NASA / TM--2001-211215 AIAA-2001-3888

NASA's Hall Thruster Program

Robert S. Jankovsky, David T. Jacobson, Vincent K. Rawlin,

Lee S. Mason, and Maris A. Mantenieks

Glenn Research Center, Cleveland, Ohio

David H. Manzella

University of Toledo, Toledo, Ohio

Richard R. Hofer and Peter Y. Peterson

QSS Group, Inc., Cleveland, Ohio

December 2001
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NASA / TM---2001-211215 AIAA-2001-3888

NASA's Hall Thruster Program

Robert S. Jankovsk)¢ David T. Jacobson, Vincent K. Rawlin,

Lee S. Mason, and Maris A. Mantenieks

Glenn Research Center, Cleveland, Ohio

David H. Manzella

University of Toledo, Toledo, Ohio

Richard R. Hofer and Peter Y. Peterson

QSS Group, Inc., Cleveland, Ohio

Prepared for the

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Salt Lake City, Utah, July 8-11, 2001

National Aeronautics and

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Glenn Research Center

December 2001
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NASA's Hall Thruster Program

Robert S. Jankovsky, David T. Jacobson, Lee S. Mason, Vincent K. Rawlin, and Maris A. Mantenieks

National Aeronautics and Space Administration

Glenn Research Center

Cleveland, Ohio 44135

David H. Manzella

University of Toledo

Toledo, Ohio 43606

Richard R. Hofer and Peter Y. Peterson

QSS Group, Inc.

Cleveland, Ohio 44135

Abstract

NASA's Hall thruster program has base research and focused development efforts in support of the

Advanced Space Transportation Program, Space-Based Program and various other programs. The

objective of the base research is to gain an improved understanding of the physical processes and

engineering constraints of Hall thrusters to enable development of advanced Hall thruster designs. Specific

technical questions that are current priorities of the base effort are: (1) How does thruster life vary frith

operating point? (2) How can thruster lifetime and wear rate be most efficiently evaluated? (3) What are

the practical limitations for discharge voltage as it pertains to high specific impulse operation (high

discharge voltage) and high thrust operation (low discharge voltage)? (4) What are the practical limits for

extending Hall thrusters to very high input powers? and (5) What can be done during thruster design to

reduce cost and integration concerns? The objective of the focused development effort is to develop a 50

kW-class Hall propulsion system, with a milestone of a 50 kW engineering model thrustersystem by the end

of program year 2006. Specific program year 2001 efforts, along with the corporate and academic

participation, are described.

.Introduction

NASA's Hall thruster program is an integrated

technology program addressing many NASA,

DoD, and commercial customer requirements.

The program is implemented through the OnBoard Propulsion Branch of the Power and OnBoard Propulsion Division at NASA Glenn

Research Center (GRC). NASA's Hall thruster

program began in the early 1990's when NASA,

along with the Ballistic Missile Defense

Organization, took great interest in Russian Hall

thruster technology. The emphasis of this work

was the evaluation of Russian technology with

respect to potential missions, thruster

performance, lifetime and integration issues. 1-18

The conclusion of these evaluations was that

Russian Hall thruster technology offered near

optimal specific impulse and favorable thrust-topower with tractable integration concerns for

many near Earth applications. NASA, and

others, extrapolated these data to various power

levels for use in spacecraft/mission design trade

studies considering the advantages of increased

spacecraft power for electric propulsion.

Significant advantages were demonstrated.

Specifically these studies showed Hall thrusters

could enable new missions using existing launch

vehicles or existing missions with a launch

vehicle step down. Moreover, high power Hall

thrusters with their unique combination of thrust

and specific impulse were shown to offer

significant benefits for missions when drag or

gravity are major constraints. 19"26 As a result of

these studies the development of 10-50 kW Hall

thruster systems became the technical objective

of the NASA Hall thruster program.

To advance the technology necessary for these

potential applications NASA initiated a

NASA/TM--2001-211215 1
comprehensiveprogramthatcontainedbasic

researchandfocusedevelopment efforts.The

elementsof this areillustratedin the work

breakdownstructure(WBS) in Figure 1.

Programyear2001fundedeffortsaredescribed.

Work Breakdown Structure

The NASA Hall thruster program is divided into

two categories: 1) base research and 2) focused

development. As currently organized the base

research element has five products areas and the

focused element has two product areas. The base

efforts address fundamental aspects of

performance, cost, life, systems/integration, and

thruster phenomenon. These efforts are at low

technology readiness levels. The focused effort is

directed towards mid technology readiness level

development of 10-50 kW Hall thruster

propulsion systems.

