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Lockheed Martin A2100
The A2100 is a model of communications satellite spacecraft made by Lockheed Martin Space Systems. It is used as the foundation for telecommunications payloads in geosynchronous orbit, as well as GOES-R weather satellites and GPS Block IIIA satellites. Over 40 satellites use the A2100 bus. History The first satellite, AMC-1, was launched September 8, 1996, and has achieved 15-year on-orbit service life. Since 1996 there have been over 45 of the A2100 based satellites launched, with over 400 years of total on-orbit service. Other A2100 spacecraft include JCSAT-13 and VINASAT-2, which were launched May, 2012 on an Ariane 5 rocket, as well as Arabsat-6A and Hellas Sat 4/SaudiGeoSat-1 of Saudi Arabia's Arabsat-6G program. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacecraft Bus
A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus-derived satellites are usually customized to customer requirements, for example with specialized sensors or transponders, in order to achieve a specific mission. They are commonly used for geosynchronous satellites, particularly communications satellites, but are also used in spacecraft which occupy lower orbits, occasionally including low Earth orbit missions. Examples Some satellite bus examples include: * Boeing DS&S 702 * Lockheed Martin Space Systems A2100 * Alphabus * INVAP ARSAT-3K * Airbus D&S Eurostar * ISRO's I-1K, I-2K, I-3K, I-4K, I-6K, and Indian Mini Satellite bus * NASA Ames MCSB * SSL 1300 * Orbital ATK GEOStar * Mitsubishi Electric DS2000 * Spacecraft bus of the James Webb Space Telescope * SPUTNIX TabletSat * S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadcast
Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum ( radio waves), in a one-to-many model. Broadcasting began with AM radio, which came into popular use around 1920 with the spread of vacuum tube radio transmitters and receivers. Before this, all forms of electronic communication (early radio, telephone, and telegraph) were one-to-one, with the message intended for a single recipient. The term ''broadcasting'' evolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about. It was later adopted for describing the widespread distribution of information by printed materials or by telegraph. Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898. Over the air broadcasting is usually associated with radio and television, though more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipropellant Rocket
A liquid-propellant rocket or liquid rocket utilizes a rocket engine that uses liquid propellants. Liquids are desirable because they have a reasonably high density and high specific impulse (''I''sp). This allows the volume of the propellant tanks to be relatively low. It is also possible to use lightweight centrifugal turbopumps to pump the rocket propellant from the tanks into the combustion chamber, which means that the propellants can be kept under low pressure. This permits the use of low-mass propellant tanks that do not need to resist the high pressures needed to store significant amounts of gasses, resulting in a low mass ratio for the rocket. An inert gas stored in a tank at a high pressure is sometimes used instead of pumps in simpler small engines to force the propellants into the combustion chamber. These engines may have a higher mass ratio, but are usually more reliable, and are therefore used widely in satellites for orbit maintenance. Liquid rockets can be mono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LEROS
Leros ( el, Λέρος) is a Greek island and municipality in the Dodecanese in the southern Aegean Sea. It lies (171 nautical miles) from Athens's port of Piraeus, from which it can be reached by an 9-hour ferry ride or by a 45-minute flight from Athens, and about 20 miles to Turkey. Leros is part of the Kalymnos regional unit. The island has been also called in it, Lero. This island has population of 7,988 Geography The municipality has an area of . The municipality includes the populated offshore island of Farmakonisi (pop. 10), as well as several uninhabited islets, including Levitha and Kinaros, and had a 2011 census population of 7,917, although this figure swells to over 15,000 during the summer peak. The island has a coastline of . It is known for its imposing medieval castle of the Knights of Saint John possibly built on a Byzantine fortress. Nearby islands are Patmos, Lipsi, Kalymnos, and the small islands of Agia Kyriaki and Farmakos. In ancient times it was c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moog Inc
Moog ( ) is an American-based designer and manufacturer of electric, electro-hydraulic and hydraulic motion, controls and systems for applications in aerospace, defense, industrial and medical devices. The company operates under four segments: aircraft controls, space and defense controls, industrial controls, and components. Moog is headquartered in Elma, New York and has sales, engineering, and manufacturing facilities in twenty-six countries.Moog Historical Information . ''moog.com'', accessed December 29, 2007. History Bill Moog In April 1950 Bill Moog (cousin of , inventor of ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Thrusters
