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REVIEW OF PLASMA PROPULSION ACTIVITIES IN ITALY

W. D. Deininger,"BPD Difesa E Spazio, Colleferro (Roma) ITALY

M. Andrenucci*Centrospazio, Pisa, ITALY

G. Paccani"University of Rome, Rome, ITALY

A. Trippi'ESA/ESTEC, Noordwijk, The NETHERLANDS

F. Rossi'ASI, Rome, ITALY

Abstract

This paper reviews the progress and results of plasma thrustertechnology development in Italy since the last International ElectricPropulsion Conference. This work includes low power (1 kW-class) andmoderate power (10-15 kW) arcjet technology development at BPD Difesa eSpazio, low power arcjet and gas-fed MPD thruster research at Centrospazioand solid Teflon propellant MPD thruster research at the University ofRome. The two arcjet test facilities at BPD are now operational Parametricperformance mapping is being conducted on low power and moderate powerarcjets. A laboratory model low power arcjet has demonstrated a specificimpulse of 440 s using simulated hydrazine while initial testing of alaboratory model moderate power arcjet has demonstrated over 650 s. Twosimilar water-cooled engines showed the same performance on hydrogen overa specific impulse range of 500 to 620 s. Preliminary estimates of gas-fedring anode MPD engine performance correspond to a specific impulse rangeof 1000 to 3000 s with efficiencies in the range of 15 to 30%. Breach-fed andradially-fed solid Teflon MPD thrusters were tested over an instanteouspower range of 0.6 to 3 MW. Future plans include engineering model arcjetdevelopment, MPD thruster testing, detailed arcjet flight system definition,arcjet breadboard PCU testing and detailed definition of the DIVAexperiment.

# Consultant, Manager Electric Propulsion Laboratory, Space Division. Member AIAA.O Director. Also Professor, University of Pisa, Aerospace Engineering. Member AIAA.* Professor, "La Sapienza," Department of Mechanical and Aeronautic Engineering.1 Engineer, Contract Monitor, Electric Propulsion Unit.§ Engineer, Electric Propulsion Program Project Manager.

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Nomenclature system definition and the DIVA experiment are alsodiscussed.

ASI Italian Space AgencyBPD BPD Difesa e Spazio ARCJET TECHNOLOGY DEVELOPMENTCS CentrospazioDACS Data acquisition and control system Two classes of arcjets are being investigated inESA European Space Agency Italy by BPD and its subcontractors. Low power arcjet (0.5FET Field effect transistor - 1.5 KW) technology development is being conducted withIRS University of Stuttgart, Institut fur support from CSI '2 15' 9""" 24 while 1 N-class arcjet (10 - 15

Raumfahrtsysteme kW) technology development is being conducted byIV2 CS MPD thruster test facility BPD' 2.1 -" 22 and has been supported by the University ofIV3 CS arcjet engine test facility Stuttgart (IRS).9' .1" 6 The recent test results from theseMPD Magnetoplasmadynamic (thruster) programs are summarized below. The facilities used atMURST Italian Ministry for University Scientific BPD and CS to conduct arcjet technology development are

and Technical Research also summarized below.NSSK - North-South station keepingPEA Propellant effective area Facilities and DiagnosticsPFN Pulse forming networkPFS Propellant feed system BPD has two operational arcjet test facilities andUoR University of Rome, La Sapienza CS has one facility operational.VP-1 Large arcjet test facility at BPDVP-2 Small arcjet test facility at BPD BPD Difesa e Spazio

BPD has installed two state-of-the-art arcjet testINTRODUCTION facilities designated VP-1 (for testing of both classes of

engine and tests with hydrazine) and VP-2 (for low powerResearch activities in plasma propulsion began in arcjet development), see Fig. 1. Detailed descriptions of

Italy in the early 1980s with system definition studies on these facilities can be found in References 7, 14, 15 and 18.MPD thruster systems for orbit raising of large spacecraft. Both facilities are operational. Each facility has fullyAdditional studies were conducted to examine solid Teflon independent vacuum pumping systems, power supplies, dataMPD thrusters for North-South station keeping (NSSK) acquisition and control systems and diagnostics. Bothmissions. These system studies were followed by facilities share the laboratory cooling water system and theexperimental development activities on gas- and Teflon-fed nitrogen and hydrogen gas supplies. Both pumping groupsMPD thrusters. In 1987 the program focus was expanded can be used to pump on the VP-1 vacuum chamberto include arcjet propulsion system technology development, providing an increased pumping speed by opening butterflyInvestigations of two classes of arcjet thrusters began, low valve CV and closing the AV butterfly valve.power arcjets (1 kW-Class) for NSSK and moderate powerarcjets (10 kW-class) for orbit change of large man-tended Facility VP-1 (Fig. 2), is composed of aspace platforms. European applications for arcjets are water-cooled vacuum chamber 1.6 m in diameter and 4.0 mforeseen in the middle to late 90's. long connected to a four-stage pumping group. The first

stage of the pumping group is composed of two 25,000This paper will review the activities performed in m'/h and one 18,000 m'/h Roots pumps connected in

