1.
Liquid-propellant rocket
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A liquid-propellant rocket or liquid rocket is a rocket engine that uses liquid propellants. This permits the use of low-mass propellant tanks, resulting in a mass ratio for the rocket. An inert gas stored in a tank at a pressure is sometimes used instead of pumps in simpler small engines to force the propellants into the combustion chamber. These engines may have a mass ratio, but are usually more reliable. And are therefore used widely in satellites for orbit maintenance, some designs are throttleable for variable thrust operation and some may be restarted after a previous in-space shutdown. Liquid propellants are used in hybrid rockets, in which a liquid oxidizer is generally combined with a solid fuel. This seminal treatise on astronautics was published in 1903, but was not distributed outside Russia until years later, german V-2 inventor Wernher von Braun considered Paulet one of the fathers of aeronautics. The National Air & Space Museum in Washington, D. C. has a plaque honoring the memory of Paulet. He was the only known developer of liquid-propellant rocket engine experiments in the 19th century, however, he did not publish his work. In 1927 he wrote a letter to a newspaper in Lima, historians of early rocketry experiments, among them Max Valier, Willy Ley, and John D. Clark, have given differing amounts of credence to Paulets report. Paulet described laboratory tests of, but did not claim to have launched a liquid rocket. Wernher von Braun, in his book World History of Aeronautics states, Pedro Paulet was in Paris in those years, experimenting with his tiny two-and-a-half kilogram motor, by this act, Paulet should be considered the pioneer of the liquid fuel propulsion motor. Further, in his History of Rocketry and Space Travel, von Braun recognizes that by his efforts, Paulet helped man reach the Moon. The rocket, which was dubbed Nell, rose just 41 feet during a 2. 5-second flight that ended in a cabbage field, goddard proposed liquid propellants about fifteen years earlier and began to seriously experiment with them in 1921. In Germany, engineers and scientists became enthralled with liquid-fuel rockets and this amateur rocket group, the VfR, included Wernher von Braun, who became the head of the army research station that secretly built the V-2 rocket weapon for the Nazis. The German-Romanian Hermann Oberth published a book in 1922 suggesting the use of liquid propellants, after World War II the American government and military finally seriously considered liquid-propellant rockets as weapons and began to fund work on them. The Soviet Union did likewise, and thus began the Space Race, bipropellant liquid rockets generally use a liquid fuel, such as liquid hydrogen or a hydrocarbon fuel such as RP-1, and a liquid oxidizer, such as liquid oxygen. The engine may be a rocket engine, where the fuel and oxidizer
2.
V-2 rocket
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The V-2, technical name Aggregat 4, was the worlds first long-range guided ballistic missile. The V-2 rocket also became the first artificial object to cross the boundary of space with the launch of MW18014 on 20 June 1944. Research into military use of long range rockets began when the studies of graduate student Wernher von Braun attracted the attention of the German Army, a series of prototypes culminated in the A-4, which went to war as the V-2. Beginning in September 1944, over 3,000 V-2s were launched by the German Wehrmacht against Allied targets during the war, first London and later Antwerp and Liège. As Germany collapsed, teams from the Allied forces—the United States, the United Kingdom, Wernher von Braun and over 100 key V-2 personnel surrendered to the Americans. Eventually, many of the original V-2 team ended up working at the Redstone Arsenal, the US also captured enough V-2 hardware to build approximately 80 of the missiles. The Soviets gained possession of the V-2 manufacturing facilities after the war, re-established V-2 production, in the late 1920s, a young Wernher von Braun bought a copy of Hermann Oberths book, Die Rakete zu den Planetenräumen. Starting in 1930, he attended the Technical University of Berlin, von Braun was working on his doctorate when the Nazi Party gained power in Germany. An artillery captain, Walter Dornberger, arranged an Ordnance Department research grant for von Braun, von Brauns thesis, Construction, Theoretical, and Experimental Solution to the Problem of the Liquid Propellant Rocket, was kept classified by the German Army and was not published until 1960. By the end of 1934, his group had launched two rockets that reached heights of 2.2 and 3.5 km. At the time, Germany was highly interested in American physicist Robert H. Goddards research, before 1939, German engineers and scientists occasionally contacted Goddard directly with technical questions. Von Braun used Goddards plans from various journals and incorporated them into the building of the Aggregat series of rockets, during 28–30 September 1939, Der Tag der Weisheit conference met at Peenemünde to initiate the funding of university research to solve rocket problems. By late 1941, the Army Research Center at Peenemünde possessed the essential to the success of the A-4. The four key technologies for the A-4 were large liquid-fuel rocket engines, supersonic aerodynamics, gyroscopic guidance, at the time, Adolf Hitler was not particularly impressed by the V-2, he pointed out that it was merely an artillery shell with a longer range and much higher cost. Hitler was sufficiently impressed by the enthusiasm of its developers, and needed a weapon to maintain German morale. The V-2s were constructed at the Mittelwerk site by prisoners from Mittelbau-Dora, the A-4 used a 74% ethanol/water mixture for fuel and liquid oxygen for oxidizer. The rocket reached a height of 80 km after shutting off the engine, the fuel and oxidizer pumps were driven by a steam turbine, and the steam was produced by concentrated hydrogen peroxide with sodium permanganate catalyst. Both the alcohol and oxygen tanks were an aluminium-magnesium alloy, the combustion burner reached a temperature of 2,500 to 2,700 °C
3.
