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100-676: The P120C is a solid-fuel rocket motor designed for use as the first stage of the Vega-C and as the boosters of the Ariane 6 launch vehicles. The solid rocket motors were developed by Europropulsion, a joint venture of Avio and ArianeGroup , for the European Space Agency . The "C" in the name signifies its "Common" use across these vehicles. As of July 2022, it holds the title of the world's largest and most-powerful single-piece solid-fuel rocket motor, surpassing its predecessor,

200-817: A candle 's flame takes the shape of a sphere. ). Microgravity combustion research contributes to the understanding of a wide variety of aspects that are relevant to both the environment of a spacecraft (e.g., fire dynamics relevant to crew safety on the International Space Station ) and terrestrial (Earth-based) conditions (e.g., droplet combustion dynamics to assist developing new fuel blends for improved combustion, materials fabrication processes , thermal management of electronic systems , multiphase flow boiling dynamics, and many others). Combustion processes that happen in very small volumes are considered micro-combustion . The high surface-to-volume ratio increases specific heat loss. Quenching distance plays

300-412: A detonation . The type of burning that actually occurs depends on the degree to which the fuel and oxidizer are mixed prior to heating: for example, a diffusion flame is formed if the fuel and oxidizer are separated initially, whereas a premixed flame is formed otherwise. Similarly, the type of burning also depends on the pressure: a detonation, for example, is an autoignitive reaction front coupled to

400-399: A triplet spin state . Bonding can be described with three bonding electron pairs and two antibonding electrons, with spins aligned, such that the molecule has nonzero total angular momentum. Most fuels, on the other hand, are in a singlet state, with paired spins and zero total angular momentum. Interaction between the two is quantum mechanically a " forbidden transition ", i.e. possible with

500-630: A 3,500 kilometres (2,200 mi) of carbon fiber, wound over 33 days in a climate-controlled environment. When operational, the P120C generates an average thrust of 4.5 meganewtons (1,000,000 lb f ). In 2022, development began on the P120C+ variant, which would evolve into the P160C. This extended version adds 1 metre (3 ft 3 in) to the motor's length and an additional 14 tonnes (14 long tons; 15 short tons) of propellant. This upgrade translates to

600-413: A casing, nozzle , grain ( propellant charge ), and igniter . The solid grain mass burns in a predictable fashion to produce exhaust gases, the flow of which is described by Taylor–Culick flow . The nozzle dimensions are calculated to maintain a design chamber pressure, while producing thrust from the exhaust gases. Once ignited, a simple solid rocket motor cannot be shut off, as it contains all

700-444: A cigarette, a short-circuited wire) and the persistent combustion of biomass behind the flaming fronts of wildfires . Spontaneous combustion is a type of combustion that occurs by self-heating (increase in temperature due to exothermic internal reactions), followed by thermal runaway (self-heating which rapidly accelerates to high temperatures) and finally, ignition. For example, phosphorus self-ignites at room temperature without

800-487: A control moment. For example, the Titan III C solid boosters injected nitrogen tetroxide for LITV; the tanks can be seen on the sides of the rocket between the main center stage and the boosters. An early Minuteman first stage used a single motor with four gimballed nozzles to provide pitch, yaw, and roll control. A typical, well-designed ammonium perchlorate composite propellant (APCP) first-stage motor may have

900-548: A given offgas temperature, the NOx level is lowest when excess oxygen is kept lowest. Adherence to these two principles is furthered by making material and heat balances on the combustion process. The material balance directly relates the air/fuel ratio to the percentage of O 2 in the combustion gas. The heat balance relates the heat available for the charge to the overall net heat produced by fuel combustion. Additional material and heat balances can be made to quantify

1000-541: A high-energy (yet unstable) monopropellant and the other acts as a lower-energy stabilizing (and gelling) monopropellant. In typical circumstances, nitroglycerin is dissolved in a nitrocellulose gel and solidified with additives. DB propellants are implemented in applications where minimal smoke is required yet a medium-high I sp of roughly 235 s (2.30 km/s) is required. The addition of metal fuels (such as aluminium ) can increase performance to around 250 s (2.5 km/s), though metal oxide nucleation in

1100-463: A hydroperoxide radical (HOO). This reacts further to give hydroperoxides, which break up to give hydroxyl radicals . There are a great variety of these processes that produce fuel radicals and oxidizing radicals. Oxidizing species include singlet oxygen, hydroxyl, monatomic oxygen, and hydroperoxyl . Such intermediates are short-lived and cannot be isolated. However, non-radical intermediates are stable and are produced in incomplete combustion. An example

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1200-564: A long history as the final boost stage for satellites due to their simplicity, reliability, compactness and reasonably high mass fraction . A spin-stabilized solid rocket motor is sometimes added when extra velocity is required, such as for a mission to a comet or the outer solar system, because a spinner does not require a guidance system (on the newly added stage). Thiokol's extensive family of mostly titanium-cased Star space motors has been widely used, especially on Delta launch vehicles and as spin-stabilized upper stages to launch satellites from

