Publication Date

9-13-2013

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Electrical Engineering

Department

Electrical and Computer Engineering

Supervisory Committee Chair

Jim Browning, Ph.D.

Supervisory Committee Member

Wan Kuang, Ph.D.

Supervisory Committee Member

Don Plumlee, Ph.D., P.E.

Abstract

The performance of a 2 cm miniature ion thruster was analyzed. A thruster of this size was predicted to produce a thrust of 200 μN. The plasma density was measured against rf input power and propellant flow rate for three configurations: the ICP source by itself; the ICP source with discharge chamber; and finally, the ICP source, the discharge chamber, and the permanent magnet cusp system. Once the optimum case was determined, electrostatic grids were added and thrust measurements were taken with a set of segmented ion collector plates.

The miniature rf ion thruster obtained a thrust of 22.35 μN and a specific impulse of 15.31 s at its optimum operating condition of 5W of rf power and and propellant flow rate of 5 sccm. With a beam divergence angle of 26.25 degrees and the assumption of a singly charged ion species, the total thrust correction factor was 0.90. The mass utilization efficiency of the thruster was calculated to be 0.24%. The electrical efficiency of thruster was calculated to be 16.94% with an electron-ion energy pair cost of 5.9 keV/ion. The total efficiency of the thruster was 0.033%, a factor of 1000 too low for practical use.

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