Der HEMP Thruster · Xe + ion beam + e-Space charge neutralised ion beam Neutral Xe Operational...

Der HEMP Thruster -Vorstellung eines neuartigen, höchst leistungsfähigen elektrischen Triebwerks

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Der HEMP Thruster -Der HEMP Thruster -(H(Hoch och EEffizienter ffizienter MMehrstufen ehrstufen PPlasma Thruster)lasma Thruster)

Vorstellung eines neuartigen, höchst leistungsfähigen elektrischen TriebwerksVorstellung eines neuartigen, höchst leistungsfähigen elektrischen Triebwerksfür Satelliten und interplanetare Sondenfür Satelliten und interplanetare Sonden

______________________________________________________________________

Günter KornfeldGünter KornfeldNorbert KochNorbert Koch

Gregory CoustouGregory CoustouThalesThales Electron Devices Electron Devices GmbH GmbH

SöflingerstrSöflingerstr.100, 89275 Ulm.100, 89275 Ulm

Machbarkeitsuntersuchung gefördert durch das DLRMachbarkeitsuntersuchung gefördert durch das DLRSchub Messungen bei ONERA, Palaiseau, gefördert durch CNESSchub Messungen bei ONERA, Palaiseau, gefördert durch CNESIonenstrahlcharakterisierungIonenstrahlcharakterisierung in Zusammenarbeit mit IOM, Leipzig in Zusammenarbeit mit IOM, Leipzig



LEO Satellite Orbit(low earth orbit)

Geo-Orbit (geostationary earth orbit)

To maintain a GEO communication satellite over 15 years on its position requires 775 kgof chemical propellant (Hydrazin), but only 75 kg of Xe for electric propulsion.To bring 1 kg into GEO orbit costs 55.000.- €

Saving in launch costs: 38.5 M €

Alternatively, more payload channels are possible.

Why electric propulsion?

The HEMP thruster concept has the potential to allow

all electric satellite propulsion: orbit raising & station keeping



Achievements within the 3 phases of the feasibility studyAchievements within the 3 phases of the feasibility studyBreakthrough of a new thruster concept achieved within the DLR supportedBreakthrough of a new thruster concept achieved within the DLR supportedfeasibility study for a new electric propulsion concept (funding was 560feasibility study for a new electric propulsion concept (funding was 560 kEur kEur):):

Test at Test at Xe-FluxXe-Flux thrust thrust Isp Isp tot. tot.efficeffic.. therm therm. . efficeffic.. sccm sccm mN mN s s % % % %

Phase 1 07/00 to Phase 1 07/00 to 09/01: TED09/01: TED 0.20.2 0.1 0.1 < 2 < 2 < 2 < 2

Phase 2 10/01 toPhase 2 10/01 to 04/02: Onera 04/02: Onera 0.5 0.5 < 1.4 < 1.4 2776 2776 13 13 <10 <10

Phase 3 05/02 to Phase 3 05/02 to 03/03:03/03:

DM3a MS2DM3a MS2 07/02: Onera 07/02: Onera 30 30 43.0 43.0 1506 1506 22 22 77 77DM3a MS1-3DM3a MS1-3 10/02: IOM 10/02: IOM 8 8 12.0 12.0 1600 1600 38 38 79 79DM6 MSJ5-PS0-EPS4 02/03: TEDDM6 MSJ5-PS0-EPS4 02/03: TED 12 12 24.3 24.3 2116 2116 61 61 85 85DM6 MSJ5-PS0-EPS4DM6 MSJ5-PS0-EPS4 1414 47.4 47.4 3544 3544 54 54 78 78DM6 MSJ5-PS0-EPS4 DM6 MSJ5-PS0-EPS4 27 27 69.5 69.5 2695 2695 47 47 66 66DM6 MSJ5-PS0-EPS4 DM6 MSJ5-PS0-EPS4 33 33 87.1 87.1 2762 2762 43 43 62 62

DM6 MSJ6-PS0-EPS5 03/03: OneraDM6 MSJ6-PS0-EPS5 03/03: Onera 50 50 128 128 2679 2679 37 37

original study goaloriginal study goal 3 3 7.0 7.0 3000 3000 60 60 70 70



Achievements within the feasibility studyAchievements within the feasibility study