Italy in plasma propulsion since the last International parallel. The second stage is composed of a single 12,000Electric Propulsion Conference'" and summarize the status m'/h Roots pump followed by the third stage 2,000 m'/hof the ongoing activities."" This work includes low power Roots pump and the fourth stage 500 m'/h rotary pump, see(1 kW-class) and moderate power (10-1.5 kW) arcjet Fig. 3. The system pumping speed is 58,000 m3/h at 0.01technology development at BPD Difesa e Spazio (BPD), mbar. The facility provides a background pressure of 0.02low power arcjet and gas fed MPD thruster research at mbar during moderate power engine operation at aCentrospazio (CS) and solid Teflon propellant MPD thruster simulated hydrazine mass flow rate of 150 mg/s.research at the University of Rome (UoR). The activitieswhich are discussed include facilities status, low power The auxiliary systems on VP-1 include thearcjet system technology development activities, 10 kW/N propellant feed system (PFS), power supply, dataarcjet engine testing progress, optical plume analysis results acquisition and control system (DACS), cooling waterand gas-fed and solid teflon-fed MPD thruster testing. The system, diagnostics and safety as shown in Fig. 3. The PFSstatus of the systems studies activities on low power arcjet can provide argon, nitrogen, helium, hydrogen and ammonia

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to the engine alone or in mixtures and is designed for Centrospazioendurance testing. The flow rates can be varied between 1and 300 mg/s'for each gas or mixture of gases. A separate Centrospazio uses the IV3 facility for low powerhydrazine propellant feed system can provide between 12.5 arcjet testing.' " ' The IV3 facility consists of a steeland 250 mg/s of hydrazine. An exhaust gas neutralization vacuum chamber connected through a gate valve assemblysystem has been installed to neutralize ammonia to the pumping system, see Fig. 4. The vacuum chamber(NaCIO/water) and hydrazine (NaOH/water). A vacuum is made up of two sections; a cylindrical test section withchamber cooling water system can continuously remove up removable end caps. 1.25 m in diameter and 1.75 m into 100 kW,. The power supply consists of start-up and run length, and a 1.25 m diameter manifold tube connecting theunits and can be operated continuously at 100 KW. A tank test section to the gate valve assembly. A 0.7 m-programmable logic controller (PLC) is used for facility diameter flange on the side of the test cell opposite thecontrol and safety functions. A continuous 10 kW battery pump access manifold tube has been mounted on a trolleypower supply and 50 kW motor/generator set provide power and supports the main instrumentation flanges (anto the PLC and fourth stage pump to maintain the facility observation window and twelve feedthroughs). Thein a safe condition in case of a power failure and enable the pumping system consists of two oil booster pumps backedPLC to shut down the systems in the proper order. by four rotary pumps with a total pumping speed of 20,000Diagnostics facilities include a thrust balance (0.05 to 1.5 Vs at a background pressure of 10' mbar. Two 24" gateN), mass flow meters, temperature probes (pyrometer and valves are used to isolate the pumping system from thethermocouples), current and voltage transducers and various vacuum chamber and facilitate modification of thefacility pressure transducers which are monitored by a experimental set-up during the course of a test run.DACS-based on a personal computer which includes 24input channels at 100 kHz for one channel. In addition. The auxiliary systems include a PFS. powerthe diagnostics facilities include an emission spectroscopy supply and DACS. The PFS was designed to providesystem (for arcjet plume velocity profiles, species argon, nitrogen, hydrogen or mixtures of these gases (toconcentrations, atom temperature and/or electron density) simulate ammonia or hydrazine) to the arcjet at flow ratesand various pressure, temperature and camera outputs. between 0 and 60 mg/s. The flow rate was measured with

a precision of 0.1% of FS. Each gas was filtered by aMesser-Grishaim Oxisorb to ensure an oxygen free

Facility VP-2 is composed of a vacuum chamber propellant supply to the arcjet. The power supply unit0.8 m in diameter and 1.6 m long connected to a four-stage consists of a start-up circuit and a run power supply. Thepumping group, see Fig. 3. The first stage consists of two start circuit provides a 2.0 kV pulse across the electrodes13.000 m'/h Roots pumps connected in parallel. The for 20 ps and the run power supply can provide up to 70 Asecond and third stages are made up of 9.000 and 2.400 and has an open circuit voltage of 150 V. A dedicatedm'/h Roots pumps, respectively, while the fourth stage DACS equipped with a high speed voltmeter and a 24consists of a 450 m'/h rotary pump. The system pumping channel FET multiplexer was implemented to record analogspeed is 19,000 m'/h at 0.03 mbar. A first stage bypass is measurements. The DAS was connected to a workstationincluded for reduced pumping speeds. for data recording and initial processing. The thrust

stand used for the arcjet tests consisted of three basicelements: a single degree of freedom suspension for the