An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. It creates thrust by accelerating ions using electricity. An ion thruster ionizes a neutral gas by extracting some electrons out of atoms, creating a cloud of positive ions. Ion thrusters are categorized as either electrostatic or electromagnetic. Electrostatic thruster ions are accelerated by the Coulomb force along the electric field direction. Temporarily stored electrons are reinjected by a ''neutralizer'' in the cloud of ions after it has passed through the electrostatic grid, so the gas becomes neutral again and can freely disperse in space without any further electrical interaction with the thruster. By contrast, electromagnetic thruster ions are accelerated by the Lorentz force to accelerate all species (free electrons as well as positive and negative ions) in the same direction whatever their electric charge, and are specifically referred to as plasma propul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Tetroxide
Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russia 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 units) ... [...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 toxic unless handled in solution as, for example, hydrazine hydrate (). Hydrazine is mainly used as a foaming agent in preparing polymer foams, but applications also include its uses as a precursor to polymerization catalysts, pharmaceuticals, and agrochemicals, as well as a long-term storable propellant for in-space spacecraft propulsion. Additionally, hydrazine is used in various rocket fuels and to prepare the gas precursors used in air bags. 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. the world hydrazine hydrate market amounted to $350 million. About two million tons of hydrazine hydrate were used in foam blowing agents in 2015. Hydrazines r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monopropellant
Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with bipropellants that release energy through the chemical reaction between an oxidizer and a fuel. While stable under defined storage conditions, monopropellants decompose very rapidly under certain other conditions to produce a large volume of its own energetic (hot) gases for the performance of mechanical work. Although solid deflagrants such as nitrocellulose, the most commonly used propellant in firearms, could be thought of as monopropellants, the term is usually reserved for liquids in engineering literature. Uses The most common use of monopropellants is in low-impulse monopropellant rocket motors, such as reaction control thrusters, the usual propellant being hydrazine, p. 230 which is generally decomposed by exposure to an iridium, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Wheels
A reaction wheel (RW) is used primarily by spacecraft for three-axis attitude control, and does not require rockets or external applicators of torque. They provide a high pointing accuracy, and are particularly useful when the spacecraft must be rotated by very small amounts, such as keeping a telescope pointed at a star. A reaction wheel is sometimes operated as (and referred to as) a momentum wheel, by operating it at a constant (or near-constant) rotation speed, to provide a satellite with a large amount of stored angular momentum. Doing so alters the spacecraft's rotational dynamics so that disturbance torques perpendicular to one axis of the satellite (the axis parallel to the wheel's spin axis) do not result directly in spacecraft angular motion about the same axis as the disturbance torque; instead, they result in (generally smaller) angular motion (precession) of that spacecraft axis about a perpendicular axis. This has the effect of tending to stabilize that spacecraft ax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-band
The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventional boundary between the UHF and SHF bands at 3.0 GHz. The S band is used by airport surveillance radar for air traffic control, weather radar, surface ship radar, and some communications satellites, especially those used by NASA to communicate with the Space Shuttle and the International Space Station. The 10 cm radar short-band ranges roughly from 1.55 to 5.2 GHz. The S band also contains the 2.4–2.483 GHz ISM band, widely used for low power unlicensed microwave devices such as cordless phones, wireless headphones (Bluetooth), wireless networking (WiFi), garage door openers, keyless vehicle locks, baby monitors as well as for medical diathermy machines and microwave ovens (typically at 2.495 GHz). India's regio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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