HEMP-Thruster Performance Evolution

Isp=2679 s

T=129 mN

ηth=78 %

ηtot=37 %Xe=50 sccm

0

1

10

100

1000

10000

Aug01

Okt01

Dez01

Feb02

Apr02

Jun02

Aug02

Okt02

Dez02

Feb03

Apr03

ISP / sThrust / mNtherm. efficiency / %total efficiency / %Xe Flow / sccm



Schematic of a RITneeds large cross section due to the space charge limitation of the ion

source

Competitive Concepts: Ion Thrusters



Competitive Concepts: Hall Thrusters



Magnet; magnet field

pol epiece (F e)

electrode 1 (1kV);electric field

cathode

accelerated Xenon-Ions

electrode 4 (≈0V)

anode

ion barrier

elect ron beam

High Eff icient Multistage Plasma ThrusterHEMP-Thruster Concept

elect ron beamXe- feeding slits

Basic TEDG patented design of a HEMP–thruster Basic TEDG patented design of a HEMP–thruster



Symmetry axis

E-Feld

∅i = 18 mm

UA1> UA2> UA3>Neutralisator =Masse

In cusp area: Radial magnet fields; axial electric fieldsazimuthal Hall currents of plasma electrons

E-Field E-Field

B-Field

Xe+ ion beam + e-

Space chargeneutralised ion beam

Neutral Xe

Operational principle of the HEMP-thrusterOperational principle of the HEMP-thruster•• As in a TWT, a permanent periodic magnet structure focuses the Xe plasma, on the axis As in a TWT, a permanent periodic magnet structure focuses the Xe plasma, on the axis

and thus prevents losses on the ionisation chamber wall.and thus prevents losses on the ionisation chamber wall.•• The applied plasma potentials The applied plasma potentials UUAAii

between the Cusps decrease towards the exit. The between the Cusps decrease towards the exit. The resulting electrical fields accelerate the Xe-ions.resulting electrical fields accelerate the Xe-ions.

•• A neutraliser may provide at the exit the electrons for neutralisation of the ion beam A neutraliser may provide at the exit the electrons for neutralisation of the ion beam current but is not necessary for thruster operation.current but is not necessary for thruster operation.

•• Due to the crossed electric and magnetic fields in the Due to the crossed electric and magnetic fields in the cusp cusp area the plasma electrons area the plasma electrons are orbiting and mirrored in closed,are orbiting and mirrored in closed, azimuthal azimuthal Hall currents loops, which Hall currents loops, which maintains a quasi-neutral space charge distribution in the plasma chamber and maintains a quasi-neutral space charge distribution in the plasma chamber and lead to a high ionisation rate.lead to a high ionisation rate.

E-Field



•• Angular & velocity distribution of ion beam on DM3a MS1-3 Angular & velocity distribution of ion beam on DM3a MS1-3 at IOM, Leipzig in Oct 02at IOM, Leipzig in Oct 02

•• Thermal diagnostic measurement results on DM6 MSJ6 EPS5 Thermal diagnostic measurement results on DM6 MSJ6 EPS5at TED, Ulm February 03at TED, Ulm February 03

•• Thrust measurements on DM6 MSJ6 EPS5 Thrust measurements on DM6 MSJ6 EPS5 at Onera, Palaiseau in March 03 at Onera, Palaiseau in March 03

Presented test results of last half year:Presented test results of last half year:



Tests with energy selective mass spectrometerTests with energy selective mass spectrometerat IOM, Leipzig in Oct 02at IOM, Leipzig in Oct 02

results inresults inMass spectroscopy andMass spectroscopy and

Ion beam angular & velocity distributionIon beam angular & velocity distributionof DM3a MS1-3of DM3a MS1-3



DM3a MS1-3 ion beam mass spectroscopy DM3a MS1-3 ion beam mass spectroscopy in an angle of 30° at kinetic energy of 500 eVin an angle of 30° at kinetic energy of 500 eV

DM3a MS1-3 ion beam mass spectroscopy at 30° , 500V

100

1 000

10 000

100 000

1 000 000

10 000 000

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Mass / amu

Inte

nsity

/ C

ount

s / s

30°

Xe1+

Xe2+Xe3+

Xe4+

Xe5+ Fe1+



DM3a MS1-3DM3a MS1-3Energy spectrum of Xe+ and Xe++ Ions at 35°Energy spectrum of Xe+ and Xe++ Ions at 35°

operating atoperating at Ua Ua=500V,=500V, Ia Ia=505mA=505mA

0100000200000300000400000500000600000700000800000900000

1000000

0 100 200 300 400 500 600 700 800 900 1000

Kinetic Energy /eV

Cou

nts

of X

e+ io

ns

Xe+Xe++



Angular and energy distribution of single charged Angular and energy distribution of single charged XeXe1+1+ ion beam in DM3a MS1-3 ion beam in DM3a MS1-3