1300-499: A loss in motor performance. Polyurethane-bound aluminium-APCP solid fuel was used in the submarine-launched Polaris missiles . APCP used in the space shuttle Solid Rocket Boosters consisted of ammonium perchlorate (oxidizer, 69.6% by weight), aluminium (fuel, 16%), iron oxide (a catalyst, 0.4%), polybutadiene acrylonitrile (PBAN) polymer (a non-urethane rubber binder that held the mixture together and acted as secondary fuel, 12.04%), and an epoxy curing agent (1.96%). It developed

1400-594: A propellant mass fraction of 92.23% while the 14,000-kilogram (31,000 lb) Castor 30 upper stage developed for Orbital Science's Taurus II COTS (Commercial Off The Shelf) (International Space Station resupply) launch vehicle has a 91.3% propellant fraction with 2.9% graphite epoxy motor casing, 2.4% nozzle, igniter and thrust vector actuator, and 3.4% non-motor hardware including such things as payload mount, interstage adapter, cable raceway, instrumentation, etc. Castor 120 and Castor 30 are 2.36 and 2.34 meters (93 and 92 in) in diameter, respectively, and serve as stages on

1500-895: A range of 5,500 metres (3.4 mi). By the end of World War II total production of rocket launchers reached about 10,000. with 12 million rockets of the RS type produced for the Soviet armed forces. In the United States modern castable composite solid rocket motors were invented by the American aerospace engineer Jack Parsons at Caltech in 1942 when he replaced double base propellant with roofing asphalt and potassium perchlorate . This made possible slow-burning rocket motors of adequate size and with sufficient shelf-life for jet-assisted take off applications. Charles Bartley , employed at JPL (Caltech), substituted curable synthetic rubber for

1600-550: A roughly 2 tonnes (4,400 lb) improvement in lift performance on the Ariane 64 with four boosters. Notably, 16 of the planned 18 Kuiper launches by Ariane 6 will utilize this enhanced booster. Solid-fuel rocket A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants ( fuel / oxidizer ). The earliest rockets were solid-fuel rockets powered by gunpowder . The inception of gunpowder rockets in warfare can be credited to

1700-492: A simple, solid-propellant rocket tube that was filled with gunpowder. One open end allowed the gas to escape and was attached to a long stick that acted as a guidance system for flight direction control. The first rockets with tubes of cast iron were used by the Kingdom of Mysore under Hyder Ali and Tipu Sultan in the 1750s. These rockets had a reach of targets up to a mile and a half away. These were extremely effective in

1800-414: A single-piece nozzle or 304 s (2.98 km/s) with a high-area-ratio telescoping nozzle. Aluminium is used as fuel because it has a reasonable specific energy density, a high volumetric energy density, and is difficult to ignite accidentally. Composite propellants are cast, and retain their shape after the rubber binder, such as Hydroxyl-terminated polybutadiene (HTPB), cross-links (solidifies) with

1900-943: A small charge that is set off when the propellant is exhausted after a time delay. This charge can be used to trigger a camera , or deploy a parachute . Without this charge and delay, the motor may ignite a second stage (black powder only). In mid- and high-power rocketry , commercially made APCP motors are widely used. They can be designed as either single-use or reloadables. These motors are available in impulse ranges from "A" (1.26 Ns– 2.50 Ns) to "O" (20.48 kNs – 40.96 kNs), from several manufacturers. They are manufactured in standardized diameters and varying lengths depending on required impulse. Standard motor diameters are 13, 18, 24, 29, 38, 54, 75, 98, and 150 millimeters. Different propellant formulations are available to produce different thrust profiles, as well as special effects such as colored flames, smoke trails, or large quantities of sparks (produced by adding titanium sponge to

2000-406: A specific impulse of 242 seconds (2.37 km/s) at sea level or 268 seconds (2.63 km/s) in a vacuum. The 2005-2009 Constellation Program was to use a similar PBAN-bound APCP. In 2009, a group succeeded in creating a propellant of water and nanoaluminium ( ALICE ). Typical HEC propellants start with a standard composite propellant mixture (such as APCP) and add a high-energy explosive to

2100-414: A strong shock wave giving it its characteristic high-pressure peak and high detonation velocity . The act of combustion consists of three relatively distinct but overlapping phases: Efficient process heating requires recovery of the largest possible part of a fuel's heat of combustion into the material being processed. There are many avenues of loss in the operation of a heating process. Typically,

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2200-466: A sugar fuel (typically dextrose , sorbitol , or sucrose ) that are cast into shape by gently melting the propellant constituents together and pouring or packing the amorphous colloid into a mold. Candy propellants generate a low-medium specific impulse of roughly 130 s (1.3 km/s) and, thus, are used primarily by amateur and experimental rocketeers. DB propellants are composed of two monopropellant fuel components where one typically acts as

2300-684: A vacuum specific impulse ( I sp ) as high as 285.6 seconds (2.801 km/s) (Titan IVB SRMU). This compares to 339.3 s (3.327 km/s) for RP1/LOX (RD-180) and 452.3 s (4.436 km/s) for LH 2 /LOX (Block II RS-25 ) bipropellant engines. Upper stage specific impulses are somewhat greater: as much as 303.8 s (2.979 km/s) for APCP (Orbus 6E), 359 s (3.52 km/s) for RP1/LOX (RD-0124) and 465.5 s (4.565 km/s) for LH 2 /LOX (RL10B-2). Propellant fractions are usually somewhat higher for (non-segmented) solid propellant first stages than for upper stages. The 53,000-kilogram (117,000 lb) Castor 120 first stage has

