Steady state applied-field magnetoplasmadynamic thruster promises good compromise between thrust density and specific impulse, making them relevant for interplanetary missions requiring high thrusts. The IRS 100 kW gas-fed steady-state AF-MPD SX3 thruster has shown promising results in previous held test campaigns. Experimental results in those campaigns showed non-linear behavior of tare forces, resulting in respective error in the thrust measurement and this error then propagates in further calculation of Isp, thrust efficiency, etc. This motivated improvement in the thrust balance and measurement technique. Various error sources in the thrust measurement technique were identified and solutions to mitigate them were presented. A number of changes in the thrust balance were made in order to improve the measurement technique and data quality. The effectiveness of improvements had been experimentally characterized and presented. Previously the thrust measurement technique featured manual control of the measurement setup which led to complex and inconsistent test procedures. A new programmable electronic control unit was specifically designed for more consistent and automated measurement and calibration procedure. Potential error sources of the measurement chain have been systematically identified, characterized and discussed. The analysis tool for thrust characterization was redesigned which gives fine control of the interval selection and data export, this ensured accurate thrust and calibration calculations. The new code is more modular to adapt for changes and is very flexible with user interaction reducing complexity while still retaining the functionality. To further improve the measurements accuracy some suggestions are made.
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