DM3a MS1-3; 500V, 505 mA; Xe+

0100000200000300000400000500000600000700000800000900000

1000000

0 100 200 300 400 500 600

Kinetic Energy /eV

Inte

nsity

of X

e+ ions

/ C

ount

s/s

55°

35°40°

30°

45°

25°

20°

50°

65°

60°

5°

0°

Anode1. Cusp2. CuspExit Cusp

Downstream



Angular Distribution of Thrust contribution

0

0.5

1

1.5

2

2.5

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90

Angle / Degree

thru

st c

on

trib

utio

n in

5°

spac

e an

gle

s/ m

N total angular thrustcomponent /mN

dual charged angular thrustcomponent /mN

single charged angularthrust component /mN

43°

Angular distribution of 12.2 mN thrust Angular distribution of 12.2 mN thrust of single and double charged Xe ionsof single and double charged Xe ions

in DM3a MS1-3 at Ua = 500 V and 8 sccm Xe flow. in DM3a MS1-3 at Ua = 500 V and 8 sccm Xe flow.



Dimension of the TEDGDimension of the TEDGtest chambertest chamber

originally a thermal vacuum testoriginally a thermal vacuum testchamber for space TWT'schamber for space TWT's

80 cm 80 cm dia dia x 100 cmx 100 cm

really required:really required:150 cm 150 cm dia dia x 500 cmx 500 cm



Thermal diagnostic set upThermal diagnostic set upin the test chamber within the test chamber with

HEMP thruster DM 6 MSJ6 EPS5HEMP thruster DM 6 MSJ6 EPS5



Comparison ofComparison ofthermal diagnostic at TED, Ulm & thermal diagnostic at TED, Ulm &

thrust balance results at Onera, Palaiseau thrust balance results at Onera, Palaiseau on HEMP thruster DM 6 MSJ6 EPS5on HEMP thruster DM 6 MSJ6 EPS5



Thrust tests at Onera PalaiseauThrust tests at Onera Palaiseau

View on the DM3a MS 1-2 at installation in the thrustbalance of ONERA Palaiseau(CNES-support!)HEMP Miniatur thruster produceslarge thrust!Thrust density more than 5- times higher than thatof a Hall thruster, 100 times higher than aconventional gridded ion thruster.

HEMP DM3a MS1-2 in ONERA's test station inoperation,Side view through window in vacuum chamber

• 43 mN thrust from 2,5 cm² exit area• up to 70% thermal efficiency and• 32% total efficiency (includes Xe-ionisation)

Thruster exit

Neutraliser



MS2; α=40°; Thrust vs. Xe-FlowParameter: Anode Voltage

0

10

20

30

40

50

0 5 10 15 20 25 30 35

Xe-Flow

Th

rust

/ m

N

JulyJuly 2002 ; DM3a-MS2 : 2002 ; DM3a-MS2 : Thrust Thrust vsvs Xe- Xe- FlowFlow

ααeffeff = 55° = 55°up to 43 mNup to 43 mNlinear increaselinear increaseof thrust with Xe-flow.of thrust with Xe-flow.Limits not tested.Limits not tested.

α=55°



March 2003; HEMP Thruster DM 6 MSJ5 March 2003; HEMP Thruster DM 6 MSJ5 (effective beam angle (effective beam angle ααeffeff = = 35°, thermal diagnostics) 35°, thermal diagnostics)

with newwith new TED neutraliserTED neutraliser

2 cm diam.



