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

Sengupta, Anita; Anderson, John A.; Garner, Charles E.; Brophy, John R.; Groh, Kim K. de; Banks, Bruce A.; Thomas, Tina

doi:10.2514/1.36549

Cited by 34 publications

(16 citation statements)

References 14 publications

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“…1͒. 10 The tests were performed in a 3-m-diameter by 10-m-long vacuum chamber with 1 ϫ 10 −5 Pa base pressure and 5 ϫ 10 −4 Pa at the NSTAR full-power flow rates. 4 A xenon propellant feed system and dc laboratory power supplies were used to run the engine.…”

Section: A Experiments Summarymentioning

confidence: 99%

“…29 and as measured during the extended life test of the DS1 flight space ion thruster. 10 Ion current may now be written in terms of the anode and beam current only,…”

Section: ͑21͒mentioning

confidence: 99%

“…Power losses demand higher temperature operation of the electron source ͑hollow cathode͒ which limits the emitter's life. [7][8][9][10][11] An understanding of plasma production and confinement can lead to increased efficiency, life, and reliability of the ion thruster technology.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic confinement in a ring-cusp ion thruster discharge plasma

Sengupta

2009

Journal of Applied Physics

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An experimental investigation, in conjunction with a volume averaged analytical model, has been developed to improve the confinement and production of the discharge plasma for plasma thrusters and ion sources. The research conducted explores the discharge performance of a ring-cusp ion source based on the magnetic field configuration, geometry, and power level. Analytical formulations for electron and ion confinement are developed to predict the ionization efficiency for a given discharge chamber design. Explicit determination of discharge loss and volume averaged plasma parameters are obtained via a series of experimental measurements on a ring-cusp NASA Solar Technology Application Readiness (NSTAR) ion thruster to assess the validity of the analytical model. Measurements of the discharge loss with multiple magnetic field configurations compare well with plasma parameter predictions for propellant utilizations between 80% and 95%. The results indicate that increasing the magnetic strength of the first closed magnetic contour line reduces Maxwellian electron diffusion and electrostatically confines the ion population and subsequent loss to the anode wall. The results also indicate that increasing the strength and minimizing the area of the magnetic cusps improves primary electron confinement, increasing the probability of an ionization collision prior to loss at the cusp.

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Section: A Experiments Summarymentioning

confidence: 99%

“…29 and as measured during the extended life test of the DS1 flight space ion thruster. 10 Ion current may now be written in terms of the anode and beam current only,…”

Section: ͑21͒mentioning

confidence: 99%

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Magnetic confinement in a ring-cusp ion thruster discharge plasma

Sengupta

2009

Journal of Applied Physics

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“…However, these assumptions are not appropriate because the doubly charged ion fraction has been reported to reach values of around 10-24% in the "10 ion engine 10) and around 3-20% in NSTAR ion engines. 11,12) Using the singly charged ion current I þ b , the doubly charged ion current I 2þ b , and the doubly charged ion fraction , the ion beam current is expressed by…”

Section: Neutralsmentioning

confidence: 99%

“…(9) using the finite element method, and the resulting simultaneous equations have nonlinear terms from Eq. (12). The nonlinear simultaneous equations are solved by the Newton-Raphson method using the incomplete Cholesky conjugate gradient (ICCG) matrix solver.…”

Section: Fundamental Equationsmentioning

confidence: 99%

Sensitivity Analysis of the Effects of Doubly Charged Ions on Ion Acceleration Grid Erosion

Nakano

2012

Trans. Japan Soc. Aero. S Sci.

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A sensitivity analysis was performed using a three-dimensional code to understand the effect of doubly charged ions on the erosion of ion acceleration grids. A preliminary analysis showed that the neutral mass flow rate, estimated by assuming all the ions are singly charged, contained significant error when the doubly charged ion fraction was nonnegligible. Calculations were conducted for the "10 EM1 ion acceleration grid system with different doubly charged ion fractions. For fractions of 0.1 and 0.2, which were similar to the experimental conditions, the simulation results for the acceleration grid current and grid mass loss were in good agreement with the experimental data. Calculations showed that when the doubly charged ion fraction was reduced from 0.1 to 0, the acceleration grid current and grid mass loss changed by À14% and À18%, respectively. Further, when the fraction was increased from 0.1 to 0.2, the acceleration grid current and grid mass loss changed by þ9.5% and þ32%, respectively. Electron backstreaming was also found to vary with the doubly charged ion fraction: it occurred 14% slower when the fraction was decreased from 0.1 to 0 and 12% faster when the fraction was increased from 0.1 to 0.2. The structural failure of the deceleration grid was less sensitive: the deceleration grid eroded 8.3% slower when the doubly charged ion fraction was reduced from 0.1 to 0 and 8.6% faster when the fraction was increased from 0.1 to 0.2. n inlet : plasma density at the inlet boundary r s , r a , r d : aperture radii of the screen grid, acceleration grid and deceleration grid, respectively t s , t a , t d : thicknesses of the screen grid, acceleration grid and deceleration grid, respectively T e : electron temperature T k : stay time of the k-th flux tube inside an element v: velocity vector V B : Bohm velocity V d : discharge voltage V element : element volume

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Ion Thrusters

Goebel¹,

Foster²

2010

Encyclopedia of Aerospace Engineering

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Ion thrusters utilize high‐voltage grids to electrostatically accelerate ions to high velocity to produce thrust. Efficient ionization of the propellant carried onboard the spacecraft is achieved by optimized hollow cathode, RF or microwave discharge chambers, and electrons from an external hollow cathode are injected into the ion beam to provide charge neutralization in order to avoid spacecraft charging. The ion thruster propulsion subsystem also contains a power processor, a propellant control system and a gimbal mechanism. The high exhaust velocities produced in present flight thrusters by acceleration of the ions to energies in the range of 1–2 keV produces a specific impulse that exceeds 3000 s, and energies of over 10 keV have been demonstrated. The low thrust produced by these devices of typically a fraction of a Newton requires that thruster lifetimes measured in years are needed for most deep space prime propulsion and earth‐orbiting station‐keeping applications. Ion thrusters feature the highest efficiency (60 to < 80%) and very high specific impulse (2000 to over 10000 s) compared to other thruster types.

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

Cited by 34 publications

References 14 publications

Magnetic confinement in a ring-cusp ion thruster discharge plasma

Magnetic confinement in a ring-cusp ion thruster discharge plasma

Sensitivity Analysis of the Effects of Doubly Charged Ions on Ion Acceleration Grid Erosion

Ion Thrusters

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