The auxiliary systems on facility VP-2 include an thruster, a load cell and a remotely-operable calibrationindependent power supply system, DACS and diagnostics system.allowing parallel testing in both facilities. The PFS canfeed nitrogen, hydrogen, ammonia vapor and mixtures ofthese gases to the engine over a flow rate range of 1 to 100 Low Power Arcjetsmg/s for each gas. A cooling water system providescooling for the vacuum chamber end caps and test stand. Testing of low power arcjets is presently underThe power supply is capable of starting and operating low way at both BPD and CS. The testing activities at CS arepower arcjets of up to 2.5 KW. A personal computer based focused on engine modelling." PCU design." operatingDACS is used in the facility (16 channels, up to 500 KHz envelope definition and parametric performance mappingper channel). Diagnostics facilities instrumentation enables using nitrogen, hydrogen and mixtures of thesethe measurement of thrust, various pressures and gases. "-5'"1 The test activities at BPD include parametrictemperatures, and engine operating voltage and current, performance mapping using nitrogen, hydrogen, ammoniaThe emergency power system (10 KW continuous battery and mixtures of these gases 2",'"S' but will be centeredand 50 KW motor/generator set) is also connected to toward testing on catalytically decomposed hydrazine andfacility VP-2. endurance testing.

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Figure 5 shows the low power arcjets being injected into the plenum chamber directly through theinvestigated. The MOD-A engine is presently under test in plenum chamber wall. Thermal analysis has beenboth laboratories for accelerated development and data cross conducted on the MOD-3A engine to examine the criticalchecking. This laboratory model engine has been designed engine temperatures. The grid used for the analysis, alongto enable simple changeout of the anode, cathode and gas with the initial results, is shown in Fig 16."injection piece for parametric testing without disassemblyof the entire engine. Typical data for the MOD-A engine MPD THRUSTER DEVELOPMENTusing a gas mixture to simulate hydrazine is shown in Fig.6."2 The specific impulse-specific power (power divided Facilitiesby the mass flow rate) characteristic is shown for a flowrate range of 40 to 50 mg/s. This section reviews the facilities at CS and UoR.

The MOD-B engine has also been designed for Centrospaziosimple changeout of the anode, cathode and injector platealong with providing a design which can be used for both Facility IV2 is used at CS for testing MPD'cold' gaseous propellants and decomposed hydrazine. thrusters.'0 The IV2 vacuum facility is shown schematicallyThermal analysis was conducted on the MOD-B design, in Fig. 17. The facility consists of a fiberglass chamber.The grid used for thermal analysis along with the initial 0.8 m in diameter and 1.0 m in length, which permitsresults are shown in Fig. 7."s' " A nozzle outer surface testing of MPD thrusters with minimal electromagnetictemperature of 1250 *C is expected during engine operation. interference from the chamber walls. The pumping systemFigures 8 and 9 show the nozzle surface temperature consists of a rotary roughing pump and an oil diffusiondistribution and specific impulse-specific power pump. This system permits operation at a backgroundcharacteristic, respectively." pressure of 2x10 s Torr with a pumping speed of 6500 1/s.

The pumping system is connected to the fiberglass chamberModerate Power Arcets by a gate valve. Testing conditions are normally reached

within 3 hours.Testing of 1 N thrusters (15 KW-class) is

underway at BPD.' Zs '.'6 2' Parametric performance mapping The electric power equipment consists of a powerof a water-cooled, laboratory model engine began at IRS in supply, a pulse forming network (PFN). a ballast resistor1988, under subcontract to BPD, and was completed earlier and an ignitron switch and is used to charge the PFN beforethis year."' Activities at BPD started with parametric each thruster pulse. The PFN consists of a ten sectiontesting of a water-cooled engine"'" and are now focused on inductive-capacitive (LC) ladder network with a totaldevelopment of radiation cooled engines.3' 2 Near term capacitance of 12500 pF and a total inductance of 20 pH.activities at BPD include parametric testing of several The characteristic impedance of the network is 40 m, withdifferent advanced laboratory model engines with different a pulse length 1000 ms and an energy storage capability ofpropellants including hydrogen, ammonia, gas mixtures to 3.6 kJ at 2400 V. When matched with a suitablesimulate hydrazine and decomposed hydrazine. impedance, this equipment provides an approximately-

rectangular, 1 ms current pulse of up to 30 kA. As a safetyA schematic of the moderate power, water-cooled measure, the PFN is equipped with a dump switch. The

arcjet tested by BPD, designated MOD-I', is shown in Fig. variable ballast resistor (0 to 40 mQ) is used in order to10 which is similar to the MOD-I engine tested by IRS. match the internal impedance of the PFN with theThe engine had a segmented, water-cooled nozzle enabling impedance of the experimental devices (MPD engines).variations in the nozzle and constrictor geometry. Figures The ignitron is an electronically controlled switch which11 and 12 show a performance comparison in terms of the permits the discharge to trigger at the appropriate time withvoltage-current characteristic and specific impulse between respect to the gas pulse in order to ensure that the dischargethe MOD-1 and MOD-l' engines operating on hydrogen.' takes place when the injected gas mass flow rate hasBoth engines showed similar performance, reached a steady value. The PFS provides carefully defined

pulses of argon gas to the MPD thruster.Radiation-cooled 1 N arcjets are being tested at