Rocketdyne J-2
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The J-2 was a liquid-fuel cryogenic rocket engine used on NASAs Saturn IB and Saturn V launch vehicles. Built in the U. S. by Rocketdyne, the J-2 burned cryogenic liquid hydrogen and liquid oxygen propellants, the engines preliminary design dates back to recommendations of the 1959 Silverstein Committee. Rocketdyne won approval to develop the J-2 in June 1960 and the first flight, AS-201, the engine produced a specific impulse of 421 seconds in a vacuum and had a mass of approximately 1,788 kilograms. Five J-2 engines were used on the Saturn Vs S-II second stage, proposals also existed to use various numbers of J-2 engines in the upper stages of an even larger rocket, the planned Nova. The J-2 was Americas largest production LH2-fuelled rocket engine before the RS-25 Space Shuttle Main Engine, a modernized version of the engine, the J-2X, was considered for use on the Earth Departure Stage of NASAs Space Shuttle replacement, the Space Launch System. Unlike most liquid-fueled rocket engines in service at the time, the J-2 was designed to be restarted once after shutdown when flown on the Saturn V S-IVB third stage, the first burn, lasting about two minutes, placed the Apollo spacecraft into a low Earth parking orbit. After the crew verified that the spacecraft was operating nominally, the J-2 was re-ignited for translunar injection, the thrust chamber was constructed of 0.30 millimetres thick stainless steel tubes, stacked longitudinally and furnace-brazed to form a single unit. The chamber was bell-shaped with a 27.5,1 expansion area ratio for efficient operation at altitude, fuel entered from a manifold, located midway between the thrust chamber throat and the exit, at a pressure of more than 6,900 kPa. In cooling the chamber, the made a one-half pass downward through 180 tubes and was returned in a full pass up to the thrust chamber injector through 360 tubes. Once propellants passed through the injector, they were ignited by the spark igniter. The thrust chamber injector received the propellants under pressure from the turbopumps,614 hollow oxidizer posts were machined to form an integral part of the injector, with fuel nozzles threaded through and installed over the oxidizer posts in concentric rings. The injector face was porous, being formed from layers of steel wire mesh. The propellants were injected uniformly to ensure satisfactory combustion, the injector and oxidizer dome assembly was located at the top of the thrust chamber. The dome provided a manifold for the distribution of the LOX to the injector and served as a mount for the gimbal bearing, the augmented spark igniter was mounted to the injector face and provided the flame to ignite the propellants in the combustion chamber. When engine start was initiated, the spark exciters energized two spark plugs mounted in the side of the combustion chamber, simultaneously, the control system started the initial flow of oxidizer and fuel to the spark igniter. As the oxidizer and fuel entered the chamber of the ASI, they mixed and were ignited. The ASI operated continuously during entire engine firing, was uncooled, thrust was transmitted through the gimbal, which consisted of a compact, highly loaded universal joint consisting of a spherical, socket-type bearing. This was covered with a Teflon/fiberglass coating that provided a dry, the propellant feed system consists of separate fuel and oxidizer turbopumps, several valves, fuel and oxidizer flowmeters, and interconnecting lines
4.
