NASA's Evolutionary Xenon Thruster (NEXT) Long-Duration Test Results

Herman, Daniel A.; Soulas, George C.; Noord, Jonathan L. Van; Patterson, Michael J.

doi:10.2514/1.b34321

Cited by 17 publications

(6 citation statements)

References 16 publications

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“…Plots of overall thruster performance including calculated thrust, specific impulse, thrust efficiency, and input power can be found in Ref. 29. Recent thruster data continue to show negligible performance degradation after 42,100 hours of operation.…”

Section: B Thruster Performancementioning

confidence: 97%

“…The NEXT LDT throttling profile, illustrated in Table 1 and described in detail in Ref. 29, was completed in May 2010 and the go-forward plan is to continue thruster operations at full-power until failure. Detailed thruster characterizations are performed periodically to assess performance over 11 of the 40 operating conditions in the NEXT throttle table.…”

Section: A Status and Test Metricsmentioning

confidence: 99%

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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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Section: B Thruster Performancementioning

confidence: 97%

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

View full text Add to dashboard Cite

show abstract

“…From manufacturing to launch, the electrodes of the ion thruster would adsorb ambient gas particles, and the ion sputtering deposits would crack or warp due to thermal expansion and contraction. The pre-treatment procedure can reduce this kind of problem and thus reduce the frequency of electric breakdowns [82], [86], [88]. The pre-treatment procedure is: the pipe-line exhaust to eliminate residual gas impurities in the pipeline and thruster, the cathode ignition to eliminate the surface contamination on electrodes, the discharge chamber ignition to eliminate the gas absorbed by the discharge chamber electrodes and grids, and the ion beam test to eliminate the gas absorbed by grids and the contaminants from outside.…”

Section: Control and Protection Technologies Of Electric Breakdown In...mentioning

confidence: 99%

Ion Electric Propulsion System Electric Breakdown Problems: Causes, Impacts and Protection Strategies

Peng,

Li,

Song

et al. 2023

IEEE Access

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Ion electric propulsion systems have been widely used in satellite station keeping, attitude control, and orbit transfer due to their advantages of high specific impulse, good flexibility, and high reliability. The electric breakdown might happen at grids or across isolators due to the disturbing effects of the power source or environment. The electric breakdown can induce spurious effects in the power processing unit (PPU) circuit from the return currents and voltage drops, which could be several orders of magnitude higher than the impulses at normal working conditions. When the electric breakdown happens, it might result in serious electromagnetic interference and damage to the electric and electronic equipment in the spacecraft. This paper provides a comprehensive summary of the various factors that can cause electric breakdown in an ion electric propulsion system, such as environmental factors, manufacturing considerations, and operational conditions of the thruster. Furthermore, a comprehensive analysis of the impact of electric breakdown on the ion thruster, electric propulsion system, and spacecraft mission is explored. The effectiveness of different grounding configurations in safeguarding against ion thruster electric breakdown has also been evaluated. Based on the analysis and discussion, the control and protection strategies are proposed for the ion electric propulsion system electric breakdown problems.

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“…In particular, buffer tests of the LBM face the problem of limited sample size and zerofailure data. On the one hand, aerospace machinery products are expensive and produced in limited batches, allowing only small-sample reliability tests [14][15][16]. On the other hand, RDTs typically do not permit sample failures; otherwise, they would be judged as unqualified [17].…”

Section: Introductionmentioning

confidence: 99%

Reliability Assessment for a Spacecraft Landing Buffer Mechanism Based on Small Sample Data

Li,

Fu,

2023

Machines

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The landing buffer mechanism (LBM) is a crucial component of aerospace landing explorations, determining the success of the entire mission. Reliability demonstration tests (RDTs) are required to ensure the LBM’s performance meets the design index. However, the RDTs of the LBM often encounter limited samples and zero-failure data, making traditional binominal test programs and reliability assessment methods based on the maximum likelihood theory unsuitable. This paper introduces a novel small-sample test verification method for the LBM, which transforms traditional binominal tests into more informative metrological tests by measuring the buffer strokes of the LBM’s subsystems. Furthermore, a confidence limit theory for the product of subsystem reliability is developed in conjunction with the reliability series model of the LBM. This theory can use the measurement data of subsystems to assess the confidence limit of the LBM’s reliability. An actual engineering application demonstrates that the proposed method can effectively handle zero-failure data and verifies that the LBM’s reliability exceeds 0.9999 with a confidence of 0.9.

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NASA's Evolutionary Xenon Thruster (NEXT) Long-Duration Test Results

Cited by 17 publications

References 16 publications

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

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

Ion Electric Propulsion System Electric Breakdown Problems: Causes, Impacts and Protection Strategies

Reliability Assessment for a Spacecraft Landing Buffer Mechanism Based on Small Sample Data

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