BPD.' s n A schematic of the MOD-2 engine is shown in The diagnostic equipment used during theFig. 13. This engine is similar to engines under test program included equipment for measurement of theelsewhere."' The voltage-current and thrust characteristics thruster performance and electrical characteristics. Thefor engine operation on a gas mixture simulating hydrazine thrust stand consists of a mobile thruster mounting piece,are shown in Figs. 14 and 15, respectively." Current supported by four bars. This arrangement allows only atesting activities are focused on the MOD-3A engine which one degree of freedom (1-DOF) of displacement along theis similar to the MOD-2 except that the propellant gas is main thruster axis. The motion of the mobile mass caused

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by a thruster shot is measured by means of a proximity Teflon-Fed MPD Thrusterstransducer. The other instrumentation included two highvoltage probes, a Rogoswski coil, a mass flow meter for the The present activities at UoR are focused onmass flow rate calibration and two piezoresistive pressure coaxial, non-steady, solid propellant (Teflon) MPD thrustersgages for calibration of the gas feeding line. The data with instantaneous powers of a few megawatts. This work.acquisition system consists of a transient recorder, a in collaboration with CS, is being funded by MURST andcomputer for data reduction and analysis and peripherals. ASI in two phases with the ultimate goal being to

experimentally define MPD thruster laws. The first phase.University of Rome which was just completed, was aimed at defining the

standard parameters to be used in engine performanceThe vacuum facilities at UoR are based on characterizations in order to analyze and compare non-

cylindrical Plexiglass chambers pumped with oil diffusion steady systems with different discharge waveforms in thepumps. The chamber volume is approximately 0.2 m3 and operating regime of interest. In addition, test procedureshas a back pressure in the range of 2 to 4 X 10" mbar. and engine geometry effects were defined. The secondThe PFN has available values of initial energy from 0.67 kJ phase, which has just begun, is dedicated to systematicto 2.67 kJ in steps of 033 kJ. The diagnostics include a experimental evaluation of the MPD thrusters according thethrust stand, Rogowsky coils with operational amplifiers, variables defined in first phase. The engine thrust, surfacevoltage probes and several Langmuir probe systems for temperature and plume electronic density are also beingplasma and velocity measurements. examined.

Tests were conducted using breech-fed andGas-Fed Ring Anode MPD Thruster radially-fed, solid Teflon propellant MPD thrusters. The

engines had a segmented anode (4, 6 or 8 segments) whichGas-fed MPD thrusters are operated in a quasi- was either cylindrical or flared in shape. The variables

steady mode at instantaneous power levels of megawatts for included the propellant effective area (PEA), anode shapeseveral milliseconds. This research is aimed at improving and length, anode to cathode radius ratio and the dischargethe understanding of the basic physical processes involved waveform and power." The engine was operated over anin pure MPD acceleration mechanisms and providing design instantaneous power range of 0.6 to 3.0 MW. The currentcriteria for future engine designs. The test activities have collected by each segment of the anode is individuallybeen focused on exploring the effects of engine scale and monitored to determine the energy distribution along thegeometry on the engine electrical and performance anode (see Fig. 22). The PFN has been fully modelled andcharacteristics, experimentally characterized. Double Langmuir probes are

used to monitor the plume temperature and electronicThree ring anode MPD thrusters are being tested density. Figure 23 shows sampled and processed data from

at CS as shown in Fig. 18' sa '2 . These engines are scaled the double Langmuir probes. A time-of-flight (TOF)such that one engine (1:42 scale) has an anode area Langmuir probe system was used to measure the plumeopening one half the size of the benchmark engine (1:1 velocity.' The detection of the delay time betweenscale) while the other engine has an anode opening area of acquisition of the signals by the two probes is the criticalone quarter (1:2 scale) the size of the benchmark engine, measurement The plume velocity and the velocityThe engines can be fired up to 2 times per minute. deviation are directly related to the spacing between theParametric test data on the full scale engine are shown in probes and inversely proportional to the delay time. TheFigs. 19 and 20. These figures show the voltage-current velocity deviation corresponding to different values of thecharacteristic (log/log) and efficiency-specific impulse ratio between the probe separation distance and the delaycharacteristic, respectively." These data are in good time is given in Fig. 24.agreement with theoretical predictions.