2400-426: A very low probability. To initiate combustion, energy is required to force dioxygen into a spin-paired state, or singlet oxygen . This intermediate is extremely reactive. The energy is supplied as heat , and the reaction then produces additional heat, which allows it to continue. Combustion of hydrocarbons is thought to be initiated by hydrogen atom abstraction (not proton abstraction) from the fuel to oxygen, to give

2500-619: A very primitive form of solid-propellant rocket. Illustrations and descriptions in the 14th century Chinese military treatise Huolongjing by the Ming dynasty military writer and philosopher Jiao Yu confirm that the Chinese in 1232 used proto solid propellant rockets then known as " fire arrows " to drive back the Mongols during the Mongol siege of Kaifeng . Each arrow took a primitive form of

2600-445: A vital role in stabilizing the flame in such combustion chambers . Generally, the chemical equation for stoichiometric combustion of a hydrocarbon in oxygen is: For example, the stoichiometric combustion of methane in oxygen is: If the stoichiometric combustion takes place using air as the oxygen source, the nitrogen present in the air ( Atmosphere of Earth ) can be added to the equation (although it does not react) to show

2700-460: Is acetaldehyde produced in the combustion of ethanol . An intermediate in the combustion of carbon and hydrocarbons, carbon monoxide , is of special importance because it is a poisonous gas , but also economically useful for the production of syngas . Solid and heavy liquid fuels also undergo a great number of pyrolysis reactions that give more easily oxidized, gaseous fuels. These reactions are endothermic and require constant energy input from

2800-454: Is stoichiometric concerning the fuel, where there is no remaining fuel, and ideally, no residual oxidant. Thermodynamically, the chemical equilibrium of combustion in air is overwhelmingly on the side of the products. However, complete combustion is almost impossible to achieve, since the chemical equilibrium is not necessarily reached, or may contain unburnt products such as carbon monoxide , hydrogen and even carbon ( soot or ash). Thus,

2900-400: Is 'low' (i.e., 'micro' in the sense of 'small' and not necessarily a millionth of Earth's normal gravity) such that the influence of buoyancy on physical processes may be considered small relative to other flow processes that would be present at normal gravity. In such an environment, the thermal and flow transport dynamics can behave quite differently than in normal gravity conditions (e.g.,

3000-419: Is 1 / (1 + 2 + 7.54) = 9.49% vol. The stoichiometric combustion reaction for C α H β O γ in air: The stoichiometric combustion reaction for C α H β O γ S δ : The stoichiometric combustion reaction for C α H β O γ N δ S ε : The stoichiometric combustion reaction for C α H β O γ F δ : Various other substances begin to appear in significant amounts in combustion products when

3100-492: Is another pressed propellant that does not find any practical application outside specialized amateur rocketry circles due to its poor performance (as most ZS burns outside the combustion chamber) and fast linear burn rates on the order of 2 m/s. ZS is most often employed as a novelty propellant as the rocket accelerates extremely quickly leaving a spectacular large orange fireball behind it. In general, rocket candy propellants are an oxidizer (typically potassium nitrate) and

P120C - Misplaced Pages Continue

3200-552: Is cheap and fairly easy to produce. The fuel grain is typically a mixture of pressed fine powder (into a solid, hard slug), with a burn rate that is highly dependent upon exact composition and operating conditions. The specific impulse of black powder is low, around 80 s (0.78 km/s). The grain is sensitive to fracture and, therefore, catastrophic failure. Black powder does not typically find use in motors above 40 newtons (9.0 pounds-force) thrust. Composed of powdered zinc metal and powdered sulfur (oxidizer), ZS or "micrograin"

3300-463: Is converted to carbon monoxide , and some of the hydrogens remain unreacted. A complete set of equations for the combustion of a hydrocarbon in the air, therefore, requires an additional calculation for the distribution of oxygen between the carbon and hydrogen in the fuel. The amount of air required for complete combustion is known as the "theoretical air" or "stoichiometric air". The amount of air above this value actually needed for optimal combustion

3400-408: Is equal to the volumetric rate times the fuel density ρ {\displaystyle \rho } : Several geometric configurations are often used depending on the application and desired thrust curve : The casing may be constructed from a range of materials. Cardboard is used for small black powder model motors, whereas aluminium is used for larger composite-fuel hobby motors. Steel

3500-581: Is greatly preferred especially as carbon monoxide is a poisonous gas. When breathed, carbon monoxide takes the place of oxygen and combines with some of the hemoglobin in the blood, rendering it unable to transport oxygen. These oxides combine with water and oxygen in the atmosphere, creating nitric acid and sulfuric acids , which return to Earth's surface as acid deposition, or "acid rain." Acid deposition harms aquatic organisms and kills trees. Due to its formation of certain nutrients that are less available to plants such as calcium and phosphorus, it reduces

3600-532: Is harvested for diverse uses such as cooking , production of electricity or industrial or domestic heating. Combustion is also currently the only reaction used to power rockets . Combustion is also used to destroy ( incinerate ) waste, both nonhazardous and hazardous. Oxidants for combustion have high oxidation potential and include atmospheric or pure oxygen , chlorine , fluorine , chlorine trifluoride , nitrous oxide and nitric acid . For instance, hydrogen burns in chlorine to form hydrogen chloride with

