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Topic: Field Emission Electric Propulsion

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	Field Emission Electric Propulsion - Wikipedia, the free encyclopedia
		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.
	en.wikipedia.org /wiki/Field_Emission_Electric_Propulsion (158 words)

	electric space propulsion
		The source of the electrical energy for EP is independent of the propellant itself and may be solar (see solar-electric propulsion) or nuclear (see nuclear-electric propulsion).
		Of these various types of electric propulsion, several are technologically mature enough to be used on spacecraft, including: the electron bombardment thruster (particularly the xenon ion thruster), the Hall effect thruster, the arcjet, the pulsed plasma thruster, and the resistojet.
		A crucial contribution to the theory of electric propulsion came in March 1949 with the publication in the Journal of the British Interplanetary Journal of the fourth installment in a series of articles titled "The Atomic Rocket" by L. Shepard and A. Cleaver.
	www.daviddarling.info /encyclopedia/E/electricprop.html (2307 words)

	Field Emission Electric Propulsion (FEEP) and Colloid thrusters (Site not responding. Last check: 2007-09-20)
		FEEP and colloid thrusters are particularly suitable for missions requiring thrusts in the sub-millinewton level with precise control abilities.
		Field Emission Electric Propulsion Capillary [1] and Needle [2] Thrusters
		Under a strong electric field generated by the application of a voltage difference between the emitter and an accelerator electrode located directly in front of it, the free surface of the liquid metal approaches a condition of local instability, due to the combined effects of the electrostatic force and the surface tension.
	hpcc.engin.umich.edu /CFD/research/NGPD/ElectricPropulsion/feep (945 words)

	Ion thruster - Wikipedia, the free encyclopedia
		An ion thruster (or ion drive), one of several types of spacecraft propulsion, uses beams of ions — electrically charged atoms or molecules— for propulsion.
		Large ion propulsion engines require large and massive electric power sources.
		Of all the electric thrusters, ion thrusters have been the most seriously considered commercially and academically in the quest for interplanetary missions and orbit raising maneuvers.
	en.wikipedia.org /wiki/Solar_electric_propulsion (1192 words)

	PERMANENT - Transportation - Electric Propulsion
		Many studies into future large scale space industrialization base all interorbital propulsion on reusable electric propulsion vehicles, with chemical rockets being used only to launch material from Earth's surface to low Earth orbit, and from the lunar surface to lunar orbit, where the cargo is transferred to an electric propulsion vehicle for interorbital transport.
		However, some very conservative "immediate term" studies assume all interorbital propulsion is based on today's chemical rockets, e.g., with oxygen and hydrogen extracted from asteroids or the Moon being used to refill the fuel tanks of the chemical rockets, which means no use of electric propulsion.
		Ion drive thrusters use an electric field to accelerate charged atoms or molecules (e.g., oxygen) to a high velocity as they are expelled out the thrust chamber, thus accelerating the spacecraft.
	www.permanent.com /t-el-iov.htm (3233 words)

	DIA - Research Area
		Current research in chemical propulsion are concerned with high-power density turbopumps for liquid propellant rockets, cavitation and two-phase flow dynamics and simulation, hypersonic aerothermodynamics and high-speed turbulent and compressible flows, modeling and numerical studies of the unsteady ballistics of solid propellant rocket motors.
		FEEP activities are concentrated on the development and flight testing of 50 to 1000 µN thrusters, which represent one of the most promising propulsion technologies recently developed in Europe.
		Chemical propulsion activities include the simulation of ignition transients of solid propellant rockets and the development of flow models for the assessment of the risk of combustion instabilities induced by vortex shedding from the intersegments.
	www.ing.unipi.it /~dia/research/propulsion.htm (1342 words)