Pulsed MPD operation is subject to high erosion FUTURE PLANSlevels from cold cathode operation. In order to quantifythis effect, a heated cathode configuration is being The ongoing programs include arcjet engineeringdeveloped to compare quasi-steady MPD operation with model development for both the low power and moderatecold and hot cathodes. The prototype heated cathode is power engines. The near-term emphasis is on the lowshown in Fig. 21. The device is based on arcjet-like power engine. These engine development efforts includeoperation where a discharge between an internal cathode design and thermal analysis, additional parametric testingand the outer electrode (anode for heating system and and endurance testing with on/off cycling. Thecathode for MPD thruster) heats the outer electrode. development activities will be centered on testing with

decomposed hydrazine although supporting tests with gas

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mixtures are planned at both BPD and CS under ASI and specific impulse using a gas mixture to simulate hydrazine.ESA sponsorship. Initial test results from the radiation-cooled, 1 N-class

engine have shown a specific impulse in excess of 650 sLow power arcjet propulsion system development with simulated hydrazine.

has begun this year under ASI sponsorship. This work isbeing conducted by BPD with CS, SEPA and ANSALDO Development testing of MPD thrusters isserving as subcontractors. The Phase 1 program, which just continuing at CS and UoR. Both gas-fed and solid Teflon-has started, will last 18 months and will include a system fed devices are under investigation. Test results to datestudy to define the- mission and first application in detail, have shown close correlation with the predictedAdditional activities include the establishment of the characteristics.mission requirements and determination of the preliminaryflight propulsion system configuration and subsystem Future activities include testing of both classes ofrequirements. The power level is expected to be between arcjets on decomposed hydrazine, endurance tests with0.5 and 1.5 KW. Detailed initial designs of all the on/off cycling and engineering model development Anpropulsion system components will be produced. The arcjet system definition study is being conducted to identifycomponents to be considered include the arcjet, gas the first application for the low power arcjet system,generator, PCU, connecting cable, propellant storage and conduct the initial design work for the flight propulsionfeed system, propulsion system controller and diagnostics. system components and design, build and test a breadboardThe design, fabrication and testing of a breadboard model PCU. Finally, the detailed definition activities for thePCU is also included in-this program. Finally, the planning DIVA low power arcjet flight experiment are expected tofor the engineering model and qualification phases will be start early next year.established.

The DIVA experiment has been tentatively ACKNOWLEDGEMENTSaccepted as one of the Columbus Precursor FlightExperiments and is scheduled for launch on the EURECA-3platform in 1997. The DIVA experiment, Fig. 25, is a The work descnbed in this paper was carried outflight test of a 1 kW-class arcjet system to demonstrate its by the staff of BPD Difesa e Spazio (BPD), Centrospazio.readiness for flight applications and will serve as a the University of Rome. "La Sapienza" and the Institiit firprecursor to the mission identified in the study cited above. Raumfahrtsysteme at University of Stuttgart (IRS). AtThe experiment is expected to demonstrate the OV and BPD, G. Cruciani conducted the radiation-cooled moderateon/off cycling characteristics needed for NSSK, verify power arcjet development, M. Glogowski and G. Crucianisystem operating procedures, measure and characterize conducted the low power arcjet development, E. Tostipropulsion system/spacecraft interactions and validate conducted the water-cooled moderate power arcjetground test data. The near-term activities include detailed development and G. Carabella and 0. Constantini provideddefinition of the experiment, facilities support At Centrospazio, F. Paganucci conducted

the MPD development and G. Saccoccia and F. Scortecciconducted the low power arcjet development. M.

CONCLUSIONS Andrenucci directed the Centrospazio activities. G. Paccanidirected the activities of students at the University of Rome.

New state-of-the-art facilities have been installed At IRS, B. Glocker conducted the water-cooled moderateat BPD to enable continuous, simultaneous testing of both power arcjet development under the direction of H. Schradelow power (0.5 to 2.0 KW) and moderate power (10 KW- and H. L. Kurtz through a subcontract with BPD.class) arcjets. Each facility is independent of the other withdedicated pumping plants, power supplies, data acquisition The research described in this paper was carriedand control systems and diagnostics. Facilities installation out by BPD and was sponsored by the European Spaceat CS has been completed for both the arcjet and MPD Agency (ESA), European Space Research and Technologyactivities. All the support equipment has been tested and is Centre (ESTEC) through the auspices of the Advancedbeing used for data collection. Space Technology Program No. 3 (ASTP-3) under contract

number 7632/88/NL/PN(SC). Additional support wasArcjet engine technology development is ongoing provided by ESA/ESTEC through the Technology Research

at BPD and its subcontractor, CS. Both low power (0.1 N) Program (TRP) under contract no. 6966/86/NL/PH.and moderate power (1.0 N) arcjets are under development Centrospazio and IRS were under subcontract to BPD.and currently being tested. Present activities include engineoperating envelope definition and parametric testing on bothengine classes. Low power engines demonstrated 440 s of

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REFERENCES -Advanced Laboratory Model, I kW-Class Arcjet Engine Testing," IEPC91-044. 22nd IEPC. October 1991.