Base Program

The objective of the base research effort is to

gain an improved understanding of the physical

processes and engineering constraints of Hall

thrusters to enable development of advanced

Hall thruster designs. It is sponsored by a

number of NASA Programs including the SpaceBased Program, the Advanced Space

Transportation Program, the Space Solar Power

Program, the Human Exploration and

Development of Space (HEDS) Technology

Commercialization Initiative, the Glenn

Research Center Strategic Research Fund, and

the Small Business Innovative Research

Program.

Specific elements within the base portion of the

Hall program are split into five areas: (1.1)

Investigations into Extending the Performance

Envelope, (1.2) Evaluation and Development of

Lightweight/Low Cost Components, (1.3)

Thruster Operational Life Assessment and

Improvement, (1.4) Investigation of Innovative

System Approaches/Integration Issues, and (1.5)

Component Level Phenomenological

Investigations.

(1.1) Investigations

Performance Envelope

into Extending the

A number of task level boxes are illustrated on

the WBS in this area. However, in program year

2001 the task efforts were limited to (1.1.1) High

Specific Impulse and (1.1.3) High Power tasks.

The high specific impulse task includes three

efforts. The first effort considers a single-stage

SPT-type thruster. The Atlantic Research

Corporation and Fakel designed and built a

derivative of the SPT-100 optimized for high

voltage operation (Figure 2). The thruster

operated satisfactorily and showed that near

gridded ion thruster performance was possible.

For example, at the target input power level of

2.3 kW, 97 mN of thrust, 2900 seconds specific

impulse and a total efficiency of 56% was

demonstrated. 27 At an elevated power level of

3.2 kW, 145 mN of thrust were demonstrated

with over 2500 seconds specific impulse and a

total thruster efficiency of 55%. 28 This

performance is comparable to the state-of-the-art

gridded ion thruster (NSTAR) performance of 91

mN of thrust, 3200 seconds specific impulse and

total thruster efficiency of 62 % at an input

power of 2.3 kW.

The second effort was a TAL investigation. The

Boeing Company and TsNIIMASH designed and

built a two-stage anode layer thruster or TAL

(Figure 3). The two-stage TAL concept utilized

a segmented anode with two power supplies to

control the voltage distribution within the

thruster. The concept was thought to separate

the ionization and acceleration regions of the

thruster allowing for optimization of each.

Testing was conducted operating this device in

both single-stage and two-stage modes. Data

collected in the two-stage configuration revealed

similar performance to single-stage performance

at the same conditions. In the single-stage

configuration, discharge efficiency of 57% and

anode specific impulse of 2625 seconds was

demonstrated at a discharge voltage and current

of 700 V and 4.1 A, respectively. 29

The third effort in this task, performed by the

University of Michigan and Glenn Research

Center, is a two-stage SPT-type concept with an

emitting electrode. This concept provides an

additional source of electrons behind the peak

magnetic field in order to optimize the ionization

process independent of the accelerating process,

making the thruster much more akin to a gridded

ion thruster. The thruster was designated the P5-

2 (Figure 4) because of it's heritage to the

University of Michigan's single-stage P5. Other

NASA/TMm2001-211215 2
additionstothisthrusterincludethe3Dmagnetic

designof aplasmalensfieldlinetopologyand

thedesignof aradialtrimcoilto enablemultimodeoperationthroughin-situ control of the

magnetic field topology. Fabrication of this

thruster has just been completed and functional

testing has been initiated. Publication of the

results is expected at the 2001 International

Electric Propulsion Conference.

These investigations provide intermediate

advances toward the high power multi-mode

(very high thrust to very low thrust) Hall

thrusters of the focused program. 3° The results

to date indicate that it is feasible to provide a

Hall thruster with performance approaching that

of gridded ion thrusters. The limiting

mechanism in meeting or exceeding gridded ion

thruster efficiency at specific impulses in excess

of 4000 seconds appears to be the increased axial

electron transport or the increased production of

multiply charged ions at the discharge voltages

needed to achieve these specific impulses.

Evidence for this includes the changing

relationship between discharge current and

voltage above approximately 700 V and the

decrease in efficiency. The concepts tested to

date do not appear to offer a solution to this in

the regimes tested.

