ConferenceAIAA Propulsion and Energy Forum and Exposition 2019 · January 1, 2019
An investigation is performed into the time-dependent correlation between the local electron resitivity in a hollow cathode plume and the enhanced electron drag induced by wave-driven turbulence. Emissive, floating, and ion saturation current probes are ap ...
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ConferenceAIAA Propulsion and Energy Forum and Exposition 2019 · January 1, 2019
The ability to mitigate facility effects by varying the cathode flow fraction of a magnetically-shielded Hall thruster is experimentally investigated. The study is performed on a 9-kW class device operating on both internally and externally mounted cathode ...
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Conference2018 Joint Propulsion Conference · January 1, 2018
A lumped circuit model is presented for the formation and propagation of a rotating magnetic field field-reversed configuration thruster. The driving coils are treated as two lumped circuit inductors operated 90◦ out of phase. The plasma is mode ...
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Conference2018 Joint Propulsion Conference · January 1, 2018
Under the NextSTEP program led by Aerojet Rocketdyne in collaboration with NASA Glenn Research Center, the University of Michigan, and the Jet Propulsion Laboratory, the XR-100 100 kW Electric Propulsion system is being developed to Technology Readiness Le ...
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Conference2018 Joint Propulsion Conference · January 1, 2018
Plasma instabilities are spatially characterized in the plume of a 20 A LaB6 hollow cathode using ion saturation probes. The wave measurements are analyzed using a continuous wavelet transform to decompose the signal into three types of oscillat ...
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Conference2018 Joint Propulsion Conference · January 1, 2018
The ion acoustic turbulence in the plume of a hollow cathode operating in a Hall effect thruster is experimentally and analytically characterized. A recent theoretical study suggests that the increased resistivity as a result of the acoustic waves may dict ...
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Conference2018 Joint Propulsion Conference · January 1, 2018
The Plasmadynamics and Electric Propulsion Laboratory at the University of Michigan is developing a mobile-demonstration platform to bring advanced propulsion technologies into high school classrooms in the greater Ann Arbor area. Public outreach is critic ...
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Conference53rd AIAA SAE ASEE Joint Propulsion Conference 2017 · January 1, 2017
A mass and cost model developed to aid in the selection of electric propulsion string sizes has been expanded to include the potential benefits of nesting the discharge channels of Hall thrusters. First, an analytical expression for the thruster specific a ...
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Conference53rd AIAA SAE ASEE Joint Propulsion Conference 2017 · January 1, 2017
A simple model is developed to capture the effect of background pressure on the cathode coupling voltage in a Hall effect thruster. Only the voltage drop from the thruster plume to the cathode exit plane is considered as the voltage drop inside the cathode ...
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Conference53rd AIAA SAE ASEE Joint Propulsion Conference 2017 · January 1, 2017
A passive, non-invasive plasma diagnostic is developed and validated to estimate the dispersion of electric propulsion plasmas. This new technique uses a Silicon photomultiplier (SiPM) to measure fluctuations in light intensity to estimate the dispersion o ...
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Conference52nd AIAA SAE ASEE Joint Propulsion Conference 2016 · January 1, 2016
Divergence angle and thrust measurements for a nested Hall thruster in different operating modes are presented. The X2 thruster, a two-channel nested Hall thruster, was run in both single channel and dual-channel modes. The divergence angle for each channe ...
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Conference52nd AIAA SAE ASEE Joint Propulsion Conference 2016 · January 1, 2016
Velocity distribution function maps were acquired using laser-induced uorescence on the centerline of each channel in a two-channel nested Hall thruster. The inner channel velocity distribution maps showed that the acceleration mechanism behaves differentl ...
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ConferenceIcops Beams 2014 41st IEEE International Conference on Plasma Science and the 20th International Conference on High Power Particle Beams · January 16, 2015Full textCite
ConferenceIcops Beams 2014 41st IEEE International Conference on Plasma Science and the 20th International Conference on High Power Particle Beams · January 16, 2015Full textCite
ConferenceIcops Beams 2014 41st IEEE International Conference on Plasma Science and the 20th International Conference on High Power Particle Beams · January 16, 2015Full textCite
Conference50th AIAA ASME SAE ASEE Joint Propulsion Conference 2014 · January 1, 2014
The X3 is a 100-kW class nested-channel Hall thruster developed by the Plasmady- namics and Electric Propulsion Laboratory at the University of Michigan in collaboration with the Air Force Research Laboratory and NASA. The cathode, magnetic circuit, boron ...
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Conference50th AIAA ASME SAE ASEE Joint Propulsion Conference 2014 · January 1, 2014
A mode transition study is conducted in magnetically shielded thrusters where the magnetic field magnitude is varied to induce mode transitions. Three different oscillatory modes are identified with the 20-kW NASA-300MS-2 and the 6-kW H6MS: Mode 1) global ...