3700-428: Is known as the "excess air", and can vary from 5% for a natural gas boiler, to 40% for anthracite coal, to 300% for a gas turbine . Incomplete combustion will occur when there is not enough oxygen to allow the fuel to react completely to produce carbon dioxide and water. It also happens when the combustion is quenched by a heat sink, such as a solid surface or flame trap. As is the case with complete combustion, water

3800-428: Is non-polluting: acid-free, solid particulates-free, and lead-free. It is also smokeless and has only a faint shock diamond pattern that is visible in the otherwise transparent exhaust. Without the bright flame and dense smoke trail produced by the burning of aluminized propellants, these smokeless propellants all but eliminate the risk of giving away the positions from which the missiles are fired. The new CL-20 propellant

3900-438: Is positively correlated with the risk of heart disease. People who survive severe carbon monoxide poisoning may suffer long-term health problems. Carbon monoxide from the air is absorbed in the lungs which then binds with hemoglobin in human's red blood cells. This reduces the capacity of red blood cells that carry oxygen throughout the body. Smoldering is the slow, low-temperature, flameless form of combustion, sustained by

4000-548: Is produced by incomplete combustion; however, carbon and carbon monoxide are produced instead of carbon dioxide. For most fuels, such as diesel oil, coal, or wood, pyrolysis occurs before combustion. In incomplete combustion, products of pyrolysis remain unburnt and contaminate the smoke with noxious particulate matter and gases. Partially oxidized compounds are also a concern; partial oxidation of ethanol can produce harmful acetaldehyde , and carbon can produce toxic carbon monoxide. The designs of combustion devices can improve

4100-411: Is shock-insensitive (hazard class 1.3) as opposed to current HMX smokeless propellants which are highly detonable (hazard class 1.1). CL-20 is considered a major breakthrough in solid rocket propellant technology but has yet to see widespread use because costs remain high. Electric solid propellants (ESPs) are a family of high performance plastisol solid propellants that can be ignited and throttled by

P120C - Misplaced Pages Continue

4200-417: Is the source of oxygen ( O 2 ). In the air, each mole of oxygen is mixed with approximately 3.71  mol of nitrogen. Nitrogen does not take part in combustion, but at high temperatures, some nitrogen will be converted to NO x (mostly NO , with much smaller amounts of NO 2 ). On the other hand, when there is insufficient oxygen to combust the fuel completely, some fuel carbon

4300-510: Is the vapor that burns, not the liquid. Therefore, a liquid will normally catch fire only above a certain temperature: its flash point . The flash point of liquid fuel is the lowest temperature at which it can form an ignitable mix with air. It is the minimum temperature at which there is enough evaporated fuel in the air to start combustion. Combustion of gaseous fuels may occur through one of four distinctive types of burning: diffusion flame , premixed flame , autoignitive reaction front , or as

4400-648: Is theoretically needed to ensure that all the fuel burns. For methane ( CH 4 ) combustion, for example, slightly more than two molecules of oxygen are required. The second principle of combustion management, however, is to not use too much oxygen. The correct amount of oxygen requires three types of measurement: first, active control of air and fuel flow; second, offgas oxygen measurement; and third, measurement of offgas combustibles. For each heating process, there exists an optimum condition of minimal offgas heat loss with acceptable levels of combustibles concentration. Minimizing excess oxygen pays an additional benefit: for

4500-434: Is to achieve mid-course exo-atmospheric ABM capability from missiles small enough to fit in existing ship-based below-deck vertical launch tubes and air-mobile truck-mounted launch tubes. CL-20 propellant compliant with Congress' 2004 insensitive munitions (IM) law has been demonstrated and may, as its cost comes down, be suitable for use in commercial launch vehicles, with a very significant increase in performance compared with

4600-664: The Battle of Khalkhin Gol . In June 1938, the RNII began developing a multiple rocket launcher based on the RS-132 rocket. In August 1939, the completed product was the BM-13 / Katyusha rocket launcher . Towards the end of 1938 the first significant large scale testing of the rocket launchers took place, 233 rockets of various types were used. A salvo of rockets could completely straddle a target at

4700-739: The P80 . Initially, production of the P120C was planned to be divided between Avio's main facility in Italy and MT Aerospace in Germany. However, in 2018, ESA decided to consolidate production entirely in Italy, with MT Aerospace focusing on Ariane 6's turbopumps. The first successful test firing occurred at the Guiana Space Centre in July 2018, lasting 140 seconds and simulating a complete first-stage burn. Subsequent tests in 2019 and 2020 confirmed

4800-668: The Reactive Scientific Research Institute (RNII) with the development of the RS-82 and RS-132 rockets , including designing several variations for ground-to-air, ground-to-ground, air-to-ground and air-to-air combat. The earliest known use by the Soviet Air Force of aircraft-launched unguided anti-aircraft rockets in combat against heavier-than-air aircraft took place in August 1939 , during

4900-788: The Second Anglo-Mysore War that ended in a humiliating defeat for the British East India Company . Word of the success of the Mysore rockets against the British triggered research in England, France, Ireland and elsewhere. When the British finally conquered the fort of Srirangapatana in 1799, hundreds of rockets were shipped off to the Royal Arsenal near London to be reverse-engineered. This led to

