Thin-film strain gauge sensors for ion thrust measurement

In order to measure the thrust produced by a stationary plasma thruster, a measurement system has been developed using a thrust balance with thin-film strain gauge sensors. For this purpose, strain gauges were designed and deposited on the columns of the thrust balance fabricated and necessary signal conditioning circuits have been used. The performance of the system developed was studied, in a vacuum chamber under space simulated conditions, by activating the thruster. In situ calibration was done using Lami's principle. For discharge powers varying from 210-275 W, the measured values of thrust were found to be in the range of 11-16 mN with an accuracy of /spl plusmn/1 mN and resolution of 0.12 mN. Specific impulse and efficiency were also estimated.