RL10
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The RL10 is a liquid-fuel cryogenic rocket engine used on the Centaur, S-IV and DCSS upper stages. Several versions of the engine have been flown, with two, the RL10A-4-2 and the RL10B-2, still being produced and flown on the Atlas V and Delta IV. The engine produces a specific impulse of 373 to 470 s in a vacuum and has a mass ranging from 131 to 317 kg, the RL10 was first tested on the ground in 1959, at Pratt and Whitneys Florida Research and Development Center in West Palm Beach, Florida. It was first flown in 1962 in a suborbital test. For that launch, two RL10A-3 engines powered the Centaur upper stage of an Atlas launch vehicle, the launch was used to conduct a heavily instrumented performance and structural integrity test of the vehicle. The RL10 was designed for the USAF from the beginning as a motor for the Lunex lunar lander. The RL10 has been upgraded over the years, one current model, the RL10B-2, powers the Delta IV second stage. It has been modified from the original RL10 to improve performance. Some of the include a extendable nozzle and electro-mechanical gimbaling for reduced weight. Current specific impulse is 464 seconds, a flaw in the brazing of an RL10B-2 combustion chamber was identified as the cause of failure for the May 4,1999, Delta III launch carrying the Orion-3 communications satellite. Four modified RL10A-5 engines, all of them with the ability to be throttled, were used in the McDonnell Douglas DC-X, up to seven RL10 engines would be used in the proposed Jupiter Upper Stage, serving an equivalent role to the Ares V Earth Departure Stage. The Common Extensible Cryogenic Engine is a testbed to develop RL10 engines that throttle well, NASA has contracted with Pratt & Whitney Rocketdyne to develop the CECE demonstrator engine. In 2007 its operability was demonstrated at 11-to-1 throttle ratios, in 2009 NASA reported successfully throttling from 104 percent thrust to eight percent thrust, a record for an engine of this type. Chugging was eliminated by injector and propellant feed system modifications that control the pressure, temperature, additional missions could include the provision of the high-energy technical capacity for the cleanup of space debris. We know the list price on an RL10, thats what this study will figure out, is it worthwhile to build an RL10 replacement. While NASA frequently uses EELVs to launch large payloads, the programmes administration is largely run through other channels. An RL10 is on display at the New England Air Museum, Windsor Locks, Connecticut An RL10 is on display at the Museum of Science and Industry, Chicago, spacecraft propulsion RL60 RD-0146 XCOR/ULA aluminum alloy nozzle engine, under development in 2011 Notes Bibliography Connors, Jack. The Engines of Pratt & Whitney, A Technical History, virginia, American Institute of Aeronautics and Astronautics
5.
Space Shuttle main engine
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Built in the United States by Rocketdyne, the RS-25 burns cryogenic liquid hydrogen and liquid oxygen propellants, with each engine producing 1,859 kN of thrust at liftoff. Although the RS-25 can trace its heritage back to the 1960s, concerted development of the began in the 1970s, with the first flight, STS-1. The RS-25 has undergone several upgrades over its history to improve the engines reliability, safety. The RS-25 operates at temperatures ranging from −253 °C to 3300 °C, the Space Shuttle used a cluster of three RS-25 engines mounted in the aft structure of the orbiter, with fuel being drawn from the external tank. Following each flight, the engines were removed from the orbiter, the RS-25 engine consists of various pumps, valves and other components which work in concert to produce thrust. Once in the MPS lines, the fuel and oxidizer each branch out into separate paths to each engine, in each branch, prevalves then allow the propellants to enter the engine. Once in the engine, the flow through low-pressure fuel and oxidizer turbopumps. From these HPTPs the propellants take different routes through the engine, meanwhile, fuel flows through the main fuel valve into regenerative cooling systems for the nozzle and MCC, or through the chamber coolant valve. Fuel passing through the MCC cooling system then passes back through the LPFTP turbine before being routed either to the tank pressurization system or to the hot gas manifold cooling system. Once in the injectors, the propellants are mixed and injected into the combustion chamber where they are ignited. The burning propellant mixture is ejected through the throat and bell of the engines nozzle. It boosts the liquid oxygens pressure from 0.7 to 2.9 MPa, during engine operation, the pressure boost permits the high-pressure oxidizer turbine to operate at high speeds without cavitating. The LPOTP, which measures approximately 450 by 450 mm, is connected to the vehicle propellant ducting, the HPOTP consists of two single-stage centrifugal pumps mounted on a common shaft and driven by a two-stage, hot-gas turbine. The main pump boosts the liquid oxygens pressure from 2.9 to 30 MPa while operating at approximately 28,120 rpm, the HPOTP discharge flow splits into several paths, one of which drives the LPOTP turbine. Another path is to, and through, the oxidizer valve. Another small flow path is tapped off and sent to the heat exchanger. The gas is sent to a manifold and then routed to pressurize the liquid oxygen tank, another path enters the HPOTP second-stage preburner pump to boost the liquid oxygens pressure from 30 to 51 MPa. It passes through the oxidizer preburner oxidizer valve into the oxidizer preburner, the HPOTP measures approximately 600 by 900 mm
6.
