Development of a Highly Precise Micronewton Thrust Balance

In this paper, we present our ongoing micronewton thrust balance development, which fulfils the laser interferometer space antenna requirements. In the context of the development of highly precise thrusters for attitude control of satellites for future space missions, test facilities for the characterization and qualification of thrusters need to be developed in parallel. The presented thrust balance has a resolution of 0.1 μN in a bandwidth between 1 and 10^-3 Hz. As a general measurement principle, we chose a pendulum balance. The setup consists of two pendulums to enable a common mode rejection. To suppress the eigenfrequency of the pendulums, a damping system based on an eddy current brake is part of the balance assembly. A heterodyne laser interferometer is used as the translation sensor. Different measurements were performed to investigate the noise performance of the pendulum. The results are presented and analyzed. The measurement system was used to measure the thrust of a micro-high efficiency multistage plasma thruster.