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Conference49th AIAA ASME SAE ASEE Joint Propulsion Conference · September 16, 2013
Mode transitions have been commonly observed in Hall Effect Thruster (HET) operation where a small change in a thruster operating parameter such as discharge voltage, magnetic field or mass flow rate causes the thruster discharge current mean value and osc ...
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ConferenceIEEE Aerospace Conference Proceedings · June 12, 2013
High-power Hall thrusters capable of throughput on the order of 100 kW are currently under development, driven by more demanding mission profiles and rapid growth in on-orbit solar power generation capability. At these power levels the nested Hall thruster ...
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ConferenceIEEE Aerospace Conference Proceedings · June 12, 2013
The plasma plume of a 6 kW Hall Effect Thruster (HET) has been investigated in order to determine time-averaged and time-resolved plasma properties in a 2-D plane. HETs are steady-state devices with a multitude of kilohertz and faster plasma oscillations t ...
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Conference49th AIAA ASME SAE ASEE Joint Propulsion Conference · January 1, 2013
Mode transitions have been commonly observed in Hall Effect Thruster (HET) operation where a small change in a thruster operating parameter such as discharge voltage, magnetic field or mass flow rate causes the thruster discharge current mean value and osc ...
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Conference48th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit 2012 · December 1, 2012
Currently, there is great interest in the development of high-power electric propulsion (EP) devices that can be employed in missions requiring >100 kW levels of propulsive power. Of the candidates for such thrusters, the Nested-channel Hall thruster (NHT) ...
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Conference48th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit 2012 · December 1, 2012
The Helicon Hall Thruster (HHT) is a two-stage thruster that was developed to investigate whether a radiofrequency ionization stage can improve the overall efficiency of a Hall thruster operating at high thrust and low specific impulse. This experiment mea ...
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Conference48th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit 2012 · January 1, 2012
This paper will present a novel procedure for performing accelerated wear test on Hall thruster discharge channels. The procedure takes advantage of a number of recent advances in optical diagnostics that have enabled increasingly accurate non-intrusive de ...
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Conference47th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit 2011 · December 1, 2011
The first direct experimental measurements of electron current due to rotating spokes in a modern highpower Hall thruster are presented. A segmented anode consisting of 12 equally spaced azimuthal sections has been retrofitted onto the H6 6-kW class Hall t ...
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Conference38th Eps Conference on Plasma Physics 2011 Eps 2011 Europhysics Conference Abstracts · December 1, 2011
Electron Energy Distribution Function (EEDF) measurements were made in a magnetically enhanced, Inductively Coupled Plasma (ICP) with and without the introduction of an axially injected neutral jet of argon gas with a small relative flow. A lab-built RF co ...
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Conference62nd International Astronautical Congress 2011 Iac 2011 · December 1, 2011
Improved Hall-effect Thruster (HET) efficiency would enable more extensive cost-capped, Discovery class NASA missions such as robotic missions to Mars and near-Earth asteroids to perform round trip sample-returns. HET efficiency would be further improved i ...
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Conference47th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit 2011 · January 1, 2011
We present the initial results from a cavity ring-down sensor for measuring the density of sputtered boron atoms originating from the discharge channel of a 6-kW Hall thruster. The sensor traps 250 nm light in a high-finesse cavity to greatly increase its ...
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Conference47th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit 2011 · January 1, 2011
In order to better understand interactions between the plasma and channel walls of a Hall thruster, the near-wall plasma was characterized within the H6 Hall thruster using five flush-mounted Langmuir probes. These probes were placed within the last 15% of ...
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ConferenceIEEE Aerospace Conference Proceedings · June 2, 2010
The Earth Sciences Decadal Survey identifies a multiangle, multispectral, high-accuracy polarization imager as one requirement for the Aerosol-Cloud-Ecosystem (ACE) mission. JPL has been developing a Multiangle SpectroPolarimetric Imager (MSPI) as a candid ...
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Conference45th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2009
The Nanoparticle Field Extraction Thruster (NanoFET) is an electric propulsion device under development at the University of Michigan to electrostatically charge and accelerate micro- and nano-particle propellant. During the 2008-2009 academic year, underg ...
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Conference45th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2009
In preparation for in-depth internal wall measurements for erosion and electron mobility studies, a flush-mounted Langmuir probe and emissive probe were used to characterize the near-wall region near the exit plane of a 6-kW Hall thruster. Various plasma p ...
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Conference40th AIAA Plasmadynamics and Lasers Conference · January 1, 2009
We present and validate a method for extracting velocity distribution functions from laser-induced fluorescence measurements obtained using a xenon ion line with unknown hyperfine constants. The method involves a direct deconvolution of intermodulated expe ...
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Conference47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition · January 1, 2009
The accuracy of a plasma impact force sensor was compared to that of the more commonly used inverted pendulum thrust stand using a 5 kW Xe Hall effect thruster (HET). An improved plasma momentum flux sensor (PMFS) was designed and constructed based on a pr ...