	Electric Rocket Engines
		Electric rocket engines use less fuel than chemical engines and therefore hold the potential for accomplishing missions that are impossible for chemical systems.
		MPD thrusters are unique among the electric rocket engine fraternity because they are capable of producing thrusts as high as 50 pounds in an engine small enough to fix in a large shoe box.
		The interplay of this magnetic field and the electric field between the anode propellant injectors and the electron cloud created outside of the thruster causes a current (called the Hall current) to be induced to flow azimuthally around the open annulus in the thruster.
	www.waynesthisandthat.com /ep2.htm (4488 words)

	Glossary
		Field The region in which a particular type of force can be observed; depending on the force, one can thus speak of a gravity field, magnetic field, electric field (or when the two are linked by fast oscillations, electromagnetic field) and nuclear field.
		Field line preservation A property of an ideal plasma, well approximated in real plasmas, characterizing the way the flow of plasma may deform the magnetic field in which it is embedded.
		Electric charge is sprayed onto a rubber band, which carries it into the inside of a metal sphere, insulated from the ground, where it is picked up and added to the charge already on the sphere.
	www-spof.gsfc.nasa.gov /stargaze/Sgloss.htm (14613 words)

	Electric Vehicles
		Electric drive vehicles (EDVs) are one way of reducing vehicle emissions that contribute two-thirds of all air pollution in most cities.
		An electric vehicle is a motor vehicle, such as an automobile, truck, or bus, which uses a rechargeable battery for fuel, replacing gasoline, diesel or other types of combustible fuels.
		The ultimate goal of the hybrid electric vehicle is to provide the equivalent power, range, cost and safety of a conventional vehicle while reducing fuel costs and harmful emissions.
	www.pge.com /about_us/environment/electric_vehicles (1765 words)

	Space Electric Propulsion (Site not responding. Last check: 2007-09-20)
		Electric Propulsion (EP): The acceleration of gases for the purpose of producing propulsive thrust by electric heating, electric body forces, and/or electric and magnetic body forces.
		Unlike chemical propulsion, which relies on the stored internal energy in the molecular bonds of its propellant, in electric propulsion the energy is obtained from an external power source.
		In chemical propulsion, the dependence on internal energy limits the maximum specific impulse to about 450 s, whereas in electric propulsion specific impulses of over 17,000 s have been obtained in the laboratory [2, 3].
	richard.hofer.com /electric_propulsion.html (1414 words)

	[No title]
		The electricity is used to ionize and electrostatically accelerate the propellant.
		Electricity ionizes and accelerates atoms in engine.J 49c Laser-Electric Ion Laser tuned to optimum absorption wavelength of photovoltaic cells.
		Electricity is used to ionize propellant and accelerate it by electrostatic voltage.
	traveller.mu.org /house/eder_transport_list.txt (8218 words)

	Science
		According to this principle, the physical laws in a reference frame falling in free fall in a gravitational field are equivalent to the physical laws in an inertial reference frame.
		Those are described according to a quantum model of theory of the fields, the Standard Model of the physics of the particles, whereas the gravitation is described by a classical theory (in opposition to quantum), the General Relativity, which connects the geometry of the space-time to the density of matter-energy that it contains.
		The orbital motions of two test-masses falling in the Earth gravity field and composed of two different materials are controlled to remain perfectly identical, thus guaranteeing that both test-masses are submitted exactly to the same gravitational field.
	smsc.cnes.fr /MICROSCOPE/GP_science.htm (639 words)

	The FEEP Principle (Site not responding. Last check: 2007-09-20)
		While attractive under the mass consumption point of view, FEEP was eventually judged not competitive with respect to other electric propulsion concepts (ion thrusters and arcjets), mainly because of its high specific power (about 60 mW/µN), and was almost abandoned at the end of the 80's.
		FEEP was soon recognized as the only existing thruster capable of accurate thrust modulation at micronewton level.
		Centrospazio is presently in charge of the development of FEEP under ESA and ASI funding, while LABEN (Milan, Italy) is currently developing the thruster power and control electronics.
	www.centrospazio.cpr.it /FEEPPrinciple.html (534 words)

