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Viking (rocket Engine)
The Viking rocket engines were members of a series of bipropellant engines for the first and second stages of the Ariane 1 through Ariane 4 commercial launch vehicles, using storable, hypergolic propellants: dinitrogen tetroxide and UH 25, a mixture of 75% UDMH and 25% hydrazine (originally UDMH). The earliest versions, developed in 1965, had a sea-level thrust of about 190 kN. By 1971, the thrust had improved to 540 kN, with resulting engine named Viking 1 and adopted for the Ariane program. The engine first flown on the Ariane 1 rocket in 1979 was Viking 2, with thrust further improved to 611 kN. The version used on the Ariane 4 first stage, which used a cluster of four, had 667 kN thrust each. The second stage of Ariane used a single Viking. Over 1000 were built, and achieved a high level of reliability from early in the programme. The 144 Ariane 1 to 4 launchers used a total of 958 Viking engines. Only two engines led to a failure. The first failure (on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vikas (rocket Engine)
The Vikas (a portmanteau from initials of ''VIK''ram ''A''mbalal ''S''arabhai ) is a family of hypergolic liquid fuelled rocket engines conceptualized and designed by the Liquid Propulsion Systems Centre (LPSC) in the 1970s. The design was based on the licensed version of the Viking engine with the chemical pressurisation system. The early production Vikas engines used some imported French components which were later replaced by domestically produced equivalents. It is used in the Polar Satellite Launch Vehicle (PSLV), Geosynchronous Satellite Launch Vehicle (GSLV) and LVM3 for space launch use. Vikas engine is used to power the second stage of PSLV, boosters and second stage of GSLV Mark I and II and also the core stage of LVM3. The propellant loading for Vikas engine in PSLV, GSLV Mark I and II is 40 tons, while in LVM3 is 55 tons. History In 1974, Societe Europeenne de Propulsion agreed to transfer Viking engine technology in return for 100 man-years of engineering work fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulcain (rocket Engine)
Vulcain is a family of European first stage rocket engines for Ariane 5 and Ariane 6. 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. The new version for Ariane 6 is called Vulcain 2.1. History The Vulcain rocket engine is named in French for Vulcan, the ancient Roman god of fire. Its development, carried out by a European partnership, began in 1988 with the Ariane 5 rocket program. 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 (flight 502). In 2002 the upgraded Vulcain 2 with 20% more thrust first flew on flight 157, although a problem with the engine turned the flight into a failure. The cause was due to flight loads being much higher than expected, as the inquiry board concluded. Subsequentl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinitrogen Tetroxide
Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russian rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium mixture with nitrogen dioxide. Its molar mass is 92.011 g/mol. Dinitrogen tetroxide is a powerful oxidizer that is hypergolic (spontaneously reacts) upon contact with various forms of hydrazine, which has made the pair a common bipropellant for rockets. Structure and properties Dinitrogen tetroxide could be regarded as two nitro groups (-NO2) bonded together. It forms an equilibrium mixture with nitrogen dioxide. The molecule is planar with an N-N bond distance of 1.78Å and N-O distances of 1.19Å. The N-N distance corresponds to a weak bond, since it is significantly longer than the average N-N single bond length of 1.45Å. This exceptionally weak σ bond (amounting to overlapping of the ''sp''2 hybrid orbitals of the two NO2 uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UDMH
Unsymmetrical dimethylhydrazine (abbreviated as UDMH; also known as 1,1-dimethylhydrazine, heptyl or Geptil) is a chemical compound with the formula H2NN(CH3)2 that is primarily used as a rocket propellant. At room temperature, UDMH is a colorless liquid, with a sharp, fishy, ammonia-like smell typical of organic amines. Samples turn yellowish on exposure to air and absorb oxygen and carbon dioxide. It is miscible with water, ethanol, and kerosene. At concentrations between 2.5% and 95% in air, its vapors are flammable. It is not sensitive to shock. Symmetrical dimethylhydrazine (1,2-dimethylhydrazine) also exists, but it is not as useful. UDMH can be oxidized in air to form many different substances, including toxic ones. Synthesis In 1875, UDMH was first prepared by Emil Fischer, who discovered and named the class of hydrazines, by reducing N-Nitrosodimethylamine with zinc in boiling acetic acid. Fischer's student Edward Renouf later studied UDMH more extensively as part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UH 25
UH 25 is a fuel mixture for rockets. It was developed for the European Ariane 2–4 launch vehicles. UH 25 was developed after a disaster during flight 2 of the Ariane 1 rocket. During launch, one of the four Viking engines on the first stage developed a combustion instability which led to an engine fire, subsequent explosion and destruction of the vehicle. Following this event and starting with Ariane 2, the fuel was changed from pure UDMH to the mixture UH 25. UH 25 was used in Ariane rocket versions 2 through 4, and in the Indian GSLV Mk III. UH 25 is a mixture of 75% UDMH and 25% hydrazine hydrate.Tim Furniss: ''Ingenieure bei der Arbeit, Raumschiffe und Raketen'', Tessloff Verlag, Nürnberg (1989), Seite: 31 (German) It is hypergolic with dinitrogen tetroxide as oxidizer, and both can be stored as liquids at room temperature. Danger Like its components, UH 25 is flammable, toxic (carcinogenic) and corrosive. Safety labels See also * Aerozine 50 - a 50:50 mix of hydraz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas-generator Cycle
