Numerical simulations of ion thruster accelerator grid erosion

The highly successful demonstration of ion propulsion on Deep Space 1 has stimulated the study of more demanding applications of this technology. These future applications require ion thrusters capable of providing significantly greater specific impulses and total impulses than the current state-of-the-art. Higher specific impulses aggravate the known wear out mechanisms of the ion accelerator system. Computer simulations of the ion accelerator system operation and erosion are essential tools for the development of ion thrusters to meet the demand for higher specific impulse and longer life. Two-dimensional and three-dimensional computer codes have been developed at JPL and are used to provide insight into the processes limiting the life of the accelerator grid. The 2D code described herein was used to identify a key feature of operation at high Isp. That is, as the beam voltage is increased the energy of the charge-exchange ions hitting the hole walls increases in proportion to the beam voltage and more rapidly than the increase in the magnitude of the accelerator grid voltage. This has serious implications for the design of long-life, high specific impulse thrusters.

[1]  Haruki Takegahara,et al.  Numerical Analysis of Ion Beam Extraction Phenomena in an Ion Thruster , 2001 .

[2]  John R. Anderson,et al.  Performance of the NSTAR ion propulsion system on the Deep Space One mission , 2001 .

[3]  Masakatsu Nakano,et al.  An efficient three-dimensional optics code for ion thruster research , 1996 .

[4]  John R. Anderson,et al.  Performance characteristics of the deep space 1 flight spare ion thruster long duration test, the first 21,300 hours of operation , 2002 .

[5]  Noriaki Itoh,et al.  Energy dependence of the ion-induced sputtering yields of monatomic solids , 1984 .

[6]  Michael J. Patterson,et al.  The 2.3 kW Ion Thruster Wear Test , 1995 .

[7]  Michael J. Patterson,et al.  Demonstration of the NSTAR ion propulsion system on the Deep Space One mission , 2001 .

[8]  James E. Polk,et al.  Low Energy Sputtering Experiments for Ion Engine Lifetime Assessment , 1999 .

[9]  Roger M. Myers,et al.  A 100 Hour Wear Test of the NASA NSTAR Ion Thruster , 1996 .

[10]  Yoshinori Nakayama,et al.  Numerical Simulation of High Specific Impulse Ion Thruster Optics , 2001 .

[11]  Paul J. Wilbur,et al.  Numerical simulation of ion beam optics for many-grid systems , 2001 .

[12]  John R. Anderson,et al.  An overview of the results from an 8200 hour wear test of the NSTAR ion thruster , 1999 .

[13]  Iain Boyd,et al.  GRID EROSION ANALYSIS OF THE T5 ION THRUSTER , 2001 .

[14]  G. K. Wehner,et al.  Sputtering Yields for Low Energy He+‐, Kr+‐, and Xe+‐Ion Bombardment , 1962 .

[15]  Harold R. Kaufman,et al.  Ion beam divergence characteristics of three-grid accelerator systems , 1978 .

[16]  David H. Lehman,et al.  Results from the Deep Space 1 technology validation mission , 2000 .

[17]  Marc D. Rayman,et al.  THE DEEP SPACE 1 EXTENDED MISSION , 2001 .

[18]  H. Kaufman.  Technology of Electron-Bombardment Ion Thrusters , 1975 .