Liquid hydrogen
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Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form, one common method of obtaining liquid hydrogen involves a compressor resembling a jet engine in both appearance and principle. Liquid hydrogen is used as a concentrated form of hydrogen storage. As in any gas, storing it as liquid takes less space than storing it as a gas at temperature and pressure. However, the density is very low compared to other common fuels. Once liquefied, it can be maintained as a liquid in pressurized, liquid hydrogen consists of 99. 79% parahydrogen,0. 21% orthohydrogen. In 1885 Zygmunt Florenty Wróblewski published hydrogens critical temperature as 33 K, critical pressure,13.3 atmospheres, hydrogen was liquefied by James Dewar in 1898 by using regenerative cooling and his invention, the vacuum flask. The first synthesis of the stable form of liquid hydrogen, parahydrogen, was achieved by Paul Harteck. Room–temperature hydrogen consists mostly of the orthohydrogen form, practical H2–O2 rocket engines run fuel-rich so that the exhaust contains some unburned hydrogen. This reduces combustion chamber and nozzle erosion and it also reduces the molecular weight of the exhaust which can actually increase specific impulse despite the incomplete combustion. Liquid hydrogen can be used as the fuel for an internal combustion engine or fuel cell, various submarines and concept hydrogen vehicles have been built using this form of hydrogen. Due to its similarity, builders can sometimes modify and share equipment with systems designed for LNG, however, because of the lower volumetric energy, the hydrogen volumes needed for combustion are large. Unless LH2 is injected instead of gas, hydrogen-fueled piston engines usually require larger fuel systems, unless direct injection is used, a severe gas-displacement effect also hampers maximum breathing and increases pumping losses. Liquid hydrogen is used to cool neutrons to be used in neutron scattering. Since neutrons and hydrogen nuclei have similar masses, kinetic energy exchange per interaction is maximum, finally, superheated liquid hydrogen was used in many bubble chamber experiments. The first thermonuclear bomb, Ivy Mike, used liquid deuterium, the product of its combustion with oxygen alone is water vapor, which can be cooled with some of the liquid hydrogen. Since water is harmless to the environment, an engine burning it can be considered zero emissions, liquid hydrogen also has a much higher specific energy than gasoline, natural gas, or diesel. The density of hydrogen is only 70.99 g/L
7.