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Conference2009 12th International Conference on Information Fusion Fusion 2009 · January 1, 2009
Single-point measurements of time-resolved plasma density fluctuations are collected throughout a planar region of the exhaust plume downstream from a Hall effect thruster. A matrix of empirical discrete time transfer functions is created between the thrus ...
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Conference45th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2009
Contact charging of micro- and nano-particles affords the Nanoparticle Field Extraction Thruster (NanoFET) flexibility to adjust its propellant's specific charge. This flexibility permits NanoFET to tune its propulsive performance by adjusting the charging ...
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Conference45th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2009
A High-speed Dual Langmuir Probe system (HDLP) and a high-speed camera tracked 19.6-kHz waves of ionized propellant emitted by the unsteady ionization process or "breathing mode" of a cluster of Hall thrusters. Two 600-W, low-power Hall thrusters were oper ...
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Conference45th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2009
We present laser-induced fluorescence velocimetry measurements of the 5d[4]7/2 → 6p[3]°5/2 transition for singly-charged xenon (Xe II) at 834.953 nm (vacuum) inside and in the near-field plume of a 6-kW Hall thruster. The thruster has ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2008
An E×B probe was used to characterize the angular distribution of multiply-charged ions in the plume of a 6-kW Hall thruster operating at discharge voltages of 150-600 V, and anode mass flow rates of 10-30 mg/s. The local ion current fractions were measure ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2008
In an effort to study the transient fluctuations of plasma properties downstream of a Hall Effect Thruster (HET) on a microsecond timescale, a high-speed Langmuir probe measurement system is developed and tested. A high-voltage (±225 V), broadband (DC - 2 ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2008
The Nanoparticle Field Extraction Thruster (NanoFET) is an electrostatic accelerator technology currently under development at the University of Michigan to accelerate micro-/nano-particles. The concept exists in two configurations: the liquid configuratio ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2008
The accuracy of a plasma impact force sensor was compared to that of the more commonly used inverted pendulum thrust stand using a 5 kW Xe Hall thruster. A plasma momentum flux sensor (PMFS) was designed and constructed based on a previous NASAMarshall Spa ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2008
Various methods for accurately determining ion species' current fractions using E×B probes in Hall thruster plumes are investigated. The effects of peak broadening and charge exchange on the calculated values of current fractions are quantified in order to ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2008
This paper introduces a nanoparticle field extraction thruster (nanoFET) concept that does not depend on the liquid delivery of micro and nano-particles for extraction and acceleration. The no-liquid approach potentially provides important advantages such ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2008
Sputter erosion of boron nitride (BN) plays a key life-limiting role in many Hall thrusters. We report on the development of cavity ring-down spectroscopy (CRDS) as a sensitive and accelerated diagnostic for sputter erosion. The measurement approach is bas ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2008
Wall-mounted Langmuir probes are a promising internal diagnostic for Hall thrusters that can help understand critical plasma-wall interactions. However, the non-ideal environment within the discharge channel can complicate the implementation and interpreta ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2008
In a previous paper,1 we demonstrated that negative muons resulting from antiproton annihilation in a relatively cold deuterium-tritium (DT) plasma confined in a gasdynamic mirror (GDM) can result in catalyzing on average over 100 fusion reactio ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2008
We present laser-induced fluorescence velocimetry measurements of the 5d[4]7/2 → 6p[3]°5/2 transition for singly-charged xenon (Xe II) at 834.953 nm (vacuum) in the near-field plume of a 6-kW Hall thruster. Axial velocity profiles wer ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2008
During the 2006-2007 and 2007-2008 academic calendar years, C-9 NanoBLUE, a team of undergraduates within the University of Michigan's Student Space Systems Fabrication Laboratory, investigated the effects of a reduced gravity environment on the Nanopartic ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2008
This study uses a stepwise regression strategy to examine the interaction between the Hall thruster operating parameters and the location of the acceleration zone. The results of the regression are then linked to the Hall thruster physics, specifically the ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2008
In an effort to understand the role of neutral flow dynamics in the operation of Hall thrusters, a floating emissive probe was used to measure the plasma potential, electric field, and electron temperature in the discharge channel of a 6-kW Hall thruster o ...
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Conference44th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2008
In an effort to understand the role of neutral flow dynamics in the operation of Hall thrusters, a cylindrical Langmuir probe was used to measure the electron temperature, floating potential, and ion number density in the discharge channel of a 6-kW Hall t ...
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ConferenceCollection of Technical Papers 43rd AIAA ASME SAE ASEE Joint Propulsion Conference · December 10, 2007
Measurements via the Top Hat Electric Propulsion Plume Analyzer (TOPAZ) on the Busek BHT-600 Hall thruster cluster are presented. TOPAZ incorporates a 'top ha design with an analyzer constant of 100 resulting in a wide energy-range capability and high angu ...
