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Post-Test Analysis of the Deep Space One Spare Flight Thruster Ion OpticsThe Deep Space 1 (DSl) spare flight thruster (FT2) was operated for 30,352 hours during the extended life test (ELT). The test was performed to validate the service life of the thruster, study known and identify unknown life limiting modes. Several of the known life limiting modes involve the ion optics system. These include loss of structural integrity for either the screen grid or accelerator grid due to sputter erosion from energetic ions striking the grid, sputter erosion enlargement of the accelerator grid apertures to the point where the accelerator grid power supply can no longer prevent electron backstreaming, unclearable shorting between the grids causes by flakes of sputtered material, and rouge hole formation due to flakes of material defocusing the ion beam. Grid gap decrease, which increases the probability of electron backstreaming and of arcing between the grids, was identified as an additional life limiting mechanism after the test. A combination of accelerator grid aperture enlargement and grid gap decrease resulted in the inability to prevent electron backstreaming at full power at 26,000 hours of the ELT. Through pits had eroded through the accelerator grid webbing and grooves had penetrated through 45% of the grid thickness in the center of the grid. The upstream surface of the screen grid eroded in a chamfered pattern around the holes in the central portion of the grid. Sputter deposited material, from the accelerator grid, adhered to the downstream surface of the screen grid and did not spall to form flakes. Although a small amount of sputter deposited material protruded into the screen grid apertures, no rouge holes were found after the ELT.
Document ID
20110013157
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
External Source(s)
Authors
Anderson, John R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Sengupta, Anita
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Brophy, John R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 25, 2013
Publication Date
July 11, 2004
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
AIAA Paper 2004-3610
Meeting Information
Meeting: 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
Location: Fort Lauderdale, FL
Country: United States
Start Date: July 11, 2004
End Date: July 14, 2004
Sponsors: American Society for Electrical Engineers, American Inst. of Aeronautics and Astronautics, Society of Automotive Engineers, Inc., American Society of Mechanical Engineers
Distribution Limits
Public
Copyright
Other
Keywords
NASA Solar electric propulsion Technology Application Readiness (NSTAR)
ion optics

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