Rocket engine
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A rocket engine is a type of jet engine that uses only stored rocket propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines, obtaining thrust in accordance with Newtons third law, most rocket engines are internal combustion engines, although non-combusting forms also exist. Vehicles propelled by rocket engines are commonly called rockets, since they need no external material to form their jet, rocket engines can perform in a vacuum and thus can be used to propel spacecraft and ballistic missiles. Compared to other types of jet engines, rocket engines have the highest thrust, are by far the lightest, the ideal exhaust is hydrogen, the lightest of all gases, but chemical rockets produce a mix of heavier species, reducing the exhaust velocity. Rocket engines become more efficient at high velocities, since they do not require an atmosphere, they are well suited for uses at very high altitude and in space. Here, rocket is used as an abbreviation for rocket engine, chemical rockets are powered by exothermic chemical reactions of the propellant. Thermal rockets use a propellant, heated by a power source such as electric or nuclear power. Solid-fuel rockets are chemical rockets which use propellant in a solid state, liquid-propellant rockets use one or more liquid propellants fed from tanks. Hybrid rockets use a propellant in the combustion chamber, to which a second liquid or gas oxidiser or propellant is added to permit combustion. Monopropellant rockets use a single propellant decomposed by a catalyst, the most common monopropellants are hydrazine and hydrogen peroxide. Rocket engines produce thrust by the expulsion of an exhaust fluid which has accelerated to a high speed through a propelling nozzle. The fluid is usually a gas created by high pressure combustion of solid or liquid propellants, consisting of fuel and oxidiser components, within a combustion chamber. The nozzle uses the energy released by expansion of the gas to accelerate the exhaust to very high speed. An alternative to combustion is the rocket, which uses water pressurised by compressed air, carbon dioxide, nitrogen, or manual pumping. Chemical rocket propellants are most commonly used, which undergo exothermic chemical reactions which produce hot gas which is used by a rocket for propulsive purposes. Alternatively, a chemically inert reaction mass can be heated using a power source via a heat exchanger. Solid rocket propellants are prepared as a mixture of fuel and oxidising components called grain, liquid-fuelled rockets force separate fuel and oxidiser components into the combustion chamber, where they mix and burn. Hybrid rocket engines use a combination of solid and liquid or gaseous propellants, both liquid and hybrid rockets use injectors to introduce the propellant into the chamber
8.
Vulcain
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Vulcain is a family of European first stage rocket engines for the Ariane 5. Its development began in 1988 and the first flight was completed in 1996, the updated version of the engine – Vulcain 2 was first successfully flown in 2005. Both members of the family use liquid oxygen/liquid hydrogen cryogenic fuel, as of 2012 no new version of the engine is in development. The development of Vulcain, carried out by a European partnership and it first flew in 1996 powering the ill-fated flight 501 without being the cause of the disaster, and had its first successful flight in 1997. In 2002 the upgraded Vulcain 2 with 20% more thrust first flew on flight 517, the cause was due to flight loads being much higher than expected, as the inquiry board concluded. The first successful flight of the Vulcain 2 occurred in 2005 on flight 521, although different upgrades to the engine have been proposed, there is no current program to develop an uprated version of the engine. If there will ever be one, it is likely that the new engine would be introduced after the PA batch of 30 Ariane 5 ECAs ordered on 10 May 2004 will be expended. On 17 June 2007 Volvo Aero announced that in spring of 2008 it expected to hot-fire test a Vulcain 2 nozzle manufactured with a new sandwich technology, the Vulcain engines are gas-generator cycle cryogenic rocket engines fed with liquid oxygen and liquid hydrogen. The engine operating time is 600 s in both configurations,3 m tall and 1.76 m in diameter, the engine weighs 1686 kg and provides 137 t of thrust in its latest version. The oxygen turbopump rotates at 13600 rpm with a power of 3 MW while the hydrogen turbopump rotates at 34000 rpm with 12 MW of power, the total mass flow rate is 235 kg/s, of which 41.2 kg/s are of hydrogen. The main contractor for the Vulcain engines is Snecma Moteurs, which provides the liquid hydrogen turbopump. The liquid oxygen turbopump is the responsibility of Avio, and the gas turbines power the turbopumps. – Volvo Aero Development of the turbines for the Vulcain 2 turbopumps, – Volvo Aero High cycle fatigue of Vulcain 2 LOx turbine blades. – Volvo Aero An efficient concept design process, – Volvo Aero Vulcain 2 nozzle. – Volvo Aero EADS N. V. – EADS welcomes contract signature for 30 Ariane 5 launchers at ILA2004 in Berlin Three billion Euros contract for 30 Ariane 5 launchers – EADS Astrium
9.