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ConferenceCollection of Technical Papers 43rd AIAA ASME SAE ASEE Joint Propulsion Conference · December 10, 2007
Boron nitride in the cubic phase has been considered a potential candidate for use as electron field emitters. This paper highlights results and challenges in characterizing boron nitride's suitability for use in electric propulsion applications and in des ...
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ConferenceAip Conference Proceedings · December 1, 2007
A new electrostatic thruster technology is under development at the University of Michigan using nanoparticles as propellant with micro-and nano-electromechanical systems. Termed the nanoparticle field extraction thruster (nanoFET), this highly integrated ...
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ConferenceAdvances in the Astronautical Sciences · December 1, 2007
We use a path based approach to find optimal spacecraft trajectories. The algorithm searches for the control and states that generate a trajectory that is dynamically consistent. The path functions allow ephemeris constraints to be directly enforced ensuri ...
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ConferenceCollection of Technical Papers 43rd AIAA ASME SAE ASEE Joint Propulsion Conference · January 1, 2007
An axisymmetric hydrodynamic model of the plasma flow within a Hall thruster channel is used to model the differences between krypton and xenon propellants. Krypton offers a higher specific impulse and lower cost than xenon, but its overall efficiency is o ...
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ConferenceCollection of Technical Papers 43rd AIAA ASME SAE ASEE Joint Propulsion Conference · January 1, 2007
This paper presents experimental results and modeling advances concerning the nanoparticle Field Extraction Thruster (nanoFET) concept under development at the University of Michigan. The nanoFET concept offers an electric propulsion approach that can have ...
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ConferenceCollection of Technical Papers 43rd AIAA ASME SAE ASEE Joint Propulsion Conference · January 1, 2007
One of the notable attributes of the Gasdynamic Mirror (GDM) fusion propulsion system is the fact that it lends itself readily to thrust control due to asymmetry in the magnetic field configuration. GDM is a magnetic plasma confinement device that has been ...
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ConferenceCollection of Technical Papers AIAA ASME SAE ASEE 42nd Joint Propulsion Conference · December 1, 2006
In an effort to verify the existence of and study the characteristics of the dynamic magnetic fields generated by supplying inner and outer coil Hall thruster electromagnets with wide bandwidth (DC to 200 kHz) currents, B-dot probe experiments have been pe ...
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ConferenceCollection of Technical Papers AIAA ASME SAE ASEE 42nd Joint Propulsion Conference · December 1, 2006
This paper presents experimental results concerning the nanoparticle Field Extraction Thruster (nanoFET) concept under development at the University of Michigan. The nanoFET concept offers an electric propulsion approach that can have a highly adjustable c ...
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ConferenceCollection of Technical Papers AIAA ASME SAE ASEE 42nd Joint Propulsion Conference · December 1, 2006
The performance of typical electrostatic propulsion systems, such as the Hall thruster, is limited in part by inefficiencies in the electron bombardment ionization process. These limitations become especially pronounced at the operating conditions required ...
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ConferenceCollection of Technical Papers AIAA ASME SAE ASEE 42nd Joint Propulsion Conference · December 1, 2006
The nanoparticle field extraction thruster (nanoFET), using charged nanoparticles to generate propulsive thrust, is currently under development at the University of Michigan. This paper discusses the theoretical aspects of nanoFET operation, including part ...
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ConferenceAdvances in the Astronautical Sciences · December 1, 2006
Conducting preliminary trade studies are critical in determining the feasibility of a mission and identifying how various spacecraft systems will scale. We develop an algorithm for automating trade studies for electric propulsion interplanetary missions. T ...
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ConferenceCollection of Technical Papers AIAA ASME SAE ASEE 42nd Joint Propulsion Conference · January 1, 2006
A cylindrical Langmuir probe is used with the Plasmadynamics and Electric Propulsion Laboratory High-speed Axial Reciprocating Probe system to map the plasma properties internal to the NASA-173Mv1 Hall thruster using xenon and krypton propellant. Measureme ...
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ConferenceCollection of Technical Papers 37th AIAA Plasmadynamics and Lasers Conference · January 1, 2006
An ion thruster discharge cathode assembly (DCA) erosion theory is presented based on near-DCA NSTAR plasma measurements and experimental results for propellant flow rate effects on ion number density. The plasma potential structures are utilized in an ion ...
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ConferenceCollection of Technical Papers AIAA ASME SAE ASEE 42nd Joint Propulsion Conference · January 1, 2006
A MEMS gate prototype is under development to extract and accelerate charged particles for use with Held emission cathodes and the nanoparticle field extraction thruster at the University of Michigan. Preliminary simulations suggest the desirability of a u ...