5000-457: The efficiency of a burner during the combustion process. Also, the efficiency of an internal combustion engine can be measured in this way, and some U.S. states and local municipalities use combustion analysis to define and rate the efficiency of vehicles on the road today. Carbon monoxide is one of the products from incomplete combustion . The formation of carbon monoxide produces less heat than formation of carbon dioxide so complete combustion

5100-410: The flame temperature is above about 1600  K . When excess air is used, nitrogen may oxidize to NO and, to a much lesser extent, to NO 2 . CO forms by disproportionation of CO 2 , and H 2 and OH form by disproportionation of H 2 O . For example, when 1  mol of propane is burned with 28.6  mol of air (120% of the stoichiometric amount),

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5200-500: The fuel and oxidizer mass. Grain geometry and chemistry are then chosen to satisfy the required motor characteristics. The following are chosen or solved simultaneously. The results are exact dimensions for grain, nozzle, and case geometries: The grain may or may not be bonded to the casing. Case-bonded motors are more difficult to design, since the deformation of the case and the grain under flight must be compatible. Common modes of failure in solid rocket motors include fracture of

5300-446: The heat-treatment of metals and for gas carburizing . The general reaction equation for incomplete combustion of one mole of a hydrocarbon in oxygen is: When z falls below roughly 50% of the stoichiometric value, CH 4 can become an important combustion product; when z falls below roughly 35% of the stoichiometric value, elemental carbon may become stable. The products of incomplete combustion can be calculated with

5400-582: The 2010s include the European Ariane 5 , US Atlas V and Space Shuttle , and Japan's H-II . The largest solid rocket motors ever built were Aerojet's three 6.60-meter (260 in) monolithic solid motors cast in Florida. Motors 260 SL-1 and SL-2 were 6.63 meters (261 in) in diameter, 24.59 meters (80 ft 8 in) long, weighed 842,900 kilograms (1,858,300 lb), and had a maximum thrust of 16 MN (3,500,000 lbf). Burn duration

5500-667: The Athena IC and IIC commercial launch vehicles. A four-stage Athena II using Castor 120s as both first and second stages became the first commercially developed launch vehicle to launch a lunar probe ( Lunar Prospector ) in 1998. Solid rockets can provide high thrust for relatively low cost. For this reason, solids have been used as initial stages in rockets (for example the Space Shuttle ), while reserving high specific impulse engines, especially less massive hydrogen-fueled engines, for higher stages. In addition, solid rockets have

5600-525: The United States and European Union enforce limits to vehicle nitrogen oxide emissions, which necessitate the use of special catalytic converters or treatment of the exhaust with urea (see Diesel exhaust fluid ). The incomplete (partial) combustion of a hydrocarbon with oxygen produces a gas mixture containing mainly CO 2 , CO , H 2 O , and H 2 . Such gas mixtures are commonly prepared for use as protective atmospheres for

5700-424: The aid of a material balance , together with the assumption that the combustion products reach equilibrium . For example, in the combustion of one mole of propane ( C 3 H 8 ) with four moles of O 2 , seven moles of combustion gas are formed, and z is 80% of the stoichiometric value. The three elemental balance equations are: These three equations are insufficient in themselves to calculate

5800-493: The aid of a curative additive. Because of its high performance, moderate ease of manufacturing, and moderate cost, APCP finds widespread use in space, military, and amateur rockets, whereas cheaper and less efficient ANCP finds use in amateur rocketry and gas generators . Ammonium dinitramide , NH 4 N(NO 2 ) 2 , is being considered as a 1-to-1 chlorine-free substitute for ammonium perchlorate in composite propellants. Unlike ammonium nitrate, ADN can be substituted for AP without

5900-1310: The ancient Chinese, and in the 13th century, the Mongols played a pivotal role in facilitating their westward adoption. All rockets used some form of solid or powdered propellant until the 20th century, when liquid-propellant rockets offered more efficient and controllable alternatives. Because of their simplicity and reliability, solid rockets are still used today in military armaments worldwide, model rockets , solid rocket boosters and on larger applications. Since solid-fuel rockets can remain in storage for an extended period without much propellant degradation, and since they almost always launch reliably, they have been frequently used in military applications such as missiles . The lower performance of solid propellants (as compared to liquids) does not favor their use as primary propulsion in modern medium-to-large launch vehicles customarily used for commercial satellites and major space probes. Solids are, however, frequently used as strap-on boosters to increase payload capacity or as spin-stabilized add-on upper stages when higher-than-normal velocities are required. Solid rockets are used as light launch vehicles for low Earth orbit (LEO) payloads under 2 tons or escape payloads up to 500 kilograms (1,100 lb). A simple solid rocket motor consists of

6000-459: The application of electric current. Unlike conventional rocket motor propellants that are difficult to control and extinguish, ESPs can be ignited reliably at precise intervals and durations. It requires no moving parts and the propellant is insensitive to flames or electrical sparks. Solid propellant rocket motors can be bought for use in model rocketry ; they are normally small cylinders of black powder fuel with an integral nozzle and optionally

