Mass Deposition Measurements from 26-Kilowatt Electric Propulsion Space Experiment Flight

Spanjers, Gregory G.; Schilling, John H.; Engelman, S. F.; Bromaghim, D. R.; Johnson, L. K.

doi:10.2514/2.6032

Cited by 3 publications

(5 citation statements)

References 2 publications

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“…The collected mass is observed to decrease during the ring, indicating that the arcjet has the effect of removing material from the sensor face presumably through vaporization or induced chemical reactions. 3 Radiometers 2 and 4 exhibit similar behavior, but to a much smaller degree. Because these radiometers are shielded from arcjet body radiation, and see the plume from a greater distance than does radiometer 1, this is unsurprising.…”

Section: A Summary Of the Esex Events Related To The Contamination mentioning

confidence: 55%

“…The TQCM sensor located adjacent to this radiometer observed a slight mass loss during arcjet ring, 3 presumably due to vaporization of previously collected material or chemical interaction with plume exhaust species. Radiometers with no view of the arcjet, or a view of only the plume, show no measurabledegradation.…”

Section: Introductionmentioning

confidence: 98%

“…Mass deposition is measured using four thermoelectric quartz crystal microbalances (TQCMs). 3 A sample gallium-arsenide (GaAs) solar array segment placed near the arcjet nozzle determines impact on the satellite power-generationcapability. 4 Electromagneticinterference is characterized using a set of onboard antennas and ground stations.…”

Section: Introductionmentioning

confidence: 99%

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Radiometric Analysis from the 26-Kilowatt Electric Propulsion Space Experiment Flight

Spanjers

Schilling

Bromaghim

et al. 2002

Journal of Propulsion and Power

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The U.S. Air Force Research Laboratory's Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications. As part of this ight, an array of onboard contamination sensors was used to assess the effect of the arcjet and other environments on the spacecraft. The sensors consisted of microbalances to measure material deposition, radiometers to assess material degradation due to thermal radiation or contamination, and solar cell segments to investigate solar array degradation. Over eight rings of the ESEX arcjet, and 33 min, 26 s operating time, the radiometer near the thruster, viewing the arcjet plume and body, experiences a change in the thermal properties of its coating from the rings. Radiometers with no view of the arcjet, or a view of only the plume, show no change. In general, degradation effects are observed only on sensors near the thruster exhaust nozzle, a location unlikely to be used in an operational high-power electric propulsion system. No degradation effects are observed in the backplane of the thruster. For future programs, although engineering measures may be needed for spacecraft equipment in the immediate vicinity of the thruster body, the arcjet environment is generally benign. Nomenclature A= area, m 2 C P = speci c heat, J/kg k = thermal conductivity, W/m ¢ K m = mass, kg . Q in = heat ux into sensor, W . Q rad = radiative heat ux, W . Q T = heat ux conducted down radiometer stem, W . Q 12 = radiative heat within radiometer body, W T = temperature, K

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Section: A Summary Of the Esex Events Related To The Contamination mentioning

confidence: 55%

Section: Introductionmentioning

confidence: 98%

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Radiometric Analysis from the 26-Kilowatt Electric Propulsion Space Experiment Flight

Spanjers

Schilling

Bromaghim

et al. 2002

Journal of Propulsion and Power

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“…34 The ESEX EMI boom was deployed on day 14, later than originally planned, 3;34 to allow additional outgassing data to be collected from the contamination sensors located on the EMI boom while it was pointed at the ESEX diagnostic deck. These results are discussed by Spanjers et al 15 Once the initialization activities were successfully completed, phase II experiment operations were initiated.…”

Section: Phase I Operationsmentioning

confidence: 99%

“…A discussion on the contamination effects from the battery venting is provided elsewhere. 15 An analysis of the failure was conducted 38 ; however, the exact cause of the battery problem could not be fully determined because the ight data do not present a complete picture of the anomaly. There was, almost certainly,a combination of effects that ultimately describe the observed data set.…”

Section: Battery Anomalymentioning

confidence: 99%

Review of the Electric Propulsion Space Experiment (ESEX) Program

Bromaghim¹,

LeDuc²,

Salasovich³

et al. 2002

Journal of Propulsion and Power

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Orbital Performance Measurements of Air Force Electric Propulsion Space Experiment Ammonia Arcjet

Fife¹,

Bromaghim²,

Chart

et al. 2002

Journal of Propulsion and Power

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Mass Deposition Measurements from 26-Kilowatt Electric Propulsion Space Experiment Flight

Cited by 3 publications

References 2 publications

Radiometric Analysis from the 26-Kilowatt Electric Propulsion Space Experiment Flight

Radiometric Analysis from the 26-Kilowatt Electric Propulsion Space Experiment Flight

Review of the Electric Propulsion Space Experiment (ESEX) Program

Orbital Performance Measurements of Air Force Electric Propulsion Space Experiment Ammonia Arcjet

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