Task (1.1.3), High Power, is an in-house Glenn

Research Center effort. The task is an

investigation into the limiting mechanisms when

scaling Hall thrusters to high power, and an

assessment of the practical limits in high power

Hall thruster system development. In this task a

50 kW-class Hall thruster is being designed and

built. The design, designated the NASA-457M

(Figure 5), has a design point of 500 V and 100

A and is estimated to produce approximately 2.5

N of thrust. The NASA-457M was designed for

use as a test bed for high power Hall research. A

unique aspect of this design is its large channel

width. The channel dimensions are 457mm

outer diameter x 64mm channel width. The large

channel width reduces thruster size by

maintaining current densities common to

commercial Hall thrusters and will help to

accommodate internal thruster diagnostics. The

design is complete and fabrication is in progress.

It is anticipated that the design and preliminary

test results will be published at the 2001

International Electric Propulsion Conference.

(1.2) Evaluation and Development

Lightweight/Low Cost Components

of

In program year 2001 there is only one task in

this element, (1.2.2) Non-traditional Fabrication

Approaches. This task was selected as part of

the Cross-Enterprise Technology Development

Program NRA and is led by VACCO Industries,

Inc. VACCO's Chemically Etched Miniature

Systems or ChEMS TM technology is being

investigated as a possible technique for creating

low cost integrated propellant management

assemblies. ChEMS TM technology consists of

multiple layers of etched and bonded metal

sheets to form components and their

interconnecting flow paths. 31 Figure 6 illustrates

an integrated pressure and flow control unit

capable of meeting many propulsion needs. The

program has recently been initiated, and over the

next three years will demonstrate functionality of

an integrated pressure and flow control unit with

a Hall thruster and gridded ion thruster.

(1.3) Thruster Operational Life Assessment and

Improvement

In program year 2001, there are three tasks in the

area of life assessment and improvement aimed

at developing the tools and processes required

for cost effective development of next generation

Hall thrusters. Hall thrusters are being

considered for applications where off nominal or

multi-mode operation will be needed. The many

possible operational mission scenarios being

considered make it impractical to perform full

lifetime qualification tests for each different case

being considered. As a result, a method of

scaling erosion/life from one set of qualification

test data to many mission profiles without

requalification is being sought. This area of

work will be a large part of NASA's program in

2002. The three tasks described below are the

initial stages of this effort. They are assessing

the magnitude of the problem and developing

tools for program year 2002.

Task (1.3.1) Thruster sensitivity to operating

point, is an investigation into the effects of

thruster erosion with higher energy plasma from

what is commonly practiced. In this task, the D80 from task 1.1.1 is being operated at a

discharge voltage of 700 V. The operating point

was chosen for maximum performance in the

thruster's thermally stable operating regime. A

NASA/TMm2001-211215 3
laserprofilometerymeasurement techniqueis

beingusedtoperiodicallymeasurethegeometry

of thethruster'sguardrings andelectrodes

(Figure7).Todate,theD-80hasbeenoperated

for300hoursandtestingison-going.Testingis

expectedto be completedthis summerand

resultspublishedat the 2001International

ElectricPropulsionConference.

Simultaneously, task1.3.6is focussedonthe

development of in situ erosion diagnostics. The

objective is to demonstrate an optical diagnostic

for measurement of the relative amount of

erosion products versus operating time. Current

efforts are relying on emission spectroscopy of

the plasma within the discharge chamber and

near the exit of the thruster.

The third effort is task 1.3.3, Discharge Chamber

Materials Influence. The influence of various

ceramic discharge chamber materials on erosion

rates and bulk performance is being investigated.

Five different ceramic materials are currently

being evaluated at the same operating conditions

in a NASA-120M 2 kW Hall thruster. The

materials initially selected include three different

grades of boron nitride and two different boron

nitride/silica compounds. Initial calculations

indicated that a 200 hour test duration would be

sufficient to assess erosion. The first specimen,

HP grade boron nitride, has accumulated the 200

hour test duration and the next material is being

installed in the thruster. Based on the results

from initial testing, this effort is anticipated to be

expanded in program year 2002 to include

considerations of fabricability, cost, as well as

the integration issues of contamination and

thruster EMI.

