Performance characteristics of ring-cusp thrusters with xenon propellant

Patterson, Michael J.

doi:10.2514/6.1986-1392

Cited by 10 publications

(14 citation statements)

References 10 publications

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“…The minimum beam ion production cost values in Figure 2 are comparable to those previously reported for the J-series thruster at lower power levels [ref. 10,11]. Discharge voltages at high propellant efficiency ranged from 25 to 36 volts.…”

Section: Resultsmentioning

confidence: 99%

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Performance of 10-kW class xenon ion thrusters

Patterson

Rawlin

1988

24th Joint Propulsion Conference

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This paper presents performance data for laboratory and engineering model 30cm-diameter ion thrusters operated with xenon propellant over a range of input power levels from approximately 2 to 20 IcW. Also presented are preliminary performance results obtained from laboratory model 50cm-diameter cusp-and divergent-field ion thrusters operating with both 30cm-and 50cm-diameter ion optics up to 20 kW input power. These data include values of discharge chamber propellant and power efficiencies, as well as values of specific impulse, thruster efficiency, thrust, and power. The operation of the 30cm-and 50cm-diameter ion optics are also discussed.

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Section: Resultsmentioning

confidence: 99%

“…The results obtained from performance characterization of several ion thrusters 11 over an extended power range to 20 kW with xenon propellant were presented. Typical discharge chamber performance for the 30DIV (J-series) thruster was 135 -155 W/A at propellant efficiencies of 90 percent.…”

Section: Discussionmentioning

confidence: 99%

Performance of 10-kW class xenon ion thrusters

Patterson

Rawlin

1988

24th Joint Propulsion Conference

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“…This restrictor was used to increase the internal discharge chamber pressure to approximate that in an operating ion thruster. With a xenon cathode flow rate of 10.0 Pa-L/s, the chamber pressure was maintained between 0.34 and 0.44 Pa. The remaining surfaces of the chamber were connected to the positive side of the discharge supply.…”

Section: Apparatusmentioning

confidence: 99%

“…This restrictor was used to increase the internal discharge chamber pressure to approximate that in an operating ion thruster. With a xenon cathode flow rate of 10 …”

Section: Apparatusmentioning

confidence: 99%

“…The extended test reported here lasted for 508 hours. The hollow cathode was operated at 23.0 A and 10 Pa-L/s (6.1 sccm (STP), 0.55 mg/s) of xenon flow to enable comparison of operation and final condition with earlier tests. The propellant feed-system leakage rate was used as the figure of merit for quantitative measure of contamination experienced by the cathode.…”

Section: Introductionmentioning

confidence: 99%

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Extended testing of xenon ion thruster hollow cathodes

Sarver-Verhey¹

1992

28th Joint Propulsion Conference and Exhibit

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A hollow cathode wear-test of 50s hours was successfully completed at an emission current of 23.0 A and a xenon flow rate of 10 Pa-Lls. This test was the continuation of a hollow cathode contamination investigation. Discharge voltage was stable at 16.7 V. The cathode temperature averaged 1050 oC with a 7% drop during the wear-test. Discharge ignition voltage was found to be approximately 20 V and was repeatable over four starts. Post-test analyses of the hollow cathode found a much improved internal cathode condition with respect to earlier wear-test cathodes. Negligible tungsten movement occurred and no formation of mono-barium tungstate was observed. These results correlated with an order-of-magnitude reduction in propellant feed-system leakage rate. Ba2CaW06 and extensive calcium crystal formation occurred on the upstream end of the insert. Ba-Ca compound depositions were found on the Mo insert collar, on the Re electrical leads, and in the gap between the insert and cathode wall. This wear-test cathode was found to be in the best internal condition and had the most stable operating performance of any hollow cathode tested during this contamination investigation. INTRODUCTIONHollow cathodes, operating on inert gases and emitting several to several tens of amperes of current, have experienced destructive effects during extended testing. The causes of hollow cathode deterioration are believed to be oxygen contamination of the propellant feedsystem by air leakage and surface outgassing and excessive cathode operating temperatures.Oxidation of components and deposition of material in the cathode orifices and on the internal surfaces have resulted in degraded performance and cathode failure, as has been reported by several researchers. 1 -6 Extended testing of hollow cathodes operating on inert gases at several amperes of emission current for longer than 1,000 hours has been limited to two xenon ion thruster life-tests. Beattie et al. reported on a 4,350 hr. test of a xenon ion propulsion subsystem operated at 1.4 kW. The main discharge hollow cathode was operated at an emission current of 6.3 A and experienced cathode orifice erosion? Brophy and Garner reported on the successful completion of a 5,000 hour test of a hollow cathode operated on xenon in an ion thruster simulator at an emission current of 25 A.8 Operating parameters such as discharge voltage and ignition voltage varied considerably during the test and cathode insert brightness temperature was found to be approximately 1500 °C throughout the test. Substantial material deposition was found on the cathode insert surface in post-test examination. Consequently, concerns have arisen about the ability of hollow cathodes to provide stable operation with long life.An effort was therefore begun to alleviate cathode degradation due to oxygen contamination by developing criteria and procedures to ensure that cathode lifelimitations were minimized.This effort consisted of a program of extended cathode testing in configurations designed to simulate 30This paper i...

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Performance and Flatness of a Multiple-Cathode, Rectangular Ion Thruster Discharge Chamber

Rovey

Gallimore²

2007

Journal of Propulsion and Power

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Results from the extended life test of the Deep Space One flight spare ion engine show that enlargement of the discharge cathode assembly orifice due to erosion of the orifice by ion bombardment limits the throughput of the ion thruster, and therefore limits its operational lifetime to approximately three years. Future deep-space missions will require significantly longer operational lifetime, perhaps as long as 7-14 years. In an effort to increase lifetime, an ion thruster discharge chamber designed for operation with multiple discharge cathode assemblies was investigated. The multiple-cathode discharge chamber approach attempts to increase lifetime by operating three discharge cathode assemblies sequentially. Simulated ion thruster operation of the multiple-cathode discharge chamber with the active discharge cathode assembly located on centerline and off centerline for a variety of magnetic field configurations was accomplished. Results indicate that the configuration with permanent magnets and 0 A electromagnet current provided the best performance and flatness with optimum values of 194 6 W=A at 0:89 0:03 propellant efficiency and 0:55 0:02, respectively. Finally, operation of the dormant cathodes with propellant flow is suggested to reduce preoperation erosion of those units.

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Performance characteristics of ring-cusp thrusters with xenon propellant

Cited by 10 publications

References 10 publications

Performance of 10-kW class xenon ion thrusters

Performance of 10-kW class xenon ion thrusters

Extended testing of xenon ion thruster hollow cathodes

Performance and Flatness of a Multiple-Cathode, Rectangular Ion Thruster Discharge Chamber

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