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Conference41st AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2005
Krypton has recently become the focus of attention in the Hall thruster community because of its relatively large specific impulse as compared to xenon and its potential to operate with comparable efficiencies. However, before krypton can be considered a v ...
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Conference41st AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2005
While preliminary experiments with a cluster of four Busek 200-Watt (BHT-200-X3) Closed Drift Hall thrusters indicate reasonable performance scalability from single thruster experiments, cluster plume interactions are believed to give rise to an increased ...
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Conference41st AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2005
Clusters of Hall thrusters are being considered for use on a variety of missions requiring electric propulsion systems capable of operating at power levels in excess of the current state of the art. One of the key factors to be considered in determining th ...
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Conference41st AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2005
This paper will present an analysis of dual grid field emitter technology, illustrating the substantial power savings that can be obtained from existing technologies by controlling the final velocity of emitted electrons. Additionally, using two grids inst ...
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ConferenceIEEE Aerospace Conference Proceedings · December 1, 2005
1,2The purpose of Interstellar Probe (ISP) is to follow NASA's exploratory mission to cross the heliospheric boundary regions and, for the first time, enter our extra-solar galactic environment. Interstellar Probe has therefore captured the imag ...
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Conference41st AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2005
Magnetic field topology has been found to be a central design concern for high-efficiency Hall thrusters. For future improvements in Hall thruster design, it is necessary to better understand the effects that magnetic field topology has on the internal pla ...
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Conference41st AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2005
A high-power, rectangular discharge chamber is being designed by the University of Michigan for operation with multiple discharge cathode assemblies (DCAs). The multiple cathode approach attempts to increase thruster lifetime by operating three DCAs sequen ...
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Conference40th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2004
Performance and plasma measurements of the high-specific impulse NASA-173Mv2 Hall thruster were analyzed using a phenomenological performance model that accounts for a partially-ionized plasma containing multiply-charged ions. Between discharge voltages of ...
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ConferenceInternational Astronautical Federation 55th International Astronautical Congress 2004 · December 1, 2004
It is the purpose of Interstellar Probe (ISP) to follow NASA's exploratory mission to cross the heliospheric boundary regions and, for the first time, enter our extra-solar galactic environment. Interstellar Probe has therefore captured the imagination of ...
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Conference39th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2003
An overview is presented of electric propulsion research carried out in U.S. academic institutions. Universities in the U.S. are engaged in a wide range of research, varying from fundamental studies in micro thruster concepts, to future flight involving ma ...
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Conference39th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2003
Double Langmuir probe measurements are presented over a two-dimensional array of locations in the near Discharge Cathode Assembly (DCA) region of a 30-cm diameter ring cusp ion thruster. Discharge plasma data taken with and without beam extraction exhibit ...
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Conference39th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2003
An ExB probe was used to measure the ion species fractions of Xe+, Xe2+, and Xe3+ in the farfield plume of the NASA-173Mv2 laboratory-model Hall thruster. The thruster was operated at a constant xenon flow rate of 10 mg/s a ...
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Conference39th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2003
The effects of the magnetic field and discharge voltage on the far-field plume of the NASA-173Mv2 laboratory-model Hall thruster were investigated. A cylindrical Langmuir probe was used to measure the plasma potential and a retarding potential analyzer was ...
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Conference39th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2003
Clusters of Hall thrusters have been proposed as a means of achieving electric propulsion systems capable of operating at very high power levels. To facilitate testing in existing vacuum facilities, initial tests have focused on a cluster of low-power Buse ...
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Conference38th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2002
A method for delivery of a symmetric double probe into the discharge chamber of a 30-cm diameter ringcusped ion thruster is discussed. Motivation for direct access of the electrostatic probe to the discharge chamber stems from the need to characterize the ...
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Conference38th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · December 1, 2002
Investigations of high-voltage Hall thrusters have indicated a peak in the efficiency versus voltage characteristic that limited the maximum efficiency to specific impulses of less than 3000 s. This peak is believed to be primarily a trait of modern magnet ...
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Conference38th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2002
The effects of dissimilar probe design and facility backpressure on the measured ion current densities of Hall thrusters are investigated. JPL and GRC designed nude Faraday probes are used to simultaneously measure the ion current density of a 5 kW Hall th ...
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Conference40th AIAA Aerospace Sciences Meeting and Exhibit · January 1, 2002
We describe chamber tests of simulated electrodynamic tethers (EDTs) of different geometries operating in a dense, high-speed plasma. The geometries tested and described here were cylindrical and flat-ribbon. Several important conclusions that can be drawn ...
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Conference38th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2002
In an effort to understand the technical issues related to running multiple Hall effect thrusters in close proximity to each other, testing of a cluster of four Busek BHT-200-X3 devices has begun in Chamber 6 at the Air Force Research Laboratory. Prelimina ...