	Field Propulsion
		The radiant pressure model suggests that the isotropic radiant energy flows may be focused, diverted or transformed in frequency with existing electrical and mechanical technology to utilize the forces called gravity and inertia.
		Electrical Induction: The mechanical force and multi-megawatts of power within a transformer and motor are not transferred from the winding to the iron and copper but from the winding to space and from space to the iron and secondary windings.
		The electric energy we are supplying is only establishing the conditions for the transformation.
	home.netcom.com /~sbyers11/grav11k.htm (2327 words)

	DST - Precision Thrusters
		The ions are then extracted from the discharge chamber via a set of electrostatic grids and accelerated in an electrostatic field to very high velocities of approx.
		ion thruster was used as the main propulsion device to fly a spacecraft past the comet “Borrelly”.
		State of the art ion thruster technology, such as the DS1 thruster, is relatively large, and scaled for main propulsion applications, i.e.
	dst.jpl.nasa.gov /thrusters/index.htm (924 words)

	[8.04] Electric Propulsion System for Constellation Deployment and Orbit Control of Minisats (Site not responding. Last check: 2007-09-20)
		The present paper, which is an up-to-date version of the one presented at IAF-99, introduces a system based on FEEP (Field Emission Electric Propulsion) technology, featuring low thrust plug-on propulsion units.
		Thanks to the self-contained concept of FEEP thrusters and to the plug-on feature of the whole system, a very low cost-impactive onboard propulsion system can be implemented in order to serve for both orbital manoeuvres (constellation / formation deployment, orbit rising) and orbit maintenance (drag compensation, station keeping relative to other satellites).
		Most convenient strategies to operate such propulsion systems with respect to orbital requirements, principal design drivers and sizing methods are presented and discussed as well as practical up-to-date case study results performed at Carlo Gavazzi Space.
	www.aas.org /publications/baas/v31n4/dps99/601.htm (390 words)

	DoD STTR Program Phase I Selections for FY02
		Due to the extreme high enhancement (>1000 times) of the electric field Cs ions near the nanotube ends may be field emitted when the intercalated materials is positively biased, thus providing a new machnism for thrust generation in field emission electric propulsion (FEEP) systems.
		Unfortunately, propulsion sub-components required to place the asset in orbit and maintain it's stability throughout its design life contribute to a significant fraction of the overall spacecraft mass and pose crucial design constraints.
		Very strong electric fields would generate high-energy electrons that are very effective in ionization, molecular dissociation, and electronic excitation at low gas temperature, while minimizing stagnation pressure losses due to reduced heating.
	www.dodsbir.com /selections/sttr1_02.htm (15287 words)

	Wired 9.01: Zip Drive
		Vasimr, which fits into the electric propulsion category, is a special case.
		But electrical power sources are heavy, and Vasimr will need a big one.
		The Jet Propulsion Laboratory in Pasadena, California, is developing ion and magnetoplasmodynamic drives, as well as a radical concept called field emission electric propulsion.
	www.wired.com /wired/archive/9.01/plasma.html?pg=4 (1086 words)

	History and Development of the Rocket Engine
		ion thrusters with some success (a form of electric propulsion).
		conservation of momentum means that in order for a propulsion method to change the momentum of a space craft it must change the momentum of something else as well.
		ion thruster, electricity is used to accelerate ions out the back.
	www.edinformatics.com /inventions_inventors/rocket_engine.htm (3031 words)

	eoPortal directory: Microscope (Site not responding. Last check: 2007-09-20)
		ESA is responsible for the procurement of the FEEP thrusters.
		To achieve this in the variable field of Earth's gravity, two restrictions are placed on the accelerometer design: the masses must be concentric to share a common center of gravity, and the shape of the masses must be chosen so that the gravity gradient effects are analogous on the two masses.
		The sensitive axes of the accelerometer are oriented in the orbital plane of the S/C x-axis, with the center of the test masses on the rotating axis of the S/C (normal to the orbital plane).
	directory.eoportal.org /pres_Microscope.html (2115 words)

