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  • 1
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    Qualification of the Flight Heaters for the NEXT-C Hollow Cathodes (2019)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: After successful validation of the design, swaged cathode heaters have been delivered by the NASA Glenn Research Center to Aerojet Rocketdyne for the fabrication of the NEXT-C ion thruster. NASA Glenn Research Center re-established and validated process controls as well as completed cyclic life testing of development heaters. Following an extensive requalification program, fabrication of a flight batch of heaters was executed using the qualified process controls. Of the 28 heaters fabricated in this flight batch, a set of six heaters were acceptance and cyclic tested to verify conformance with operational requirements. Upon completion of 200 percent of the NEXT-C cyclic requirement, the heater batch was certified by NASA for use in the flight hollow cathodes. Nine heaters from the batch of 28 were provided to Aerojet Rocketdyne in early 2018 for cathode fabrication. This paper summarizes the acceptance and cyclic life testing of the flight heaters and preliminary findings of post-test analyses.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN70161 , Joint Propulsion Energy Forum; Aug 19, 2019 - Aug 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Ion Thruster Produced Roll Torque (2019)
    In:  CASI
    Details
    Publication Date: 2019-09-04
    Description: Disturbances to the ion engines thrust vector will cause a spacecraft to spin about its axis if left unmanaged. Spin about the yaw and pitch axis can be easily handled by a gimbal with enough authority. Spin about the roll axis however must be handled by additional thrusters or reaction wheels. In order to capitalize on the high efficiency of their thrusters, missions utilizing electric propulsion as primary propulsion generally include long periods of thrusting (several years). It is necessary to quantify and understand the ion thruster produced roll torque because it will define the amount of chemical propellant that must be carried or the lifetime and quantity of momentum wheels required for the mission. The roll torque produced by the NEXT ion thruster is analyzed through a combination of theoretical calculations and magnetic field simulations. Experimental techniques for measuring roll torque and past flight data are also discussed.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN70967 , 2019 AIAA Propulsion and Energy Forum; Aug 19, 2019 - Sep 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Near Field Probe Measurements in the Plume of a NEXT Ion Thruster (2019)
    In:  CASI
    Details
    Publication Date: 2019-10-02
    Description: Due to the extremely long lifetime and ground testing complications, such as facility backpressure effects, modeling is a necessary tool for validating mission lifetime requirements. Both NASA's Glenn Research Center and Jet Propulsion Laboratory have developed lifetime validation models for the NEXT ion thruster. The largest uncertainties in these models are due to unknown plasma properties, such as plasma potential, that occur very near to the grid. Previous studies have made measurements in the mid to far field. Here, we make very near field measurements of the plasma properties in the ion beam within 0.1 thruster radii of the grid using various probes. Emissive and triple Langmuir probes are swept through the plume to spatially resolve plasma potential, electron temperature and ion density very near to the grid. The goal is to provide refined inputs to the lifetime modeling efforts and increase the accuracy of the models.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN72115 , IEPC 2019 - International Electric Propulsion Conference; Sep 15, 2019 - Sep 20, 2019; Vienna; Austria
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Unknown
    QualifiCation of the Flight Heaters for the NEXT-C Hollow Cathodes (2020)
    In:  CASI
    Details
    Publication Date: 2020-01-18
    Description: After successful validation of the design, swaged cathode heaters have been delivered by the NASA Glenn Research Center to Aerojet Rocketdyne for the fabrication of the NEXT-C ion thruster . NASA Glenn Research Center re-established and validated process controls as well as completed cyclic life testing of development heaters. Following an extensive requalification program, fabrication of a flight batch of heaters was executed using the qualified process controls. Of the 28 heaters fabricated in this flight batch, a set of six heaters were acceptance and cyclic tested to verify conformance with operational requirements. Upon completion of 200 percent of the NEXT-C cyclic requirement, the heater batch was certified by NASA for use in the flight hollow cathodes. Nine heaters from the batch of 28 were provided to Aerojet Rocketdyne in early 2018 for cathode fabrication. This paper summarizes the acceptance and cyclic life testing of the flight heaters and preliminary findings of post-test analyses.
    Keywords: Spacecraft Propulsion and Power
    Type: NASA/TM-2020-219454 , E-19773 , AIAA Paper–2019–4167 , GRC-E-DAA-TN72218 , Propulsion and Energy Forum and Exposition; Aug 19, 2019 - Aug 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Unknown
    Ion Thruster Produced Roll Torque (2019)
    In:  CASI
    Details
    Publication Date: 2019-10-25
    Description: Disturbances to the ion engine's thrust vector will cause a spacecraft to spin about its axis if left unmanaged. Spin about the yaw and pitch axis can be easily handled by a gimbal with enough authority. Spin about the roll axis however must be handled by additional thrusters or reaction wheels. In order to capitalize on the high efficiency of their thrusters, missions utilizing electric propulsion as primary propulsion generally include long periods of thrusting (several years). It is necessary to quantify and understand the ion thruster produced roll torque because it will define the amount of chemical propellant that must be carried or the lifetime and quantity of momentum wheels required for the mission. The roll torque produced by the NEXT ion thruster is analyzed through a combination of theoretical calculations and magnetic field simulations. Experimental techniques for measuring roll torque and past flight data are also discussed.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN72186 , 2019 AIAA Propulsion and Energy Forum; Aug 19, 2019 - Sep 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
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    Unknown
    Near Field Probe Measurements in the Plume of a NEXT Ion Thruster (2019)
    In:  CASI
    Details
    Publication Date: 2019-12-12
    Description: Due to the extremely long lifetime and ground testing complications, such as facility backpressure effects, modeling is a necessary tool for validating mission lifetime requirements. Both NASA's Glenn Research Center and Jet Propulsion Laboratory have developed lifetime validation models for the NEXT ion thruster. The largest uncertaintiesin these models are due to unknown plasma properties, such as fields plasma potential, that occur very near to the grid. Previous studies have made measurements in the mid to far field. Here, we make very near field measurements of the plasma properties in the ion beam within 0.1 thruster radii of the grid using various probes. Emissive and triple Lang-muir probes are swept through the plume to spatially resolve plasma potential, electron temperature and ion density very near to the grid. The goal is to provide refined inputs to the lifetime modeling efforts and increase the accuracy of the models.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN72319 , International Electric Propulsion Conference; Sep 15, 2019 - Sep 20, 2019; Vienna; Austria
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Qualification of the Flight Heaters for the NEXT-C Hollow Cathodes (2019)
    In:  CASI
    Details
    Publication Date: 2019-12-10
    Description: After successful validation of the design, swaged cathode heaters have been delivered by the NASA Glenn Research Center to Aerojet Rocketdyne for the fabrication of the NEXT-C ion thruster . NASA Glenn Research Center re-established and validated process controls as well as completed cyclic life testing of development heaters. Following an extensive requalification program, fabrication of a flight batch of heaters was executed using the qualified process controls. Of the 28 heaters fabricated in this flight batch, a set of six heaters were acceptance and cyclic tested to verify conformance with operational requirements. Upon completion of 200 percent of the NEXT-C cyclic requirement, the heater batch was certified by NASA for use in the flight hollow cathodes. Nine heaters from the batch of 28 were provided to Aerojet Rocketdyne in early 2018 for cathode fabrication. This paper summarizes the acceptance and cyclic life testing of the flight heaters and preliminary findings of post-test analyses.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN72187 , Joint Propulsion Energy Forum; Aug 19, 2019 - Aug 22, 2019; Indianapolis, IN; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
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