Modeling of Total Thruster Performance for NASA's Evolutionary Xenon Thruster Ion Optics

Emhoff, Jerold; Boyd, Iain D.

doi:10.2514/1.18975

Cited by 6 publications

(2 citation statements)

References 18 publications

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“…Locally higher erosion rates at AG holes near the chamber's side wall. In the numerical study on the erosion rates of the AG holes [41], simulated values in the central region were in good agreement with measured ones. However, at the periphery of the AG where crossover ion impingement was more serious, simulated erosion rates were only about one-third of the measured ones.…”

Section: Second Humps Insupporting

confidence: 71%

Effects of secondary γ-electrons from accelerator grid under ion impingement in gridded ion sources

Fu¹,

Tian²,

Ding³

2022

Plasma Sources Sci. Technol.

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Thus far, effects of secondary γ-electrons emitted from accelerator grids of gridded ion sources on ionization in discharge chambers have not been studied. The presence and induced processes of such secondary electrons in a microwave electron cyclotron resonance gridded ion source are confirmed by the consistent explanations of: (1) the observed jump of ion beam current (Ib) in case of a low-density plasma appearing at the chamber’s radial center due to the microwave skin effect; (2) the evolution of glow images recorded from the end-view of the ion source during the jump of Ib; (3) the over-large jump step of Ib with the increasing microwave power; (4) the pattern appearing on the temperature sticker exposed to the discharge operated in the regime where the arrayed energetic-electron beamlets are injected into the discharge chamber; (5) the measured step-increment in the voltage drop across the screen grid sheath. A positive feedback loop composed of involved processes are established to elucidate the underlying mechanism. Energetic γ-electrons from the accelerator grid and warm δ-electrons from the opposite antenna do not produce direct excitation and ionization, but they enhance the electrical confinement of cold electrons by elevating the voltage drop across the sheaths at the antenna and screen grid, thus leading to the jump of Ib. The energetic γ-electrons-based model can be also modified to explain abnormal results observed in the other gridded ion sources. Energetic γ-electrons from accelerator grids should be taken into account in understanding gridded ion sources.

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Section: Second Humps Insupporting

confidence: 71%

Effects of secondary γ-electrons from accelerator grid under ion impingement in gridded ion sources

Fu¹,

Tian²,

Ding³

2022

Plasma Sources Sci. Technol.

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“…Several electric propulsion technologies are in use such as the arcjet, Hall effect, and gridded ion thrusters [9]. Modern examples of electric engines are NASA's Evolutionary Xenon Thruster (NEXT), an evolution of the already tested NASA Solar Technology Application Readiness (NSTAR) used in the Deep Space 1 mission [30] and Dawn [31], the radio frequency ion thruster RIT-XT, which works by generating ions using high frequency electromagnetic fields and is very similar to the RIT-22 engine (in design and thrust-to-weight ratio) but has higher I sp [23,32], and the PPS 1350-G, which is a plasma thruster with flight proven capability (SMART-1 mission) [33].…”

Section: Modern Electric Enginesmentioning

confidence: 99%

Comparison of Four Space Propulsion Methods for Reducing Transfer Times of Crewed Mars Mission

Guerra¹,

Bertolami²,

Gil³

2015

Preprint

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We assess the possibility of reducing the travel time of a manned mission to Mars by examining four different propulsion methods, and keeping the mass at departure under 2, 500 tonnes, for a fixed architecture. We evaluated representative systems of three different state of the art technologies (chemical, nuclear thermal, and electric), and one advance technology, the "Pure Electro-Magnetic Thrust" (PEMT) concept (proposed by Rubbia). A mission architecture mostly based on the Design Reference Architecture 5.0 is assumed in order to estimate the mass budget, that influences the performance of the propulsion system. Pareto curves of the duration of the mission and time of flight versus mass of mission are drawn. We conclude that the ion engine technology, combined with the classical chemical engine, yields the shortest mission times for this architecture with the lowest mass, and that chemical propulsion alone is the best to minimise travel time. The results obtained using the PEMT suggest that it could be a more suitable solution for farther destinations than Mars.

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Comparison of Four Space Propulsion Methods for Reducing Transfer Times of Crewed Mars Missions

2022

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Modeling of Total Thruster Performance for NASA's Evolutionary Xenon Thruster Ion Optics

Cited by 6 publications

References 18 publications

Effects of secondary γ-electrons from accelerator grid under ion impingement in gridded ion sources

Effects of secondary γ-electrons from accelerator grid under ion impingement in gridded ion sources

Comparison of Four Space Propulsion Methods for Reducing Transfer Times of Crewed Mars Mission

Comparison of Four Space Propulsion Methods for Reducing Transfer Times of Crewed Mars Missions

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