively sweet odor. Diborane mixes well with air, easily forming explosive mixtures. Diborane will ignite spontaneously in moist air at room temperature... | 3342 | 1.16 | 2231 | 0.63 | 2080 | 3953 | 1.16 | 2231 | 0.63 | 2080 | |
| B5H9 Pentaborane Pentaborane, also called pentaborane to distinguish it from B5H11, is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel... | 3204 | 1.27 | 2441 | 0.80 | 1960 | 3819 | 1.27 | 2441 | 0.80 | 1960 | ||
| Oxidizer | Fuel | comment | Ve | r | Tc | d | C* | Ve | r | Tc | d | C* |
Definitions of some of the mixtures:
- IRFNA IIIa: 83.4% HNO3Nitric 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...
, 14% NO2Nitrogen dioxideNitrogen dioxide is the chemical compound with the formula it is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...
, 2% H2O, 0.6% HFHydrogen fluorideHydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the... - IRFNA IV HDA: 54.3% HNO3, 44% NO2, 1% H2O, 0.7% HF
- RP-1RP-1RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...
: see MIL-P-25576C, basically 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...
(approximately C10H18) - MMHMonomethylhydrazineMonomethylhydrazine 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...
: CH3NHNH2
| r | Mixture ratio: mass oxidizer / mass fuel |
| Ve | Average exhaust velocity, m/s. The same measure as specific impulse in different units, numerically equal to specific impulse in N·s/kg. |
| C* | Characteristic velocity, m/s. Equal to chamber pressure multiplied by throat area, divided by mass flow rate Mass flow rate Mass flow rate is the mass of substance which passes through a given surface per unit time. Its unit is mass divided by time, so kilogram per second in SI units, and slug per second or pound per second in US customary units... . Used to check experimental rocket's combustion efficiency. |
| Tc | Chamber temperature, °C |
| d | Bulk density Bulk density Bulk density is a property of powders, granules and other "divided" solids, especially used in reference to mineral components , chemical substances, ingredients, foodstuff or any other masses of corpuscular or particulate matter. It is defined as the mass of many particles of the material... of fuel and oxidizer, g/cm³ |
Monopropellants
| Optimum expansion from 68.05 atm to 1 atm | Optimum expansion from 68.05 atm to 0 atm (vacuum) (Areanozzle = 40:1) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Propellant | comment | Ve | Tc | d | C* | Ve | Tc | d | C* |
| 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... | common | ||||||||
| 100% Hydrogen peroxide Hydrogen peroxide Hydrogen 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... | common | 1610 | 1270 | 1.4 | 1040 | 1860 | 1270 | 1.4 | 1040 |
| Propellant | comment | Ve | Tc | d | C* | Ve | Tc | d | C* |
External links
- Cpropep-Web an online computer program to calculate propellant performance in rocket engines
- Design Tool for Liquid Rocket Engine Thermodynamic Analysis is a computer program to predict the performance of the liquid-propellant rocket engines. for a history of liquid rocket propellants in the US.