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  • 1
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    Electric Propulsion and the Gateway: Sustainable Exploration of Cis-Lunar Space (2019)
    In:  CASI
    Details
    Publication Date: 2019-05-23
    Description: NASA is committed to a sustainable return of humans to the Moon for long-term exploration and utilization. Gateway will enable this sustained cis-lunar presence and provide the capabilities necessary to develop and deploy critical infrastructure.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN67049
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    In-Situ Diagnostic for Assessing Hall Thruster Wear (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The design of a new diagnostic to measure the net erosion of Hall thruster surfaces is presented. This diagnostic consists of a pair of optical non-contact profilometer pens mounted to a set of motion stages, which can interrogate the surface features of multiple components of interest including the hollow cathode assembly, magnet front pole covers, and discharge channel. By comparing scans of these surfaces to reference features, estimates of the component erosion rates can be acquired throughout long-duration lifetime tests without venting and removing the thruster from the vacuum facility for external profilometry. This work presents a detailed overview of the diagnostic design including the precision positioning system. In addition, preliminary data are shown which verify diagnostic operation and establish a baseline that will be used to track the erosion of the Hall Effect Rocket with Magnetic Shielding (HERMeS) Technology Demonstration Unit 3 (TDU-3) during an ongoing long-duration wear test.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN58468 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    In-Situ Diagnostic for Assessing Hall Thruster Wear (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The design of a new diagnostic to measure the net erosion of Hall thruster surfaces is presented. This diagnostic consists of a pair of optical non-contact profilometer pens mounted to a set of motion stages, which can interrogate the surface features of multiple components of interest including the hollow cathode assembly, magnet front pole covers, and discharge channel. By comparing scans of these surfaces to reference features, estimates of the component erosion rates can be acquired throughout long-duration lifetime tests without venting and removing the thruster from the vacuum facility for external profilometry. This work presents a detailed overview of the diagnostic design including the precision positioning system. In addition, preliminary data are shown which verify diagnostic operation and establish a baseline that will be used to track the erosion of the Hall Effect Rocket with Magnetic Shielding (HERMeS) Technology Demonstration Unit 3 (TDU-3) during an ongoing long-duration wear test.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN57697 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    In-situ Diagnostic for Assessing Hall Thruster Wear (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The design of a new diagnostic to measure the net erosion of Hall thruster surfaces is presented. This diagnostic consists of a pair of optical noncontact profilometer pens mounted to a set of motion stages, which can interrogate the surface features of multiple components of interest including the hollow cathode assembly, magnet front pole covers, and discharge channel. By comparing scans of these surfaces to reference features, estimates of the component erosion rates can be acquired throughout long-duration lifetime tests without venting and removing the thruster from the vacuum facility for external profilometry. This work presents a detailed overview of the diagnostic design including the precision positioning system. In addition, preliminary data are shown which verify diagnostic operation and establish a baseline that will be used to track the erosion of the Hall Effect Rocket with Magnetic Shielding (HERMeS) Technology Demonstration Unit 3 (TDU-3) during an ongoing long-duration wear test.
    Keywords: Spacecraft Propulsion and Power
    Type: NASA/TM-2018-219961 , E-19571 , AIAA-2018-4721 , GRC-E-DAA-TN59234 , Joint Propulsion Conference; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Long Duration Wear Test of the NASA HERMeS Hall Thruster (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The NASA Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5-kW Hall thruster is the subject of extensive technology maturation by NASA GRC (Glenn Research Center) and JPL (Jet Propulsion Laboratory) in preparation for development into a flight propulsion system. As part of this on-going effort, a series of three wear tests have been conducted to identify erosion phenomena and the accompanying failure modes as well as to validate service-life models for magnetically-shielded thrusters. This paper presents an overview and summary of the results obtained over the first 1715 hours of the third wear test, which has the overall goal of serving as a pathfinder to identify and correct design or facility issues prior to the flight qualification campaign. Overall, negligible changes in performance and stability are observed as a function of operating time as well as relative to previous wear tests. Erosion of the inner and outer front pole covers is shown to vary by 76-300 percent as a function of discharge voltage and by up to 40 percent as a function of magnetic field strength. Shifting the cathode position upstream relative to the pole covers is shown to reduce keeper erosion rates by 84 percent, which supports this approach for mitigating the elevated keeper wear observed during previous wear tests.