6100-418: The application of heat. Organic materials undergoing bacterial composting can generate enough heat to reach the point of combustion. Combustion resulting in a turbulent flame is the most used for industrial applications (e.g. gas turbines , gasoline engines , etc.) because the turbulence helps the mixing process between the fuel and oxidizer . The term 'micro' gravity refers to a gravitational state that

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6200-467: The cargo bay of the Space Shuttle. Star motors have propellant fractions as high as 94.6% but add-on structures and equipment reduce the operating mass fraction by 2% or more. Higher performing solid rocket propellants are used in large strategic missiles (as opposed to commercial launch vehicles). HMX , C 4 H 8 N 4 (NO 2 ) 4 , a nitramine with greater energy than ammonium perchlorate,

6300-452: The casing is often implemented, which ablates to prolong the life of the motor casing. A convergent-divergent design accelerates the exhaust gas out of the nozzle to produce thrust. The nozzle must be constructed from a material that can withstand the heat of the combustion gas flow. Often, heat-resistant carbon-based materials are used, such as amorphous graphite or reinforced carbon–carbon . Some designs include directional control of

6400-408: The combustion gas composition. However, at the equilibrium position, the water-gas shift reaction gives another equation: For example, at 1200  K the value of K eq is 0.728. Solving, the combustion gas consists of 42.4% H 2 O , 29.0% CO 2 , 14.7% H 2 , and 13.9% CO . Carbon becomes a stable phase at 1200  K and 1  atm pressure when z is less than 30% of

6500-457: The combustion products contain 3.3% O 2 . At 1400  K , the equilibrium combustion products contain 0.03% NO and 0.002% OH . At 1800  K , the combustion products contain 0.17% NO , 0.05% OH , 0.01% CO , and 0.004% H 2 . Diesel engines are run with an excess of oxygen to combust small particles that tend to form with only a stoichiometric amount of oxygen, necessarily producing nitrogen oxide emissions. Both

6600-454: The currently favored APCP solid propellants. With a specific impulse of 309 s already demonstrated by Peacekeeper's second stage using HMX propellant, the higher energy of CL-20 propellant can be expected to increase specific impulse to around 320 s in similar ICBM or launch vehicle upper stage applications, without the explosive hazard of HMX. An attractive attribute for military use is the ability for solid rocket propellant to remain loaded in

6700-400: The dominant loss is sensible heat leaving with the offgas (i.e., the flue gas ). The temperature and quantity of offgas indicates its heat content ( enthalpy ), so keeping its quantity low minimizes heat loss. In a perfect furnace, the combustion air flow would be matched to the fuel flow to give each fuel molecule the exact amount of oxygen needed to cause complete combustion. However, in

6800-611: The exhaust can turn the smoke opaque. A powdered oxidizer and powdered metal fuel are intimately mixed and immobilized with a rubbery binder (that also acts as a fuel). Composite propellants are often either ammonium-nitrate -based (ANCP) or ammonium-perchlorate -based (APCP). Ammonium nitrate composite propellant often uses magnesium and/or aluminium as fuel and delivers medium performance (I sp of about 210 s (2.1 km/s)) whereas ammonium perchlorate composite propellant often uses aluminium fuel and delivers high performance: vacuum I sp up to 296 s (2.90 km/s) with

6900-542: The exhaust. This can be accomplished by gimballing the nozzle, as in the Space Shuttle SRBs, by the use of jet vanes in the exhaust as in the V-2 rocket, or by liquid injection thrust vectoring (LITV). LITV consists of injecting a liquid into the exhaust stream after the nozzle throat. The liquid then vaporizes, and in most cases chemically reacts, adding mass flow to one side of the exhaust stream and thus providing

7000-563: The first industrial manufacture of military rockets with the Congreve rocket in 1804. In 1921 the Soviet research and development laboratory Gas Dynamics Laboratory began developing solid-propellant rockets, which resulted in the first launch in 1928, that flew for approximately 1,300 metres. These rockets were used in 1931 for the world's first successful use of rockets to assist take-off of aircraft . The research continued from 1933 by

7100-445: The functional definition of double base propellants. One of the most active areas of solid propellant research is the development of high-energy, minimum-signature propellant using C 6 H 6 N 6 (NO 2 ) 6 CL-20 nitroamine ( China Lake compound #20), which has 14% higher energy per mass and 20% higher energy density than HMX. The new propellant has been successfully developed and tested in tactical rocket motors. The propellant

7200-470: The gooey asphalt, creating a flexible but geometrically stable load-bearing propellant grain that bonded securely to the motor casing. This made possible much larger solid rocket motors. Atlantic Research Corporation significantly boosted composite propellant I sp in 1954 by increasing the amount of powdered aluminium in the propellant to as much as 20%. Solid-propellant rocket technology got its largest boost in technical innovation, size and capability with

7300-440: The grain, failure of case bonding, and air pockets in the grain. All of these produce an instantaneous increase in burn surface area and a corresponding increase in exhaust gas production rate and pressure, which may rupture the casing. Another failure mode is casing seal failure. Seals are required in casings that have to be opened to load the grain. Once a seal fails, hot gas will erode the escape path and result in failure. This