(1.4) Investigation of Innovative System

Approaches / Integration Issues

Task 1.4.2, Performance/Integration GroundSpace Correlation, is work remaining from the

Advanced Space Transportation funded Future-X

portion of the EXPRESS program. 32'33 This

work focuses on data analysis and reporting on

in flight data from two Russian geostationary

communication spacecraft presently in orbit,

EXPRESS A2 and A3 (Figure 8a). These two

spacecraft have a number of plasma probes

mounted at various locations on their structures.

These plasma probes are designed to measure ion

current, and ion energy. Data from these probes

was collected during the operation of eight onboard SPT-100 thrusters used for north-south

and east-west station keeping. These data will be

compared to data from past SPT-100 thruster

ground testing. An example of the type of data

and comparisons being made can be seen in

Figure 8b. This task should be completed and

data published at the 2001 International Electric

Propulsion Conference.

Task 1.4.5, Alternate Operational Strategies,

which has been supported at a low level during

this program year, considers the issues

associated with pulsed (multiple minute) Hall

thruster operation. Pulsed operation of this type

is primarily advantageous for low power

spacecraft with advanced energy storage. These

spacecraft can benefit from the thrust level and

efficiency of a high power Hall thruster by

operating it impulsively. This type of operation

can combine the efficient impulsive orbital

maneuvering used with chemical thrusters with

the high specific impulse of electric propulsion

for overall system advantages. The program

year 2001 effort has considered system

architecture issues and thermal modeling of

thrusters.

Task 1.4.6, Alternate Power /Propulsion

Systems, attempts to capitalize on a key strength

of the Glenn Research Center. The Power and

On-Board Propulsion Division, at NASA GRC,

combines both the power and propulsion

disciplines allowing both groups to easily

leverage each others research. This year two

efforts are under way within this task.

First, an integrated test of a dynamic power

system with an electric propulsion system was

achieved when a Hall-effect thruster was

successfully operated with a free-piston Stirling

power source. The system is picture in Figure 9.

The electrically-heated, 350 W Stirling converter

was designed and built by Stirling Technology

Company of Kennewick, WA and provided to

GRC under a Small Business Innovative

Research (SBIR) agreement. The Hall-effect

thruster used was a 300 W SPT-50. GRC

developed the interface Power Processing Unit

(PPU), which accepted the 48 V DC Stirling

controller output and distributed the power to all

the loads of the SPT-50 including the magnets,

keeper, heater, and discharge chamber. This test

provided an important stepping stone to high

NASA/TM--2001-211215 4
power,propulsionsystemsfor futurerobotic

scienceandhumanexplorationmissionsthatwill

utilizethistypeof powersystem.Dynamic

powersystemswithnuclearsourcesalsoprovide

oneof themostviablepathsfor outerplanet

electricpropulsionmissionswithpowerlevelsin

excessof50kW.

Additionallyunderthistask,aportionof adirect

drive effort, selectedas part of the Cross

EnterpriseTechnologyDevelopment Program

NRA,is beingconducted.Thiseffortbeing

implementedbyMarshallSpaceFlightCenter

(MSFC),ScienceApplicationsInternational

Corporation(SAIC)andGeneralDynamicsis

consideringthe environmentand issues

associatedwithdirectlypoweringaHallthruster

from photovoltaic(PV) poweron-boarda

spacecraft. Theeffortisprimarilypowersystem

related;however, theissuesofassessingtheHall

thrusterenvironment andthecouplingof the

thrusterdirectlywiththePVarrayissupported

underthistask.

(1.5) Component Level Phenomenological

Investigations.

One task is funded within this area under task

1.5.5, Thruster Intemal Plasma and Plume Model

Development. Three modeling efforts are

underway. The first was selected as part of the

Cross-Enterprise Technology Development

Program NRA and is being implemented by MIT

and Busek Co. Inc. It is a comprehensive

modeling effort intended to enhance the

understanding of the limiting physics in efficient

high specific impulse Hall thruster operation. A

multi-dimensional hybrid PIC code is being

used. Results are to be compared to

experimental data from the University of

Michigan P5 and P5-2 thrusters as well as data

from a series of Busek Co. thrusters.

The second effort within this task is the

development of a finite element continuum based

model using a higher-order accurate sub-grid

embedded model to efficiently simulate plasma

flows. This effort is being conducted by

Kettering University and is being investigated

for it's computational accuracy advantages and

ability to deal with different boundary conditions

in a straightforward manner.

