In spacecraft propulsion, a Hall thruster is a type of ion thruster in which the propellant is accelerated by an electric field. Hall 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 thrusters are sometimes referred to as Hall Effect Thrusters or Hall Current Thrusters.
Hall thrusters operate on a variety of propellants, the most common being xenon. Other propellants of interest include krypton, argon, bismuth, magnesium, and zinc.
Hall thrusters are able to accelerate their exhaust to speeds between 10–80 km/s (1000-8000 s specific impulse), with most models operating between 15–30 km/s (1500-3000 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 thrusters were studied independently in the US and the USSR in the 1950s and 1960s. However, the Hall thruster was only developed into an efficient propulsion device in the former Soviet Union, whereas in the US, scientists focused instead on developing gridded ion thrusters.
Two types of Hall thrusters were developed in the Soviet Union:
The common SPT design was largely the work of A. I. Morozov. The first SPT to operate in space, an SPT-50 launched on the 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.
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