7400-486: The heat evolved when oxygen directly attacks the surface of a condensed-phase fuel. It is a typically incomplete combustion reaction. Solid materials that can sustain a smoldering reaction include coal, cellulose , wood , cotton , tobacco , peat , duff , humus , synthetic foams, charring polymers (including polyurethane foam ) and dust . Common examples of smoldering phenomena are the initiation of residential fires on upholstered furniture by weak heat sources (e.g.,

7500-536: The heat required to produce more of them. Combustion is often hot enough that incandescent light in the form of either glowing or a flame is produced. A simple example can be seen in the combustion of hydrogen and oxygen into water vapor , a reaction which is commonly used to fuel rocket engines . This reaction releases 242   kJ/mol of heat and reduces the enthalpy accordingly (at constant temperature and pressure): Uncatalyzed combustion in air requires relatively high temperatures. Complete combustion

7600-658: The ingredients necessary for combustion within the chamber in which they are burned. More advanced solid rocket motors can be throttled , or extinguished and re-ignited, by control of the nozzle geometry or through the use of vent ports. Further, pulsed rocket motors that burn in segments, and that can be ignited upon command are available. Modern designs may also include a steerable nozzle for guidance, avionics , recovery hardware ( parachutes ), self-destruct mechanisms, APUs , controllable tactical motors, controllable divert and attitude control motors, and thermal management materials. The medieval Song dynasty Chinese invented

7700-402: The liberation of heat and light characteristic of combustion. Although usually not catalyzed, combustion can be catalyzed by platinum or vanadium , as in the contact process . In complete combustion, the reactant burns in oxygen and produces a limited number of products. When a hydrocarbon burns in oxygen, the reaction will primarily yield carbon dioxide and water. When elements are burned,

7800-420: The maximum degree of oxidation, and it can be temperature-dependent. For example, sulfur trioxide is not produced quantitatively by the combustion of sulfur. NO x species appear in significant amounts above about 2,800 °F (1,540 °C), and more is produced at higher temperatures. The amount of NO x is also a function of oxygen excess. In most industrial applications and in fires , air

7900-568: The mix). Almost all sounding rockets use solid motors. Due to reliability, ease of storage and handling, solid rockets are used on missiles and ICBMs. Solid rockets are suitable for launching small payloads to orbital velocities, especially if three or more stages are used. Many of these are based on repurposed ICBMs. Combustion Combustion is often a complicated sequence of elementary radical reactions . Solid fuels , such as wood and coal , first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies

8000-560: The mix. This extra component usually is in the form of small crystals of RDX or HMX , both of which have higher energy than ammonium perchlorate. Despite a modest increase in specific impulse, implementation is limited due to the increased hazards of the high-explosive additives. Composite modified double base propellants start with a nitrocellulose/nitroglycerin double base propellant as a binder and add solids (typically ammonium perchlorate (AP) and powdered aluminium ) normally used in composite propellants. The ammonium perchlorate makes up

8100-503: The motor's flight readiness for both launcher configurations. The P120C builds upon the P80's design, utilizing a carbon fibre casing constructed via filament winding and fabric deposition techniques. It houses a 143.6 tonnes (317,000 lb) of HTPB 1912 propellant, a blend of 19% aluminium powder , 69% ammonium perchlorate with 12% of hydroxyl terminated polybutadiene binder. The motor's 25 centimetres (9.8 in) thick walls require

8200-420: The next 50 years. By the later 1980s and continuing to 2020, these government-developed highly-capable solid rocket technologies have been applied to orbital spaceflight by many government-directed programs , most often as booster rockets to add extra thrust during the early ascent of their primarily liquid rocket launch vehicles . Some designs have had solid rocket upper stages as well. Examples flying in

8300-569: The oxygen deficit introduced by using nitrocellulose , improving the overall specific impulse. The aluminium improves specific impulse as well as combustion stability. High performing propellants such as NEPE-75 used to fuel the Trident II D-5 SLBM replace most of the AP with polyethylene glycol -bound HMX , further increasing specific impulse. The mixing of composite and double base propellant ingredients has become so common as to blur

8400-576: The produced smoke is usually toxic and contains unburned or partially oxidized products. Any combustion at high temperatures in atmospheric air , which is 78 percent nitrogen , will also create small amounts of several nitrogen oxides , commonly referred to as NOx , since the combustion of nitrogen is thermodynamically favored at high, but not low temperatures. Since burning is rarely clean, fuel gas cleaning or catalytic converters may be required by law. Fires occur naturally, ignited by lightning strikes or by volcanic products. Combustion ( fire )

8500-463: The productivity of the ecosystem and farms. An additional problem associated with nitrogen oxides is that they, along with hydrocarbon pollutants, contribute to the formation of ground level ozone , a major component of smog. Breathing carbon monoxide causes headache, dizziness, vomiting, and nausea. If carbon monoxide levels are high enough, humans become unconscious or die. Exposure to moderate and high levels of carbon monoxide over long periods

8600-425: The products are primarily the most common oxides. Carbon will yield carbon dioxide , sulfur will yield sulfur dioxide , and iron will yield iron(III) oxide . Nitrogen is not considered to be a combustible substance when oxygen is the oxidant . Still, small amounts of various nitrogen oxides (commonly designated NO x species) form when the air is the oxidative. Combustion is not necessarily favorable to

