Field Emission Electric Propulsion (FEEP) is an advanced electrostatic propulsion concept, a form of ion thruster, that uses liquid metal (usually either cesium or indium) as a propellant. A FEEP device consists of an emitter and an accelerator electrode. A potential difference on the order of 10 kV is applied between the two, which generates a strong electric field at the tip of the metal surface. The field extracts ions, which then are accelerated to high velocities, typically more than 100 km/s. A separate electron source is required to keep the spacecraft electrically neutral. This article or section does not cite its references or sources. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... General Name, Symbol, Number Caesium, Cs, 55 Series Alkali metals Group, Period, Block 1(IA), 6, s Density, Hardness 1879 kg/m3, 0. ... General Name, Symbol, Number indium, In, 49 Chemical series poor metals Group, Period, Block 13, 5, p Appearance silvery lustrous gray Atomic mass 114. ... In physics, an electric field or E-field is an effect produced by an electric charge (or a time-varying magnetic field) that exerts a force on charged objects in the field. ...

Due to its very low thrust (in the micronewton to millinewton range), FEEPs are primarily used for microradian, micronewton attitude control on spacecraft. The newton (symbol: N) is the SI unit of force. ... In the context of spacecraft, attitude control is control of the angular position and rotation of the spacecraft, either relative to the object that it is orbiting, or relative to the celestial sphere. ... A spacecraft is designed to leave Earths atmosphere and operate beyond the surface of the Earth in outer space. ...

See also

• Spacecraft propulsion
• Magnetic sail
  • Ion thruster
    • Electrostatic ion thruster
    • Hall effect thruster
    • Field Emission Electric Propulsion
    • Pulsed inductive thruster

A remote camera captures a close-up view of a Space Shuttle Main Engine during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi Spacecraft propulsion is used to change the velocity of spacecraft and artificial satellites, or in short, to provide delta-v. ... A magnetic sail or magsail is a proposed method of spacecraft propulsion. ... This article or section does not cite its references or sources. ... The electrostatic ion thruster is a kind of design for ion thrusters (a kind of highly-efficient low-thrust spacecraft propulsion running on electrical power). ... 2 kW Laboratory Hall Thruster in operation at the Princeton Plasma Physics Laboratory A Hall effect thruster is a type of ion thruster in which the propellant is accelerated by an electric field in a plasma discharge with a radial magnetic field. ... Pulsed inductive thrusters or PITs as they are commonly abbreviated are a form of spacecraft propulsion that uses perpendicular electric and magnetic fields to accelerate a propellant. ...

External links

• FEEP thrusters at the University of Michigan
• FEEP thrusters at islandone.org