	ESA Science & Technology: Spacecraft
		Capacitive sensing in three dimensions measures the displacements of the proof masses relative to the spacecraft.
		These position signals are used in a feedback loop to command Field Emission Electric Propulsion (FEEP) thrusters to follow the proof masses precisely.
		The FEEP thrusters are also used to control the attitude of the spacecraft relative to the incoming optical wave fronts using signals derived from the quadrant photodiodes.
	sci.esa.int /science-e/www/object/index.cfm?fobjectid=35617 (570 words)

	LISA propulsion module separation study
		The only propulsion system currently included in the sciencecraft design are micronewton level thrusters, such as field emission electric propulsion (FEEP) or colloid thrusters, that are used to balance the 30–40 µN of solar radiation pressure and provide the drag-free and attitude control of the sciencecraft.
		Due to these thrusters' limited authority, the separation of the propulsion module from the sciencecraft must be well controlled to not induce a large tip-off rotation of the sciencecraft.
		We present here the results of a study of the propulsion module separation system requirements that are necessary to safely deliver the three LISA sciencecraft to their final operational orbits.
	stacks.iop.org /0264-9381/22/S413 (335 words)

	Micropropulsion technology assessment for DARWIN: evaluation of existing and emerging micropropulsion technologies for ...
		The purpose of this report is to evaluate both current and emerging micropropulsion technologies, resulting in a recommendation and further investigation of the systems best suited for the DARWIN micropropulsion system.
		Field-Emission Electric Propulsion (FEEP), colloid thrusters, Cold Gas Microthrusters and pulsed-plasma thrusters (PPT) are among the technologies included in the study.
		Contamination of the telescopes and other highly sensitive optical hardware is one of the main issues, together with the extreme demands on resolution and variable thrust in the micronewton range.
	epubl.luth.se /1402-1617/2004/288 (345 words)

	Centrospazio - FEEP
		FEEP (Field Emission Electric Propulsion) is an advanced electrostatic thruster capable of delivering very low thrust with very high accuracy and controllability.
		The FEEP technology is developed at Centrospazio under ESA/ESTEC and ASI funding.
		Due to its high specific impulse, FEEP is best suited for very low to low thrust missions.
	www.centrospazio.cpr.it /Centrospazio6FEEP.html (301 words)

	Untitled Document
		You are invited to present your latest electric propulsion research, development or application results at the 27th International Electric Propulsion Conference (IEPC), which is scheduled for the week of October 15-19, 2001 at the Pasadena Convention Center in Pasadena, California, U.S.A. More information on the conference can be found at the IEPC website:
		The IEPC is the primary technical specialists' conference for electric propulsion technologies and applications.
		Because of recent advances in electric propulsion technology and much wider application on commercial, military and science spacecraft, this promises to be a very exciting conference.
	www.engin.umich.edu /dept/aero/ERPS/conferenceletter.html (266 words)

	Technical and Quality Management - Home - Electric Propulsion Laboratory (EPL)
		The EPL provides test services to the Propulsion and Aerothermodynamics division, which is responsible for R&D activities and support to projects in the areas of chemical propulsion, electric and advanced propulsion, and aerothermodynamics.
		The EPL testing capability is currently focused on low/medium-power electric propulsion technologies (field-emission thrusters, ion engines, Hall-effect thrusters, and resistojets) and cold-gas systems.
		The domain of competence of the EPL includes direct or indirect measurements of thrust, mass flow, and electrical parameters related to propulsion system operation (ISO 17025 and ISO 9001 accreditation process for these activities under finalisation).
	www.esa.int /techresources/ESTEC-Article-art_print_friendly_1100182718946.html (566 words)

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