Diagnostic for Verifying the Thrust Vector Requirement of the AEPS Hall-Effect Thruster and Comparison to the NEXT-C Thrust Vector Diagnostic

Benavides, Gabriel F.; Mackey, Jeffrey R.; Ahern, Drew M.; Thomas, Robert E.

doi:10.2514/6.2018-4514

Cited by 7 publications

(5 citation statements)

References 11 publications

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“…The corrected thrust vector eccentricity angle and beam divergence half angle are thus calculated as follows: In equation (12), R 1 90% ¢ and R 2 90% ¢ respectively represent the optimized radius of the beam corresponding to 90% of the two planes downstream from the thruster.…”

Section: ¢ ¢ (mentioning

confidence: 99%

“…The beam divergence angle and thrust vector eccentricity angle are determined by employing equations (11) and (12) with the Gaussian distribution function fitting, respectively. The optimized results of the calculation of the beam divergence angle and thrust vector eccentricity angle are shown in figure 17.…”

Section: ¢ ¢ (mentioning

confidence: 99%

“…However, because of the low transparency effect of multiple grids, it is necessary to dwell for a considerable time at each measurement location in the plume, which substantially increases the risk of probe failure. A linear array of 23 Faraday probes located 1 m from the center of the thruster was adopted by NASA's Benavides [12] to identify the beam density and thrust vector eccentricity of a 12.5 kW Hall thruster. The LIPS-200 [13] ion thruster beam current divergence characteristics were obtained using a Faraday probe array (FPA) combined with a moving mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Study of beam divergence and thrust vector eccentricity characteristics of the Hall thruster based on dual Faraday probe array planes and its applications

Chen

Zhao²,

Tian

et al. 2023

Plasma Sci. Technol.

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The accurate knowledge of the thrust vector eccentricity and beam divergence characteristics of Hall thrusters are of significant engineering value for the beneficial integration and successful application of Hall thrusters on spacecraft. For the characteristics of the plume bipolar diffusion owing to the annular discharge channel of the Hall thruster, a Gaussian fitted method for thrust vector deviation angle and beam divergence of Hall thrusters based on dual Faraday probe array planes was proposed in respect of the Hall thruster beam characteristics. The results show that the ratios of the deviation between the maximum and minimum values of the beam divergence angle and the thrust vector eccentricity angle using a Gaussian fit to the optimized Faraday probe dual plane to the mean value are 1.4% and 11.5%, respectively. The optimized thrust vector eccentricity angle obtained has been substantially improved, by approximately 20%. The beam divergence angle calculated using a Gaussian fitting to the optimized Faraday probe dual plane is approximately identical to the non-optimized one. The beam divergence and thrust vector eccentricity angles for different anode mass flow rates were obtained by averaging the beam divergence and thrust vector eccentricity angles calculated by the two-plane, Gaussian-fitted ion current density method for different cross-sections. The study not only allows for an immediate and effective tool for determining the design of thrust vector adjustment mechanisms of spacecraft with different power Hall thrusters but also for characterizing the three-dimensional spatial distribution of the Hall thruster plume.

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Section: ¢ ¢ (mentioning

confidence: 99%

Section: ¢ ¢ (mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of beam divergence and thrust vector eccentricity characteristics of the Hall thruster based on dual Faraday probe array planes and its applications

Chen

Zhao²,

Tian

et al. 2023

Plasma Sci. Technol.

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“…The thrust vector mis-alignment angle was assumed to be no greater than 2º. A concurrent study at NASA GRC is developing a thrust vector diagnostic system to assist in better approximating this magnitude, see reference [23]. The calibration slope repeatability was calculated as the standard deviation of a set of 47 calibration runs spanning day-to-day operation for two months.…”

Section: Uncertainty Analysis Case Studymentioning

confidence: 99%

Uncertainty in Inverted Pendulum Thrust Measurements

Mackey

Haag

Kamhawi

et al. 2018

2018 Joint Propulsion Conference

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An uncertainty analysis of a common configuration of electric propulsion thrust stand is presented. The analysis applies to inverted pendulum thrust stands operating in a null-coil configuration with in-situ calibration. Several sources of bias and precision uncertainty are discussed, propagated, and combined to form conservative estimates of the relative and absolute thrust uncertainties. A case study of the NASA Glenn Research Center Vacuum Facility 6 thrust stand is presented. For the thruster investigated, the uncertainty was estimated to be ±6.9mN over the entire span of thrust. This uncertainty represents a maximum instrument bias introduced by the thrust stand. The paper does not address repeatability of actual thrust measurements, as this is generally beyond the influence of the thrust stand and can be dependent on a large number of factors.

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“…Hall Effect Thrusters find wide-range applications in space propulsion, starting from propulsion devices for orbit transfer [1] to deep space travel ( [2], [3]), among others. In recent years, a significant volume of literature has been devoted to the simulation ( [4,5]) and diagnostics of HET's ( [6,7]), tackling several open problems along the way. However, the physics of the thrusters is still not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Visualization of Spokes Mode in a Hall Effect Thruster

2023

5th ISSE National Conference (INAC-05) on Systems Approach for Self-Reliance in Advanced Technologies

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The present work investigates the dynamics of rotating spokes modes in a Hall Effect Thruster (HET) also known as a Stationary Plasma Thruster (SPT). Understanding these modes is important to investigate electron transport phenomena which constitute power losses for the thruster. Furthermore, the results may be inputs to future simulation studies. In this paper, post processing technique of raw images to visualize the spoke modes is presented. Images of an 85 mm mean diameter SPT anode channel, operated at 783 W at a pressure of 3.2 𝑥 10 𝑚𝑏𝑎𝑟 were acquired via a High-Speed Camera. The images so obtained were extremely saturated with the cathode intensity while the anode channel intensity was dominated by its DC component. Automated image processing techniques were then applied. In this process, the images were normalized with respect to the camera specifications and the cathode and anode were segmented from the anode channel image frames using Otsu's thresholding. The normalized and extracted regions are subjected to a string of post-processing involving normalization by mean image and removal of noise and the DC component. This resulted in an improved contrast as well as removal of saturation in the images due to the cathode, enabling one to focus exclusively on spokes modes.

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Diagnostic for Verifying the Thrust Vector Requirement of the AEPS Hall-Effect Thruster and Comparison to the NEXT-C Thrust Vector Diagnostic

Cited by 7 publications

References 11 publications

Study of beam divergence and thrust vector eccentricity characteristics of the Hall thruster based on dual Faraday probe array planes and its applications

Study of beam divergence and thrust vector eccentricity characteristics of the Hall thruster based on dual Faraday probe array planes and its applications

Uncertainty in Inverted Pendulum Thrust Measurements

Visualization of Spokes Mode in a Hall Effect Thruster

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