The gas-generator cycle, also referred to as the GG cycle or colloquially as an open cycle, is one of the most commonly used power cycles in bipropellant liquid rocket engines. Propellant is burned in a gas generator (analogous to, but distinct from, a preburner in a staged combustion cycle) and the resulting hot gas is used to power the propellant pumps before being exhausted overboard and lost. Because of this loss, this type of engine is considered an open cycle (note other open cycles exist, e.g. the tap-off bleed cycle). The gas generator cycle exhaust products pass over the turbine's rotor(s) first. Then they are expelled overboard. They can be expelled directly from the turbine, or are sometimes expelled into the nozzle (downstream from the throat) for both a small gain in efficiency, and can serve as film cooling. An advantage of this cycle is the high pressure drop available to the turbine (GG chamber pressure down to ambient) for extracting work from the drive gas; at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariane 1
Ariane 1 () was the first rocket in the Ariane family of expendable launch systems. It was developed for and operated by the European Space Agency (ESA), which had been formed in 1973, the same year that development of the launcher had commenced. Aérospatiale was designated to lead the programme. Ariane 1 was the first launcher to be developed with the primary purpose of sending commercial satellites into geosynchronous orbit. Crucially, it was designed with the ability of sending a pair of satellites into orbit on a single launcher, thus reducing costs. As the size of satellites grew, Ariane 1 quickly gave way to the more powerful Ariane 2 and Ariane 3 launchers, which were heavily based upon the original rocket. The Ariane 4 was the last rocket to heavily draw upon the Ariane 1, as the successor rocket Ariane 5 uses a far greater proportion of all-new elements. Development Origins In 1975, ten European countries decided to pursue joint collaboration in the field of sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariane 4
The Ariane 4 was a European expendable rocket, expendable launch vehicle in the Ariane (rocket family), Ariane family, developed by the (CNES), the Government of France, French space agency, for the European Space Agency (ESA). The manufacturing of the launch vehicle was led by Aérospatiale and it was marketed by Arianespace. Since its first flight on 15 June 1988 until the final flight on 15 February 2003, it attained 113 successful launches out of 116 total launches. In 1982, the Ariane 4 program was approved by ESA. Drawing heavily upon the preceding Ariane 3, it was designed to provide a launcher capable of delivering heavier payloads and at a lower cost per kilogram than the earlier members of the Ariane family. The Ariane 4 was principally an evolution of the existing technologies used, as opposed to being revolutionary in its design ethos; this approach quickly gained the backing of most ESA members, who funded and participated in its development and operation. Capable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipropellant Rocket
A liquid-propellant rocket or liquid rocket uses a rocket engine burning liquid propellants. (Alternate approaches use gaseous or solid propellants.) Liquids are desirable propellants because they have reasonably high density and their combustion products have high specific impulse (''I''sp). This allows the volume of the propellant tanks to be relatively low. Types Liquid rockets can be monopropellant rockets using a single type of propellant, or bipropellant rockets using two types of propellant. Tripropellant rockets using three types of propellant are rare. Liquid oxidizer propellants are also used in hybrid rockets, with some of the advantages of a solid rocket. Bipropellant liquid rockets use a liquid fuel such as liquid hydrogen or RP-1, and a liquid oxidizer such as liquid oxygen. The engine may be a cryogenic rocket engine, where the fuel and oxidizer, such as hydrogen and oxygen, are gases which have been liquefied at very low temperatures. Most designs of liq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypergolic
A hypergolic propellant is a rocket propellant combination used in a rocket engine, whose components spontaneously ignite when they come into contact with each other. The two propellant components usually consist of a fuel and an oxidizer. The main advantages of hypergolic propellants are that they can be stored as liquids at room temperature and that engines which are powered by them are easy to ignite reliably and repeatedly. Common hypergolic propellants are extremely toxic or corrosive, making them difficult to handle. In contemporary usage, the terms "hypergol" and "hypergolic propellant" usually mean the most common such propellant combination: dinitrogen tetroxide plus hydrazine. History The fact that turpentine may spontaneously combust when mixed with nitric acid was discovered as early as the late 17th century by Frederick Slare, but it remained a scientific curiosity for centuries until it was proposed to use it for rocket-assisted take off during WWII. In 1935, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinitrogen Tetroxide
Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russian rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium mixture with nitrogen dioxide. Its molar mass is 92.011 g/mol. Dinitrogen tetroxide is a powerful oxidizer that is hypergolic (spontaneously reacts) upon contact with various forms of hydrazine, which has made the pair a common bipropellant for rockets. Structure and properties Dinitrogen tetroxide could be regarded as two nitro groups (-NO2) bonded together. It forms an equilibrium mixture with nitrogen dioxide. The molecule is planar with an N-N bond distance of 1.78Å and N-O distances of 1.19Å. The N-N distance corresponds to a weak bond, since it is significantly longer than the average N-N single bond length of 1.45Å. This exceptionally weak σ bond (amounting to overlapping of the ''sp''2 hybrid orbitals of the two NO2 uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrazine
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydrazine hydrate (). Hydrazine is mainly used as a foaming agent in preparing Polymeric foam, polymer foams, but applications also include its uses as a precursor (chemistry), precursor to pharmaceuticals and agrochemicals, as well as a long-term storable propellant for in-outer space, space spacecraft propulsion. Additionally, hydrazine is used in various rocket propellant, rocket fuels and to prepare the gas precursors used in airbags. Hydrazine is used within both nuclear and conventional electrical power plant steam cycles as an oxygen scavenger to control concentrations of dissolved oxygen in an effort to reduce corrosion. , approximately 120,000 tons of hydrazine hydrate (corresponding to a 64% solution of hydrazine in water by weight) we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
