Titles:

• Transport of Sputtered Carbon during Ground-Based Life Testing of Ion Thrusters   2005

• Single-String Integration Test Measurements of the NEXT Ion Engine Plume, July 11-14, 2004  July 11-14, 2004
   

Marker, C. L., Clemons, L. A., Banks, B. A., Miller, S. K., Snyder, A., Hung, C., Karniotis, C. A., and Waters, D., “Transport of Sputtered Carbon During Ground-Based Life Testing of Ion Thrusters,” NASA TM-2005-213798, Paper No. AIAA-2005-4413, presented at the 41th Joint Propulsion Conference cosponsored by the AIAA, ASME, SAE, and ASEE, Tucson, Arizona, July 10-13, 2005

High voltage, high power electron bombardment ion thrusters needed for deep space missions will be required to be operated for long durations in space as well as during ground laboratory life testing.  Carbon based ion optics are being considered for such thrusters.  The sputter deposition of carbon and arc vaporized carbon flakes from long duration operation of ion thrusters can result in deposition on insulating surfaces, causing them to become conducting.  Because the sticking coefficient is less than one, secondary deposition needs to be considered to assure that shorting of critical components does not occur.  The sticking coefficient for sputtered carbon and arc vaporized carbon is measured as well as directional ejection distribution data for carbon that does not stick upon first impact.  

Snyder, Aaron, Kamhawi, Hani, Patterson, Michael and Britton, Melissa, “Single-String Integration Test Measurements of the NEXT Ion Engine Plume”, Presented at the 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit Fort Lauderdale, Florida, July 11-14, 2004

Measurements were made of a 40 cm ion-thruster plume as part of the single-string-integration-test (SSIT) activity of Phase I of the NASA’s Evolutionary Xenon Thruster (NEXT) project. The NEXT ion engine incorporates design improvements that extend NSTAR power levels and efficiencies. During SSIT, an engineering model (EM2) 40 cm engine was operated using an advanced xenon propellant system in combination with either a GRC power console or advanced power processing unit.  Integral goals of the single-string phase were to characterize engine performance over the full input power range and to detail thruster operation within the specification of the NEXT throttle table.  Plume diagnostics measurements of relative Xe+ and Xe++ currents were made using near-field and far-field ExB probes.   Planar geometry Faraday probes were used to obtain beam current density profiles.  This paper reports on the characterization of the EM2 plume over a range of SSIT operating conditions, first with the advanced propellant management system teamed with the GRC power console and then with the power-processing unit.

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Last Updated: 04/07/2008