The third effort within this task is an empirical

performance model developed at GRC. This

model was developed to enable the prediction of

thrust, specific impulse, and efficiency as design

points and operational envelopes depart from

current state-of-the-art thrusters. For use at high

voltage, the model incorporates the effects of

multi charged species. 34

Focused Program

The objective of the focused effort is to develop

a 50 kW-class Hall propulsion system. System

design trade studies have shown that high power

Hall thrusters are well suited for providing high

thrust with good specific impulse for many

applications. 22-26 This type of propulsion system

is enabling for cost and time critical missions for

Earth orbital applications as well as HEDS and

other space science applications. This effort is

sponsored by NASA's Advanced Space

Transportation Program at MSFC. Additionally

this propulsion system may be enabling for

lower power spacecraft when combined with an

advanced energy storage device and operated in

a pulsed mode as previously mentioned.

The focused program areas are: (2.1) 50 kW

Propulsion System, (2.2) 10 kW Propulsion

System.

C2.1) 50 kW Propulsion System

The 50 kW Propulsion System area has two

funded sub-tasks in program year 2001, (2.1.1.1)

Thruster Development, and (2.1.1.4) Cathode

Development. The thruster development is

being conducted via two contracted efforts. The

first, with General Dynamics, is providing

NASA with multiple variations of a high plasma

density thruster. The design will push the stateof-the-art in both power density and

performance. The second effort, with Busek Co.

Inc., is providing NASA with a thruster design

incorporating a non-circular, or racetrack shaped

discharge chamber. In theory, the racetrack

concept is reconfigurable from 20-50 kW. The

contracted efforts are structured to have a base

thruster design effort with an optional thruster

build effort. Completion of the design efforts is

anticipated by October 2001 with a decision on

the optional build coming shortly thereafter. The

cathode development effort is being conducted

in-house at GRC and is leveraging the Space

NASA/TM--2001-211215 5
StationPlasmaContactorinfrastructure.A

laboratorymodel100A cathodeis presently

beingtested.

(2.2) 10 kW Propulsion System

(2.2) 10 kW Propulsion System work is limited

to reducing the data from the T220 erosion

characterization completed early this program

year. This test provided insight on lifetime

limitations at higher powers and higher discharge

voltage (500 V) than have been previously

investigated in the community. A summary of

these data can be found in Mason et.al. 35

Concluding Remarks

NASA's Hall thruster program consists of both

base research and focused development efforts.

The base effort addresses issues at a low

technology readiness level (TRL) and provides

fundamental understanding required for the

focused development of high TRL Hall thruster

propulsion products. Current questions being

addressed by the base research effort include: (1)

How does thruster life vary with operating point?

(2) How can thruster lifetime and wear rate be

most efficiently evaluated? (3) What are the

practical limitations for discharge voltage as it

pertains to extending the operation of Hall

thrusters to high specific impulse (high discharge

voltage) and high thrust (low discharge voltage)

operation? (4) What are the practical limits for

extending Hall thrusters to very high input

powers? and (5) What can be done during

thruster design to reduce cost and integration

concems? The focused effort is working towards

the development of a 50 kW-class Hall

propulsion system with a program milestone of a

50 kW engineering model thruster/system by the

end of program year 2006.

References

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System Analysis for Electric Propulsion

Missions," 34 th Intersociety Energy

Conversion Engineering Conference,

Vancouver, BC, Canada, August 1999.

25. Gefert, L.P., Hack, K.J., "Options for the

Human Exploration of Mars using Solar

Electric Propulsion," AIP Conference

Proceedings, No. 458, pp1275-1280,

STAIF-99, Nov. 1999.

26. Oleson, S.R., Sankovic, J.M.., "Advanced

Hall Electric Propulsion for Future InSpace Transportation," NASA TM-2001-

210676.

27. Atlantic Research Corporation, NASA

Contract NAS3-99159, Final Report,

"Phase I feasibility Study of the 2,300 W

Hall Current Thruster," July 2000.

28. Manzella, D.H., Jacobson, D.T., and

Jankovsky, R.S., "High Voltage SPT

Performance," AIAA-2001-3774, July

2001.

29. Jacobson, D.T., Jankovsky, R.S., Rawlin,

V.K., Manzella, D.H., "High Voltage TAL

Performance," AIAA-2001-3777, July

2001.

30. Oleson, S.R., "Mission Advantages of

Constant Power, Variable Isp Electrostatic

Thrusters," AIAA-2000-3413, July 2000.