Launch vehicle
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In spaceflight, a launch vehicle or carrier rocket is a rocket used to carry a payload from Earths surface into outer space. A launch system includes the launch vehicle, the launch pad, Earth orbital launch vehicles typically have at least two stages, and sometimes as many as four or more. Expendable launch vehicles are designed for one-time use and they usually separate from their payload and disintegrate during atmospheric reentry. In contrast, reusable vehicles are designed to be recovered intact. The Space Shuttle was a part of a vehicle with components used for multiple orbital spaceflights. SpaceX has developed a rocket launching system to successfully bring back a part—the first stage—of their Falcon 9 and launch it again. A fully reusable VTVL design is planned for all parts of the ITS launch vehicle, Launch vehicles are often classified by the amount of mass they can carry into orbit. For example, a Proton rocket can lift 22,000 kilograms into low Earth orbit, Launch vehicles are also characterized by their number of stages. Rockets with as many as five stages have been successfully launched, additionally, launch vehicles are very often supplied with boosters supplying high early thrust, normally burning with other engines. Boosters allow the engines to be smaller, reducing the burnout mass of later stages to allow larger payloads. Other frequently reported characteristics of vehicles are the launching nation or space agency. For example, the European Space Agency is responsible for the Ariane V, many launch vehicles are considered part of a historical line of vehicles of same or similar name, e. g. the Atlas V is the latest Atlas rocket. A small-lift launch vehicle is capable of lifting up to 2,000 kg of payload into low Earth orbit, a medium-lift launch vehicle is capable of lifting 2,000 to 20,000 kg of payload into LEO. A heavy-lift launch vehicle is capable of lifting 20,000 to 50,000 kg of payload into LEO, a super-heavy lift vehicle is capable of lifting more than 50,000 kg of payload into LEO. It refers to its 1,500 kg to LEO Vega launch vehicle as light lift, sounding rockets have long been used for brief, inexpensive unmanned space and microgravity experiments. Current human-rated suborbital launch vehicles include SpaceShipOne and the upcoming SpaceShipTwo, minimizing air drag requires a reasonably high ballistic coefficient, a ratio of length to diameter greater than ten. This generally results in a vehicle that is at least 20 m long. Leaving the atmosphere as early on in the flight as possible provides a velocity loss due to air drag of around 300 m/s, Launch vehicles of sufficient size are capable of launching payloads smaller than their orbital capability, to the Moon or beyond
10.
Liquid oxygen
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Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is one of the physical forms of elemental oxygen. Liquid oxygen has a blue color and is strongly paramagnetic. Liquid oxygen has a density of 1.141 g/cm3 and is cryogenic with a point of 54.36 K. Because of its nature, liquid oxygen can cause the materials it touches to become extremely brittle. Liquid oxygen is also a powerful oxidizing agent, organic materials will burn rapidly and energetically in liquid oxygen. Further, if soaked in liquid oxygen, some such as coal briquettes, carbon black, etc. can detonate unpredictably from sources of ignition such as flames. Petrochemicals, including asphalt, often exhibit this behavior, the tetraoxygen molecule was first predicted in 1924 by Gilbert N. Lewis, who proposed it to explain why liquid oxygen defied Curies law. Modern computer simulations indicate that there are no stable O4 molecules in liquid oxygen, O2 molecules do tend to associate in pairs with antiparallel spins. Conversely, liquid nitrogen or liquid air can be oxygen-enriched by letting it stand in air, atmospheric oxygen dissolves in it. In commerce, liquid oxygen is classified as a gas and is widely used for industrial and medical purposes. Liquid oxygen is obtained from the oxygen found naturally in air by fractional distillation in an air separation plant. Liquid oxygen is a cryogenic liquid oxidizer propellant for spacecraft rocket applications, usually in combination with liquid hydrogen. Liquid oxygen is useful in this role because it creates a specific impulse. It was used in the very first rocket applications like the V2 missile and Redstone, R-7 Semyorka, Atlas boosters, many modern rockets use liquid oxygen, including the main engines on the now-retired Space Shuttle. U. S. Army has long recognized the importance of liquid oxygen. In 1985 it started a program of building its own facilities at all major consumption bases. By 1845, Michael Faraday had managed to liquefy most gases then known to exist, six gases, however, resisted every attempt at liquefaction and were known at the time as permanent gases. They were oxygen, hydrogen, nitrogen, carbon monoxide, methane, in 1877, Louis Paul Cailletet in France and Raoul Pictet in Switzerland succeeded in producing the first droplets of liquid air
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