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Ferroelectric Emission Cathodes for Low-Power Electric PropulsionLow- or no-flow electron emitters are required for low-power electric thrusters, spacecraft plasma contactors, and electrodynamic tether systems to reduce or eliminate the need for propellant/expellant. Expellant-less neutralizers can improve the viability of very low-power colloid thrusters, field emission electric propulsion devices, ion engines, Hall thrusters, and gridded vacuum arc thrusters. The NASA Glenn Research Center (GRC) is evaluating ferroelectric emission (FEE) cathodes as zero expellant flow rate cathode sources for the applications listed above. At GRC, low voltage (100s to approx. 1500 V) operation of FEE cathodes is examined. Initial experiments, with unipolar, bipolar, and RF burst applied voltage, have produced current pulses 250 to 1000 ns in duration with peak currents of up to 2 A at voltages at or below 1500 V. In particular, FEE cathodes driven by RF burst voltages from 1400 to 2000 V peak to peak, at burst frequencies from 70 to 400 kHz, emitted average current densities from 0.1 to 0.7 A/sq cm. Pulse repeatability as a function of input voltage has been initially established. Reliable emission has been achieved in air background at pressures as high as 10(exp -6) Torr.
Document ID
20020085155
Acquisition Source
Glenn Research Center
Document Type
Contractor Report (CR)
Authors
Kovaleski, Scott D.
(QSS Group, Inc. Cleveland, OH United States)
Burke, Tom
Date Acquired
September 7, 2013
Publication Date
September 1, 2002
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
E-13554
AIAA Paper 2002-4242
NAS 1.26:211872
NASA/CR-2002-211872
Meeting Information
Meeting: 38th Joint Propulsion Conference and Exhibit
Location: Indianapolis, IN
Country: United States
Start Date: July 7, 2002
End Date: July 10, 2002
Sponsors: American Society for Electrical Engineers, American Society of Mechanical Engineers, Society of Automotive Engineers, Inc., American Inst. of Aeronautics and Astronautics
Funding Number(s)
PROJECT: RTOP 755-B4-04
CONTRACT_GRANT: NAS3-00145
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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