    Keywords: Spacecraft Propulsion and Power
    Type: NASA/TM-2018-219960 , AIAA Paper 2018-4645 , E-19570 , GRC-E-DAA-TN59240 , AIAA, SAE and ASEE Joint Propulsion Conference; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Preparation for Hollow Cathode Testing for the Advanced Electric Propulsion System at NASA Glenn Research Center (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: NASA Glenn Research Center is performing activities to support the unique needs of hollow cathode development and testing for the Advanced Electric Propulsion System (AEPS). Three existing vacuum facilities have been outfitted as cathode test facilities, and each will serve a different role in upcoming testing. Vacuum Facility 67 is being developed to serve as a long-duration test facility for the Engineering Development Unit cathode, which is to be delivered by the AEPS contractor. It will feature a thruster-like magnetic field simulator and cold-cycle capability via a liquid nitrogen-cooled cold plate. Vacuum Facility 17 is being developed as a test facility for short- to medium-duration experiments in order to provide auxiliary support for the long-duration testing. It will feature a magnetic field simulator but not cold-cycling. Finally, Vacuum Facility 1 will be a high-pumping speed cathode development environment, and will feature an array of plasma and temperature diagnostics. In addition to the facility preparation work, a new cathode, referred to as the Mark II, has been designed. The Mark II is an evolution of the Technology Demonstration Unit cathodes that better evokes the geometry, fabrication, and construction of the forthcoming Engineering Development Unit. This cathode serves as a transition between the Technology Demonstration Unit cathodes used during early thruster development and the forthcoming Engineering Development Unit cathodes. It will be used as a means of verifying the new test facilities prior to arrival of Engineering Development Unit hardware. Details of the Mark II design and key features are presented, as well as details of future work to be performed.
    Keywords: Spacecraft Propulsion and Power
    Type: AIAA-2018-4425 , NASA/TM-2018-219954 , GRC-E-DAA-TN59236 , 2018 Joint Propulsion Conference; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Long Duration Wear Test of the NASA HERMeS Hall Thruster (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The NASA Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5-kW Hall thruster is the subject of extensive technology maturation by NASA GRC and JPL in preparation for development into a flight propulsion system. As part of this on-going effort, a series of three wear tests have been conducted to identify erosion phenomena and the accompanying failure modes as well as to validate service-life models for magnetically-shielded thrusters. This paper presents an overview and summary of the results obtained over the first 1715 hours of the third wear test, which has the overall goal of serving as a pathfinder to identify and correct design or facility issues prior to the flight qualification campaign. Overall, negligible changes in performance and stability are observed as a function of operating time as well as relative to previous wear tests. Erosion of the inner and outer front pole covers is shown to vary by 76-300 percent as a function of discharge voltage and by up to 40 percent as a function of magnetic field strength. Shifting the cathode position upstream relative to the pole covers is shown to reduce keeper erosion rates by 84 percent, which supports this approach for mitigating the elevated keeper wear observed during previous wear tests.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN57037 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 09, 2018 - Jul 11, 2018; Cincinnati, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 8
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    Uncertainty in Electric Propulsion Erosion Measurements (2019)
    In:  CASI
    Details
    Publication Date: 2019-09-10
    Description: Uncertainty in erosion rates as measured by different methods is discussed and quantified. The work focuses on case studies from components on the Hall Effect Rocket with Magnetic Shielding (HERMeS) Hall thruster, but the methods can be extended for many electric propulsion applications. The primary method used for evaluating erosion is non-contact profilometry of masked and exposed components. Accurate quantification of the erosion rates of components is critical to determining lifetime and is therefore critical to mission planning purposes.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN72106 , AIAA Propulsion and Energy Forum 2019; Aug 19, 2019 - Aug 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 9
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    Non-Intrusive Characterization of the Wear of the HERMeS Thruster Using Optical Emission Spectroscopy (2019)
    In:  CASI
    Details
    Publication Date: 2019-10-12
    Description: The Hall Effect Rocket with Magnetic Shielding (HERMeS) is a 12.5 kW Hall thrusterelectric propulsion string that has been in development by NASA Glenn Research Center(GRC) and NASA JPL since 2012. Due to the magnetically shielded design, service life-limiting erosion of the boron nitride discharge has been virtually eliminated. The innerfront pole cover (IFPC) has now been identied as the component dening erosion-basedservice life. Optical emission spectroscopy (OES) is used as an in-situ diagnostic to measurerelative erosion trends during operation of the HERMeS thruster during a series of shortduration wear tests. Erosion trends obtained from the OES data will be compared totraditional erosion data measured with a non-contact prolometer.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN72597 , International Electric Propulsion Conference; Sep 15, 2019 - Sep 20, 2019; Vienna; Austria
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 10
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    Non-Intrusive Characterization of the Wear of the HERMeS Thruster Using Optical Emission Spectroscopy (2019)
    In:  CASI
    Details
    Publication Date: 2019-10-12
    Description: The Hall Effect Rocket with Magnetic Shielding (HERMeS) is a 12.5 kW Hall thruster electric propulsion string that has been in development by NASA Glenn Research Center(GRC) and NASA JPL since 2012. Due to the magnetically shielded design, service life-limiting erosion of the boron nitride discharge has been virtually eliminated. The inner front pole cover (IFPC) has now been identified as the component defining erosion-based service life. Optical emission spectroscopy (OES) is used as an in-situ diagnostic to measure relative erosion trends during operation of the HERMeS thruster during a series of short duration wear tests. Erosion trends obtained from the OES data will be compared to traditional erosion data measured with a non-contact profilometer.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN72554 , International Electric Propulsion Conference; Sep 15, 2019 - Sep 20, 2019; Vienna; Austria
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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