1. E. Tosti. H. Schrade. C. Petagna "Test Results of a 15 kWWater-Cooled Arcjet at BPD and IRS." AIAA 90-2535, 21st IEPC, July 19. M. Andrenucci. G. Saccoccia, U. Schulz. F. Scortecci. N. Panatton.

1990. C. Didier and W. D. Deininger "Performance Study of a Laboratory Modelof a Low Power Arcjet." IEPC 91-045. 22nd IEPC, October 1991.

2. G. Crnciaim W. Deininger, and C. Petagna, "Development of a I NRadiative-Cooled Arjet," AIAA 90-2536. 21st IEPC, July 1990. 20 W. D. Denunger, G. Cruciai, M. Glogowski. F. Scortecci M.

Andrenucci and A. Trippi, "Comparison of Low Power Arcjet Operation

3. M. Andrenucci -G. Saccoccia G. Baiocchi, and C. Petagna, At BPD and Centrospazio." IEPC 91-046. 22nd IEPC. October 1991.

Experimental Performance ofa I kW Arcjet," AIAA 90-2583,21st IEPC.July 1990. 21 M. Andrenucci F. Paganucci. A Venurini, A. Turco and G. Paccani.

Plasma Diagnostics i MPD Thruster Plumes," IEPC 91-047, 22nd IEPC,

4. G. Baiocchi and W. D. Deininger. "Review of Plasma Propulsion October 1991.

Developments at BPD,' AIAA 90-2559. 21st IEPC, July 1990.22. E. Tosti and W. D. Deinnger. "Plume Analysis of a 10 kW/N Arcjet

5 M. Andrenucci G. Baiocchi. and A. Trippi. "The DIVA In- Flight Using Emission Spectroscopy." IEPC 91-092. 22nd IEPC, October 1991.

Arcjet Experiment Program," AIAA 90-2538. 21st IEPC, July 1990.23. E. CardeUi, M. Raugl. N. Esposito and G. Tina. "An Optimal Design

6. E. Tosti, V. Mazzacurati, G. Ruocco and W. D. Deminger, "Emision Procedure for Pulse Forming Network," IEPC 91-115, 22nd IEPC, October

Spectroscopy of 15 KWe Arcjet Plumes," AIAA 90-2446,21st IEPC, July 1991.

1990.24. M. Andrenucci. F. Scortecci G. Capecchi and T. Wonsch,

7. G. Cruciani, E Tosti, M. Glogowski, W. D. Deuinger and G. Baiocchi, "Development of a Computer Programme for the Analysis of Arcjet

Description of Arcjet Test Facilities at BPD," AIAA 90-2660. 21st IEPC, Nozzles." IEPC 912-113, 22nd IEPC. October 1991.

July 1990.25. M. Andrenucci, F. Paganucci M. Frazzetta, G. LaMotta and G.

8. G. Paccai. "Non-Steady Solid Propellant MPD Thruster Experimental Schlanchi, "Geometry and Scale Effects on the Performance of MPD

Analysis Concepts," AIAA 90-2674. 21st IEPC. July 1990. Thnusters, IEPC 91-123. 22nd IEPC, October 1991.

9. B. Glocker, M. Auweter-Kurtz. T. Goelz, H. Kurtz, H. Schrade, T. 26. ILL Kurtz M. Auweter-Kurtz. B. Glocker, W. Merke, ILO. Schrade,

Wegmann, "Medium Power Arcjet Thruster Experiments," AIAA 90-2531. "A 15 kW Experimental Arcjet," IEPC 88-107, Proceedings 20th IEPC

21st IEPC, July 1990. (DGLR - Bencht 88-02), October 1988, pp. 606.

10 M. Andrenucci, "CENTROSPAZIO A New Italian Electric Propulsion 27. P. G. Lichon and R J. Cassady, "Performance Improvement of 26

Laboratory," AIAA 90-2661, 21st IEPC, July 1990. KWe Ammonia Arcjet." AIAA 90-2532, 21st IEPC, July 1990.

11. M. Andrenucci and F. Paganucci, "Experimental Performance of MPD 28. K. Goodfellow and J. Polk. Throttling Capability of a 30-KW Class

Thrusters," AIAA 90-2560, 21st IEPC, July 1990. Ammonia Arcjet." AIAA 91-2577, 27th JPC, June 1991.

12. G. Cruciani. M. Glogowski, E Tosti, W. D. Deininger. F. Paganucci, 29. G. Paccani, A Coaxial Non-Steady Solid Propellant MPD Thruster

G. Saccoccia, F. Scortecci and M. Andrenucci. "MPD-Arcjet Development Experimental Analysts," AIAA 87-1095. 19th IEPC, May 1987 (see also

Program," Review Report No. 4, BPD Difesa e Spazio, Colleferro. Italy, Journal of the British Interplanetary Society, Vol.41, pp. 240-253, 1988).

