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In spacecraft propulsion, a Hall-effect thruster (HET) is a type of ion thruster in which the propellant is accelerated by an electric field. Hall-effect thrusters trap electrons in a magnetic field and then use the electrons to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume. Hall-effect thrusters are sometimes referred to as Hall thrusters or Hall-current thrusters. Hall thrusters are often regarded as a moderate specific impulse (1,600 s) space propulsion technology. The Hall-effect thruster has benefited from considerable theoretical and experimental research since the 1960s. Hall thrusters operate on a variety of propellants, the most common being xenon. Other propellants of interest include krypton, argon, bismuth, iodine, magnesium, and zinc. Hall thrusters are able to accelerate their exhaust to speeds between 10 and 80 km/s (1,000–8,000 s specific impulse), with most models operating between 15 and 30 km/s (1,500–3,000 s specific impulse). The thrust produced by a Hall thruster varies depending on the power level. Devices operating at 1.35 kW produce about 83 mN of thrust. High-power models have demonstrated up to 3 N in the laboratory. Power levels up to 100 kW have been demonstrated by xenon Hall thrusters. , Hall-effect thrusters ranged in input power levels from 1.35 to 10 kilowatts and had exhaust velocities of 10–50 kilometers per second, with thrust of 40–600 millinewtons and efficiency in the range of 45–60 percent. The applications of Hall-effect thrusters include control of the orientation and position of orbiting satellites and use as a main propulsion engine for medium-size robotic space vehicles.〔 == History == Hall thrusters were studied independently in the United States and the Soviet Union. They were first described publicly in the US in the early 1960s. However, the Hall thruster was first developed into an efficient propulsion device in the Soviet Union. In the US, scientists focused instead on developing gridded ion thrusters. Two types of Hall thrusters were developed in the Soviet Union: *thrusters with wide acceleration zone, SPT ((ロシア語:''СПД'', ''стационарный плазменный двигатель''); (英語:''SPT''), ''Stationary Plasma Thruster'') at Design Bureau Fakel *thrusters with narrow acceleration zone, DAS (Russian: ''ДАС'', ''двигатель с анодным слоем''; English: ''TAL'', ''Thruster with Anode Layer''), at the Central Research Institute for Machine Building (TsNIIMASH). The SPT design was largely the work of A. I. Morozov. The first SPT to operate in space, an SPT-50 aboard a Soviet Meteor spacecraft, was launched December 1971. They were mainly used for satellite stabilization in North-South and in East-West directions. Since then until the late 1990s 118 SPT engines completed their mission and some 50 continued to be operated. Thrust of the first generation of SPT engines, SPT-50 and SPT-60 was 20 and 30 mN respectively. In 1982, SPT-70 and SPT-100 were introduced, their thrusts being 40 and 83 mN, respectively. In the post-Soviet Russia high-power (a few kilowatts) SPT-140, SPT-160, SPT-200, T-160 and low-power (less than 500 W) SPT-35 were introduced. Soviet and Russian TAL-type thrusters include the D-38, D-55, D-80, and D-100.〔 Soviet-built thrusters were introduced to the West in 1992 after a team of electric propulsion specialists from NASA's Jet Propulsion Laboratory, Glenn Research Center, and the Air Force Research Laboratory, under the support of the Ballistic Missile Defense Organization, visited Russian laboratories and experimentally evaluated the SPT-100 (i.e., a 100 mm diameter SPT thruster). Over 200 Hall thrusters have been flown on Soviet/Russian satellites in the past thirty years. No failures have ever occurred on orbit. Hall thruster continue to be used on Russian spacecraft and have also flown on European and American spacecraft. Space Systems/Loral, an American commercial satellite manufacturer, now flies Fakel SPT-100's on their GEO communications spacecraft. Since their introduction to the west in the early 1990s, Hall thrusters have been the subject of a large number of research efforts throughout the United States, France, Italy, Japan, and Russia (with many smaller efforts scattered in various countries across the globe). Hall thruster research in the US is conducted at several government laboratories, universities and private companies. Government and government funded centers include NASA's Jet Propulsion Laboratory, NASA's Glenn Research Center, the Air Force Research Laboratory (Edwards AFB, CA), and The Aerospace Corporation. Universities include the (US Air Force Institute of Technology ), University of Michigan, Stanford University, The Massachusetts Institute of Technology, Princeton University, Michigan Technological University, and Georgia Tech. A considerable amount of development is being conducted in industry, such as Aerojet and Busek in the USA, SNECMA in France and in Italy.〔(ALTA )〕 Also, TÜBITAK Space of Turkey has recently developed a Hall thruster prototype. Which will be further enhanced and used in satellites and possible future spacecrafts.〔(TÜBITAK Hale )〕〔(Plasmacongress )〕 The first use of Hall thrusters on lunar orbit was the European Space Agency (ESA) lunar mission SMART-1 in 2003. On a western satellite Hall thrusters were first demonstrated on the Naval Research Laboratory (NRL) STEX spacecraft, which flew the Russian D-55. The first American Hall thruster to fly in space was the Busek BHT-200 on TacSat-2 technology demonstration spacecraft. The first flight of an American Hall thruster on an operational mission, was the Aerojet BPT-4000, which launched August 2010 on the military Advanced Extremely High Frequency GEO communications satellite. At 4.5 kW, the BPT-4000 is also the highest power Hall thruster ever flown in space. Besides the usual stationkeeping tasks, the BPT-4000 is also providing orbit raising capability to the spacecraft. Several countries worldwide continue efforts to qualify Hall thruster technology for commercial uses. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hall-effect thruster」の詳細全文を読む スポンサード リンク
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