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Conference38th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2002
A neutral gas background pressure map of the Large Vacuum Test Facility (LVTF) at the University of Michigan is presented. The LVTF was mapped at a series of cold anode flow rates corresponding to P5 Hall thruster operating conditions of 1.5, 3.0, and 9.0 ...
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Conference39th Aerospace Sciences Meeting and Exhibit · December 1, 2001
We describe chamber tests of simulated electrodynamic tethers (EDTs) of different geometries operating in a dense, high-speed plasma. The geometries tested and described here were cylindrical and flat-ribbon. Several important conclusions that can be drawn ...
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Conference37th Joint Propulsion Conference and Exhibit · December 1, 2001
The design of the Linear Gridless Ion Thruster, or LGIT, is presented in detail. The LGIT is a hybrid thruster that combines an ionization stage similar to those normally found on gridded ion engines with the acceleration mechanism of a Hall effect thruste ...
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Conference37th Joint Propulsion Conference and Exhibit · December 1, 2001
A review of electric propulsion (EP) research activities at academic institutions throughout the United States is presented. The research presented here encompasses experimental, computational, and theoretical investigations of a wide variety of electric p ...
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Conference37th Joint Propulsion Conference and Exhibit · January 1, 2001
Magnetic field measurements were made in the discharge channel of the 5-kW-class P5 laboratory-model Hall thruster to investigate what effect the Hall current has on the static, applied magnetic field topology. The P5 was operated at 1.6 kW and 3.0 kW with ...
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Conference37th Joint Propulsion Conference and Exhibit · January 1, 2001
Hall current magnitude and spatial distribution are presented for the plasma discharge in the University of Michigan/Air Force Research Laboratory P5 5 kW laboratory-model Hall thruster. The data are calculated from direct, probe-based measurements of the ...
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Conference37th Joint Propulsion Conference and Exhibit · January 1, 2001
We describe chamber tests of simulated electro dynamic tethers (EDTs) of different geometries operating in a dense, high-speed plasma. The geometries tested and described here were cylindrical and flat-ribbon. Several important conclusions that can be draw ...
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Conference37th Joint Propulsion Conference and Exhibit · January 1, 2001
A time-accurate 2D axisymmetric Hybrid PIC-MCC model is used to simulate the plasma flow in the acceleration channel and near-field plume of a Hall thruster. The model is applied to the P5 Hall thruster due to known magnetic configuration and the availabil ...
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Conference35th Intersociety Energy Conversion Engineering Conference and Exhibit · December 1, 2000
Ground rests were performed to help characterize modes of interaction between the SPT-140 Hall thruster and spacecraft components. The experiments were performed at NASA Glenn Research Center and at the University of Michigan. Measurements were made of thr ...
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Conference35th Intersociety Energy Conversion Engineering Conference and Exhibit · December 1, 2000
Relative erosion-rates and impingement ion production mechanisms have been identified for the discharge cathode of a 30 cm ion engine using laser-induced fluorescence (LIF). Mo and W erosion products as well as neutral and singly ionized xenon were interro ...
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Conference38th Aerospace Sciences Meeting and Exhibit · December 1, 2000
The High Performance Hall System (HPHS) program supports the development and flight qualification of a 4.5 kW electric propulsion system that includes the SPT-140 Hall thruster. The Air Force Research Laboratory (AFRL) and International Space Technology, I ...
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Conference36th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2000
Experiments have been conducted at the University of Michigan Plasmadynamics and Electric Propulsion Laboratory (PEPL) to investigate the acceleration and ionization mechanisms in the P5 laboratory-model Hall thruster. A cylindrical, double Langmuir probe ...
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Conference36th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2000
Ground rests were performed to help characterize modes of interaction between the SPT-140 Hall thruster and spacecraft components. The experiments were performed at NASA Glenn Research Center and at the University of Michigan. Measurements were made of thr ...
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Conference35th Intersociety Energy Conversion Engineering Conference and Exhibit · January 1, 2000
Field Emitter Array Cathodes (FEAC) are a new technology being developed for several potential spacecraft electron emission and charge control applications. Instead of a single hot (i.e. high powered) emitter, or a gas dependant plasma contactor, FEAC syst ...
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Conference36th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2000
Field Emitter Array Cathodes (FEAC) are a new technology being developed for several potential spacecraft electron emission and charge control applications. Instead of a single hot (i.e. high powered) emitter, or a gas dependant plasma contactor, FEAC syst ...
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Conference36th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2000
Relative erosion-rates and impingement ion production mechanisms have been identified for the discharge cathode of a 30 cm ion engine using laser-induced fluorescence (LIF). Mo and W erosion products as well as neutral and singly ionized xenon were interro ...