31. Cardin, J., Otsap, B., "A Digital Xenon

Flow Controller Based on ChEMS TM

Technology," IEPC-99-064, October 1999.

32. Peterson, T., Allen, D., Koester, K.,

Baranov, V., Romashko, A., "The

EXPRESS/T-160E Flight Hardware

Development Effort," AIAA-98-3328, July

1998.

NASA/TM--2001-211215 7
33. Peterson,T., Koester,K., Petrosov,V.,

Romashko, A.,Petrusevich, V.,"Updateof

the EXPRESS/T-160EFlightHardware

Development Effort,"AIAA-99-2275, June 1999.

34. Hofer,R.R.andJankovsky, R.S.,"A Hall

ThrusterPerformanceModelIncorporating

theEffectsof a Multi-ChargedPlasma,"

AIAA-2001-3322, July2001.

35. Mason,L.S.,Jankovsky,R.S.,Manzella,

D.H.,"1000Hoursof Testingon a 10

KilowattHall Effect Thruster,"AIAA2001-3773, July2001.

NASA/TMR2001-211215 8
:Z

>

to

O

O

to

L_h

I

1.1

Investigations into

Extending the

Performance Envelope

Evaluation and

Development of

Lightweight/Low Cost

Components

1.1.1

High Specific Impulse

(High Voltage)

t 1.1.2

High thrust density

(Low Voltage)

t 1.1.3

High Power

f 1.1.4

Low Power

f 1.1.5

Cathode Performance

i 1.1.6

Multi-mode

t 1.2.1

COTS PPU Electronics

t 1.2.2

Non-traditional

fabrication approaches

1.0

Base Research

Hall Thruster

Delevopment Program

I

1.0.1

Technology Impact

Assessment

1.3

Thruster Operational

Life Assessment and

Improvement

1.3.1

Thruster Sensitivity to

Operating Point

1.3.2

Accelerated Thruster

Life Testing

1.3.3

Discharge Chamber

Material Influence

1.3.4

Cathode Life Limitations

1.3.5

Lifetime Predictions

1.3.6

Erosion Diagnostics

14li Investigation of

Innovative System

Approaches/Integration

Issues

1.4.1

Alternate Thruster

Geometries

1.4.2

PerformanceIntegration

Ground-Space

Correlations

1.4.3

Alternate System

Configurations

1.4.4

Alternate Propellants

1.4.5

Alternate Operational

Strategies

1.4.6

Alternate

Power/Propulsion

System Approach

I

1.5

Component Level

Phenomenological

Investigations

1.5.1

Transient/Oscillitory

Behavior

1.5.2

Ionization Efficiency and

Effects

1.5.3

Ion Acceleration Effects

t 1.5.4

Thruster Internal

Diagnostic

Development

t. 1.5.5

Thruster Internal

Plasma and Plume

Model Development

2.1.1

Development

2.1.1.1

Thruster

2.1.1.2 m

PPU

2.1.1.3 m

PMA

2.1.1.4

Cathode

___Thermal 2.1.1.5 Control System

.J System2.1.1.6 Definition

__ 2.1.1.7 System Engineering

i

2.1

50 kW Propulsion

System

1

Focused Development 2.0

2.0.1

System Design Trade

Studies

1

r

]

!

2.2

10 kW Propulsion

System

i

2.1.2

Assessment

2.1.2.1

Facilities

2.1.2.2

Personnel

Figure 1 - Hall Propulsion Work Breakdown Structure
Figure 2- SPT-1 Single-Stage High Specific Impulse Hall Thruster

Figure 3- D-80 High Specific Impulse Two-Stage Hall Thruster

NASA/TM--2001-21121.5 l0
Figure 4- P5-2 High Specific Impulse Two-Stage Hall Thruster w/Emitting Electrode

Figure 5- NASA-457M Solid Model

NASA/TM_2001-211215 11
!ili!:!!:_. i_ ._....

Figure 6 - VACCO Integrated Propellant Management Assembly

,£

_ i

...... i ................ _; 1_.......

Figure 7 - D-80 Thruster Geometry Measurement

NASA/TM_2001-211215 12
. : .,,,,:i.:),;:::,:,. _ r. _

• To p tru-_ end pa._ioad

__. .......::.:i_:,::_..;_:.z o.... h--55om_,

Bm'te_ries . .......... : ... _" D 1300 rrrr,,

Satell_ ,:_r_erofqra_fb/ ....::.':........ -f :-::? :-.:_ :.... .': :_ ": .'.. -. :::..: _.320Dmrr,

v=o_, "--I_ ...... I"3_\_ __ .....