BPD Publication No. NT AST 11.01, 31 May 1991.30. G. Paccam. " Anode-Nozzle Experimental Analysis in a Coaxial Non

13. M. Andrenucci, G. Baiocchi, W. D. Demmger and A Trippi, "DIVA: Steady Solid Propellant MPD Thruster." IEPC 88-076.20th IEPC. October

Flight Demonstration of a 1 KW Arcjet Propulsion System." IAF 90-006, 1988.

41st IAF, October 1990.

14. G. Cruciani, ETosti, W. D. Deiniger. B. Glocker. H. L Kurtz andH. O. Schrade, "Experimental Testing of I N-Class Arcjet Engines -Design, Manufacturing and Testing of Thnrster Laboratory Models,"Review Report No. 3, BPD Difesa e Spazio, Colleferro, Italy, BPDPublication No. NT TRP 11.02, 31 January 1991.

15. G. Cruciani, M. Glogowski. E. Tosti, W. D. Deinger. F. Paganucci,G. Saccoccia. F. Scortecci and M. Andrenucci, "MPD-Arcjet DevelopmentProgram." Review Report No. 5. BPD Difesa e Spazio. Colleferro, Italy,BPD Publication No. NT AS3 11.02 Is.:2, 30 September 1991.

16. E. Tosti, B. Glocker and A. Trippi, "Final Results of 15 kWe Water-Cooled Arcjet Testing," IEPC 91-014. 22nd IEPC, October 1991.

17 M Andrenucci and M Sandrucci, "Development of a PowerConditioner for a I kW Arcjet. IEPC 91-029. 22nd IEPC, October 1991.

18. G. Cruciani, M. Glogowski, W. D Deininger and A. Trippi.

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C ROLLER.2

--- v--- -a ! - SI

FACILITY VP-1 FACILITY VP-2

Figure 1. General schematic of BPD arcjet test facilities.

LEGEND ,. T:,

SPW I1TIC VALVC - TO FACILITY

igr 2ECT-Me tTIC BfVALV It* n900

r n .T it C T *

41. I. laIin I

ITY 0CP*3 -2 . PILLER

SIGNA.1 - r

Figure 2. Schematic of BPD facility VP-1.

IEPC 91-005

8

91-005

LEGEND

Figure 3.IV SceatcoALVfaiiyEP

~ITVLVE

IR _ AILT _ _ I

UNI

Figue 4.1V3 acuu failit at enb~s NIT

9PTP 1-0

91-005

0I -

MOD-A ARCJET (CENTROSPAZIO)

CIII.l l In.ll i

--

C's.... Ch....

7/'? Aa CapS • S---lk lGasecl -/Sa-,1lt n i!,i I C.IIC.A

QOs p RF IIms !asert Cah~e

MOD-B ARCJET (BPD)

Figure 5. Schematics of MOD-A and MOD-B low power arcjets.

SPECIFIC POWER vs. SPECIFIC IMPULSE

.oo4

300-

3 00- :5 mps-- " .50~ m l s 11

100-

00 10 !0 30 40

SPECIFIC POWER ( J/nn ]

Figure 6. Specific impulse/specific power characteristic of MOD-A on simulated hydrazine.

10 IEPC 91-005

91-005

MOD-B ENGINE GRID1) 9.333*2

2) 1.030U33) 1.127134) 1.224*3

5) 1.3213

6) 1.418,3

1) 1.515,3

U) 1.10921310) 1.0063

AI II) I. 0313

Z 12) 2. X '3

CALCULATED TEMPERATURE DISTRIBUTION (T, 2000K & T. = 1500K)

Figure 7. Grid and thermal analysis results for MOD-B engine.

1400Propellant: N2+2H2 mixture

1300 - : 31±0.5 mg/s 0

o and +: 41±0.5 mg/s1200 - and : 51±0.5 mg/s

0 11000

S 1000

3 900 -0O.-S-800 -E-U 700 -

600Gap= 0.4 mm

500 Constrictor-Filled symbols:(= 0.62 mm; L= 0.64 mmOpen symbols:C(= 1.02 mm; L= 0.59 mm

400 -0-0 ,500 1000 1500 2000

Power (W)Figure 8. Measured MOD-B nozzle surface temperature.

11 IEPC 91-005

91-005

600- 100Propellant: N2+2H2 mixture

*: 31±0.5 mg/s 90o and : 41±0.5 mg/s

500 - o and : 510.5 mg/s 800

O

00-0 0 " 70

U3 400 -* 60

E Isp * 50

S 300 - 40U Eff.* *(1. o *0 ** , *o o

L 00

C1 " 30

200 - 20Gap= 0.4 mmConstrictor-Filled symbols:A= 0.62 mm; L= 0.64 mm 10

Open symbols:=l.01 mm; L= 0.59 mm100 I I I ' I I I I I I I , I I I 0

0 10 20 3- 0 40 50Specific Power [J/mg]

Figure 9. Specific impulse/specific power characteristics for MOD-B.

COPPERANOOE COOUNG.WATER INLET ANODE

CATHODE COOUNO.WATER CIRCUIT 7 .. " '.