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ConferenceIEEE International Conference on Plasma Science · December 1, 1999
Field emission (FE) cathodes are currently being considered to supply electrons in electric propulsion systems for propellant ionization and ion beam neutralization. Hollow cathodes with thermionic electron emitters typically used with Hall and ion thruste ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
Interferometry was used to investigate the impact of the plasma plume of the University of Michigan P5 thruster on microwave signals. Measurements were made at 34 GHz using a newly built Ka-band interferometer and also at 17 GHz similar to other measuremen ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
Laser induced fluorescence (LIF) was used to measure the mean and variance of the velocity distribution of xenon ions emitted from two hollow cathode assemblies operating at low power. High-energy ions detected in plumemode and spot-mode operation are cons ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
We are developing a resonance-probe plasma diagnostic that uses a microwave network analyzer for use in electric-propulsion research. To show the feasibility of our resonance-probe implementation, we have measured plasma densities in the plume of the 5-kW- ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
The ion energy distribution of each ion species in the SPT-100 plume was obtained at various angles off thruster axis at 1 m and 50 cm from the thruster exit using an ExB probe. Each peak of the measured ExB probe traces was fitted using a model based on t ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
The Plasmadynamics and Electric Propulsion Laboratory (PEPL) has used its Molecular Beam Mass Spectrometer (MBMS) to determine the ion energy distribution of the P5 5 kW laboratory Hall thruster. A skimmer was used to obtain a sample of the plasma in the n ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
An experimental investigation of the operating characteristics of 3.2 mm diameter orificed hollow cathodes was conducted to examine low-current and low flow rate operation. Cathode power was minimized with low orifice aspect ratio and the use of an enclose ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
Using a hollow cathode assembly (HCA) in a large vacuum chamber, such as the University of Michigan’s Large Vacuum Test Facility (LVTF), provides the capability of generating a plasma environment that closely approximates that of the ionosphere. This capab ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
Laser induced fluorescence (LIF) was used to measure the mean and variance of the velocity distribution of xenon ions in the plume of the P5 Hall thruster. The data indicate an acceleration region extending several centimeters downstream of the exit plane. ...
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Conference35th Joint Propulsion Conference and Exhibit · January 1, 1999
Electron temperature, number density, plasma potential and floating potential were measured in the interior and very-near-field region of the P5 Hall thruster using the newly developed High-speed Axial Reciprocating Probe (HARP) positioning system. The HAR ...
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Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
In an effort to support the needs of emerging low-power electric propulsion systems, efficient, low-current hollow cathodes are being developed at the NASA Lewis Research Center. A thermal model of the hollow cathode is currently under development, and a l ...
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Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
Compatibility issues associated with using field emission array (FEA) cathodes as the electron sources for Hall and ion thrusters were explored and FEA cathode performance is discussed. The cathode environment was characterized using a Faraday probe and NP ...
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Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
The University of Michigan and United States Air Force Research Laboratory have jointly developed a 5 kW class Hall effect thruster. This thruster was developed to investigate, with a variety of diagnostics, a thruster similar to that specified by IHPRPT g ...
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Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
As part of an effort to develop efficient hollow cathodes for the International Space Station and low power electric propulsion systems, the effects of orifice length-to-diameter aspect-ratio on the performance of 0.5 to 2 A hollow cathodes were examined t ...
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Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
RPA and Langmuir probe measurements were made in the near-field plume on the axis of a hollow cathode assembly (HCA). High-energy ions were detected at low-powers consistent with the detection of such ions at high powers in previous investigations. The abs ...
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Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
Knowledge of the ion species emitted by the SPT-100 Hall thruster provides considerable insight to the basic thruster performance. In order to gain detailed information concerning the composition of the plume plasma a custom molecular beam mass spectromete ...
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Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
Of primary concern with the integration of Hall thrusters on conventional satellite designs is the possible damaging effect of high-energy exhaust ions impinging upon spacecraft surfaces. This paper reports on measurements of plasma ion energy distribution ...
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Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
We report on electromagnetic wave (EM) scattering experiments using a 17 GHz signal propagated through an electric propulsion Hall thruster plume at different radial and axial distances. The goals of the experiments were to evaluate the spectral modificati ...
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ConferenceIEEE International Conference on Plasma Science · January 1, 1998
The recent drive towards utilizing electric propulsion systems for micro spacecraft warrants the development of efficient, low power and low propellant consumption cathodes. Because of the lower limits on size, power and propellant consumption of hollow ca ...
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Conference33rd Joint Propulsion Conference and Exhibit · January 1, 1997
The motivation behind the construction of a Molecular Beam Mass Spectrometer (MBMS) for transport property measurements in Hall thruster plumes is presented. This system utilizes a set of orifice plates to skim off a small beam of plasma from the plume of ...
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Conference33rd Joint Propulsion Conference and Exhibit · January 1, 1997
Microwave interferometry was used to investigate the impact of the plume of a D-55 anode layer thruster on satellite communications. A 17 GHz microwave signal was transmitted through the plume in order to measure phase shift and signal attenuation at vario ...