..... P'Y ........... it

___ --1--..... Y.I _III, F_,,_YL(_ ..........

_--,--...__, - _ ....-- -.._

..nI-''- _ 2050 rrm

Pa dia_nr l_,errr, i_-lor (T 19_,)__. __---_ _

Figure 8a- Russian EXPRESS Spacecraft

O

@

¢-

C5

¢-

,IJ

C3

¢-

O

1.E-_1

I.E+O0

1._01

1.E-02

1.E-03

1.E-04

-100.0 -50.0 0.0 50.0 100.0 150.0

Angle, Degrees

Figure 8b- SPT-100 Ground and Space Data

NASA/TM_2001-211215 13
Direct

Drive?

Figure 9- Stirling-Hall Direct Drive Testbed

NASA/TM_2001-211215 14

REPORT DOCUIVlENTATION p_ v FormApproved OMB No. 0704-0188

Public reporting burden for this collection of information is _e"d_o _ _ Tl_-uur err .....

lewmg instructions, searching existing data sources,

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this

collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson

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1. AGENCY USE ONLY (Leave blank) __ DATES COVERED "-"---'-"

O__....._.__.___ 2001 l Technical Memorandum 4. TITLE AND SUBTITLE

5. FUNDING NUMBERS

NASA's Hall Thruster Program

6. AUTHOR(S)

Robert S. Jankovsky, David T. Jacobson, Vincent K. Rawlin,,Lee S. Mason,

Maris A. Mantenieks, David H. Manzella, Richard R. Hofer, and Peter Y. Peterson

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

John H. Glenn Research Center at Lewis Field

Cleveland, Ohio 44135-3191

WU-755-B4--05-00

8. PERFORMING ORGANIZATION

REPORT NUMBER

E-13067

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

11. SUPPLEMENTARY NOTES

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

NASA TM--2001-211215

AIAA-2001-3888

Prepared for the 37th Joint Propulsion Conference and Exhibit cosponsored by the AIAA, SAE, AIChE, and ASME, Salt Lake City,

Utah, July 8-11,2001. Robert S. Jankovsky, David T. Jacobson, Vincent K. Rawlin, Lee S. Mason, and Maris A. Mantenieks, NASA

Glenn Research Center; David H. Manzella, University of Toledo, 2801 W. Bancroft Street, Toledo, Ohio 43606-3328; and

Richard R. Hofer and Peter Y. Peterson, QSS Group, Inc., 21000 Brookpark Road, Cleveland, Ohio 44135. Responsible person,

Robert S. Jankovsky, organization code 5430, 216-977-7515.

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Unclassified- Unlimited

Subject Category: 20 Distribution: Nonstandard

Available electronically at htm://gltrs.grc.nasa.gov/GLTRS_

This publication is available from the NASA Center for AeroSpace Information, 301-621-0390.

13. ABSTRACT (Maximum 200 words)

NASA's Hall thruster program has base research and focused development efforts in support of the Advanced Space

Transportation Program, Space-Based Program and various other programs. The objective of the base research is to gain

an improved understanding of the physical processes and engineering constraints of Hall thrusters to enable development

of advanced Hall thruster designs. Specific technical questions that are current priorities of the base effort are: (1) How

does thruster life vary with operating point? (2) How can thruster lifetime and wear rate be most efficiently evaluated?

(3) What are the practical limitations for discharge voltage as it pertains to high specific impulse operation (high discharge

voltage) and high thrust operation (low discharge voltage)? (4) What are the practical limits for extending Hall thrusters to

very high input powers? and (5) What can be done during thruster design to reduce cost and integration concerns? The

objective of the focused development effort is to develop a 50 kW-class Hall propulsion system, with a milestone of a

50 kW engineering model thruster/system by the end of program year 2006. Specific program year 2001 efforts, along

with the corporate and academic participation, are described.

14. SUBJECT TERMS

Hall thruster

17. SECURITY CLASSIFICATION

OF REPORT

Unclassified

NSN 7540-01-280-5500

15. NUMBER OF PAGES

2O

16. PRICE CODE

19.SECU._

, ur , n,_ r'/_L_- ' OF ABSTRACT. ,

Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39-18

298-102