Status of the Dawn Ion Propulsion System

Brophy, John R.; Marcucci, M.; Gates, Jason; Garner, Charles E.; Nakazono, Barry; Ganapathi, Gani B.

doi:10.2514/6.2004-3433

Cited by 25 publications

(12 citation statements)

References 6 publications

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“…5) delivers low pressure gas to the thruster from a supercritical xenon supply source, and it consists of HPA and LPA (ref. 14). The PMS provides independent xenon flow control to the thruster main discharge, and discharge and neutralizer cathodes.…”

Section: Propellant Management Systemmentioning

confidence: 99%

NEXT Ion Propulsion System Development Status and Performance

Patterson

Benson²

2007

43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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Section: Propellant Management Systemmentioning

confidence: 99%

NEXT Ion Propulsion System Development Status and Performance

Patterson

Benson²

2007

43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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“…Figure 2 shows the propellant throughput as a function of elapsed time with reference to the NSTAR Extended Life Test (ELT), the requirements from various mission analyses conducted using NEXT propulsion, and the original target NEXT qualification level throughput of 450 kg. [32][33][34][35][36][37][38][39] One motivation for the continuation of the NEXT LDT is highlighted by the missions requiring thruster throughput capability in excess of 300 kg. As the thruster demonstrates greater throughput capability, new NEXT mission applications are enabled and existing mission concepts that carried additional strings to meet a lifetime requirement can be simplified reducing both spacecraft complexity and cost.…”

Section: A Status and Test Metricsmentioning

confidence: 99%

NASA's Evolutionary Xenon Thruster (NEXT) Long-Duration Test as of 736 kg of Propellant Throughput

Shastry¹,

Herman²,

Soulas³

et al. 2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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The NASA's Evolutionary Xenon Thruster (NEXT) program is developing the next-generation solar-electric ion propulsion system with significant enhancements beyond the state-of-the-art NASA Solar Electric Propulsion Technology Application Readiness (NSTAR) ion propulsion system to provide future NASA science missions with enhanced mission capabilities. A Long-Duration Test (LDT) was initiated in June 2005 to validate the thruster service life modeling and to qualify the thruster propellant throughput capability. The thruster has set electric propulsion records for the longest operating duration, highest propellant throughput, and most total impulse demonstrated. At the time of this publication, the NEXT LDT has surpassed 42,100 h of operation, processed more than 736 kg of xenon propellant, and demonstrated greater than 28.1 MN•s total impulse.Thruster performance has been steady with negligible degradation. The NEXT thruster design has mitigated several lifetime limiting mechanisms encountered in the NSTAR design, including the NSTAR first failure mode, thereby drastically improving thruster capabilities. Component erosion rates and the progression of the predicted life-limiting erosion mechanism for the thruster compare favorably to pretest predictions based upon semi-empirical ion thruster models used in the thruster service life assessment. Service life model validation has been accomplished by the NEXT LDT. Assuming full-power operation until test article failure, the models and extrapolated erosion data predict penetration of the accelerator grid grooves after more than 45,000 hours of operation while processing over 800 kg of xenon propellant. Thruster failure due to degradation of the accelerator grid structural integrity is expected after groove penetration.

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“…Operations at 0.5 kW (TH0) and 1.46 kW (TH8) were chosen to investigate potential wear and failure mechanisms at the throttled conditions. Operation at TH5 was specifically chosen to support the Dawn mission, to understand neutralizer performance degradation at the power level planned for the transfer from Vesta to Ceres [10]. During each test segment, thruster electrical parameters were monitored and recorded every 5 s by a computer-based dataacquisition system.…”

Section: Test Facility and Planmentioning

confidence: 99%

Deep Space 1 Flight Spare Ion Thruster 30,000-Hour Life Test

Sengupta¹,

Anderson²,

Garner³

et al. 2009

Journal of Propulsion and Power

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The extended-life test of the Deep Space 1 flight spare ion thruster was voluntarily terminated on 26 June 2003. During its five-year run, the thruster operated for a total of 30,352 h, processed 235.1 kg of xenon propellant, and demonstrated extended operation at multiple throttled conditions. The objectives of the test were to characterize failure modes and quantify thruster performance as a function of engine wear and throttle level. Degradation processes included erosion of the discharge cathode keeper, accelerator-grid sputter erosion, and deposition of material in the neutralizer cathode at low power. Performance degradation was limited to a reduction in measured thrust at the full-power point for the final 1000 h of operation. Posttest inspection of the engine was initiated following the test termination to ascertain causes of the wear and to look for any previously unknown wear processes. Significant findings included facility-induced flakes in the discharge chamber, the presence of through-pits in the accelerator-grid webbing, significant erosion of the discharge cathode orifice plate, and healthy cathode inserts. A summary of the beginning-of-test and end-of-test performances and results of the posttest destructive evaluation are presented.

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Status of the Dawn Ion Propulsion System

Cited by 25 publications

References 6 publications

NEXT Ion Propulsion System Development Status and Performance

NEXT Ion Propulsion System Development Status and Performance

NASA's Evolutionary Xenon Thruster (NEXT) Long-Duration Test as of 736 kg of Propellant Throughput

Deep Space 1 Flight Spare Ion Thruster 30,000-Hour Life Test

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