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Conference33rd Joint Propulsion Conference and Exhibit · January 1, 1997
The plasma properties of the very near-field (10 to 50 mm) plume of the D55 anode layer thruster (TAL) were measured as part of an effort lead by NumerEx of Albuquerque, NM to model the processes within TALs. The D55 is the 1.35 kW TAL counterpart to the S ...
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Conference32nd Joint Propulsion Conference and Exhibit · January 1, 1996
In order to understand the interaction between the SPT-100 thruster and the spacecraft accurate knowledge of exhaust plume properties must be obtained. This investigation utilized a suite of inter-related diagnostic probes in an effort to provide detailed ...
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Conference32nd Joint Propulsion Conference and Exhibit · January 1, 1996
Stationary plasma thrusters (SPTs) are currently being tested and considered for use aboard next generation spacecraft for North-South station keeping, repositioning, and orbit transfer due to their high thrust efficiency and nearly optimal specific impuls ...
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Conference32nd Joint Propulsion Conference and Exhibit · January 1, 1996
The performance of a D-100 thruster with anode layer, designed to operate on xenon at a nominal operating power of 4.5 kW, was investigated during operation on krypton. This evaluation was preliminary to a more thorough investigation of D-100 operation on ...
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Conference32nd Joint Propulsion Conference and Exhibit · January 1, 1996
Ion current density and electron number density profiles were measured in the very-nearfield plume of a 1.35 kW stationary plasma thruster (SPT-100) loaned from Space Systems/Loraland Fakel Enterprises. In order to take these measurements without significa ...
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Conference32nd Joint Propulsion Conference and Exhibit · January 1, 1996
The following provides a first year summary of a research program sponsored by the AFOSR to characterize the SPT-100 for far-field plume plasma and transport properties as well as thruster operation impact to electromagnetic signals used for communication, ...
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Conference32nd Joint Propulsion Conference and Exhibit · January 1, 1996
Although classical electrostatic plasma probes can provide detailed information regarding electrons and ions, these devices rely on charge-carrying particles both for energy filtering and detection Neutral particles are transparent to such diagnostics. In ...
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ConferenceIEEE International Conference on Plasma Science · January 1, 1996
In an attempt to reduce the large anode fall voltages associated with transverse discharges, the use of a secondary discharge to introduce or generate more electrons in the near-anode region is investigated. Changes in near-anode plasma properties are meas ...
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ConferenceIEEE International Conference on Plasma Science · January 1, 1996
The bulk flow velocity is an important parameter in characterizing moving plasmas, such as electric propulsion plasma plumes. The bulk flow velocity can be found directly through interpretation of the propagating characteristics of an ion acoustic wave. Th ...
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Conference31st Joint Propulsion Conference and Exhibit · January 1, 1995
A thrust stand was modified, and a primary calibration technique was developed to evaluate the performance of applied-field pulsed magnetoplasmadynamic thrusters (MPDTs) for 10 kW class solar electric orbit transfer vehicle (SEOTV) missions. The NASA Lewis ...
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Conference31st Joint Propulsion Conference and Exhibit · January 1, 1995
This paper presents a comprehensive theoretical numerical, and experimental investigation of the phenomena encountered when analyzing exo-atmospheric plume impingement loads. An analytic model combined with Monte Carlo simulations is used to study the rela ...
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Conference31st Joint Propulsion Conference and Exhibit · January 1, 1995
The plasma plumes from two stationary plasma thrusters (SPTs), a flight qualified SPT-100 using xenon and a laboratory model SIT using krypton, have been measured using microwave diagnostic systems capable of differential phase, differential amplitude, and ...
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Conference31st Joint Propulsion Conference and Exhibit · January 1, 1995
The objective of this research was to characterize the performance of a 1.35 kW stationary plasma thruster (SPT) with krypton as the propellant. Research carried out by Bugrova et al. [l] demonstrated that SPT performance on krypton is comparable to that o ...
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ConferenceAIAA ASME SAE ASEE 28th Joint Propulsion Conference and Exhibit 1992 · January 1, 1992
Results from previous studies indicate that the anode fall increases monotonically with the electron Hall parameter calculated from electron temperature, number density, and magnetic field data obtained near the anode. In an attempt to reduce the anode fal ...
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ConferenceAlaa Dglr Jsass 21st International Electric Propulsion Conference 1990 · January 1, 1990
Spatially resolved anode heat flux measurements of a pulsed quasi-steady MPD thruster have been made by embedding thermocouples to the inner surface of a hollowed anode. Results obtained using argon propellant at mass flow rates of 4 and 16 g/s with the th ...
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ConferenceAIAA Paper · December 1, 1986
The objective of this study was to determine the performance of an External Radiation Heated (ERH) Thruster. In this thruster, high intensity laser energy is focused to ignite either a Laser Supported Combustion (LSC) wave or a Laser Supported Detonation ( ...
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