HEMP thruster DM 6 MSJ6HEMP thruster DM 6 MSJ6

(thermal diagnostic TED) (thermal diagnostic TED) (thrust balance ONERA) (thrust balance ONERA)

0102030405060708090

100110120130140150

0 200 400 600 800 1000 1200 1400

Anode Voltage / V

Thr

ust /

mN

50sccm

40sccm

30sccm

20sccm

14sccm

Thrust vs. Anode VoltageDM6 J6-PS0-EPS5

0102030405060708090

100110120130140150

0 200 400 600 800 1000 1200 1400

Anode Voltage / V

Thr

ust /

mN

50sccm

40sccm

30sccm

20sccm

14sccm

30cl.gv

30ONG

Thrust vs. Anode VoltageDM6 J6-PS0-EPS5





0250500750

1000125015001750200022502500275030003250350037504000

0 200 400 600 800 1000 1200 1400

Anode Voltage / V

Spec

ific

Impu

lse

/ s 50sccm

40sccm

30sccm

20sccm

14sccm

Specific Impulse vs. Anode VoltageDM6 J6-PS0-EPS5

0250500750

1000125015001750200022502500275030003250350037504000

0 200 400 600 800 1000 1200 1400

Anode Voltage / V

Spec

ific

Impu

lse

/ s

50sccm

40sccm

30sccm

20sccm

14sccm

30clgv

30ONG

Specific Impulse vs. Anode VoltageDM6 J6-PS0-EPS5

Isp = T / (QXe. 9.81 m/s²); with T = thrust ; QXe = Xe mass flow



HEMP thruster DM 6 MSJ6 EPS5HEMP thruster DM 6 MSJ6 EPS5

(thermal (thermal diagnosticTEDdiagnosticTED) ) (thrust balance ONERA) (thrust balance ONERA)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0 200 400 600 800 1000 1200 1400

Anode Voltage / V

Tot

al E

ffic

ienc

y

50sccm

40sccm

30sccm

20sccm

14sccm

Total Efficiency vs. Anode VoltageDM6 J6-PS0-EPS5

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

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0.550

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0 200 400 600 800 1000 1200 1400

Anode Voltage / V

Tot

al E

ffic

ienc

y

50sccm

40sccm

30sccm

20sccm

14sccm

30clgv

30ONG

Total Efficiency vs. Anode VoltageDM6 J6-PS0-EPS5

ηtot = T² / (2 . Pa. QXe ) with T = thrust ; QXe = Xe mass flow; Pa = anode power



0250500750

10001250150017502000225025002750300032503500375040004250450047505000525055005750600062506500

0 200 400 600 800 1000 1200 1400

Anode Voltage / V

Ano

de C

urre

nt/ m

A 50sccm

40sccm

30sccm

20sccm

14sccm

Anode Current vs. Anode VoltageDM6 J6-PS0-EPS5



0250500750

10001250150017502000225025002750300032503500375040004250450047505000525055005750600062506500

0 200 400 600 800 1000 1200 1400

Anode Voltage / V

Ano

de C

urre

nt/ m

A

50sccm

40sccm

30sccm

20sccm

14sccm

30clgv

30ONG

Anode Current vs. Anode VoltageDM6 J6-PS0-EPS5



HEMP thruster characteristics in comparison HEMP thruster characteristics in comparison with Hall effect and grid ion thrusters with Hall effect and grid ion thrusters



Parameter Ion thruster Hall thruster HEMP thruster

Plasma thrust density 0,2 mN/cm² 2mN/cm² >20 mN/cm² (32 achieved)

Mass & Volume large medium small

Acceleration grids required yes no noIon emission space charge limited yes no no

Neutraliser required yes yes optionally no(depends on space plasma density)

Erosion effects at grids at channel walls minimal, PPM focused plasmaReliability & Life sufficient sufficient not tested, but no wear mechan.

Additional supplies required: for e.g. RF-source for magnet coils no

Power supply & control unit complex complex simple

Total efficiency good(65%) medium (30%-55%) good (>75%, fut. potential)

Beam angle < 15° < 45° < 30 ° (future potential)

Flexible application & adjustabilityHigh thrust/W or high spec.impulse good to medium low very good

Specific impulse / s 2000 to 4000 1000 to 2000 1000 to >3500

Comparison of HEMP thruster design potentials with state of the art Comparison of HEMP thruster design potentials with state of the art Hall effect and grid ion thrusters Hall effect and grid ion thrusters



RIT- XTRIT- 35/ ESA XXHEMP DM3aachieved =07/02

HEMP DM6 measured:03/03

HEMP planned 06/05 with

future potential by scaling

Key performance of grid ion thrusters and Hall thruster SPT 100 inKey performance of grid ion thrusters and Hall thruster SPT 100 incomparison with HEMP thrusters, updated 10/02comparison with HEMP thrusters, updated 10/02



References:

1) A. Smirnov et al., ”Parametric Investigations of Miniaturized Cylindrical and Annnular Hall Thrusters”, International Electric Propulsion Conference IEPC 2001, Pasadena.2) A.I. Bugrova et al., ”Design and Experimental Investigation of a Small Closed Drift Thruster”, International Electric Propulsion Conference IEPC 2001, Pasadena.3) J.D. Filliben, ”Electric Thruster Systems”, Chemical Propulsion Information Agency, June 1997

Comparison of HEMP thruster with Comparison of HEMP thruster with smallsmallHall effect Thrusters (HET)Hall effect Thrusters (HET)

Thruster type

Parameter

HEMP-DM3,

ONERA 1 test

HEMP-DM3aMS1-2

ONERA 2 test

HEMP-DM3aMS1-3

IOM test

HEMP-DM6MSJ5

TEDG test

CylindricalHET 1)

KM-20MHET 2)

SPT 50HET 3)

April 2002 July 2002 Oct. 2002 Feb. 2003

Q / sccm 0.55 15 8 12 4 3 10

T / mN 1.4 24 12 24.3 4.5 4 17.3

η tot / % 13 32 38 61 26 30 32

η ion / % 132 73 90 110 ~100 ~100 ~90

Isp /sec 2776 1680 1600 2116 1330 1360 1160

Input Power/ W 150 638 252 414 135 105 300

Thrust density/ mN/cm2 2.2 9.5 4.75 6.4 0.85 2.0 2.0Power to thrustratio / W/mN 107 26.6 21 17.0 30.0 26.3 17.3



Type Name / Reference Input Power Thrust Spec. Imp. Tot. Eff. Mass Thrust density [W] [mN] [s] [%] [kg] [mN/cm²]

Arc Jet MR-508 / Primex 1800 200 500 30 1.36

cyl. HET / PPL Princeton Univ. 160 5.9 1450 27 0.85HET THT-3A-BN / Osaka Univ. 960 39 1990 43HET SPT-50 / Fakel 300 17 1160 32 2HET SPT-70 / Fakel 660 40 1600 40 1.5HET SPT-100 / Fakel 1350 83 1600 48 3.5 2HET T100-SPT / NIITP 1350 80 1600 49 3

TAL-HET D-55 / TsNIIMASH 1350 ~ 80 1600 48

GIT NSTAR-30 / NASA - Hughes 2500 92 3300 65 7GIT XIPS-25 1400 63 2800 65GIT RIT-XT 2900 100 4050 64 ( 5 to 10) ? 0.3GIT RIT-35 6000 200 3200 52 ? 0.21

HEMP DM6 MSJ5 414 24.3 2116 61 6.4HEMP " 1526 47.4 3544 54 12.5HEMP " 2184 80 2536 46 21.5HEMP 100 to be developed 2000 100 3550 >70 1.3 incl. Neutr. 30

Comparison of HEMP thruster with state of the art Comparison of HEMP thruster with state of the art Hall effect and grid ion thrusters Hall effect and grid ion thrusters

Data source J.D.Data source J.D.FillibenFilliben (1997); IEPC Conferences up to 2001 and TEDG(2002) (1997); IEPC Conferences up to 2001 and TEDG(2002)



TEDG hollow cathode neutraliser TEDG hollow cathode neutraliser based on space proven based on space proven

W/Os mixed metal cathode technologyW/Os mixed metal cathode technology



TEDG hollow cathode neutraliser TEDG hollow cathode neutraliser - design -- design -



TEDG hollow cathode neutraliserTEDG hollow cathode neutraliser- assembly -- assembly -



TEDG hollow cathode neutraliser TEDG hollow cathode neutraliser - preliminary characterisation -- preliminary characterisation -

•• Dimensions: Dimensions: φ φ 20 mm x 25 mm length20 mm x 25 mm length

•• Mass: Mass: 30 g30 g

•• Performance: stable operation at Performance: stable operation at

–– low gas consumption < 0.2 sccm (~ 0.02 mg/s) low gas consumption < 0.2 sccm (~ 0.02 mg/s)–– low power consumption: keeper 400 mA x 17 V ~ 7 W, heater ~ 6 W low power consumption: keeper 400 mA x 17 V ~ 7 W, heater ~ 6 W–– high keeper currents >> 2000 mA possible (power supply limitation) high keeper currents >> 2000 mA possible (power supply limitation)

Der HEMP Thruster · Xe + ion beam + e-Space charge neutralised ion beam Neutral Xe Operational...

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