8700-463: The propellant surface area exposed to the combustion gases. Since the propellant volume is equal to the cross sectional area A s {\displaystyle A_{s}} times the fuel length, the volumetric propellant consumption rate is the cross section area times the linear burn rate b ˙ {\displaystyle {\dot {b}}} , and the instantaneous mass flow rate of combustion gases generated

8800-644: The quality of combustion, such as burners and internal combustion engines . Further improvements are achievable by catalytic after-burning devices (such as catalytic converters ) or by the simple partial return of the exhaust gases into the combustion process. Such devices are required by environmental legislation for cars in most countries. They may be necessary to enable large combustion devices, such as thermal power stations , to reach legal emission standards . The degree of combustion can be measured and analyzed with test equipment. HVAC contractors, firefighters and engineers use combustion analyzers to test

8900-422: The real world, combustion does not proceed in a perfect manner. Unburned fuel (usually CO and H 2 ) discharged from the system represents a heating value loss (as well as a safety hazard). Since combustibles are undesirable in the offgas, while the presence of unreacted oxygen there presents minimal safety and environmental concerns, the first principle of combustion management is to provide more oxygen than

9000-417: The retired Peacekeeper ICBMs). The Naval Air Weapons Station at China Lake, California, developed a new compound, C 6 H 6 N 6 (NO 2 ) 6 , called simply CL-20 (China Lake compound 20). Compared to HMX, CL-20 has 14% more energy per mass, 20% more energy per volume, and a higher oxygen-to-fuel ratio. One of the motivations for development of these very high energy density military solid propellants

9100-403: The rocket for long durations and then be reliably launched at a moment's notice. Black powder (gunpowder) is composed of charcoal (fuel), potassium nitrate (oxidizer), and sulfur (fuel and catalyst). It is one of the oldest pyrotechnic compositions with application to rocketry. In modern times, black powder finds use in low-power model rockets (such as Estes and Quest rockets), as it

9200-499: The stoichiometric composition of the fuel in air and the composition of the resultant flue gas. Treating all non-oxygen components in air as nitrogen gives a 'nitrogen' to oxygen ratio of 3.77, i.e. (100% − O 2 %) / O 2 % where O 2 % is 20.95% vol: where z = x + y 4 {\displaystyle z=x+{y \over 4}} . For example, the stoichiometric combustion of methane in air is: The stoichiometric composition of methane in air

9300-414: The stoichiometric value, at which point the combustion products contain more than 98% H 2 and CO and about 0.5% CH 4 . Substances or materials which undergo combustion are called fuels . The most common examples are natural gas, propane, kerosene , diesel , petrol, charcoal, coal, wood, etc. Combustion of a liquid fuel in an oxidizing atmosphere actually happens in the gas phase. It

9400-404: The thermal advantage from preheating the combustion air, or enriching it in oxygen. Combustion in oxygen is a chain reaction in which many distinct radical intermediates participate. The high energy required for initiation is explained by the unusual structure of the dioxygen molecule. The lowest-energy configuration of the dioxygen molecule is a stable, relatively unreactive diradical in

9500-616: The various mid-20th century government initiatives to develop increasingly capable military missiles. After initial designs of ballistic missile military technology designed with liquid-propellant rockets in the 1940s and 1950s, both the Soviet Union and the United States embarked on major initiatives to develop solid-propellant local , regional , and intercontinental ballistic missiles, including solid-propellant missiles that could be launched from air or sea . Many other governments also developed these military technologies over

9600-488: Was the cause of the Space Shuttle Challenger disaster . Solid rocket fuel deflagrates from the surface of exposed propellant in the combustion chamber. In this fashion, the geometry of the propellant inside the rocket motor plays an important role in the overall motor performance. As the surface of the propellant burns, the shape evolves (a subject of study in internal ballistics), most often changing

9700-456: Was the first controlled chemical reaction discovered by humans, in the form of campfires and bonfires , and continues to be the main method to produce energy for humanity. Usually, the fuel is carbon , hydrocarbons , or more complicated mixtures such as wood that contain partially oxidized hydrocarbons. The thermal energy produced from the combustion of either fossil fuels such as coal or oil , or from renewable fuels such as firewood ,

9800-423: Was two minutes. The nozzle throat was large enough to walk through standing up. The motor was capable of serving as a 1-to-1 replacement for the 8-engine Saturn I liquid-propellant first stage but was never used as such. Motor 260 SL-3 was of similar length and weight but had a maximum thrust of 24 MN (5,400,000 lbf) and a shorter duration. Design begins with the total impulse required, which determines

9900-407: Was used for the space shuttle boosters . Filament-wound graphite epoxy casings are used for high-performance motors. The casing must be designed to withstand the pressure and resulting stresses of the rocket motor, possibly at elevated temperature. For design, the casing is considered a pressure vessel . To protect the casing from corrosive hot gases, a sacrificial thermal liner on the inside of

10000-673: Was used in the propellant of the Peacekeeper ICBM and is the main ingredient in NEPE-75 propellant used in the Trident II D-5 Fleet Ballistic Missile. It is because of explosive hazard that the higher energy military solid propellants containing HMX are not used in commercial launch vehicles except when the LV is an adapted ballistic missile already containing HMX propellant (Minotaur IV and V based on

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