CATHOOE-CONSTRICTOR 0AP \ c o -ADJUSTMENT DEVICE

NOZZLE PRESSURE TAP

TUNGSTEN (2% Th) --

CATHODE

PLEHUM PRESSURE TAP

PROPELLANT FEEDING PIPE

SEGMENT I

ANOOE COOUNG-WATER OUTLET L SEGMENT 2

-SEGMENT

SEGMENT i

Figure 10. Schematic of MOD-I' water-cooled, 1 N arcjet.

12 IEPC 91-005

91-005

ELECTRICAL CHARACTERISTIC

Am ODson *Ieon

300

250

V0L 200

T .A ACE ISO A

V

100

s0

40 60 o 10 120 140 160 180

CURRENT / A

Figure 11. Voltage-current characteristic comparison between MOD-1 and MOD-I' arcjets with hydrogen.

SPECIFIC IMPULSEsea c *rra s

800

SPEC 700

IF

C 600

I A

S500 A

ULS 400

/

300 .

6 8 10 12 14 16 1s 20 22 24 26

POWER / kWe

Figure 12. Specific impulse comparison between MOD-I and MOD-I' arcjets with hydrogen.

13 IEPC 91-005

91-005

PROPELLANT FEEDING PIPETUNGSTEN (2% Th)

TUNGSTEN (2% Th) ANODE

CATHODE -ii:.

MOLYBDENUMA.

Figure 13. Schematic of MOD-2 radiation-cooled, 1 N arcjet.

MOO-2 CHARACTERIZATIONN2+2H2 MIXTURE

140

12001 0 003 0 *oo 0 0Ug* *

> mm

0)M 00 0 0 0

0 0

> 80-

50 4 4 . **40

30 2Jrwjs; constrictor I~'5rv30 o. ~~tAJ sr os ctrictor o j

s; cJrrjr rKtor' dIp .rm20 a Z~e~s; constrictor dw-1 r

10 #03 mg/rs constrictor 6o3.5 mmi0: W3 ma/s: conrctor do=2.5 mmv

0-50 70 go Ho 30L50 I0 190 210 230 ~

Current (A)

Figure 14. Voltage-current charactrinstic of MOD-2 on simulated hydrazine.

14 IEPC 91-005

91-005

MOO-2 PERFORMANCEN2+2H2 MIXTURE

0.0

4001

00 : 50 mg/S., 2.5mm *ros r~

0: 100mg/s, 0=2.5mmi 0, 75m~s 0mm0 20 30 40 30 d0 70 30 0W i 20 1015

Specific Power fJ/mg)

Figure 15. Specific impulse/specific power characteristic of MOD-2 on simulated hydrazine.

... I

6 5 0 6o

Figure 16. Grid and thermal analysis results for MOD-3A engine.

15 IEPC 91-005

91-005

VACUUMCHAMBER PLATEVALVE

OIL

TWO STAGEROTARY VANE PUMP

GROUND FLOOR

Figure 17. IV2 facility at Centrospazio for MPD testing.

1:1 SCALE

1: '2 SCALE

1:2 SCALE

Figure 18. Family of ring anode MPD thrusters.

16 IEPC 91-005

91-005

1A5BAC Characteristics Comparison (logaritmic)1000 I

° o I100

SV-Vo(2gs)> 10 I* V-Vo (4gs)

10

1000 10000 100000

S(2gs)

Figure 19. Voltage-current characteristic for benchmark thruster.

Efficiency vs Specific Impulse @ 4 g/s

30

20

10

0.0 1000 2000

Isp (s)

Figure 20. Specific impulse-efficiency characteristic for benchmark thruster.

17 IEPC 91-005

91-005

7, 7

Figure 21. Prototype MPD heated cathode

358 EPJ __

I , '- E9 -188 i

38E9 : 1333

250- --EO :1666

SE8 : 29828 0-- E0 : 2333

-E0 266615 .".'.x.. .. .

g SECTOR

8,5 1 1,5 2 25 3 3.5 4 4.5 5 5,5 6

Figure 22. Energy distribution along a six segment anode.

18 IEPC 91-005

91-005

- A US1LIO UISIQO

~Te [eU]:

ISOLO COMPUTES

Te 'pLeUVI:I1.2&Gf4O

4 U~ He (*I E419) :11,258

E:1666 J Rj:356 Ps Ra--9cm D:IGcm

U (Volt) -11.72 1 (MA) 2903 U~~i .

Figure 23. Characteristic of double Langmuir probessampled and processed data.

4.~

Il.A 1",

u~n. 4-

Figure 24. Plume velocity deviation for different values of the

ratio between the probe separation distance and delay time.

19 IEPC 91-005

91-005

EMI ANTENNA PLUME CONTAMINATIONDIAGNOSTICS

TANK

PCU & EMS

PFS

1 ESP

ARCJET

Figure 25. DIVA experiment package.

20 IEPC 91-005